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Автор: Grafiati
Опубліковано: 7 вересня 2023

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1

Waiskopf, Nir, Rany Rotem, Itzhak Shweky, Lior Yedidya, Hermona Soreq, and Uri Banin. "Labeling Acetyl- and Butyrylcholinesterase Using Semiconductor Nanocrystals for Biological Applications." BioNanoScience 3, no. 1 (January 4, 2013): 1–11. http://dx.doi.org/10.1007/s12668-012-0072-3.

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2

Michalet, Xavier, Fabien Pinaud, Thilo D. Lacoste, Maxime Dahan, Marcel P. Bruchez, A. Paul Alivisatos, and Shimon Weiss. "Properties of Fluorescent Semiconductor Nanocrystals and their Application to Biological Labeling." Single Molecules 2, no. 4 (December 2001): 261–76. http://dx.doi.org/10.1002/1438-5171(200112)2:4<261::aid-simo261>3.0.co;2-p.

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3

Sathe, Komal Pramod, Neha Sunil Garud, Vilas Balasaheb Bangar, and Namrata Ramesh Gadakh. "A REVIEW ON QUANTUM DOTS (QDS)." Journal of Advanced Scientific Research 13, no. 06 (July 31, 2022): 23–27. http://dx.doi.org/10.55218/jasr.202213603.

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Анотація:
Recently, the drugs in nanometer size range have found to increase the performance of various dosage forms. Quantum dots (QDs) have gained attention and interest of scientists due to their targeting and imaging potential in nano based drug delivery, in pharmaceutical and biomedical (cell biology) applications. They are artificial semiconductor nanocrystals that have tunable and efficient photo luminescence with narrow emission spectra and high light stability making them excellent probes for bioimaging applications. QDs absorb white light and can produce different colors determined by the size of the particles and band Gap. Nowadays, quantum dots are used for labeling live biological material in vitro and in vivo in animals (other than humans) for research purposes and also useful for immunoassay studies. In the present article, we have discussed various aspects of QDs, highlighting their pharmaceutical and biomedical applications and current challenges in introducing QDs into clinical practice.
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4

Luccardini, Camilla, Aleksey Yakovlev, Stéphane Gaillard, Marcel van ‘t Hoff, Alicia Piera Alberola, Jean-Maurice Mallet, Wolfgang J. Parak, Anne Feltz, and Martin Oheim. "Getting Across the Plasma Membrane and Beyond: Intracellular Uses of Colloidal Semiconductor Nanocrystals." Journal of Biomedicine and Biotechnology 2007 (2007): 1–9. http://dx.doi.org/10.1155/2007/68963.

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Semiconductor nanocrystals (NCs) are increasingly being used as photoluminescen markers in biological imaging. Their brightness, large Stokes shift, and high photostability compared to organic fluorophores permit the exploration of biological phenomena at the single-molecule scale with superior temporal resolution and spatial precision. NCs have predominantly been used as extracellular markers for tagging and tracking membrane proteins. Successful internalization and intracellular labelling with NCs have been demonstrated for both fixed immunolabelled and live cells. However, the precise localization and subcellular compartment labelled are less clear. Generally, live cell studies are limited by the requirement of fairly invasive protocols for loading NCs and the relatively large size of NCs compared to the cellular machinery, along with the subsequent sequestration of NCs in endosomal/lysosomal compartments. For long-period observation the potential cytotoxicity of cytoplasmically loaded NCs must be evaluated. This review focuses on the challenges of intracellular uses of NCs.
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5

Azizi, Seyed Naser, Mohammad Javad Chaichi, Parmis Shakeri, Ahmadreza Bekhradnia, Mehdi Taghavi, and Mousa Ghaemy. "Chemiluminescence of Mn-Doped ZnS Nanocrystals Induced by Direct Chemical Oxidation and Ionic Liquid-Sensitized Effect as an Efficient and Green Catalyst." Journal of Spectroscopy 2013 (2013): 1–8. http://dx.doi.org/10.1155/2013/803592.

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A novel chemiluminescence (CL) method was proposed for doping water-soluble Mn in ZnS quantum dots (QDs) as CL emitter. Water-soluble Mn-doped ZnS QDs were synthesized by using L-cysteine as stabilizer in aqueous solution. These nanoparticles were structurally and optically characterized by X-ray powder diffraction (XRD), dynamic light scattering (DLS), Fourier transform infrared spectroscopy (FTIR), UV-Vis absorption spectroscopy, and photoluminescence (PL) emission spectroscopy. The CL of ZnS QDs was induced directly by chemical oxidation and its ionic liquid-sensitized effect in aqueous solution was then investigated. It was found that oxidants, especially hydrogen peroxide, could directly oxidize ZnS QDs to produce weak CL emission in basic solutions. In the presence of 1,3-dipropylimidazolium bromide/copper, a drastic light emission enhancement was observed which is related to a strong interaction between Cu2+and the imidazolium ring. In these conditions, an efficient CL light was produced at low pH which is suggested to be beneficial to the biological analysis. The CL properties of QDs not only will be helpful to study physical chemistry properties of semiconductor nanocrystals but also they are expected to find use in many fields such as luminescence devices, bioanalysis, and multicolor labeling probes.
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6

Camellini, Andrea, Haiguang Zhao, Sergio Brovelli, Ranjani Viswanatha, Alberto Vomiero, and Margherita Zavelani-Rossi. "(Invited) Ultrafast Spectroscopy in Semiconductor Nanocrystals: Revealing the Origin of Single Vs Double Emission, of Optical Gain and the Role of Dopants." ECS Meeting Abstracts MA2022-01, no. 20 (July 7, 2022): 1104. http://dx.doi.org/10.1149/ma2022-01201104mtgabs.

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Анотація:
A wide variety of materials with nanometre dimensions are increasingly explored for photonic applications. Among them, semiconductor nanocrystals (NCs) are very promising for a variety of uses, including light emission devices (LEDs), lasers, detectors, photovoltaic cells, biological labelling and sensing [1]. Key advantage of NCs is the possibility to tailor their optical response by controlling the electronic structure (“wave function engineering”) through the choice of composition, size and shape. Significant and interesting results have been obtained with heterostructured and doped NCs. Beyond single wavelength tuneable band-edge emission, other regimes have been demonstrated such as intragap emission, simultaneous emission on two different wavelengths, amplified spontaneous emission and laser emission. The luminescent properties are governed by exciton decay, which can proceed through radiative or nonradiative pathways, following different routes. The study of exciton dynamics can allow elucidating the processes connected to single or dual emission and to optical gain. This, in turn, can lead to the identification of the functional and structural characteristics that are responsible for these behaviors. Exciton relaxation occurs on picosecond timescales, so ultrafast optical techniques are required to perform these studies. In this talk, we present studies carried out by ultrafast pump-probe spectroscopy technique, with 100-fs time resolution, on CdSe/CdS and PbS/CdS heterostructured NCs, with different geometries (core/shell, dot-in-rod, dot-in-bulk, with sharp or graded interface) [2-6] and CdSeS and CdZnSe doped NCs [7,8]. These NCs are optically active in the visible and near-infrared spectral region, show single and dual colour photoluminescence emission, optical gain, laser emission and intragap emission [2-9]. The analysis of the experimental data allowed us to unravel the decay processes: the initials take place in a few ps, leading to the ultimate emitting state whose lifetime can extend to hundreds of ps to few ns, allowing for efficient luminescence and optical gain. Our data on heterostructures allowed us to clarify the role of the volume and of the shape of the outer component and the effect of the interface [2-4]. We found that dual emission is possible for both thick and thin quantum-confined shells, and for different interfaces. We studied the decoupling of excitons lying in the two different component of the NC (core exciton and shell exciton) and we revealed the evolution of the exciton barrier known as dynamic hole-blockade effect. We showed that these phenomena are strictly connected to dual emission and optical gain and we identified the condition for their maximum efficiency, in term of band alignment and band transitions. Our results provide a comprehensive understanding of the physical phenomena governing dual-emission mechanisms, suppression of Auger recombination, optical gain and laser emission in heterostructured NCs. Experiments on CdZnSe NCs doped with Mn and on CdSeS NCs engineered with sulfur vacancies, enabled us to disclose donor and acceptor localized states in the band gap. We observed the carrier dynamics responsible for intragap emission which is associated to the emergence of a transient Mn3+ state [7], in the first case, and to a donor state below the conduction band introduced by sulfur vacancies [8], in the latter case. In conclusion, the study of the exciton dynamics in different NCs allowed us to elucidate the relation between structural-morphological characteristics (shape, volume, and interface) and unconventional emission capabilities (dual emission and optical gain) in heterostructures and the photophysics of electronic states introduced by doping. This knowledge is very important to control NC functionalities toward new multilevel electronic or photonic schemes and in applications such as lasers [9], photoelectrochemical (PEC) cell [10], white light emission [11], ratiometric sensing [12]. [1] P. V. Kamat and G. D. Scholes, J. Phys. Chem. Lett. 7, 584 (2016) [2] G. Sirigu et al., Phys. Rev. B 96, 155303 (2017) [3] V. Pinchetti et al., ACS Nano 10, 6877-6887 (2016) [4] H. Zhao et al., Nanoscale 8, 4217-4226 (2016) [5] M. Zavelani-Rossi et al., Nano Lett. 10, 3142-3150 (2010) [6] R. Krahne et al., Appl. Phys. Lett. 98, 063105 (2011) [7] K. Gahlot et al., ACS Energy Lett. 4, 729−735 (2019) [8] F. Carulli et al., Nano Lett. 21, 6211−6219 (2021) [9] M. Zavelani-Rossi et al., Laser & Photonics Reviews 6, 678-683 (2012) [10] L. Jin et al., Nano Energy 30, 531-541 (2016) [11] S. Sapra et al., Adv. Mater. 19, 569 (2007) [12] J. Liu et al., ACS Photonics, 2479 (2019)
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7

Fu, Aihua, Weiwei Gu, Carolyn Larabell, and A. Paul Alivisatos. "Semiconductor nanocrystals for biological imaging." Current Opinion in Neurobiology 15, no. 5 (October 2005): 568–75. http://dx.doi.org/10.1016/j.conb.2005.08.004.

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8

Bruchez Jr., M. "Semiconductor Nanocrystals as Fluorescent Biological Labels." Science 281, no. 5385 (September 25, 1998): 2013–16. http://dx.doi.org/10.1126/science.281.5385.2013.

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9

Kang, Bin, Shu-Quan Chang, Hao Sun, Yao-Dong Dai та Da Chen. "γ-Radiation Synthesis and Properties of Superparamagnetic CS-ZnSe:Mn Nanocrystals for Biological Labeling". Journal of Nanoscience and Nanotechnology 8, № 8 (1 серпня 2008): 3857–63. http://dx.doi.org/10.1166/jnn.2008.174.

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Анотація:
Chitosan coated ZnSe:Mn (CS-ZnSe:Mn) nanocrystals were successfully synthesized in aqueous system through a γ-radiation route at room temperature under ambient pressure. The structure and properties of nanocrystals were investigated with transmission electron microscope (TEM), fourier transform infrared spectrometer (FT-IR), ultraviolet-visible (UV-vis) spectrometer, photoluminescence emission (PL) spectra, X-ray Diffraction (XRD) and energy dispersion spectrum (EDS). Results showed that the diameter of these nanocrystals was about 4 nm with narrow size distribution. With the increase of doped Mn2+ concentration, strong emission peak at 610 nm was observed besides the weak emission peak at 425 nm since the non-radiative transition of 4T1(4G)–6A1(6S) level, resulting the transfer of fluorescence color from blue to orange. Moreover, analysis of SQUID magnetometer indicated that the nanocrystals were superparamagnetic with a saturation magnetization of 1.7 emu/g and a Curie-Weiss temperature of 14–15 K. Hep G2 cells were incubated in solution of nanocrystals and results showed that the synthesized nanocrystals could stain cytoplasm but could not enter into nucleus.
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10

Santos, B. S., P. M. A. Farias, A. Fontes, A. G. Brasil, C. N. Jovino, A. G. C. Neto, D. C. N. Silva, F. D. de Menezes, and R. Ferreira. "Semiconductor nanocrystals obtained by colloidal chemistry for biological applications." Applied Surface Science 255, no. 3 (November 2008): 796–98. http://dx.doi.org/10.1016/j.apsusc.2008.07.026.

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11

Wang, Ying. "Luminescent CdTe and CdSe Semiconductor Nanocrystals: Preparation, Optical Properties and Applications." Journal of Nanoscience and Nanotechnology 8, no. 3 (March 1, 2008): 1068–91. http://dx.doi.org/10.1166/jnn.2008.18156.

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The novel optical and electrical properties of luminescent semiconductor nanocrystals are appealing for ultrasensitive multiplexing and multicolor applications in a variety of fields, such as biotechnology, nanoscale electronics, and opto-electronics. Luminescent CdSe and CdTe nanocrystals are archetypes for this dynamic research area and have gained interest from diverse research communities. In this review, we first describe the advances in preparation of size- and shape-controlled CdSe and CdTe semiconductor nanocrystals with the organometallic approach. This article gives particular focus to water soluble nanocrystals due to the increasing interest of using semiconductor nanocrystals for biological applications. Post-synthetic methods to obtain water solubility, the direct synthesis routes in aqueous medium, and the strategies to improve the photoluminescence efficiency in both organic and aqueous phase are discussed. The shape evolution in aqueous medium via self-organization of preformed nanoparticles is a versatile and powerful method for production of nanocrystals with different geometries, and some recent advances in this field are presented with a qualitative discussion on the mechanism. Some examples of CdSe and CdTe nanocrystals that have been applied successfully to problems in biosensing and bioimaging are introduced, which may profoundly impact biological and biomedical research. Finally we present the research on the use of luminescent semiconductor nanocrystals for construction of light emitting diodes, solar cells, and chemical sensors, which demonstrate that they are promising building blocks for next generation electronics.
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12

Gao, Xiaohu, Warren C. W. Chan, and Shuming Nie. "Quantum-dot nanocrystals for ultrasensitive biological labeling and multicolor optical encoding." Journal of Biomedical Optics 7, no. 4 (2002): 532. http://dx.doi.org/10.1117/1.1506706.

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13

Mushonga, Paul, Martin O. Onani, Abram M. Madiehe, and Mervin Meyer. "Indium Phosphide-Based Semiconductor Nanocrystals and Their Applications." Journal of Nanomaterials 2012 (2012): 1–11. http://dx.doi.org/10.1155/2012/869284.

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Анотація:
Semiconductor nanocrystals or quantum dots (QDs) are nanometer-sized fluorescent materials with optical properties that can be fine-tuned by varying the core size or growing a shell around the core. They have recently found wide use in the biological field which has further enhanced their importance. This review focuses on the synthesis of indium phosphide (InP) colloidal semiconductor nanocrystals. The two synthetic techniques, namely, the hot-injection and heating-up methods are discussed. Different types of the InP-based QDs involving their use as core, core/shell, alloyed, and doped systems are reviewed. The use of inorganic shells for surface passivation is also highlighted. The paper is concluded by some highlights of the applications of these systems in biological studies.
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14

Sato, Keiichi, Yasuhiro Tachibana, Shinya Hattori, Taeko Chiba, and Susumu Kuwabata. "Polyacrylic acid coating of highly luminescent CdS nanocrystals for biological labeling applications." Journal of Colloid and Interface Science 324, no. 1-2 (August 2008): 257–60. http://dx.doi.org/10.1016/j.jcis.2008.04.075.

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15

Ren, Dahai, Bin Wang, Chen Hu, and Zheng You. "Quantum dot probes for cellular analysis." Analytical Methods 9, no. 18 (2017): 2621–32. http://dx.doi.org/10.1039/c7ay00018a.

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16

Singh, Amit T., Mahendra M. Khandepekar, M. M. Khandpekar, and S. G. Gaurkhede. "Enhanced Luminescence of L-Alanine Capped LaF3:Ce Nanoparticles Useful in Biological Labeling." Journal of Nano Research 32 (May 2015): 81–92. http://dx.doi.org/10.4028/www.scientific.net/jnanor.32.81.

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Анотація:
Hexahedral nanocrystals of L-Alanine [CH3CH(NH2)COOH] doped LaF3:Ce (ALFC) of assorted sizes have been synthesized in deionized water using water soluble chlorides of lanthanides with subsequent microwave irradiation to reduce agglomeration. The average particle sizes obtained by XRD, SEM, and TEM have been 22nm, 37nm and 23nm respectively. The surface modification by functional groups of L-Alanine is observed in the FTIR and FT-RAMAN spectra and their decomposition is studied in TGA/DTA spectrum .The electron-phonon interaction of A1gphonon mode and fundamental Egphonon mode have been observed in far infra-red region by FT-RAMAN spectra. The UV-Vis spectrum shows multiple absorption edges corresponding to energies at E1= 5.11eV, E2= 4.47eV, and E3=5.781eV which indicates the quantum dot nature of the nanocrystals and its application in optoelectronic devices. ALFC nanocrystals showed green color emission peak centered at 554 nm with their potential application in bio imaging and bio tagging.Keywords: nanostructures, fluorides, Transmission electron microscopy, Raman spectroscopy, Thermogravimetric analysis (TGA).
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17

Ioannou, Andriani, Iro Eleftheriou, Andrea Lubatti, Anna Charalambous, and Paris A. Skourides. "High-Resolution Whole-MountIn SituHybridization Using Quantum Dot Nanocrystals." Journal of Biomedicine and Biotechnology 2012 (2012): 1–9. http://dx.doi.org/10.1155/2012/627602.

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The photostability and narrow emission spectra of nanometer-scale semiconductor crystallites (QDs) make them desirable candidates for whole-mount fluorescentin situhybridization to detect mRNA transcripts in morphologically preserved intact embryos. We describe a method for direct QD labeling of modified oligonucleotide probes through streptavidin-biotin and antibody-mediated interactions (anti-FITC and anti-digoxigenin). To overcome permeability issues and allow QD conjugate penetration, embryos were treated with proteinase K. The use of QDs dramatically increased sensitivity of whole-mountin situhybridization (WISH) in comparison with organic fluorophores and enabled fluorescent detection of specific transcripts within cells without the use of enzymatic amplification. Therefore, this method offers significant advantages both in terms of sensitivity, as well as resolution. Specifically, the use of QDs alleviates issues of photostability and limited brightness plaguing organic fluorophores and allows fluorescent imaging of cleared embryos. It also offers new imaging possibilities, including intracellular localization of mRNAs, simultaneous multiple-transcript detection, and visualization of mRNA expression patterns in 3D.
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18

Wang, Wentao, Xin Ji, Anshika Kapur, and Hedi Mattoussi. "Surface-Functionalizing Metal, Metal Oxide and Semiconductor Nanocrystals with a Multi-coordinating Polymer Platform." MRS Advances 1, no. 56 (2016): 3741–47. http://dx.doi.org/10.1557/adv.2016.375.

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ABSTRACTWe introduce a new set of multifunctional metal-coordinating polymers as ligands for the surface functionalization of three different inorganic nanocrystals: luminescent quantum dots (QDs), magnetic iron oxide nanocrystals and metal gold nanoparticles. The ligand design relies on the introduction of a large but controllable number of anchoring groups, hydrophilic moieties and reactive functionalities all in the same polymer chain, via a one-step nucleophilic addition reaction. Nanocrystals capped with these polymer ligands exhibit long-term stability over a broad range of biological conditions. Furthermore, when zwitterion groups are introduced as hydrophilic blocks, this yields a compact ligand coating that allows conjugation of biomolecules to the nanocrystals via metal-histidine self-assembly. The resulting hydrophilic nanocrystals have been used to develop a few specific sensing platforms targeting soluble iron ions and cysteine.
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19

Wang, Dong, Yibin Zhu, Xiaodong Wan, Xiaowei Zhang, and Jiatao Zhang. "Colloidal semiconductor nanocrystals for biological photodynamic therapy applications: Recent progress and perspectives." Progress in Natural Science: Materials International 30, no. 4 (August 2020): 443–55. http://dx.doi.org/10.1016/j.pnsc.2020.08.016.

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20

Erdem, Talha, and Hilmi Volkan Demir. "Color-Enrichment Semiconductor Nanocrystals for Biorhythm-Friendly Backlighting." Zeitschrift für Physikalische Chemie 232, no. 9-11 (August 28, 2018): 1457–68. http://dx.doi.org/10.1515/zpch-2018-1134.

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Abstract Nanocrystals (NCs) offer great opportunities for developing novel light-emitting devices possessing superior properties such as high quality indoor lighting, efficient outdoor lighting, and display backlighting with increased color definition. The narrow-band emission spectra of these materials also offer opportunities to protect the human daily biological rhythm against the adverse effects of display backlighting. For this purpose, here we address this problem using color converting NCs and analyzed the effect of the NC integrated color converting light-emitting diode (NC LED) backlight spectra on the human circadian rhythm. We employed the three existing models including the circadian light, the melanopic sensitivity function, and the circadian effect factor by simultaneously satisfying the National Television Standards Committee (NTSC) requirements. The results show that NC LED backlighting exhibits (i) 33% less disruption on the circadian cycle if the same color gamut of the commercially available YAG:Ce LED is targeted and (ii) 34% wider color gamut while causing 4.1% weaker disruption on the circadian rhythm compared to YAG:Ce LED backlight if the NTSC color gamut is fully reproduced. Furthermore, we found out that blue and green emission peaks have to be located at 465 with 30 nm bandwidth and at 535 nm with 20 nm bandwidth, respectively, for a circadian rhythm friendly design while the red component offers flexibility around the peak emission wavelength at 636 nm as opposed to the requirements of quality indoor lighting. These design considerations introduced as a new design perspective for the displays of future will help avoiding the disruption of the human circadian rhythm.
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21

Berestovoy, Mikhail A., Regina S. Bilan, Victor Krivenkov, Igor Nabiev, and Alyona Sukhanova. "Use of semiconductor nanocrystals to encode microbeads for multiplexed analysis of biological samples." Journal of Physics: Conference Series 784 (January 2017): 012012. http://dx.doi.org/10.1088/1742-6596/784/1/012012.

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22

Blume, Ya B. "«Green» Synthesis of Noble Metal Nanoparticles and CdS Semiconductor Nanocrystals Using Biological Material." Nauka ta innovacii 11, no. 1 (January 30, 2015): 59–71. http://dx.doi.org/10.15407/scin11.01.059.

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23

Blume, Ya B. "«Green» Synthesis of Noble Metal Nanoparticles and CdS Semiconductor Nanocrystals Using Biological Materials." Science and innovation 11, no. 1 (January 30, 2015): 55–66. http://dx.doi.org/10.15407/scine11.01.055.

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24

Liu, Li-wei, Si-yi Hu, Ying Pan, Jia-qi Zhang, Yue-shu Feng, and Xi-he Zhang. "Optimizing the synthesis of CdS/ZnS core/shell semiconductor nanocrystals for bioimaging applications." Beilstein Journal of Nanotechnology 5 (June 27, 2014): 919–26. http://dx.doi.org/10.3762/bjnano.5.105.

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In this study, we report on CdS/ZnS nanocrystals as a luminescence probe for bioimaging applications. CdS nanocrystals capped with a ZnS shell had enhanced luminescence intensity, stronger stability and exhibited a longer lifetime compared to uncapped CdS. The CdS/ZnS nanocrystals were stabilized in Pluronic F127 block copolymer micelles, offering an optically and colloidally stable contrast agents for in vitro and in vivo imaging. Photostability test exhibited that the ZnS protective shell not only enhances the brightness of the QDs but also improves their stability in a biological environment. An in-vivo imaging study showed that F127-CdS/ZnS micelles had strong luminescence. These results suggest that these nanoparticles have significant advantages for bioimaging applications and may offer a new direction for the early detection of cancer in humans.
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25

Yukawa, Hiroshi, Shogo Mizufune, Chiharu Mamori, Yukimasa Kagami, Koichi Oishi, Noritada Kaji, Yukihiro Okamoto, et al. "Quantum Dots for Labeling Adipose Tissue-Derived Stem Cells." Cell Transplantation 18, no. 5-6 (May 2009): 591–600. http://dx.doi.org/10.1177/096368970901805-615.

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Анотація:
Adipose tissue-derived stem cells (ASCs) have a self-renewing ability and can be induced to differentiate into various types of mesenchymal tissue. Because of their potential for clinical application, it has become desirable to label the cells for tracing transplanted cells and for in vivo imaging. Quantum dots (QDs) are novel inorganic probes that consist of CdSe/ZnS-core/shell semiconductor nanocrystals and have recently been explored as fluorescent probes for stem cell labeling. In this study, negatively charged QDs655 were applied for ASCs labeling, with the cationic liposome, Lipofectamine. The cytotoxicity of QDs655-Lipofectamine was assessed for ASCs. Although some cytotoxicity was observed in ASCs transfected with more than 2.0 nM of QDs655, none was observed with less than 0.8 nM. To evaluate the time dependency, the fluorescent intensity with QDs655 was observed until 24 h after transfection. The fluorescent intensity gradually increased until 2 h at the concentrations of 0.2 and 0.4 nM, while the intensity increased until 4 h at 0.8 nM. The ASCs were differentiated into both adipogenic and osteogenic cells with red fluorescence after transfection with QDs655, thus suggesting that the cells retain their potential for differentiation even after transfected with QDs655. These data suggest that QDs could be utilized for the labeling of ASCs.
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26

Baruah, S., Gamolwan Tumcharern, and Joydeep Dutta. "Chitosan Clad Manganese Doped Zing Sulphide Nanocrystallites for Biolabeling." Advanced Materials Research 55-57 (August 2008): 589–92. http://dx.doi.org/10.4028/www.scientific.net/amr.55-57.589.

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The synthesis of fluorescent nanocrystals is receiving a lot of attention for potential application in biological labeling as well as phosphors for field emission devices. Zinc sulphide doped with manganese (ZnS:Mn2+) is one of the most efficient electroluminescent phosphor displaying a wide emission band centred around 590 nm resulting from the intra-ionic transition in Mn2+ ions. We report a unique synthesis of zinc sulphide nanoparticles doped with manganese using a biocompatible passivating agent ‘chitosan’, with bright luminescence peaking at 590 nm. This high luminescence efficiency of the synthesized nanocrystals are ideal for quantum dot based bio-labeling applications. Synthesis of the nanoparticles was carried out by precipitation reaction in aqueous media of zinc acetate and sodium sulphide where manganese acetate was added as the dopant. The obtained nanoparticles were around 4 to 6 nm in size and were found to be stable for months of shelf life. The photoluminescence intensity did not degrade when the colloid was heated up to 65 oC for prolonged periods.
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27

Wu, Su Li, Liu Ye, Yan Hui Ning, Wen Bin Niu, and Shu Fen Zhang. "Approaches to the Multicolor Tuning of Lanthanide-Ion Doped Upconversion Nanoparticles." Advanced Materials Research 679 (April 2013): 69–74. http://dx.doi.org/10.4028/www.scientific.net/amr.679.69.

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Анотація:
In recent years, lanthanide-ion doped nanocrystals have attracted considerable attention for its promising applications in multiplexed biological labeling. These materials can convert near-infrared (NIR) light into visible and offer low autofluorescence, high resistance to photobleaching, high penetration depth and large anti-Stokes shifts. With the development of these techniques, the ability to manipulate multicolor output has become more important for its biological and photovoltaic applications. This review mainly focuses on the recent development of various approaches for the multicolor tuning of lanthanide-ion doped upconversion nanoparticles.
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28

Chalmers, Natalia I., Robert J. Palmer, Laurence Du-Thumm, Richard Sullivan, Wenyuan Shi, and Paul E. Kolenbrander. "Use of Quantum Dot Luminescent Probes To Achieve Single-Cell Resolution of Human Oral Bacteria in Biofilms." Applied and Environmental Microbiology 73, no. 2 (November 17, 2006): 630–36. http://dx.doi.org/10.1128/aem.02164-06.

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ABSTRACT Oral biofilms are multispecies communities, and in their nascent stages of development, numerous bacterial species engage in interspecies interactions. Better insight into the spatial relationship between different species and how species diversity increases over time can guide our understanding of the role of interspecies interactions in the development of the biofilms. Quantum dots (QD) are semiconductor nanocrystals and have emerged as a promising tool for labeling and detection of bacteria. We sought to apply QD-based primary immunofluorescence for labeling of bacterial cells with in vitro and in vivo biofilms and to compare this approach with the fluorophore-based primary immunofluorescence approach we have used previously. To investigate QD-based primary immunofluorescence as the means to detect distinct targets with single-cell resolution, we conjugated polyclonal and monoclonal antibodies to the QD surface. We also conducted simultaneous QD conjugate-based and fluorophore conjugate-based immunofluorescence and showed that these conjugates were complementary tools in immunofluorescence applications. Planktonic and biofilm cells were labeled effectively by considering two factors: the final nanomolar concentration of QD conjugate and the amount of antibody conjugated to the QD, which we define as the degree of labeling. These advances in the application of QD-based immunofluorescence for the study of biofilms in vitro and in vivo will help to define bacterial community architecture and to facilitate investigations of interactions between bacterial species in these communities.
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29

Liu, Peng, Zhengqiang Li, Long Yuan, Xiaolin Sun, and Yanmin Zhou. "Pourbaix-Guided Mineralization and Site-Selective Photoluminescence Properties of Rare Earth Substituted B-Type Carbonated Hydroxyapatite Nanocrystals." Molecules 26, no. 3 (January 21, 2021): 540. http://dx.doi.org/10.3390/molecules26030540.

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Анотація:
Rare-earth labeling in biological apatite could provide critical information for the pathologic transition (osteoclastic) and physiologic regeneration (osteogenesis) of bone and teeth because of their characteristic site-sensitive fluorescence in different coordinative conditions of various tissues in many biological processes. However, the rare-earth labeling method for biological apatites, i.e., carbonated-hydroxyapatite, has been rarely found in the literature. In this paper, we report a Pourbaix-diagram guided mineralizing strategy to controllable carbonation and doping of rare-earth ions in the hydroxyapatite (HA) lattice. The carbonation process of hydroxyapatite was achieved by controllable mineralization in hydrothermal condition with K2CO3 as the carbonate source, which results into the pure B-type carbonated hydroxyapatite (CHA) with tunable carbonate substitution degree. All of the as-synthesized materials crystalized into P63/m (No. 176) space group with the lattice parameter of a decreases and c increases with the increasing of carbonate content in the reactants. Structural refinement results revealed that the substitution of planar CO32− is superimposed on one of the faces of PO43− tetrahedral sub-units with a rotation angle of 30° in reference to c-axis. All of the hydrothermally synthesized CHA nanocrystals show hexagonal rod-like morphology with the length of 70–110 nm and diameter of 21–35 nm, and the decreasing length/diameter ratio from 3.61 to 2.96 from low to high carbonated level of the samples. Five rare-earth cations, of Pr3+, Sm3+, Eu3+, Tb3+, and Ho3+, were used as possible probe ions that can be doped into either HA or CHA lattice. The site-preference of Tb3+ doping is the same in the crystallographic site of HA and CHA according to characteristic emission peaks of 5D4–7Fj (j = 3–6) transitions in their photoluminescent spectroscopy. Our work provides a controllable carbonation method for rare-earth labeling hydroxyapatite nanomaterials with potential biologically active implant powders for bone repair and tissue regeneration.
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30

Zhang, Dan, He Zhang, Cheng Xun Sun, and Bao Yu Zhu. "Non-Injection One-Pot Synthesized Lanthanide Ions Doped CdSe Nanocrystals with their Energy Transfer." Advanced Materials Research 662 (February 2013): 28–34. http://dx.doi.org/10.4028/www.scientific.net/amr.662.28.

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The OA protected, Eu doped CdSe nanocrystals (NCs), which optical property could be control by temperature and reactant molar ratio, were prepared by non-injection one-pot synthesized method. And after modifying TTA, the Eu doped NCs showed energy transfer from NCs to Eu. The size, crystal structure, composition and the optical property of product were further studied in detail by TEM, PL, UV, XRD and EDS. The Eu doped NCs with excellent lanthanide characteristic fluorescence were possessed many potential applications in various fields, such as biological labeling, immunoassays, optical sensing, and so on.
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31

García, Daniela Armijo, Lupe Mendoza, Karla Vizuete, Alexis Debut, Marbel Torres Arias, Alex Gavilanes, Thibault Terencio, Edward Ávila, Clayton Jeffryes, and Si Amar Dahoumane. "Sugar-Mediated Green Synthesis of Silver Selenide Semiconductor Nanocrystals under Ultrasound Irradiation." Molecules 25, no. 21 (November 8, 2020): 5193. http://dx.doi.org/10.3390/molecules25215193.

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Silver selenide (Ag2Se) is a promising nanomaterial due to its outstanding optoelectronic properties and countless bio-applications. To the best of our knowledge, we report, for the first time, a simple and easy method for the ultrasound-assisted synthesis of Ag2Se nanoparticles (NPs) by mixing aqueous solutions of silver nitrate (AgNO3) and selenous acid (H2SeO3) that act as Ag and Se sources, respectively, in the presence of dissolved fructose and starch that act as reducing and stabilizing agents, respectively. The concentrations of mono- and polysaccharides were screened to determine their effect on the size, shape and colloidal stability of the as-synthesized Ag2Se NPs which, in turn, impact the optical properties of these NPs. The morphology of the as-synthesized Ag2Se NPs was characterized by transmission electron microscopy (TEM) and both α- and β-phases of Ag2Se were determined by X-ray diffraction (XRD). The optical properties of Ag2Se were studied using UV–Vis spectroscopy and its elemental composition was determined non-destructively using scanning electron microscopy–energy-dispersive spectroscopy (SEM–EDS). The biological activity of the Ag2Se NPs was assessed using cytotoxic and bactericidal approaches. Our findings pave the way to the cost-effective, fast and scalable production of valuable Ag2Se NPs that may be utilized in numerous fields.
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32

Ali, Haydar, Santu Ghosh, and Nikhil R. Jana. "Biomolecule-derived Fluorescent Carbon Nanoparticle as Bioimaging Probe." MRS Advances 3, no. 15-16 (2018): 779–88. http://dx.doi.org/10.1557/adv.2018.80.

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ABSTRACTNanomaterials have broad application potential in biomedical and environmental science. Engineered nanomaterials are required to explore such potential. Among them carbon-based fluorescent nanoparticles offer promising alternative of conventionally used semiconductor nanocrystals, as they do not have heavy metals and associated toxicity issues. We are developing synthetic methods for high quality fluorescent carbon nanoparticle, suitable for biological staining and diagnostics. Here we focus on synthesis of fluorescent carbon nanoparticle from biomolecules, exploiting the conventionally used nucleation-growth conditions for synthesis of high quality nanocrystals such as quantum dot and metal oxides. We have shown that high quality fluorescent carbon nanoparticle can be synthesized from folic acid, riboflavin and lactose and they can be used as non-toxic bio-imaging probe.
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33

Secu, Corina, Cristina Bartha, Elena Matei, Cristian Radu, and Mihail Secu. "Structural and Optical Characterization of Silica Nanospheres Embedded with Monodisperse CeO2-Eu3+ Nanocrystals." Magnetochemistry 8, no. 2 (February 4, 2022): 22. http://dx.doi.org/10.3390/magnetochemistry8020022.

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Luminescent nanocrystals embedded into silica microspheres were shown to be useful for silica labeling for biological applications, ensuring mechanical and chemical stability, nontoxicity, biocompatibility and optical properties. We used sol–gel technology to prepare silica nanospheres embedded with fluorescent and magnetic Eu3+(1 mol%)-doped CeO2 nanocrystals. The X-ray diffraction pattern analysis and transmission electron microscopy investigations showed CeO2:Eu3+(1 mol%) nanocrystals of about 9 nm size and Ce3+ ions substitution by the Eu3+ ions; the nanocrystals dispersed inside the nanosized silica spheres of about 400 nm diameters. The photoluminescence spectra recorded under UV-light excitation showed Eu3+ ions luminescence peaks (5D0-7FJ, J = 0–4) accompanied by a weaker 425 nm luminescence due to the silica matrix; the quantum yield was 0.14. The weak hysteresis loop and magnetization curves recorded up to 20,000 Oe showed dominantly paramagnetic behavior associated with the silica matrix; a slight opening of the hysteresis loop to a very small magnetic field (about 0.005 Oe) was due to the presence of the two rare earth ions. The photonic crystal properties of SiO2-CeO2:Eu3+(1 mol%) silica nanospheres deposited as films on quartz plates were revealed by the two weak attenuation peaks at 420 and 500 nm and were associated with the reflection from different planes. The SiO2-CeO2:Eu3+(1 mol%) nanospheres are attractive potential candidates for photonics-related applications or for multifunctional bio-labels by combining the luminescence and magnetic properties of the nanocrystals.
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34

Alivisatos, Paul. "Colloidal quantum dots. From scaling laws to biological applications." Pure and Applied Chemistry 72, no. 1-2 (January 1, 2000): 3–9. http://dx.doi.org/10.1351/pac200072010003.

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Анотація:
Over a twenty-year period, condensed matter physicists and physical chemists have elucidated a series of scaling laws which successfully describe the size dependence of solid state properties [1,2]. Often the experiments were performed under somewhat exotic conditions, for instance on mass-selected clusters isolated in molecular beams or on quantum dots grown by molecular beam epitaxy and interrogated at low temperatures and in high magnetic fields. As a result, we now have an understanding of how thermodynamic, optical, electrical, and magnetic properties evolve from the atomic to the solid state limit. This area of research is presently undergoing a remarkable transformation. The scaling laws, previously the direct subject of research, now provide a tool for the design of advanced new materials. In the case of colloidal quantum dots, or semiconductor nanocrystals, these new insights are poised to have impact in disciplines remote from solid state physics [3].
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35

Heine, Markus, Alexander Bartelt, Oliver T. Bruns, Denise Bargheer, Artur Giemsa, Barbara Freund, Ludger Scheja, et al. "The cell-type specific uptake of polymer-coated or micelle-embedded QDs and SPIOs does not provoke an acute pro-inflammatory response in the liver." Beilstein Journal of Nanotechnology 5 (September 2, 2014): 1432–40. http://dx.doi.org/10.3762/bjnano.5.155.

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Semiconductor quantum dots (QD) and superparamagnetic iron oxide nanocrystals (SPIO) have exceptional physical properties that are well suited for biomedical applications in vitro and in vivo. For future applications, the direct injection of nanocrystals for imaging and therapy represents an important entry route into the human body. Therefore, it is crucial to investigate biological responses of the body to nanocrystals to avoid harmful side effects. In recent years, we established a system to embed nanocrystals with a hydrophobic oleic acid shell either by lipid micelles or by the amphiphilic polymer poly(maleic anhydride-alt-1-octadecene) (PMAOD). The goal of the current study is to investigate the uptake processes as well as pro-inflammatory responses in the liver after the injection of these encapsulated nanocrystals. By immunofluorescence and electron microscopy studies using wild type mice, we show that 30 min after injection polymer-coated nanocrystals are primarily taken up by liver sinusoidal endothelial cells. In contrast, by using wild type, Ldlr -/- as well as Apoe -/- mice we show that nanocrystals embedded within lipid micelles are internalized by Kupffer cells and, in a process that is dependent on the LDL receptor and apolipoprotein E, by hepatocytes. Gene expression analysis of pro-inflammatory markers such as tumor necrosis factor alpha (TNFα) or chemokine (C-X-C motif) ligand 10 (Cxcl10) indicated that 48 h after injection internalized nanocrystals did not provoke pro-inflammatory pathways. In conclusion, internalized nanocrystals at least in mouse liver cells, namely endothelial cells, Kupffer cells and hepatocytes are at least not acutely associated with potential adverse side effects, underlining their potential for biomedical applications.
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36

Delille, Fanny, Yuzhou Pu, Nicolas Lequeux, and Thomas Pons. "Designing the Surface Chemistry of Inorganic Nanocrystals for Cancer Imaging and Therapy." Cancers 14, no. 10 (May 16, 2022): 2456. http://dx.doi.org/10.3390/cancers14102456.

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Inorganic nanocrystals, such as gold, iron oxide and semiconductor quantum dots, offer promising prospects for cancer diagnostics, imaging and therapy, due to their specific plasmonic, magnetic or fluorescent properties. The organic coating, or surface ligands, of these nanoparticles ensures their colloidal stability in complex biological fluids and enables their functionalization with targeting functions. It also controls the interactions of the nanoparticle with biomolecules in their environment. It therefore plays a crucial role in determining nanoparticle biodistribution and, ultimately, the imaging or therapeutic efficiency. This review summarizes the various strategies used to develop optimal surface chemistries for the in vivo preclinical and clinical application of inorganic nanocrystals. It discusses the current understanding of the influence of the nanoparticle surface chemistry on its colloidal stability, interaction with proteins, biodistribution and tumor uptake, and the requirements to develop an optimal surface chemistry.
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37

Zhang, Chun Yan, Chuan Tao Wang, Shu Hao Wang, and Ling Yun Du. "Biological Conjugate between Antibody and ZnS Nanoparticles as Probe for Atomic Absorption Spectrophotometry Determination of Estriol." Applied Mechanics and Materials 556-562 (May 2014): 64–66. http://dx.doi.org/10.4028/www.scientific.net/amm.556-562.64.

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ZnS semiconductor nanocrystals (NCs) were prepared by ways from primary materials of ZnCl2 and Na2S in water solution. Using the synthesized ZnS NCs, a polyclonal antibody-based ZnS-labelled immunosorbent assay for the determination of estriol (E3) was developed with atomic absorption spectrophotometry (AAS) as a detector. An immunoaffinity column was applied to testify conjugation between antibody and ZnS NCs. The linear range for determination of estriol is 40.0~600.0 ng.mL-1, and the limit of detection (LOD) is 10.0 ng.mL-1. Some serum samples have been analyzed with satisfactory results which are in good agreement with those obtained using ELISA. This work suggests the potential application of NCs as biological probes and AAS as detector in nonisotopic immunoassay.
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38

Doskaliuk, N. M., Y. V. Babyuk, O. O. Tynkevych, A. V. Sachko, and Y. B. Khalavka. "Influence of the cationic composition on the optical properties and photostability of AgInS2 and AgInS2/ZnS quantum dots." Chernivtsi University Scientific Herald. Chemistry, no. 827 (2020): 7–15. http://dx.doi.org/10.31861/chem-2020-827-1.

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Semiconductor I-III-VI nanocrystals are highly luminescent low toxic materials with direct band gap and tunable emission in visible and near infrared region which can be synthesized in aqueous media via simple procedure making them competitive object in compare with well developed and investigated II-VI quantum dots. However the nature of radiative recombination pathways definition and effect of synthesis conditions on spectral characteristics of the nanocrystals investigation remains an important task. In the present work influence of the cation precursors ratio as well as the heat treatment duration on the composition, optical properties and photostability of AgInS2 and AgInS2/ZnS nanocrystals synthesized in aqueous media have been investigated. Due to the low reactivity of indium salts in aqueous solution coused by formation of a stable complexes with stabilizer or hydroxycomplexes the nearest stoichiometric Ag1,1InSx quantum dots are formed at the initial [In]:[Ag] ratio 7:1. Under high excess of Ag formation of Ag2S/AgInS2 core/shell quantum dots confirming by presence of large 12-15 nm nanocrystals and red shift of the photoluminescence maximum with increasing [In]:[Ag] ratio from 1 to 3 (shell thickness should increase proportionally) is possible. With a further increase of the [In]:[Ag] ratio the absorption edge and the photoluminescence maximum are green shifted indicating increase of the quantum dots band energy. That can be explained by lowering of the valence band ceiling energy and rising of the conduction band bottom energy due to decrease of density of states of Ag 4d orbitals and increase of density of states of In 5s and 5p orbitals involved in the AgInS2 band gap formation. Increase of Indium content leads to significant increase of the photoluminescence intensity of AgInS2 nanocrystals eliminating nonradiative defects such as Agi. It have been shown that the ZnS shell epitaxial grow occurs due to the cation exchange between Zn2+ and In3+ and takes place only at low concentration of Zinc precursor ([Zn]:[Ag] ≤ 4). With further enhancement of the ratio the solid solution of AgInS2-ZnS is forming. To achieve the highest possible photoluminescence intensity and energy the AgInS2-ZnS nanocrystals should be heated at 950C at least for 120 minutes. It have been shown that the nearly stoichiometric Ag1,1InSx nanocrystals posess the highest photostability under UV light irradiation.
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39

Smith, Andrew M. "(Keynote) Quantum Dot Coatings for Aqueous Stabilization and Applications in Biomolecular Analysis." ECS Meeting Abstracts MA2022-02, no. 20 (October 9, 2022): 909. http://dx.doi.org/10.1149/ma2022-0220909mtgabs.

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Semiconductor quantum dots have been commercially available as molecular probes for applications in the life sciences and clinical diagnostics for two decades, however they have only been adopted in niche applications. Part of the reason for limited adoption is attributable to challenges in colloidal stabilization, as these solid nanocrystals tend to aggregate and nonspecifically adsorb to surfaces and cellular structures. This can largely be alleviated by use of nanocrystal coatings that resist nonspecific binding and promote aqueous dispersion, however the vast majority of such coatings are based on neutral and zwitterionic polymers that add considerable hydrodynamic size to the product. This size increase is due to the bulk of the coating itself as well as adsorption of water molecules and ions in solution. The size increase causes steric hindrance and inaccurate molecular labeling when these probes are used to analyze targets that have considerable size or ones that are located in crowded regions of cells or tissues. Furthermore, the bioaffinity label that attaches the quantum dot to its intended molecular target often contributes substantially to the final size and stability of the probe. This is especially challenging for protein labeling using antibodies, which themselves are fairly large proteins that attach heterogeneously to quantum dots, typically yielding large, polydisperse products. This talk will focus on developments in quantum dot engineering, monolayer polymeric coatings, and bioconjugation strategies to optimize offsetting characteristics of size, homogeneity, bioaffinity, and specificity. In particular, multidentate polymer coatings in recent years have enabled the production of quantum dots with long-term shelf life, small hydrodynamic diameters, and efficient click chemistry conjugations. By tuning the conjugation methods to antibody fragments and single-stranded DNA, we can now prepare bioaffinity labels for proteins and nucleic acids in the ~10 nm range, with further size reductions possible through nanocrystal heterostructure engineering. This talk will also cover how in situ protein and nucleic acid labeling applications can benefit from these advances in addition to current challenges in processing, scale-up, and user adoption.
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40

Kaul, Zeenia, Tomoko Yaguchi, Jun I. Harada, Yutaka Ikeda, Takashi Hirano, Hiroshi X. Chiura, Sunil C. Kaul, and Renu Wadhwa. "An antibody-conjugated internalizing quantum dot suitable for long-term live imaging of cells." Biochemistry and Cell Biology 85, no. 1 (February 2007): 133–40. http://dx.doi.org/10.1139/o06-205.

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Quantum dots (QD) are fluorescent semiconductor nanocrystals that are emerging as superior alternatives to the conventional organic dyes used in biological applications. Although QDs offer several advantages over conventional fluorescent dyes, including greater photostability and a wider range of excitation and (or) emission wavelengths, their toxicity has been an issue in its wider use as an analytic, diagnostic and therapeutic tool. We prepared a conjugate QD with an internalizing antibody and demonstrated that the QD–antibody conjugate is efficiently internalized into cells and is visible even after multiple divisions. We demonstrate that the internalized QD is nontoxic to cells and provides a sensitive tool for long-term molecular imaging.
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41

Martins, Graziella Santos, Suzete Araújo Oliveira Gomes, Sônia Renaux Wanderley Louro, Eliane Wajnberg, Odivaldo Cambraia Alves, Diogo Burigo Almeida, Carlos Lenz Cesar, and Denise Feder. "Evaluation of Biological Toxicity of CdTe Quantum Dots in Trypanosoma cruzi." Research, Society and Development 9, no. 12 (December 26, 2020): e34391211274. http://dx.doi.org/10.33448/rsd-v9i12.11274.

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Анотація:
Luminescent semiconductor nanocrystals or quantum dots (QDs) emerge as important fluorescent probes for in vitro and in vivo Trypanosoma cruzi cells studies. However, to ensure applicability to living organisms, several tests still need to be done. Since several toxic events are caused by QDs, such as loss of mitochondrial membrane potential, ROS generation, DNA damage and cell death by autophagy. We performed a review of the literature on mechanisms of cellular uptake, internalization and citotoxicity of nanoparticles including our results about the evaluation of biological toxicity in T. cruzi. We evaluated the possible effects on parasite growth curves in a time - scale of control and incubated cells with different concentrations of CdTe – QDs (0.2; 2.0; 20 and 200µM) to determine the development cells changes. In addition, intracellular ROS were measured by Electron Paramagnetic Resonance Spectroscopy (EPR) technique. According our results, we can infer that the toxic effects of QDs in T. cruzi are dose-dependent and that high levels of ROS are involved in cellular toxicity promoted by higher concentrations of QDs. In summary, parasites labeled with low concentrations of nanoparticles are suitable and can be used as bioimaging tools for living parasites. However, more studies on QDs cytotoxicity need to be carried out.
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42

Matsuno, Akira, Johbu Itoh, Susumu Takekoshi, Tadashi Nagashima, and R. Yoshiyuki Osamura. "Three-dimensional Imaging of the Intracellular Localization of Growth Hormone and Prolactin and Their mRNA Using Nanocrystal (Quantum Dot) and Confocal Laser Scanning Microscopy Techniques." Journal of Histochemistry & Cytochemistry 53, no. 7 (July 2005): 833–38. http://dx.doi.org/10.1369/jhc.4a6577.2005.

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Анотація:
Semiconductor nanocrystals (Quantum dots, Qdots) have recently been used in biological research, because they do not fade on exposure to light, and they enable us to obtain multicolor imaging because of a narrow emission peak that can be excited via a single wavelength of light. There have been no reports of simultaneous localization of mRNA and protein using Qdots. We successfully applied these advantages of Qdot and confocal laser scanning microscopy (CLSM) to three-dimensional images of the intracellular localization of growth hormone and prolactin and to their mRNA. In situ hybridization and immunohistochemistry using Qdots combined with CLSM can optimally illustrate the relationship between protein and mRNA simultaneously in three dimensions. Such an approach enables us to visualize functional images of proteins in relation with mRNA synthesis and localization.
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43

Zhao, Xiaofan, Zeyun Wu, Zining Yang, Xu Yang, Yiyang Zhang, Maohui Yuan, Kai Han, et al. "Dual-Wavelength Excited Intense Red Upconversion Luminescence from Er3+-Sensitized Y2O3 Nanocrystals Fabricated by Spray Flame Synthesis." Nanomaterials 10, no. 8 (July 28, 2020): 1475. http://dx.doi.org/10.3390/nano10081475.

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Er3+-sensitized upconversion nanoparticles (UCNPs) have attracted great attention due to their tunable upconversion (UC) emissions, low cytotoxicity, high resistance to photobleaching and especially multiple effective excitation wavelengths. However, detailed energy conversion between Er3+ and Tm3+ ions in Y2O3 UCNPs is still a problem, especially under multi-wavelength and variable pulse width excitation. In this work, we successfully fabricated a series of Er3+-sensitized Y2O3 nanocrystals by a spray flame synthesis method with a production rate of 40.5 g h−1. The as-prepared UCNPs are a pure cubic phase with a mean size of 14 nm. Excited by both 980 and 808 nm lasers, the tunable upconversion luminescence (UCL) from Er3+ ions was achieved by increasing the Er3+ doping concentration, co-doping Tm3+ ions and extending excitation pulse-width. The investigations of the lifetimes and the laser power dependence of UC emissions further support the proposed mechanism, which provides guidance for achieving effective color control in anticounterfeiting and multiplexed labeling applications. In addition, the red UC emission at about 5 mm beneath the tissue surface was observed in an ex vivo imaging experiment under the excitation of 808 nm laser, indicating that the Y2O3:Er3+/Tm3+ UCNPs have great prospects in further biological applications.
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44

Beard, Matthew C., Justin C. Johnson, Joseph M. Luther, and Arthur J. Nozik. "Multiple exciton generation in quantum dots versus singlet fission in molecular chromophores for solar photon conversion." Philosophical Transactions of the Royal Society A: Mathematical, Physical and Engineering Sciences 373, no. 2044 (June 28, 2015): 20140412. http://dx.doi.org/10.1098/rsta.2014.0412.

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Both multiple exciton generation (MEG) in semiconductor nanocrystals and singlet fission (SF) in molecular chromophores have the potential to greatly increase the power conversion efficiency of solar cells for the production of solar electricity (photovoltaics) and solar fuels (artificial photosynthesis) when used in solar photoconverters. MEG creates two or more excitons per absorbed photon, and SF produces two triplet states from a single singlet state. In both cases, multiple charge carriers from a single absorbed photon can be extracted from the cell and used to create higher power conversion efficiencies for a photovoltaic cell or a cell that produces solar fuels, like hydrogen from water splitting or reduced carbon fuels from carbon dioxide and water (analogous to biological photosynthesis). The similarities and differences in the mechanisms and photoconversion cell architectures between MEG and SF are discussed.
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45

Mazumder, Sonal, Rajib Dey, M. K. Mitra, S. Mukherjee, and G. C. Das. "Review: Biofunctionalized Quantum Dots in Biology and Medicine." Journal of Nanomaterials 2009 (2009): 1–17. http://dx.doi.org/10.1155/2009/815734.

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Анотація:
Quantum dot (QD) nanocrystals which have important optical properties, in particular, the wavelength of their fluorescence, depend strongly on their size. Colloidal QDs once dispersed in a solvent are quite interesting fluorescence probes for all types of labelling studies because of their reduced tendency to photo bleach. In this review, we will give an overview on how QDs have been used so far in cell biology. In particular, we will discuss the biologically relevant properties of QDs and focus on four topics: labeling of cellular structures and receptors with QDs, incorporation of QDs by living cells, tracking the path and the fate of individual cells using QD labels, and QDs as contrast agents. QDs are seen to be much better in terms of efficacy over radioisotopes in tracing medicine in vivo. They are rapidly being applied to existing and emerging technologies but here this review deals with a comprehensive compilation of the biological relevance of quantum dots. It covers important information from 1999 till 2008 with few from 1982 to 1997.
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46

LI, WENJIANG, MINGRUI WANG, FEI XIE, SHA ZHU, and YUE ZHAO. "SYNTHESIS OF NANOCRYSTALLINE CdS QUANTUM DOTS VIA PARAFFIN LIQUID AS SOLVENT AND OLEIC ACID AS THE REACTING MEDIA." International Journal of Nanoscience 11, no. 06 (December 2012): 1240038. http://dx.doi.org/10.1142/s0219581x12400388.

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Fluorescent semiconductor nanocrystals have been widely used as fluorescent materials in chemical sensors, biotechnology, medical diagnostics, biological imaging and many other fields. Compared to the conventional organic fluorophores, the inorganic quantum dots (QDs) have many advantages, including broad absorption spectra, narrow emission spectra, good photostability and long fluorescent lifetime after excitation. Here, the high quality CdS QDs were synthesized directly from sulfur and CdO using the paraffin liquid as solvent and the oleic acid as the reacting media. The synthesized CdS QDs with a zinc blende (cubic) crystal structure were proved by X-ray diffraction. HRTEM observation revealed that the CdS QDs were uniform and the average grain size was about 4 nm. The optical properties of the CdS QDs were characterized by using photoluminescence (PL) spectrophotometer and Ultraviolet-visible (UV-Vis) absorption spectrophotometer. The formation mechanism of CdS QDs in the paraffin liquid and oleic acid system was proposed.
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47

Sayevich, Vladimir, Chris Guhrenz, and Nikolai Gaponik. "All-Inorganic and Hybrid Capping of Nanocrystals as Key to Their Application-Relevant Processing." MRS Advances 3, no. 47-48 (2018): 2923–30. http://dx.doi.org/10.1557/adv.2018.445.

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AbstractThe design of the surface chemistry of colloidal semiconductor nanocrystals (NCs) presents a powerful synthetic approach that allows to tune the optical and electronic properties of the particles in independent and precisely desired manner, to provide chemical and colloidal stability in diverse media, and, finally, to control their targeted applicability ranging from catalysis, medicine to advanced electronic devices. In this article, we summarize the successful functionalization of colloidal NCs with specifically chosen ligands using a novel ligand-exchange strategy. To transform diverse colloidal NCs into a competitive class of solution-processed semiconductors for electronic applications, we replaced the pristine, insulating ligands with tiny inorganic and hybrid inorganic/organic species. The surface modification with inorganic ions modulates the charge carrier density in NC units and guarantees enhanced interparticle interactions. The subsequent functionalization of the all-inorganic-capped NCs with organic molecules leads to the formation of hybrid inorganic/organic-capped NCs. For example, the introduction of short amine molecules enables to preserve the optical and electronic characteristics of their all-inorganic counterparts, while extending the solubility range and improving the ability to form long-range ordered 2D and 3D superstructures. Moreover, these short amines can be further used as convenient axillary co-ligands facilitating the surface functionalization of all-inorganic NCs with other biocompatible molecules, such as polyethylene glycol (PEG). This opens further perspectives for NCs not only in optoelectronic but also in biological and medical applications.
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48

Mirnajafizadeh, Fatemeh, Deborah Ramsey, Shelli McAlpine, Fan Wang, and John Stride. "Nanoparticles for Bioapplications: Study of the Cytotoxicity of Water Dispersible CdSe(S) and CdSe(S)/ZnO Quantum Dots." Nanomaterials 9, no. 3 (March 20, 2019): 465. http://dx.doi.org/10.3390/nano9030465.

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Semiconductor nanocrystals or quantum dots (QDs) have unique optical and physical properties that make them potential imaging tools in biological and medical applications. However, concerns over the aqueous dispersivity, toxicity to cells, and stability in biological environments may limit the use of QDs in such applications. Here, we report an investigation into the cytotoxicity of aqueously dispersed CdSe(S) and CdSe(S)/ZnO core/shell QDs in the presence of human colorectal carcinoma cells (HCT-116) and a human skin fibroblast cell line (WS1). The cytotoxicity of the precursor solutions used in the synthesis of the CdSe(S) QDs was also determined in the presence of HCT-116 cells. CdSe(S) QDs were found to have a low toxicity at concentrations up to 100 µg/mL, with a decreased cell viability at higher concentrations, indicating a highly dose-dependent response. Meanwhile, CdSe(S)/ZnO core/shell QDs exhibited lower toxicity than uncoated QDs at higher concentrations. Confocal microscopy images of HCT-116 cells after incubation with CdSe(S) and CdSe(S)/ZnO QDs showed that the cells were stable in aqueous concentrations of 100 µg of QDs per mL, with no sign of cell necrosis, confirming the cytotoxicity data.
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49

Abdel-Salam, Mohamed, Basma Omran, Kathryn Whitehead, and Kwang-Hyun Baek. "Superior Properties and Biomedical Applications of Microorganism-Derived Fluorescent Quantum Dots." Molecules 25, no. 19 (September 30, 2020): 4486. http://dx.doi.org/10.3390/molecules25194486.

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Quantum dots (QDs) are fluorescent nanocrystals with superb photo-physical properties. Applications of QDs have been exponentially increased during the past decade. They can be employed in several disciplines, including biological, optical, biomedical, engineering, and energy applications. This review highlights the structural composition and distinctive features of QDs, such as resistance to photo-bleaching, wide range of excitations, and size-dependent light emission features. Physical and chemical preparation of QDs have prominent downsides, including high costs, regeneration of hazardous byproducts, and use of external noxious chemicals for capping and stabilization purposes. To eliminate the demerits of these methods, an emphasis on the latest progress of microbial synthesis of QDs by bacteria, yeast, and fungi is introduced. Some of the biomedical applications of QDs are overviewed as well, such as tumor and microRNA detection, drug delivery, photodynamic therapy, and microbial labeling. Challenges facing the microbial fabrication of QDs are discussed with the future prospects to fully maximize the yield of QDs by elucidating the key enzymes intermediating the nucleation and growth of QDs. Exploration of the distribution and mode of action of QDs is required to promote their biomedical applications.
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50

Pedroso, Cassio, Changhwan Lee, Emma Xu, Victor Mann, Emory Chan, P. James Schuck, and Bruce E. Cohen. "(Invited) The Evolution of Inorganic Nanocrystals for Bioimaging." ECS Meeting Abstracts MA2022-02, no. 20 (October 9, 2022): 910. http://dx.doi.org/10.1149/ma2022-0220910mtgabs.

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The first applications of luminescent nanocrystals to bioimaging were semiconductor quantum dots with optoelectronic properties that largely mirror those of organics and proteins, but with substantially increased stability and brightness that have enabled single molecule and other challenging imaging applications. Building on this success, newer nanocrystals have been engineered with optical properties unlike anything found in traditional probes, including perfect photostability,1,2 anti-Stokes emission a billion-fold more efficient than 2-photon excitation,3 and most recently, photon avalanches hosted within nanostructures.4 Avalanches are steeply nonlinear events in which outsized responses arise from a series of minute inputs. With light, photon avalanching (PA) had been observed only in bulk materials and aggregates, often at cryogenic temperatures, preventing its application to bioimaging. We recently reported the realization of PA at room temperature in sub-30 nm Tm3+-doped NaYF4 upconverting nanoparticles (UCNPs) and demonstrated their use in high-resolution imaging at wavelengths that fall within NIR spectral windows of maximal biological transparency. Avalanching nanoparticles (ANPs) can be pumped by either continuous-wave or pulsed lasers and exhibit all of the defining features of PA: clear excitation power thresholds, exceptionally long rise time at threshold, and a dominant excited-state absorption that is >10,000 times larger than ground-state absorption. Beyond the avalanching threshold, ANP emission scales with up to the 31st power of pump intensity, an extreme nonlinearity caused by the induced positive optical feedback within each nanocrystal. This enables sub-70 nm spatial resolution using only simple scanning confocal microscopy and before any computational data analysis. NaYF4 ANPs with 8-20% Tm3+content can be excited at either 1064 or 1450 nm, with avalanching emission at 800 nm. Pairing the steep nonlinearity of ANPs with existing superresolution techniques and computational methods allows for imaging with higher resolution and at ca. 100-fold lower excitation intensities than is possible with other probes. For application of ANPs to live-cell imaging, we have developed synthetic chemistry-free methods for conjugating engineered antibodies to NP-surface SpyCatcher proteins,5 which bind and spontaneously form covalent isopeptide bonds with cognate SpyTag peptides. This enables controlled and irreversible attachment of antibodies to nanoparticle surfaces, for specific targeting of cell-surface receptors in quantitative live-cell study of their distribution, trafficking, and physiology. Wu, S. et al. Non-blinking and photostable upconverted luminescence from single lanthanide-doped nanocrystals. Proc. Natl. Acad. Sci. 106, 10917–10921 (2009). Fernandez-Bravo, A. et al. Continuous-wave upconverting nanoparticle microlasers. Nat. Nanotechnol. 13, 572–577 (2018). Tian, B. et al. Low irradiance multiphoton imaging with alloyed lanthanide nanocrystals. Nat. Commun. 9, 3082 (2018). Lee, C. et al. Giant nonlinear optical responses from photon-avalanching nanoparticles. Nature 589, 230–235 (2021). Pedroso, C. C. S. et al. Immunotargeting of nanocrystals by SpyCatcher conjugation of engineered antibodies. ACS Nano 15, 18374–18384 (2021). Figure 1
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