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Relevant bibliographies by topics / ATP aptamer

Academic literature on the topic 'ATP aptamer'

Author: Grafiati

Published: 10 December 2022

Last updated: 28 January 2023

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Journal articles on the topic "ATP aptamer"

1

Zhang, Li, and John C. Chaput. "In Vitro Selection of an ATP-Binding TNA Aptamer." Molecules 25, no. 18 (September 13, 2020): 4194. http://dx.doi.org/10.3390/molecules25184194.

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Recent advances in polymerase engineering have made it possible to isolate aptamers from libraries of synthetic genetic polymers (XNAs) with backbone structures that are distinct from those found in nature. However, nearly all of the XNA aptamers produced thus far have been generated against protein targets, raising significant questions about the ability of XNA aptamers to recognize small molecule targets. Here, we report the evolution of an ATP-binding aptamer composed entirely of α-L-threose nucleic acid (TNA). A chemically synthesized version of the best aptamer sequence shows high affinity to ATP and strong specificity against other naturally occurring ribonucleotide triphosphates. Unlike its DNA and RNA counterparts that are susceptible to nuclease digestion, the ATP-binding TNA aptamer exhibits high biological stability against hydrolytic enzymes that rapidly degrade DNA and RNA. Based on these findings, we suggest that TNA aptamers could find widespread use as molecular recognition elements in diagnostic and therapeutic applications that require high biological stability.

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Esawi, Ezaldeen, Walhan Alshaer, Ismail Sami Mahmoud, Dana A. Alqudah, Bilal Azab, and Abdalla Awidi. "Aptamer-Aptamer Chimera for Targeted Delivery and ATP-Responsive Release of Doxorubicin into Cancer Cells." International Journal of Molecular Sciences 22, no. 23 (November 30, 2021): 12940. http://dx.doi.org/10.3390/ijms222312940.

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Aptamers offer a great opportunity to develop innovative drug delivery systems that can deliver cargos specifically into targeted cells. In this study, a chimera consisting of two aptamers was developed to deliver doxorubicin into cancer cells and release the drug in cytoplasm in response to adenosine-5′-triphosphate (ATP) binding. The chimera was composed of the AS1411 anti-nucleolin aptamer for cancer cell targeting and the ATP aptamer for loading and triggering the release of doxorubicin in cells. The chimera was first produced by hybridizing the ATP aptamer with its complementary DNA sequence, which is linked with the AS1411 aptamer via a poly-thymine linker. Doxorubicin was then loaded inside the hybridized DNA region of the chimera. Our results show that the AS1411–ATP aptamer chimera was able to release loaded doxorubicin in cells in response to ATP. In addition, selective uptake of the chimera into cancer cells was demonstrated using flow cytometry. Furthermore, confocal laser scanning microscopy showed the successful delivery of the doxorubicin loaded in chimeras to the nuclei of targeted cells. Moreover, the doxorubicin-loaded chimeras effectively inhibited the growth of cancer cell lines and reduced the cytotoxic effect on the normal cells. Overall, the results of this study show that the AS1411–ATP aptamer chimera could be used as an innovative approach for the selective delivery of doxorubicin to cancer cells, which may improve the therapeutic potency and decrease the off-target cytotoxicity of doxorubicin.

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Xie, Ya-chen, Leif A. Eriksson, and Ru-bo Zhang. "Molecular dynamics study of the recognition of ATP by nucleic acid aptamers." Nucleic Acids Research 48, no. 12 (May 22, 2020): 6471–80. http://dx.doi.org/10.1093/nar/gkaa428.

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Abstract Despite their great success in recognizing small molecules in vitro, nucleic acid aptamers are rarely used in clinical settings. This is partially due to the lack of structure-based mechanistic information. In this work, atomistic molecular dynamics simulations are used to study the static and dynamic supramolecular structures relevant to the process of the wild-type (wt) nucleic acid aptamer recognition and binding of ATP. The effects brought about by mutation of key residues in the recognition site are also explored. The simulations reveal that the aptamer displays a high degree of rigidity and is structurally very little affected by the binding of ATP. Interaction energy decomposition shows that dispersion forces from π-stacking between ATP and the G6 and A23 nucleobases in the aptamer binding site plays a more important role in stabilizing the supramolecular complex, compared to hydrogen-bond interaction between ATP and G22. Moreover, metadynamics simulations show that during the association process, water molecules act as essential bridges connecting ATP with G22, which favors the dynamic stability of the complex. The calculations carried out on three mutated aptamer structures confirm the crucial role of the hydrogen bonds and π-stacking interactions for the binding affinity of the ATP nucleic acid aptamer.

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Zhang, Zijie, and Juewen Liu. "An engineered one-site aptamer with higher sensitivity for label-free detection of adenosine on graphene oxide." Canadian Journal of Chemistry 96, no. 11 (November 2018): 957–63. http://dx.doi.org/10.1139/cjc-2017-0601.

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The 27-nucleotide DNA aptamer for adenosine and ATP, originally selected by the Szostak lab in 1995, has been a very popular model system for biosensor development. This unique aptamer has two target binding sites, and we recently showed that it is possible to remove either site while the other one still retains binding. From an analytical perspective, tuning the number of binding sites has important implications in modulating sensitivity of the resulting biosensors. In this work, we report that the engineered one-site aptamer showed excellent signaling properties with a 2.6-fold stronger signal intensity and also a 4.2-fold increased detection limit compared with the wild-type two-site aptamer. The aptamer has a hairpin structure, and the length of the hairpin stem was systematically varied for the one-site aptamers. Isothermal titration calorimetry and a label-free fluorescence signaling method with graphene oxide and SYBR Green I were respectively used to evaluate binding and sensor performance. Although longer stemmed aptamers produced better adenosine binding affinity, the signaling was quite independent of the stem length as long as more than three base pairs were left. This was explained by the higher affinity of binding to GO by the longer aptamers, cancelling out the higher affinity for adenosine binding. This work further confirms the analytical applications of such one-site adenosine aptamers, which are potentially useful for improved ATP imaging and for developing new biosensors.

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Mulyani, Rahmaniar, Nida Yumna, Iman Permana Maksum, Toto Subroto, and Yeni Wahyuni Hartati. "Optimization of Aptamer-Based Electrochemical Biosensor for ATP Detection Using Screen-Printed Carbon Electrode/Gold Nanoparticles (SPCE/AuNP)." Indonesian Journal of Chemistry 22, no. 5 (September 28, 2022): 1256. http://dx.doi.org/10.22146/ijc.72820.

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Electrochemical biosensors are used to detect adenosine triphosphate (ATP) levels, which are involved in a variety of biological processes, such as regulating cellular metabolism and biochemical pathways. Therefore, this research aims to develop an aptamer-based electrochemical biosensor with Screen Printed Carbon Electrode/gold nanoparticles (SPCE/AuNP) and collect data as well as information related to ATP detection. The modification of SPCE with AuNP increased the analyte’s binding sensitivity and biocompatibility. The aptamer was selected based on its excellent bioreceptor characteristics. Furthermore, aptamer–SH (F1) and aptamer-NH2 (F2) were immobilized on the SPCE/AuNP surface, which had been characterized using SEM, EIS, and DPV. Also, the ATP-binding aptamers were electrochemically characterized using the K3[Fe(CN)6] redox system and Differential Pulse Voltammetry (DPV). According to the optimization results using the Box-Behnken experimental design, the ideal conditions obtained from the factors influencing the experiment were the F1 concentration and incubation time of 4 µM and 24 h, respectively, as well as F1/F2/ATP incubation time of 7.5 min. Meanwhile, for the range of 0.1 to 100 µM, the detection (LoD) and quantification (LoQ) limits were 7.43 and 24.78 µM, respectively. Therefore, this aptasensor method can be used to measure ATP levels in real samples.

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Wulf, Verena, and Itamar Willner. "Nucleoapzymes: catalyst-aptamer conjugates as enzyme-mimicking structures." Emerging Topics in Life Sciences 3, no. 5 (August 23, 2019): 493–99. http://dx.doi.org/10.1042/etls20190054.

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The conjugation of catalytic sites to sequence-specific, ligand-binding nucleic acid aptamers yields functional catalytic ensembles mimicking the catalytic/binding properties of native enzymes. These catalyst-aptamer conjugates termed ‘nucleoapzymes’ reveal structural diversity, and thus, vary in their catalytic activity, due to the different modes of conjugation of the catalytic units to the nucleic acid aptamer scaffold. The concept of nucleoapzymes is introduced with the assembly of a set of catalysts consisting of the hemin/G-quadruplex DNAzyme (hGQ) conjugated to the dopamine aptamer. The nucleoapzymes catalyze the oxidation of dopamine by H2O2 to yield aminochrome. The catalytic processes are controlled by the structures of the nucleoapzymes, and chiroselective oxidation of l-DOPA and d-DOPA by the nucleoapzymes is demonstrated. In addition, the conjugation of a Fe(III)-terpyridine complex to the dopamine aptamer and of a bis-Zn(II)-pyridyl-salen-type complex to the ATP-aptamer yields hybrid nucleoapzymes (conjugates where the catalytic site is not a biomolecule) that catalyze the oxidation of dopamine to aminochrome by H2O2 and the hydrolysis of ATP to ADP, respectively. Variable, structure-controlled catalytic activities of the different nucleoapzymes are demonstrated. Molecular dynamic simulations are applied to rationalize the structure-catalytic function relationships of the different nucleoapzymes. The challenges and perspectives of the research field are discussed.

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Heddinga, Marius H., and Jens Müller. "Incorporation of a metal-mediated base pair into an ATP aptamer – using silver(I) ions to modulate aptamer function." Beilstein Journal of Organic Chemistry 16 (November 25, 2020): 2870–79. http://dx.doi.org/10.3762/bjoc.16.236.

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For the first time, a metal-mediated base pair has been used to modulate the affinity of an aptamer towards its target. In particular, two artificial imidazole 2’-deoxyribonucleosides (Im) were incorporated into various positions of an established ATP-binding aptamer (ATP, adenosine triphosphate), resulting in the formation of three aptamer derivatives bearing Im:Im mispairs with a reduced ATP affinity. A fluorescence spectroscopy assay and a binding assay with immobilized ATP were used to evaluate the aptamer derivatives. Upon the addition of one Ag(I) ion per mispair, stabilizing Im–Ag(I)–Im base pairs were formed. As a result, the affinity of the aptamer derivative towards ATP is restored again. The silver(I)-mediated base-pair formation was particularly suitable to modulate the aptamer function when the Im:Im mispairs (and hence the resulting metal-mediated base pairs) were located close to the ATP-binding pocket of the aptamer. Being able to trigger the aptamer function opens new possibilities for applications of oligonucleotides.

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Nandimandalam, Manasa, Francesca Costantini, Nicola Lovecchio, Lorenzo Iannascoli, Augusto Nascetti, Giampiero de Cesare, Domenico Caputo, and Cesare Manetti. "Split Aptamers Immobilized on Polymer Brushes Integrated in a Lab-on-Chip System Based on an Array of Amorphous Silicon Photosensors: A Novel Sensor Assay." Materials 14, no. 23 (November 26, 2021): 7210. http://dx.doi.org/10.3390/ma14237210.

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Innovative materials for the integration of aptamers in Lab-on-Chip systems are important for the development of miniaturized portable devices in the field of health-care and diagnostics. Herein we highlight a general method to tailor an aptamer sequence in two subunits that are randomly immobilized into a layer of polymer brushes grown on the internal surface of microfluidic channels, optically aligned with an array of amorphous silicon photosensors for the detection of fluorescence. Our approach relies on the use of split aptamer sequences maintaining their binding affinity to the target molecule. After binding the target molecule, the fragments, separately immobilized to the brush layer, form an assembled structure that in presence of a “light switching” complex [Ru(phen)2(dppz)]2+, emit a fluorescent signal detected by the photosensors positioned underneath. The fluorescent intensity is proportional to the concentration of the target molecule. As proof of principle, we selected fragments derived from an aptamer sequence with binding affinity towards ATP. Using this assay, a limit of detection down to 0.9 µM ATP has been achieved. The sensitivity is compared with an assay where the original aptamer sequence is used. The possibility to re-use both the aptamer assays for several times is demonstrated.

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Biniuri, Yonatan, Bauke Albada, and Itamar Willner. "Probing ATP/ATP-Aptamer or ATP-Aptamer Mutant Complexes by Microscale Thermophoresis and Molecular Dynamics Simulations: Discovery of an ATP-Aptamer Sequence of Superior Binding Properties." Journal of Physical Chemistry B 122, no. 39 (September 6, 2018): 9102–9. http://dx.doi.org/10.1021/acs.jpcb.8b06802.

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Xu, Peipei, and Guangfu Liao. "A Novel Fluorescent Biosensor for Adenosine Triphosphate Detection Based on a Metal–Organic Framework Coating Polydopamine Layer." Materials 11, no. 9 (September 5, 2018): 1616. http://dx.doi.org/10.3390/ma11091616.

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In this work, a novel and sensitive fluorescent biosensor based on polydopamine coated Zr-based metal–organic framework (PDA/UiO-66) is presented for adenosine triphosphate (ATP) detection. This PDA/UiO-66 nanoparticle which holds a great potential to be excellent fluorescence quencher can protect the 6-carboxyfluorescein (FAM)-labeled probe from cleaved by DNase I dispersed in solution and the flurescence of labeled FAM is quenched. When ATP molecules exist, aptamers on the PDA/UiO-66 nanoparticles can hybridize with ATP molecule to form complex structure that will be desorbed from the PDA/UiO-66 and digested by DNase I. After that, the released ATP molecule can react with another aptamer on the PDA/UiO-66 complexes, then restarts a new cycle. Herein, the excellent strong fluorescence quenching ability and uploading more amount of aptamer probes of PDA/UiO-66 composites make them efficient biosensors, leading to a high sensitivity with detection limit of 35 nM. Compared with ATP detection directly by UiO-66-based method, the LOD is about 5.7 times higher with PDA/UiO-66 nanoparticle. Moreover, the enhanced biocompatibility and bioactivity with PDA layer of the composites render a proposed strategy for clinical diagnosis field of detecting small biological molecules in vivo in the future.

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Dissertations / Theses on the topic "ATP aptamer"

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Santos, Cancel Mirelis. "Development of Electrochemical Sensors with Enhanced Specificity and Temporal Resolution for Biological Applications." University of Cincinnati / OhioLINK, 2019. http://rave.ohiolink.edu/etdc/view?acc_num=ucin1553613866098747.

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Reinemann, Christine. "Aptamere als neue molekulare Erkennungselemente in Biosensoren /." Leipzig : Helmholtz-Zentrum für Umweltforschung, 2007. http://bvbr.bib-bvb.de:8991/F?func=service&doc_library=BVB01&doc_number=016271117&line_number=0001&func_code=DB_RECORDS&service_type=MEDIA.

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Haarberg, Hans Eirik. "Theophylline IMAGEtags (intracellular multi aptamer genetic tags) the development and evaluation of an RNA reporter system based on the theophylline aptamer /." [Ames, Iowa : Iowa State University], 2009. http://gateway.proquest.com/openurl?url_ver=Z39.88-2004&rft_val_fmt=info:ofi/fmt:kev:mtx:dissertation&res_dat=xri:pqdiss&rft_dat=xri:pqdiss:1464205.

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Dalton, Colette. "Aptamers as biosensors." Thesis, University of Strathclyde, 2010. http://oleg.lib.strath.ac.uk:80/R/?func=dbin-jump-full&object_id=15484.

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Park, Euisun. "Probing dynamics of ERBB3 receptor signaling with an RNA aptamer." Diss., Restricted to subscribing institutions, 2008. http://proquest.umi.com/pqdweb?did=1790313701&sid=2&Fmt=2&clientId=1564&RQT=309&VName=PQD.

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Held, Daniel M. "RNA aptamer inhibitors of HIV reverse transcriptase molecular evolution and determinants of target specificity /." [Bloomington, Ind.] : Indiana University, 2006. http://gateway.proquest.com/openurl?url_ver=Z39.88-2004&rft_val_fmt=info:ofi/fmt:kev:mtx:dissertation&res_dat=xri:pqdiss&rft_dat=xri:pqdiss:3219914.

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Thesis (Ph. D.)--Indiana University, Dept. of Biology, 2006.
"Title from dissertation home page (viewed June 28, 2007)." Source: Dissertation Abstracts International, Volume: 67-06, Section: B, page: 2963. Adviser: Donald H. Burke.

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Kissel, Jay D. "Target specificity and structural characterization of single-stranded DNA aptamer RT1t49, a broad inhibitor of HIV-1 reverse transcriptases." [Bloomington, Ind.] : Indiana University, 2007. http://gateway.proquest.com/openurl?url_ver=Z39.88-2004&rft_val_fmt=info:ofi/fmt:kev:mtx:dissertation&res_dat=xri:pqdiss&rft_dat=xri:pqdiss:3274917.

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Thesis (Ph.D.)--Indiana University, Dept. of Biology, 2007.
Source: Dissertation Abstracts International, Volume: 68-07, Section: B, page: 4320. Adviser: Donald H. Burke-Aguero. Title from dissertation home page (viewed Apr. 22, 2008).

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Pappas, Allison L. "Selection and characterization of RNA aptamers that detect a quaternary structure for ribosomal protein S7." [Ames, Iowa : Iowa State University], 2009. http://gateway.proquest.com/openurl?url_ver=Z39.88-2004&rft_val_fmt=info:ofi/fmt:kev:mtx:dissertation&res_dat=xri:pqdiss&rft_dat=xri:pqdiss:3369933.

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Cash, Daniel Dennis. "Solution NMR studies of the Class II GTP-binding RNA aptamer complex to determine the role of conserved residues in complex formation." Connect to online resource, 2008. http://gateway.proquest.com/openurl?url_ver=Z39.88-2004&rft_val_fmt=info:ofi/fmt:kev:mtx:dissertation&res_dat=xri:pqdiss&rft_dat=xri:pqdiss:1456668.

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Rato, Carla Cristina Pereira Salgueiro Catarino. "The life marker chip : potential use of aptamers against small molecules and consideration of instrument planetary protection." Thesis, Cranfield University, 2013. http://dspace.lib.cranfield.ac.uk/handle/1826/8272.

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The Life Marker Chip (LMC) instrument was developed with the aim to detect evidence of life on Mars. The detection was based on an inhibition immunoassay. In this work aptamers were evaluated as potential alternative to antibodies for the LMC. Aptamers were synthetic oligonucleotides able to bind specifically with high affinity to a wide range of target molecules, and have been also integrated as bioreceptors in several detection instruments. The generation of new aptamers against two small molecules using the FluMag-SELEX method was tested and was verified the adaptability of pre-existing aptamers against small targets to the LMC assay type. Based on the fact that the LMC was going to be integrated into the space programme ExoMars, it was also implemented into a small scale experiment the Planetary Protection and Contamination Control requirements found on a life-search mission. In addition to that aptamers compatibility with a sterilisation procedure used in life-search missions was also tested. Furthermore because of the nature of the small molecules studied, multiple analytical chemistry techniques were assessed to verify covalent chemistry surface immobilisation. Within the project timeline it was not possible to achieve a full aptamer generation process but it was possible to understand the methodology behind the procedure and give input for future work. It was found that the direct implementation of existing aptamers against small molecules into the LMC assay was not successful. It was also seen that in the case of aptamer integration onto the LMC some assay changes would probably have to be made. This information was very useful to understand if aptamers could be an alternative to antibodies and be implemented directly into the LMC. It was found that aptamers survived the preliminary sterilisation method applied, which might open the possibility of making aptamers convenient space bioreceptors, reducing time and costs of instrument Planetary Protection implementation. In conclusion aptamers were not straightforward alternatives to antibodies for the LMC because aptamers interacted differently with their targets in comparison to antibodies, particularly with small molecules. Also the biochemical simplicity of the small molecule targets introduced difficulties in aptamers generation that more complex targets would have not. Although aptamers shown incompatibility with the LMC assay format against small targets, they presented resilience to a sterilisation procedure implemented on space missions which could lead to the development of more robust bioreceptors for space missions. This information was helpful in understanding which assay formats were better for detection of small molecules using aptamers and that might contribute for future assay choices applied in detection instruments. It was also possible to make recommendations for the LMC regarding design and validation methods used in life-search missions based on the lessons learn from the developed of a small scale experiment. The developed work was presented at conferences and mentioned in an article journal, and in that way contributed to the knowledge of the space community in general.

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Book chapters on the topic "ATP aptamer"

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Goyal, Meenu, Citu, Nidhi Singh, Varsha Singla, and Ankit Singla. "Aptamer: Apt System for Target-Specific Drug Delivery." In Aptamers, 59–71. Singapore: Springer Singapore, 2019. http://dx.doi.org/10.1007/978-981-13-8836-1_4.

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de Franciscis, Vittorio, and Laura Cerchia. "Aptamer-Based Technologies as New Tools for Proteomics in Diagnosis and Therapy." In Frontiers in Drug Design &amp Discovery (Volume 2), 103–19. BENTHAM SCIENCE PUBLISHERS, 2012. http://dx.doi.org/10.2174/978160805200410602010103.

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Conference papers on the topic "ATP aptamer"

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Phan, Dinh-Tuan, Chia-Hung Chen, Lin Jin, and Shofarul Wustoni. "REAL-TIME ATP MONITORING IN HUMAN SERUM BY AN NANOFLUIDIC DEVICE INTEGRATED WITH AN APTAMER SENSOR." In The 7th International Multidisciplinary Conference on Optofluidics 2017. Basel, Switzerland: MDPI, 2017. http://dx.doi.org/10.3390/optofluidics2017-04488.

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Nguyen, ThaiHuu, and Qiao Lin. "Thermally Responsive Aptamer Surfaces for Microfluidic Sample Preparation." In 2008 Second International Conference on Integration and Commercialization of Micro and Nanosystems. ASMEDC, 2008. http://dx.doi.org/10.1115/micronano2008-70264.

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For many bioanalytical systems, the quality of the sample under scrutiny greatly affects the success of its analysis by the analytical instrument. Thus, sample preparatory techniques such as solid-phase extraction (SPE), purification and concentration are used to improve the quality of the sample before introduction into the equipment. This work overviews our effort in developing microdevices which exploit thermally responsive aptamers for biomolecular sample extraction, purification and concentration. We demonstrate the feasibility of this approach with a model system which consists of an adenosine monophosphate (AMP) analyte and adenosine triphosphate derived aptamer. Through systematic experimentation, we demonstrate the extraction and enrichment of AMP at physiologically relevant concentrations, release of AMP and regeneration of the aptamer through thermal stimulation, and detection of AMP by either fluorescence or mass spectrometry. In addition, completely aqueous operation of the device eliminates the use of potentially harsh reagents.

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Chen, Kok Hao, and Jong Hyun Choi. "Nanoparticle-Aptamer: An Effective Growth Inhibitor for Human Cancer Cells." In ASME 2009 International Mechanical Engineering Congress and Exposition. ASMEDC, 2009. http://dx.doi.org/10.1115/imece2009-11966.

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Semiconductor nanocrystals have unique optical properties due to quantum confinement effects, and a variety of promising approaches have been devised to interface the nanomaterials with biomolecules for bioimaging and therapeutic applications. Such bio-interface can be facilitated via a DNA template for nanoparticles as oligonucleotides can mediate the aqueous-phase nucleation and capping of semiconductor nanocrystals.[1,2] Here, we report a novel scheme of synthesizing fluorescent nanocrystal quantum dots (NQDs) using DNA aptamers and the use of this biotic/abiotic nanoparticle system for growth inhibition of MCF-7 human breast cancer cells for the first time. Particularly, we used two DNA sequences for this purpose, which have been developed as anti-cancer agents: 5-GGT GGT GGT GGT TGT GGT GGT GGT GG-3 (also called, AGRO) and 5-(GT)15-3.[3–5] This study may ultimately form the basis of unique nanoparticle-based therapeutics with the additional ability to optically report molecular recognition. Figure 1a shows the photoluminescence (PL) spectra of GT- and AGRO-passivated PbS QD that fluoresce in the near IR, centered at approximately 980 nm. A typical synthesis procedure involves rapid addition of sodium sulfide in the mixture solution of DNA and Pb acetate at a molar ratio of 2:4:1. The resulting nanocrystals are washed to remove unreacted DNA and ions by adding mixture solution of NaCl and isopropanol, followed by centrifugation. The precipitated nanocrystals are collected and re-suspended in aqueous solution by mild sonication. Optical absorption measurements reveal that approximately 90 and 77% of GT and AGRO DNA is removed after the washing process. The particle size distribution in Figure 1b suggests that the GT sequence-capped PbS particles are primarily in 3–5 nm diameter range. These nanocrystals can be easily incorporated with mammalian cells and remain highly fluorescent in sub-cellular environments. Figure 1c serially presents an optical image of a MCF-7 cell and a PL image of the AGRO-capped QD incorporated with the cell. Figure 1. (a) Normalized fluorescence spectra of PbS QD synthesized with GT and AGRO sequences, which were previously developed as anti-cancer agents. The DNA-capped QD fluoresce in the near IR centered at ∼980 nm. (b) TEM image of GT-templated nanocrystals ranging 3–5 nm in diameter. (c) Optical image of an MCF-7 human breast cancer cell after a 12-hour exposure to aptamer-capped QD. (d) PL image of AGRO-QD incorporated with the cell, indicating that these nanocrystals remain highly fluorescent in sub-cellular environments. One immediate concern for interfacing inorganic nanocrystals with cells and tissue for labeling or therapeutics is their cytotoxicity. The nanoparticle cytotoxicity is primarily determined by material composition and surface chemistry, and QD are potentially toxic by generating reactive oxygen species or by leaching heavy metal ions when decomposed.[6] We examined the toxicity of aptamer-passivated nanocrystals with NIH-3T3 mouse fibroblast cells. The cells were exposed to PbS nanocrystals for 2 days before a standard MTT assay as shown in Figure 2, where there is no apparent cytotoxicity at these doses. In contrast, Pb acetate exerts statistically significant toxicity. This observation suggests a stable surface passivation by the DNA aptamers and the absence of appreciable Pb2+ leaching. Figure 2. Viability of 3T3 mouse fibroblast cells after a 2-day exposure to DNA aptamer-capped nanocrystals. There is no apparent dose-dependent toxicity, whereas a statistically significant reduction in cell viability is observed with Pb ions. Note that Pb acetate at 133 μM is equivalent to the Pb2+ amount that was used for PbS nanocrystal synthesis at maximum concentration. Error bars are standard deviations of independent experiments. *Statistically different from control (p<0.005). Finally, we examined if these cyto-compatible nanoparticle-aptamers remained therapeutically active for cancer cell growth inhibition. The MTT assay results in Figure 3a show significantly decreased growth of breast cancer cells incorporated with AGRO, GT, and the corresponding templated nanocrystals, as anticipated. In contrast, 5-(GC)15-3 and the QDs synthesized with the same sequence, which were used as negative controls along with zero-dose control cells, did not alter cell viability significantly. Here, we define the growth inhibition efficacy as (100 − cell viability) per DNA of a sample, because the DNA concentration is significantly decreased during the particle washing. The nanoparticle-aptamers demonstrate 3–4 times greater therapeutic activities compared to the corresponding aptamer drugs (Figure 3b). We speculate that when a nanoparticle-aptamer is internalized by the cancer cells, it forms an intracellular complex with nucleolin and nuclear factor-κB (NF-κB) essential modulator, thereby inhibiting NF-κB activation that would cause transcription of proliferation and anti-apoptotic genes.[7] The nanoparticle-aptamers may more effectively block the pathways for creating anti-apoptotic genes or facilitate the cellular delivery of aptamers via nanoparticle uptake. Our additional investigation indicates that the same DNA capping chemistry can be utilized to produce aptamer-mediated Fe3O4 nanocrystals, which may be potentially useful in MRI and therapeutics, considering their magnetic properties and biocompatibility. In summary, the nanoparticle-based therapeutic schemes developed here should be valuable in developing a multifunctional drug delivery and imaging agent for biological systems. Figure 3. Anti-proliferation of MCF-7 human breast cancer cells with aptamer-passivated nanocrystals. (a) Viability of MCF-7 cells exposed to AGRO and GT sequences, and AGRO-/GT-capped QD for 7 days. The DNA concentration was 10 uM, while the particles were incubated with cells at 75 nM. (b) Growth inhibition efficacy is defined as (100 − cell viability) per DNA to correct the DNA concentration after particle washing.

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Huang, Chao-Jyun, Hsin-I. Lin, Shu-Chu Shiesh, and Gwo-Bin Lee. "Rapid measurement of AFP using AFP-specific aptamer on a microfluidic chip." In 2012 IEEE 25th International Conference on Micro Electro Mechanical Systems (MEMS). IEEE, 2012. http://dx.doi.org/10.1109/memsys.2012.6170325.

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Klett-Mingo, José Ignacio, Julio Cambronero-Plaza, Celia Pinto-Díez, Miriam Barragán-Usero, María V. T. Lobo, Víctor M. González, and M. Elena Martín. "Selection and characterization of aptamers to inhibit <em>in vitro</em> activity of histone acetyl transferase 1 (HAT1)." In 7th International Electronic Conference on Medicinal Chemistry. Basel, Switzerland: MDPI, 2021. http://dx.doi.org/10.3390/ecmc2021-11473.

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Devaraj, Santhana Gowri Thangavelu, Lokesh Ganesh Lakshmana Rao, Youli Zu, Jenny C. Chang, and Swaminathan P. Iyer. "Abstract 3243: Development of specific DNA aptamers against programmed cell death-1 (Anti-PD1-Apt) for diagnosis and treatment of cancers." In Proceedings: AACR Annual Meeting 2017; April 1-5, 2017; Washington, DC. American Association for Cancer Research, 2017. http://dx.doi.org/10.1158/1538-7445.am2017-3243.

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