Journal articles on the topic 'Carbon Dots - Bio-medicine'

Although neurotransmitters are present in human serum at the nM level, any dysfunction of the catecholamines concentration may lead to numerous serious health problems. Due to this fact, rapid and sensitive catecholamines detection is extremely important in modern medicine. However, there is no device that would measure the concentration of these compounds in body fluids. The main goal of the present study is to design a simple as possible, cost-effective new biosensor-based system for the detection of neurotransmitters, using nontoxic reagents. The miniature Au-E biosensor was designed and constructed through the immobilization of tyrosinase on an electroactive layer of cysteamine and carbon nanoparticles covering the gold electrode. This sensing arrangement utilized the catalytic oxidation of norepinephrine (NE) to NE quinone, measured with voltammetric techniques: cyclic voltammetry and differential pulse voltammetry. The prepared bio-system exhibited good parameters: a broad linear range (1–200 μM), limit of detection equal to 196 nM, limit of quantification equal to 312 nM, and high selectivity and sensitivity. It is noteworthy that described method was successfully applied for NE determination in real samples.

The new era of nanotechnology has produced advanced nanomaterials applicable to various fields of medicine, including diagnostic bio-imaging, chemotherapy, targeted drug delivery, and biosensors. Various materials are formed into nanoparticles, such as gold nanomaterials, carbon quantum dots, and liposomes. The nanomaterials have been functionalized and widely used because they are biocompatible and easy to design and prepare. This review mainly focuses on nanomaterials responsive to the external stimuli used in drug-delivery systems. To overcome the drawbacks of conventional therapeutics to a tumor, the dual- and multi-responsive behaviors of nanoparticles have been harnessed to improve efficiency from a drug delivery point of view. Issues and future research related to these nanomaterial-based stimuli sensitivities and the scope of stimuli-responsive systems for nanomedicine applications are discussed.

AbstractGraphene quantum dots (GQDs) - zero-dimensional materials - are sheets of a few nanometers in lateral dimension and exhibit quantum confinement and edge site effects where sp2-bonded carbon nanocore surrounded with edged plane functional moieties is promising as advanced electroactive sensing platforms. In this work, GQDs are synthesized by solvothermal and hydrothermal techniques, with optimal size of 5 nm. Their potential in fundamental (direct electron transfer) and applied (enzymatic glucose biosensor) electrochemistry are demonstrated. Glucose oxidase (GOx) immobilized on glassy carbon (GC) electrodes modified with GQDs are investigated by means of cyclic voltammetry, differential pulse voltammetry, and amperometry. Well-defined quasi-reversible redox peaks observed under various electrochemical parameters helped to determine diffusion coefficient (D) and first-order electron transfer rate (kET). The cyclic voltammetry curves showed homogeneous ion transport for GQD with D ranging between 8.45 × 10−9 m2 s−1 and 3 × 10−8 m2 s−1 following GO < rGO < GQD < GQD (with FcMeOH as redox probe) < GOx/rGO < GOx/GO < HRP/GQDs < GOx/GQDs. The developed GOx-GQDs biosensor responds efficiently and linearly to the presence of glucose over concentrations ranging 10 μM and 3 mM with limit of detection 1.35 μM and sensitivity 0.00769 μA μM−1·cm−2 as compared with rGO (0.025 μA μM−1 cm−2, 4.16 μM) and GO (0.064 μA μM−1 cm−2, 4.82 μM) nanosheets. The high performance and stability of GQDs is attributed to sufficiently large surface-to-volume ratio, excellent biocompatibility, abundant hydrophilic edge site density, and partially hydrophobic planar sites that favors GOx adsorption on the electrode surface and versatile architectures to ensure rapid charge transfer and electron/ion conduction (<10 ms). We also carried out similar studies with other enzymatic protein biomolecules on electrode surfaces prepared from GQD precursors for electrochemical comparison, thus opening up potential sensing applications in medicine as well as bio-nanotechnology.

The transformation of biowaste into products with added value offers a lucrative role in nation-building. The current work describes the synthesis of highly water-soluble, luminous carbon quantum dots (CQDs) in the size range of 5–10 nm from discarded rice straw. The small spherical CQDs that were formed had outstanding optical and luminescent qualities as well as good photostabilities. By performing quantitative multi-assay tests that included antioxidant activities, in vitro stability and colloidal assay investigations as a function of different CQD concentrations, the biocompatibility of CQDs was evaluated. To clearly visualize the type of surface defects and emissive states in produced CQDs, excitation-dependent fluorescence emission experiments have also been carried out. The “waste-to-wealth” strategy that has been devised is a successful step toward the quick and accurate detection of Cu2+ ion in aqueous conditions. The fluorescence-quenching behavior has specified the concentration dependency of the developed sensor in the range of 50 μM to 10 nM, with detection limit value of 0.31 nM. The main advantage of the current research is that it offers a more environmentally friendly, economically viable and scaled-up synthesis of toxicologically screened CQDs for the quick fluorescence detection of Cu2+ ions and opens up new possibilities in wastewater management.

Background: Cancer is a great threat of human health worldwide due to the uncontrollable spread of malignant cells throughout the body. Accurate diagnosis and targeted therapy approaches are critical factors for cancer treatment. Combination of therapeutic and diagnostic agents in a single nanocarrier enables to simultaneously monitor the cancer progression and tune disease therapy with minimum side effect. Objective: Carbon dots are a novel class of small fluorescence carbon nanostructures with size less than 10 nm at least in one dimension, which exhibit excellent optical properties, larger surface area to volume ratio and low toxicity. The unique properties of carbon dots make it as an ideal carrier for incorporation of cancer targeting moieties, bio-imaging agents and antineoplastic agents in one delivery system. Methods: An literature search was conducted using Web of Science to find out articles related to carbon dots and tumor theranostics. Results: Numerous applications of carbon dots in cancer theranostics have been reported during the past 10 years. This review introduces a brief history and basic fluorescent properties of carbon dots, and then discusses synthesis strategies and applications of carbon dots in biological imaging, targeted anti-cancer drug delivery, photodynamic therapy, photothermal therapy as well as gene delivery for cancer theranostics. Future directions of carbon dots in cancer theranostics are also highlighted.

Among the carbon allotrope, graphene quantum-dots (GQDs) have been attracted tremendous attention due to unique physicochemical properties, such as high surface area, sustainable photoluminecent properties, excellent electrochemical properties, good biocompatibility, unique drag delivery capacity, etc. The major source of GQDs are carbonaceous materials and hydrocarbon based bio-resources. Interestingly, this short review focuses on synthesis methods of GQDs from biomolecules. Basically, biomolecules consisted with multiple bonded carbon with oxygen, hydrogen, and oxyhydrogen moieties. By chemical reactions it will converted into GQDs by removal of oxyhydrogen moieties by different routes of preparation and applicable for many advance applications, mainly in optoelectronics applications and biomedical applications. Moreover, the GQDs are capable for many other applications, such as energy storage and chemical sensing. However, we have focus on the bio-derived GQDs by different methods and reported applications.

This review paper aimed to reveal several methods that have been used in the preparation of carbon dots (C-Dots). C-Dots were principal to be studied because they have luminous properties that can be used in photocatalyst processes, heavy metal sensors, glowing paints, and nanoparticles for biomedical applications such as bio-tagging. The methods that have been developed were also varied using the two principal approaches, i.e., top-down and bottom-up. Here, we tried to reveal the arc-discharge, laser ablation techniques for top-down approaches, while simple heating methods (simple hydrothermal methods), and microwave for bottom-up. Furthermore, the microwave method was excellent because of the vibration process which caused the carbon chains to undergo rearrangement so that the result was not much reducing the water content in the solution.

Bio foam is an alternative packaging to replace Styrofoam made from natural raw materials such as starch, with the addition of fiber to strengthen its structure. Bio foam is a product that is not only biodegradable but also renewable. The raw material for packaging bio-foam in this service activity is peanut shell waste, a combination of rice husk waste. Peanut shell and rice husk waste are used as ingredients in manufacturing bio-foam because these materials contain high carbon elements, producing K-dots compounds that can benefit human life if processed. This service activity was carried out in Pationgi Village, Patimpeng District, Bone Regency, with three main stages: counseling, training, and mentoring. This community service activity aims to provide knowledge and skills to Karang Taruna Group partners in processing peanut shell waste and rice husks into environmentally friendly alternative packaging (bio-foam) as a substitute for Styrofoam. As a result of this community service, the Pationgi Village Youth Group partners now have more knowledge and skills about how to process nutshell and rice husk waste to make bio-foam packaging that is better for the environment and can be used instead of Styrofoam.

Multifunctional photoluminescent (PL) nanomaterials have attracted considerable interest in terms of their potential applications in the field of clinical medicine. Carbon dots (CDs), as emerging optical nanomaterials, are promising in various fields including biological imaging, drug transport and nerve tracing. However, little research has investigated on bone tissue engineering as of now. In this study, a new kind of bifunctional Zn[Formula: see text]-doped carbon dots (Zn-CDs) has been synthesized by a one-step hydrothermal method, Zn-CDs show effective fluorescent imaging and induce osteoblastic differentiation abilities in vitro. Moreover, compared with the raw material, Zn-CDs exhibited more effective osteoblastic differentiation promoting capability. Overall, the biocompatible nanomaterial Zn-CDs show potential to be used as a promising novel nanodrug for bone loss therapy and also a monitor of cell variation by fluorescence imaging.

Aggregation-induced emission of organic dyes is a phenomenon in which organic luminophores show higher photoluminescence (PL) efficiency in the aggregated state than in a free molecule, due to the freezing rotational degrees of freedom of the luminophore which otherwise quench the PL emission. In many cases, however, coupling of molecules leads to quenching of their emission due to the concentration quenching or self-quenching (exciton-exciton annihilation) effect. Therefore, in order to realize an enhanced PL emission as a result of molecule-molecule interaction a fine balance should be achieved between freezing rotational degrees of freedom of the molecule and escaping self-quenching effect. This could be realized via immobilization of the luminophore onto the inert surface. Here, we demonstrate an enhancement of specific S2 emission of the near-infrared (NIR) dyes of tricarbocyanine family due to their immobilization on the surface of carbon nanoparticles that induce freezing a specific planar conformation of the molecule imposed by the carbon plane of the particle it interact with. Carbon quantum dots serve as inert particles that render an opposite influence on the S1 and S2 emission of the tricarbocyanine dyes. We demonstrate a dual emission of the NIR tricarbocyanine dyes with a bright green S2 fluorescence, which is relatively weak for the free dye molecule but whose quantum yield increases by 2-4 times, together with a strong enhancement of the spontaneous rate of S2 fluorescence, whereas the quantum yield of S1 emission in the NIR decreases by 2-7 times, respectively, as a result of immobilization of the dye molecule via the interaction with carbon quantum dots. The above changes are dependent on the terminal and meso-groups of the dye and the solvent used. The dye immobilization due to interaction with carbon quantum dots causes freezing rotational degrees of freedom of the molecule as indicated by suppression of the dye hot band absorption-assisted anti-Stokes S1 emission. The observed “lighting up” of an anti-Kasha emission, i.e., the emission from Sn (n>1) excited levels, of the NIR chromophores which possess intensive S1 absorption and emission in the NIR region, but which are spectrally silent in the visible, can lead to their potential applications in the fields such as energy conversion, bio-imaging and bio-sensing, sensitization of solar cells, etc.

AbstractAs a new class of fluorescent carbon materials, graphene quantum dots (GQDs) have attracted tremendous attention due to their outstanding properties and potential applications in biological, optoelectronic, and energy-related fields. Herein, top-down and bottom-up strategies for the fabrication of GQDs, mainly containing oxidative cleavage, the hydrothermal or solvothermal method, the ultrasonic-assisted or microwave-assisted process, electrochemical oxidation, controllable synthesis, and carbonization from small molecules or polymers, are discussed. Different methods are presented in order to study their characteristics and their influence on the final properties of the GQDs. The respective advantages and disadvantages of the methods are introduced. With regard to some important or novel methods, the mechanisms are proposed for reference. Moreover, recent exciting progresses on the applications of GQD, such as sensors, bio-imaging, drug carriers, and solar cells are highlighted. Finally, a brief outlook is given, pointing out the issues still to be settled for further development. We believe that new preparation methods and properties of GQDs will be found, and GQDs will play more important roles in novel devices and various applications.

Doping with heteroatoms allows the retention of the general characteristics of carbon dots while allowing their physicochemical and photochemical properties to be effectively modulated. In this work, we report the preparation of ultrastable P and N co-doped carbon dots (PNCDs) that can be used for the highly selective detection of Fe3+ and the tracking of lysosomes in living cells. Fluorescent PNCDs were facilely prepared via a hydrothermal treatment of ethylenediamine and phytic acid, and they exhibited a high quantum yield of 22.0%. The strong coordination interaction between the phosphorus groups of PNCDs and Fe3+ rendered them efficient probes for use in selective Fe3+ detection, with a detection limit of 0.39 μM, and we demonstrated their practicability by accurately detecting the Fe3+ contents in bio-samples. At the same time, PNCDs exhibited high lysosomal location specificity in different cell lines due to surface lipophilic amino groups, and real-time tracking of the lysosome morphology in HeLa cells was achieved. The present work suggests that the fabrication of heteroatom-doped CDs might be an effective strategy to provide promising tools for cytology, such as organelle tracking.

Ionic liquids are gaining high attention due to their extremely unique physiochemical properties and are being utilized in numerous applications in the field of electrochemistry and bio-nanotechnology. The excellent ionic conductivity and the wide electrochemical window open a new avenue in the construction of electrochemical devices. On the other hand, carbon nanomaterials, such as graphene (GR), graphene oxide (GO), carbon dots (CDs), and carbon nanotubes (CNTs), are highly utilized in electrochemical applications. Since they have a large surface area, high conductivity, stability, and functionality, they are promising in biosensor applications. Nevertheless, the combination of ionic liquids (ILs) and carbon nanomaterials (CNMs) results in the functional ILs-CNMs hybrid nanocomposites with considerably improved surface chemistry and electrochemical properties. Moreover, the high functionality and biocompatibility of ILs favor the high loading of biomolecules on the electrode surface. They extremely enhance the sensitivity of the biosensor that reaches the ability of ultra-low detection limit. This review aims to provide the studies of the synthesis, properties, and bonding of functional ILs-CNMs. Further, their electrochemical sensors and biosensor applications for the detection of numerous analytes are also discussed.

Metal doped carbon dots (CDs) have been extensively studied due to their tunable and strong fluorescence emission properties, which make them applicable for sensing, organic catalysis, optronics, and biomedicine. This has attracted the attention of many researchers to develop transition metal-doped CDs. In this article, we have discussed various syntheses and applications of copper doped CDs (Cu@CDs). We have mainly focused on copper because of its various advantages, such as low cost, low toxicity, natural abundance, and ability to show 0-III oxidation states which give them access to show both one and two-electron processes. Majorly, we have briefed on the recent progress in the synthesis, functionalization, and applications of Cu@CDs using chemical reduction, hydrothermal, solvothermal, thermolysis, and green synthesis from various chemical and natural carbon pre-cursors. Afterward, we have discussed their applications in analyte detection and sensing, organic catalysis, anti-microbial activity, bio-imaging, and cancer therapy.

The knowledge of the ways in which post-synthesis treatments may influence the properties of carbon quantum dots (CDs) is of paramount importance for their employment in biosensors. It enables the definition of the mechanism of sensing, which is essential for the application of the suited design strategy of the device. In the present work, we studied the ways in which post-synthesis thermal treatments influence the optical and electrochemical properties of Nitrogen-doped CDs (N-CDs). Blue-emitting, N-CDs for application in biosensors were synthesized through the hydrothermal route, starting from citric acid and urea as bio-synthesizable and low-cost precursors. The CDs samples were thermally post-treated and then characterized through a combination of spectroscopic, structural, and electrochemical techniques. We observed that the post-synthesis thermal treatments show an oxidative effect on CDs graphitic N-atoms. They cause their partially oxidation with the formation of mixed valence state systems, [CDs]0+, which could be further oxidized into the graphitic N-oxide forms. We also observed that thermal treatments cause the decomposition of the CDs external ammonium ions into ammonia and protons, which protonate their pyridinic N-atoms. Photoluminescence (PL) emission is quenched.

Ionic liquids are a potent class of organic compounds exhibiting unique physico-chemical properties and structural compositions that are different from the classical dipolar organic liquids. These molecules have found diverse applications in different chemical, biochemical, biophysical fields, and a number of industrial usages. The ionic liquids-based products and procedural applications are being developed for a number of newer industrial purposes, and academic uses in nanotechnology related procedures, processes, and products, especially in nanobiotechnology and nanomedicine. The current article overviews their uses in different fields, including applications, functions, and as parts of products and processes at primary and advanced levels. The application and product examples, and prospects in various fields of nanotechnology, domains of nanosystem syntheses, nano-scale product development, the process of membrane filtering, biofilm formation, and bio-separations are prominently discussed. The applications in carbon nanotubes; quantum dots; and drug, gene, and other payload delivery vehicle developments in the nanobiotechnology field are also covered. The broader scopes of applications of ionic liquids, future developmental possibilities in chemistry and different bio-aspects, promises in the newer genres of nanobiotechnology products, certain bioprocesses controls, and toxicity, together with emerging trends, challenges, and prospects are also elaborated.

The scope of application of carbon nanomaterials in biomedical, environmental and industrial fields is recently substantially increasing. Since in vitro toxicity testing is the first essential step for any commercial usage, it is crucial to have a reliable method to analyze the potentially harmful effects of carbon nanomaterials. Even though researchers already reported the interference of carbon nanomaterials with common toxicity assays, there is still, unfortunately, a large number of studies that neglect this fact. In this study, we investigated interference of four bio-promising carbon nanomaterials (graphene acid (GA), cyanographene (GCN), graphitic carbon nitride (g-C3N4) and carbon dots (QCDs)) in commonly used LIVE/DEAD assay. When a standard procedure was applied, materials caused various types of interference. While positively charged g-C3N4 and QCDs induced false results through the creation of free agglomerates and intrinsic fluorescence properties, negatively charged GA and GCN led to false signals due to the complex quenching effect of the fluorescent dye of a LIVE/DEAD kit. Thus, we developed a new approach using a specific gating strategy based on additional controls that successfully overcame all types of interference and lead to reliable results in LIVE/DEAD assay. We suggest that the newly developed procedure should be a mandatory tool for all in vitro flow cytometry assays of any class of carbon nanomaterials.

Non-small cell lung cancer (NSCLC) is an important sub-type of lung cancer associated with poor diagnosis and therapy. Innovative multi-functional systems are urgently needed to overcome the invasiveness of NSCLC. Carbon quantum dots (CQDs) derived from natural sources have received interest for their potential in medical bio-imaging due to their unique properties, which are characterized by their water solubility, biocompatibility, simple synthesis, and low cytotoxicity. In the current study, ethylene-diamine doped CQDs enhanced their cytotoxicity (98 ± 0.4%, 97 ± 0.38%, 95.8 ± 0.15%, 86 ± 0.15%, 12.5 ± 0.14%) compared to CQDs alone (99 ± 0.2%, 98 ± 1.7%, 96 ± 0.8%, 93 ± 0.38%, 91 ± 1.3%) at serial concentrations (0.1, 1, 10, 100, 1000 μg/mL). In order to increase their location in a specific tumor site, folic acid was used to raise their functional folate recognition. The apoptotic feature of A549 lung cells exposed to N-CQDs and FA-NCQDs was characterized by a light orange-red color under fluorescence microscopy. Additionally, much nuclear fragmentation and condensation were seen. Flow cytometry results showed that the percentage of cells in late apoptosis and necrosis increased significantly in treated cells to (19.7 ± 0.03%), (27.6 ± 0.06%) compared to untreated cells (4.6 ± 0.02%), (3.5 ± 0.02%), respectively. Additionally, cell cycle arrest showed a strong reduction in cell numbers in the S phase (14 ± 0.9%) compared to untreated cells (29 ± 0.5%). Caspase-3 levels were increased significantly in A549 exposed to N-CQDs (2.67 ± 0.2 ng/mL) and FA-NCQDs (3.43 ± 0.05 ng/mL) compared to untreated cells (0.34 ± 0.04 ng/mL). The functionalization of CQDs derived from natural sources has proven their potential application to fight off non-small lung cancer.

Biosensors are modern engineering tools that can be widely used for various technological applications. In the recent past, biosensors have been widely used in a broad application spectrum including industrial process control, the military, environmental monitoring, health care, microbiology, and food quality control. Biosensors are also used specifically for monitoring environmental pollution, detecting toxic elements’ presence, the presence of bio-hazardous viruses or bacteria in organic matter, and biomolecule detection in clinical diagnostics. Moreover, deep medical applications such as well-being monitoring, chronic disease treatment, and in vitro medical examination studies such as the screening of infectious diseases for early detection. The scope for expanding the use of biosensors is very high owing to their inherent advantages such as ease of use, scalability, and simple manufacturing process. Biosensor technology is more prevalent as a large-scale, low cost, and enhanced technology in the modern medical field. Integration of nanotechnology with biosensors has shown the development path for the novel sensing mechanisms and biosensors as they enhance the performance and sensing ability of the currently used biosensors. Nanoscale dimensional integration promotes the formulation of biosensors with simple and rapid detection of molecules along with the detection of single biomolecules where they can also be evaluated and analyzed critically. Nanomaterials are used for the manufacturing of nano-biosensors and the nanomaterials commonly used include nanoparticles, nanowires, carbon nanotubes (CNTs), nanorods, and quantum dots (QDs). Nanomaterials possess various advantages such as color tunability, high detection sensitivity, a large surface area, high carrier capacity, high stability, and high thermal and electrical conductivity. The current review focuses on nanotechnology-enabled biosensors, their fundamentals, and architectural design. The review also expands the view on the materials used for fabricating biosensors and the probable applications of nanotechnology-enabled biosensors.

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In the twenty-first century, nanotechnology has become cutting-edge technology. It is interdisciplinary and multidisciplinary, covering numerous fields such as medicine, engineering, biology, physics, material sciences, and chemistry. The present work aims to cover the optical properties, method of preparations, surface modifications, bio-conjugation, characterization, stability, and cytotoxicity of quantum dots (QDs). Articles were reviewed in English literature reporting the pharmaceutical and bio-pharmaceutical aspects of QDs which were indexed in Scopus, web of science, google scholar and PubMed without applying the year of publication criterion. One significant value of utilizing nanotechnology is that one can alter and control the properties in a genuinely unsurprising way to address explicit applications' issues. In science and biomedicine, the usage of functional nanomaterials has been broadly investigated and has become one of the quick-moving and stimulating research directions. Different types of nanomaterial (silicon nanowires, QDs, carbon nanotubes, nanoparticles of gold/silver) were extensively utilized for biological purposes. Nanomedicine shows numerous advantages in the natural characteristics of targeted drug delivery and therapeutics. For instance, protection of drugs against degradation, improvement in the drug's stability, prolonged circulation time, deceased side effects, and enhanced distribution in tissues. The present review article deals with the quantum dots, their optical properties, method of preparations, surface modifications, bio-conjugation, characterization, stability, and cytotoxicity of quantum dots. The review also discusses various biomedical applications of QDs. The QDs-based bio-nanotechnology will always be in the growing list of unique applications, with progress being made in specialized nanoparticle development, the detection of elegant conjugation methods, and the discovery of new targeting ligands.

AbstractCarbon dots (CDs) are light-emitting nanoparticles that show great promise for applications in biology and medicine due to the ease of fabrication, biocompatibility, and attractive optical properties. Optical chirality, on the other hand, is an intrinsic feature inherent in many objects in nature, and it can play an important role in the formation of artificial complexes based on CDs that are implemented for enantiomer recognition, site-specific bonding, etc. We employed a one-step hydrothermal synthesis to produce chiral CDs from the commonly used precursors citric acid and ethylenediamine together with a set of different chiral precursors, namely, L-isomers of cysteine, glutathione, phenylglycine, and tryptophan. The resulting CDs consisted of O,N-doped (and also S-doped, in some cases) carbonized cores with surfaces rich in amide and hydroxyl groups; they exhibited high photoluminescence quantum yields reaching 57%, chiral optical signals in the UV and visible spectral regions, and two-photon absorption. Chiral signals of CDs were rather complex and originated from a combination of the chiral precursors attached to the CD surface, hybridization of lower-energy levels of chiral chromophores formed within CDs, and intrinsic chirality of the CD cores. Using DFT analysis, we showed how incorporation of the chiral precursors at the optical centers induced a strong response in their circular dichroism spectra. The optical characteristics of these CDs, which can easily be dispersed in solvents of different polarities, remained stable during pH changes in the environment and after UV exposure for more than 400 min, which opens a wide range of bio-applications.

AbstractCarbon dots (CDs) are categorized as an emerging class of zero-dimension nanomaterials having high biocompatibility, photoluminescence, tunable surface, and hydrophilic property. CDs, therefore, are currently of interest for bio-imaging and nano-medicine applications. In this work, polyethylene glycol functionalized CDs (CD-PEG) were prepared from oil palm empty fruit bunch by a one-pot hydrothermal technique. PEG was chosen as a passivating agent for the enhancement of functionality and photoluminescence properties of CDs. To prepare the CDs-PEG, the effects of temperature, time, and concentration of PEG were investigated on the properties of CDs. The as-prepared CDs-PEG were characterized by several techniques including dynamic light scattering, high-resolution transmission electron microscopy, X-ray photoelectron spectroscopy, fluorescence spectroscopy, Raman spectroscopy, Fourier-transform infrared spectroscopy and Thermogravimetric analysis. The as-prepared CDs under hydrothermal condition at 220 °C for 6 h had spherical morphology with an average diameter of 4.47 nm. Upon modification, CDs-PEG were photo-responsive with excellent photoluminescence property. The CDs-PEG was subsequently used as a drug carrier for doxorubicin [DOX] delivery to CaCo-2, colon cancer cells in vitro. DOX was successfully loaded onto CDs-PEG surface confirmed by FT-IR and Matrix-Assisted Laser Desorption/Ionization Time-of-Flight Mass Spectrometer (MALDI-TOF/MS) patterns. The selective treatment of CDs-PEG-DOX against the colorectal cancer cells, , relative to normal human fibroblast cells was succesfully demonstrated.

Abstract: This overview describes the synthesis, characterization, and application of different carbon dots hybrid nanostructures obtained by chemical interaction between nanomaterials or nanomaterials bonded to another material, i.e. silicon (SiO2/Carbon dots-N), reduced graphene oxide (rGO/Carbon dots), multiwalled carbon nanotubes (MWCNTs/Carbon dots), nano magnetite (Carbon dots/Fe3O4), reduced graphene oxide and gold nanoparticles (rGO/Carbon dots/AuNPs), copper oxide (CuO/Carbon dots), and Carbon dots/Metallic NPs that were employed in the development of electrochemical (bio)sensors. The formation of different carbon dots hybrid nanostructures has been characterized by X-ray diffraction (XRD), Raman and ultraviolet-visible spectroscopy, atomic force microscopy (AFM), high-resolution transmission electron microscopy (HR-TEM), and electrochemical techniques. These carbon dots hybrid nanostructures have been used to modify the surface of glassy carbon and screen-printed electrodes and to determine various analytes, i.e., dopamine, uric acid, paracetamol, ephynefrin, dihydroxybenzenes, pesticides, endocrine disruptors, NADH, and other substances in real samples.

Abstract Background Despite novel advances in screening, targeting and immunotherapies, early diagnosis and satisfactory treatments against hepatocellular carcinoma (HCC) remain formidable challenges. Given the unique advantages, carbon quantum dots (CQDs) become a smart theranostic nanomaterial for cancer diagnosis and therapy. Results In this work, a type of bio-friendly CQDs, trichrome-tryptophan-sorbitol CQDs (TC-WS-CQDs), is synthesized from natural biocompatible tryptophan via the one-pot hydrothermal method. Compared with normal hepatocytes, a much stronger green fluorescence is detected in HCC cells, indicating the ability of TC-WS-CQDs to target HCC cells. Furthermore, green-emitting TC-WS-CQDs generate large amounts of reactive oxygen species (ROS), leading to autophagy of HCC cells. Additionally, the green-emitting TC-WS-CQDs perform significant tumor inhibition by inducing autophagy via p53-AMPK pathway in vitro and in vivo studies with almost no systemic toxicity. Conclusions The results may highlight a promising anticancer nanotheranostic strategy with integration of diagnosis, targeting, and therapy. Graphical Abstract

The use of quantum technology to deliver drugs has the potential to increase the efficacy of many rare disease treatments. Semiconductor nanoparticles are a new type of treatment for life-threatening disorders. The term "quantum dots" refers to semiconductor nanoparticles. These quantum dots have a one-of-a-kind shape, size, fluorescence characteristics, and shape-dependent optoelectronic capacities. As a result, we believe that quantum dots&#039; (QDs) has the potential to be destined as medication carriers, biosensors, and similarly much more. Due to improvements in research, medicinal, and clinical domains, an in-depth examination of Quantum dots is now possible. Quantum dots are also classed as carbon-based quantum dots, graphene-based quantum dots, and cadmium-based quantum dots, with variations in their main structure leading to the discovery of more comparable and diversified quantum dots. Semiconductor quantum dots, or QDs, have also made tremendous progress in the field of fluorescence bioimaging research. After examining their in-vitro and in-vivo applications, we may currently use QDs as agents for gene transport, medication delivery, and enhancing the biocompatibility of other medications. This article discusses the significant breakthroughs and challenges in the field of quantum dots as biosensors for bioimaging, surface changes, quantum dots in the treatment of numerous diseases, and future features of quantum dots and their improvements in bio-medical applications.

Substantial advancements in the field of Carbon Dots (CDs) and their derivatives in recent years can be accredited to their tunable properties. Recently Carbonized Polymer Dots (CPDs) are the emerging form in the CDs family, which possesses a typical polymer/Carbon hybrid structure and properties due to its incomplete carbonization. Alteration of various parameters during the synthesis process suggested that the properties of CPDs depend on temperature and pH. It was found that doping of CPDs using nitrogen enhanced its optical properties, thereby being used as biomarkers. CPDs generally hold a strong green and blue emission, while intense red luminescence was observed doping with nitrogen. Photoluminescence Quantum Yield (PLQY) was also found to increase with the increase in doping and temperature. Doped CPDs find several applications, including bio-imaging, LEDs, etc. In this review, we focus on analyzing the increase in efficiency of CPDs with the process of doping considering optical and antibacterial applications.

Nanozyme-based colorimetric assays have attracted much attention due to their cost-effectiveness, high stability, and sensitivity. In particular, the catalytic cascade composed of the biological enzyme is highly selective. Yet, developing...

There is a moment in Al Gore’s 2006 documentary An Inconvenient Truth devised to expose the sheer audacity of fossil fuel lobby groups in the United States. In their attempts to address significant scientific consensus and growing public concern over climate change, these groups are resorting to what Gore’s film suggests are grotesque distortions of fact. A particular example highlighted in the film is the Competitive Enterprise Institute’s (CPE—a lobby group funded by ExxonMobil) “pro” energy industry advertisement: “Carbon dioxide”, the ad states. “They call it pollution, we call it life.” While on the one hand employing rhetoric against the “inconvenient truth” that carbon dioxide emissions are ratcheting up the Earth’s temperature, these advertisements also pose a question – though perhaps unintended – that is worth addressing. Where does life reside? This is not an issue of essentialism, but relates to the claims, materials and technologies through which life as a political object emerges. The danger of entertaining the vested interests of polluting industry in a discussion of climate change and its biopolitics is countered by an imperative to acknowledge the ways in which multiple positions in the climate change debate invoke and appeal to ‘life’ as the bottom line, or inviolable interest, of their political, social or economic work. In doing so, other questions come to the fore that a politics of climate change framed in terms of moral positions or competing values will tend to overlook. These questions concern the manifold practices of life that constitute the contemporary terrain of the political, and the actors and instruments put in this employ. Who speaks for life? And who or what produces it? Climate change as a matter of concern (Latour) has gathered and generated a host of experts, communities, narratives and technical devices all invested in the administration of life. It is, as Malcom Bull argues, “the paradigmatic issue of the new politics,” a politics which “draws people towards the public realm and makes life itself subject to the caprices of state and market” (2). This paper seeks to highlight the politics of life that have emerged around climate change as a public issue. It will argue that these politics appear in incremental and multiple ways that situate an array of actors and interests as active in both contesting and generating the terms of life: what life is and how we come to know it. This way of thinking about climate change debates opposes a prevalent moralistic framework that reads the practices and discourses of debate in terms of oppositional positions alone. While sympathies may flow in varying directions, especially when it comes to such a highly charged and massively consequential issue as climate change, there is little insight to be had from charging the CPE (for example) with manipulating consumers, or misrepresenting well-known facts. Where new and more productive understandings open up is in relation to the fields through which these gathering actors play out their claims to the project of life. These fields, from the state, to the corporation, to the domestic sphere, reveal a complex network of strategies and devices that seek to secure life in constantly renovated terms. Life Politics Biopolitical scholarship in the wake of Foucault has challenged life as a pre-given uncritical category, and sought to highlight the means through which it is put under question and constituted through varying and composing assemblages of practitioners and practices. Such work regards the project of human well-being as highly complex and technical, and has undertaken to document this empirically through close attention to the everyday ecologies in which humans are enmeshed. This is a political and theoretical project in itself, situating political processes in micro, as well as macro, registers, including daily life as a site of (self) management and governance. Rabinow and Rose refer to biopolitical circuits that draw together and inter-relate the multiple sites and scales operative in the administration of life. These involve not just technologies, rationalities and regimes of authority and control, but also politics “from below” in the form of rights claims and community formation and agitation (198). Active in these circuits, too, are corporate and non-state interests for whom the pursuit of maximising life’s qualities and capabilities has become a concern through which “market relations and shareholder value” are negotiated (Rabinow and Rose 211). As many biopolitical scholars argue, biopower—the strategies through which biopolitics are enacted—is characteristic of the “disciplinary neo-liberalism” that has come to define the modern state, and through which the conduct of conduct is practiced (Di Muzio 305). Foucault’s concept of governmentality describes the devolution of state-based disciplinarity and sovereignty to a host of non-state actors, rationalities and strategies of governing, including the self-managing subject, not in opposition to the state, but contributing to its form. According to Bratich, Packer and McCarthy, everyday life is thus “saturated with governmental techniques” (18) in which we are all enrolled. Unlike regimes of biopolitics identified with what Agamben terms “thanopolitics”—the exercise of biopower “which ultimately rests on the power of some to threaten the death of others” (Rabinow and Rose 198), such as the Nazi’s National Socialism and other eugenic campaigns—governmental arts in the service of “vitalist” biopolitics (Rose 1) are increasingly diffused amongst all those with an “interest” in sustaining life, from organisations to individuals. The integration of techniques of self-governance which ask the individual to work on themselves and their own dispositions with State functions has broadened the base by which life is governed, and foregrounded an unsettled terrain of life claims. Rose argues that medical science is at the forefront of these contemporary biopolitics, and to this effect “has […] been fully engaged in the ethical questions of how we should live—of what kinds of creatures we are, of the kinds of obligations that we have to ourselves and to others, of the kinds of techniques we can and should use to improve ourselves” (20). Asking individuals to self-identify through their medical histories and bodily specificities, medical cultures are also shaping new political arrangements, as communities connected by shared genetics or physical conditions, for instance, emerge, evolve and agitate according to the latest medical knowledge. Yet it is not just medicine that provokes ethical work and new political forms. The environment is a key site for life politics that entails a multi-faceted discourse of obligations and entitlements, across fields and scales of engagement. Calculating Environments In line with neo-liberal logic, environmental discourse concerned with ameliorating climate change has increasingly focused upon the individual as an agent of self-monitoring, to both facilitate government agendas at a distance, and to “self-fashion” in the mode of the autonomous subject, securing against external risks (Ong 501). Climate change is commonly represented as such a risk, to both human and non-human life. A recent letter published by the Royal Australasian College of Physicians in two leading British medical journals, named climate change as the “biggest global health threat of the twenty-first century” (Morton). As I have argued elsewhere (Potter), security is central to dominant cultures of environmental governance in the West; these cultures tie sustainability goals to various and interrelated regimes of monitoring which attach to concepts of what Clark and Stevenson call “the good ecological citizen” (238). Citizenship is thus practiced through strategies of governmentality which call on individuals to invest not just in their own well-being, but in the broader project of life. Calculation is a primary technique through which modern environmental governance is enacted; calculative strategies are seen to mediate risk, according to Foucault, and consequently to “assure living” (Elden 575). Rationalised schemes for self-monitoring are proliferating under climate change and the project of environmentalism more broadly, something which critics of neo-liberalism have identified as symptomatic of the privatisation of politics that liberal governmentality has fostered. As we have seen in Australia, an evolving policy emphasis on individual practices and the domestic sphere as crucial sites of environmental action – for instance, the introduction of domestic water restrictions, and the phasing out of energy-inefficient light bulbs in the home—provides a leading discourse of ethico-political responsibility. The rise of carbon dioxide counting is symptomatic of this culture, and indicates the distributed fields of life management in contemporary governmentality. Carbon dioxide, as the CPE is keen to point out, is crucial to life, but it is also—in too large an amount—a force of destruction. Its management, in vitalist terms, is thus established as an effort to protect life in the face of death. The concept of “carbon footprinting” has been promoted by governments, NGOs, industry and individuals as a way of securing this goal, and a host of calculative techniques and strategies are employed to this end, across a spectrum of activities and contexts all framed in the interests of life. The footprinting measure seeks to secure living via self-policed limits, which also—in classic biopolitical form—shift previously private practices into a public realm of count-ability and accountability. The carbon footprint, like its associates the ecological footprint and the water footprint, has developed as a multi-faceted tool of citizenship beyond the traditional boundaries of the state. Suggesting an ecological conception of territory and of our relationships and responsibilities to this, the footprint, as a measure of resource use and emissions relative to the Earth’s capacities to absorb these, calculates and visualises the “specific qualities” (Elden 575) that, in a spatialised understanding of security, constitute and define this territory. The carbon footprint’s relatively simple remit of measuring carbon emissions per unit of assessment—be that the individual, the corporation, or the nation—belies the ways in which life is formatted and produced through its calculations. A tangled set of devices, practices and discourses is employed to make carbon and thus life calculable and manageable. Treading Lightly The old environmental adage to “tread lightly upon the Earth” has been literalised in the metaphor of the footprint, which attempts both to symbolise environmental practice and to directly translate data in order to meaningfully communicate necessary boundaries for our living. The World Wildlife Fund’s Living Planet Report 2008 exemplifies the growing popularity of the footprint as a political and poetic hook: speaking in terms of our “ecological overshoot,” and the move from “ecological credit to ecological deficit”, the report urges an attendance to our “global footprint” which “now exceeds the world’s capacity to regenerate by about 30 per cent” (1). Angela Crombie’s A Lighter Footprint, an instruction manual for sustainable living, is one of a host of media through which individuals are educated in modes of footprint calculation and management. She presents a range of techniques, including carbon offsetting, shifting to sustainable modes of transport, eating and buying differently, recycling and conserving water, to mediate our carbon dioxide output, and to “show […] politicians how easy it is” (13). Governments however, need no persuading from citizens that carbon calculation is an exercise to be harnessed. As governments around the world move (slowly) to address climate change, policies that instrumentalise carbon dioxide emission and reduction via an auditing of credits and deficits have come to the fore—for example, the European Union Emissions Trading Scheme and the Chicago Climate Exchange. In Australia, we have the currently-under-debate Carbon Pollution Reduction Scheme, a part of which is the Australian Emissions Trading Scheme (AETS) that will introduce a system of “carbon credits” and trading in a market-based model of supply and demand. This initiative will put a price on carbon dioxide emissions, and cap the amount of emissions any one polluter can produce without purchasing further credits. In readiness for the scheme, business initiatives are forming to take advantage of this new carbon market. Industries in carbon auditing and off-setting services are consolidating; hectares of trees, already active in the carbon sequestration market, are being cultivated as “carbon sinks” and key sites of compliance for polluters under the AETS. Governments are also planning to turn their tracts of forested public land into carbon credits worth billions of dollars (Arup 7). The attachment of emission measures to goods and services requires a range of calculative experts, and the implementation of new marketing and branding strategies, aimed at conveying the carbon “health” of a product. The introduction of “food mile” labelling (the amount of carbon dioxide emitted in the transportation of the food from source to consumer) in certain supermarkets in the United Kingdom is an example of this. Carbon risk analysis and management programs are being introduced across businesses in readiness for the forthcoming “carbon economy”. As one flyer selling “a suite of carbon related services” explains, “early action will give you the edge in understanding and mitigating the risks, and puts you in a prime position to capitalise on the rewards” (MGI Business Solutions Worldwide). In addition, lobby groups are working to ensure exclusions from or the free allocation of permits within the proposed AETS, with degrees of compulsion applied to different industries – the Federal Government, for instance, will provide a $3.9 billion compensation package for the electric power sector when the AETS commences, to enable their “adjustment” to this carbon regime. Performing Life Noortje Mares provides a further means of thinking through the politics of life in the context of climate change by complicating the distinction between public and private interest. Her study of “green living experiments” describes the rise of carbon calculation in the home in recent years, and the implementation of technologies such as the smart electricity meter that provides a constantly updating display of data relating to amounts and cost of energy consumed and the carbon dioxide emitted in the routines of domestic life. Her research tracks the entry of these personal calculative regimes into public life via internet forums such as blogs, where individuals notate or discuss their experiences of pursing low-carbon lifestyles. On the one hand, these calculative practices of living and their public representation can be read as evidencing the pervasive neo-liberal governmentality at work in contemporary environmental practice, where individuals are encouraged to scrupulously monitor their domestic cultures. The rise of auditing as a technology of self, and more broadly as a technique of public accountability, has come under fire for its “immunity-granting role” (Charkiewicz 79), where internal audits become substituted for external compliance and regulation. Mares challenges this reading, however, by demonstrating the ways in which green living experiments “transform everyday material practices into practices of public involvement” that (118) don’t resolve or pin down relations between the individual, the non-human environment, and the social, or reveal a mappable flow of actions and effects between the public realm and the home. The empirical modes of publicity that these individuals employ, “the careful recording of measurements and the reliable descriptions of sensory observation, so as to enable ‘virtual witnessing’ by wider audiences”, open up to much more complex understandings than one of calculative self-discipline at work. As “instrument[s] of public involvement” (120), the experiments that Mares describe locate the politics of life in the embodied socio-material entanglements of the domestic sphere, in arrangements of humans and non-human technologies. Such arrangements, she suggests, are ontologically productive in that they introduce “not only new knowledge, but also new entities […] to society” (119), and as such these experiments and the modes of calculation they employ become active in the composition of reality. Recent work in economic sociology and cultural studies has similarly contended that calculation, far from either a naturalised or thoroughly abstract process, relies upon a host of devices, relations, and techniques: that is, as Gay Hawkins explains, calculative processes “have to be enacted” (108). Environmental governmentality in the service of securing life is a networked practice that draws in a host of actors, not a top-down imposition. The institution of carbon economies and carbon emissions as a new register of public accountability, brings alternative ways to calculate the world into being, and consequently re-calibrates life as it emerges from these heterogeneous arrangements. All That Gathers Latour writes that we come to know a matter of concern by all the things that gather around it (Latour). This includes the human, as well as the non-human actors, policies, practices and technologies that are put to work in the making of our realities. Climate change is routinely represented as a threat to life, with predicted (and occurring) species extinction, growing numbers of climate change refugees, dispossessed from uninhabitable lands, and the rise of diseases and extreme weather scenarios that put human life in peril. There is no doubt, of course, that climate change does mean death for some: indeed, there are thanopolitical overtones in inequitable relations between the fall-out of impacts from major polluting nations on poorer countries, or those much more susceptible to rising sea levels. Biosocial equity, as Bull points out, is a “matter of being equally alive and equally dead” (2). Yet in the biopolitical project of assuring living, life is burgeoning around the problem of climate change. The critique of neo-liberalism as a blanketing system that subjects all aspects of life to market logic, and in which the cynical techniques of industry seek to appropriate ethico-political stances for their own material ends, are insufficient responses to what is actually unfolding in the messy terrain of climate change and its biopolitics. What this paper has attempted to show is that there is no particular purchase on life that can be had by any one actor who gathers around this concern. Varying interests, ambitions, and intentions, without moral hierarchy, stake their claim in life as a constantly constituting site in which they participate, and from this perspective, the ways in which we understand life to be both produced and managed expand. This is to refuse either an opposition or a conflation between the market and nature, or the market and life. It is also to argue that we cannot essentialise human-ness in the climate change debate. For while human relations with animals, plants and weathers may make us what we are, so too do our relations with (in a much less romantic view) non-human things, technologies, schemes, and even markets—from carbon auditing services, to the label on a tin on the supermarket shelf. As these intersect and entangle, the project of life, in the new politics of climate change, is far from straightforward. References An Inconvenient Truth. Dir. Davis Guggenheim. Village Roadshow, 2006. Arup, Tom. “Victoria Makes Enormous Carbon Stocktake in Bid for Offset Billions.” The Age 24 Sep. 2009: 7. Bratich, Jack Z., Jeremy Packer, and Cameron McCarthy. “Governing the Present.” Foucault, Cultural Studies and Governmentality. Ed. Bratich, Packer and McCarthy. Albany: State University of New York Press, 2003. 3-21. Bull, Malcolm. “Globalization and Biopolitics.” New Left Review 45 (2007): 12 May 2009 . < http://newleftreview.org/?page=article&view=2675 >. 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