One-Step Synthesis of Fluorescent Carbon Dots for Bio-Labeling Assay (original) (raw)
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The Scientific World Journal, 2013
We have successfully demonstrated the use of capped carbon dot systems, namely, CDs/β-cd, CDs/LMH, and CDs/Suc, as fluorescent sensors for the detection of hemin. The capped carbon dot systems showed quenching of PL intensity in the presence of hemin. The minimum detection limit was determined to be ~1 μM. The PL response with free Fe(II) and Fe(III) was also studied. It was observed that PL quenching of capped carbon dot systems in the presence of hemin is dependent on the number of –OH groups in the capping agent. The order of quenching towards hemin was determined to be CDs/β-cd > CDs/LMH = CDs/Suc > CDs. A possible mechanism to account for the observation is also discussed in the paper.
ACS Omega, 2018
Early detection is the critical phase in the prognostic strategy of various life-threatening maladies like infectious diseases and cancer. The mortality rate caused by these diseases could be considerably reduced if they were diagnosed in the early stages of disease development. Carbon dots (C-dots), a relatively new and promising candidate in the fluorescent nanomaterial category, possess a perceptible impact on various bioapplications. Herein, we report a one-step facile hydrothermal synthesis that yields a novel surface-passivated carbon dot (CDP) from curcumin (as a green substrate) displaying high aqueous solubility. The physico-chemical characterization of thus synthesized C-dots was accomplished by an UV−visible spectrophotometer, fluorescence spectrophotometer, zetasizer, TEM, and FE-SEM to understand the formation of carbon dots with a 4−5 nm size near spherical nanoparticle with high colloidal stability. E. coli DH5α was engaged as the Gram-negative test organism and S. aureus as the Gram-positive in the biolabeling of bacteria. Cancer cell lines including colon cancer (HCT-15), lung cancer (A549), and mouse fibroblast (NIH 3T3) were evaluated and resulted in good biolabeling potential and less cytotoxicity. Zebrafish (ASWT) embryos as an animal model system were bioimaged, and in vivo toxicity was inferred. Moreover, the synthesized C-dots were shown to have free radical scavenging activity in a dose-dependent manner. The unpassivated C-dots (CD) were found to sense ferric ions at the micromolar concentration level. The findings of our study suggest that the multifunctional potentiality of CDPs serves as high-performance optical nanoprobes and can be a suitable alternative for various biolabeling and contrasting agents.
Journal of Molecular Liquids, 2018
Fluorescent Carbon Dots (CDs) have gained paramount interest in chemical biological and biomedical fields. In this work, in vitro molecular interaction of CDs with various serum albumins (Human serum albumins (HSA), Bovine serum albumins (BSA) and Rabbit serum albumins (RSA)) have been systematically studied by various spectroscopic techniques. Spherical and monodispersed CDs with an average diameter across of 10 nm successfully fabricated in water-(Polyethylene glycol) PEG medium utilizing glucose as carbon source. Thermodynamic and kinetic parameters of CDs with serum albumins (SA) have also been studied. The binding interaction between serum albumins (SA) and CDs were come about because of the complex formation of HSA-CDs, BSA-CDs and RSA-CDs. The altered Stern-Volmer quenching constant K a at different temperatures and their comparing thermodynamic parameters ΔH, ΔG and ΔS were calculated. The binding location of CDs with SA is around site I (subdomain IIA) and substantial conformational changes at both secondary and tertiary structures level.
Synthesis of ecofriendly fluorescent carbon dots and their biomedical and environmental applications
Materials Technology, 2018
Green Synthesis of nanoparticles is an emerging field with enormous advantages over conventional synthesis methods. Herein we have reported a green method for the preparation of water soluble polydisperse carbon dots (c-dots) from Cocos nucifera frond pinnae by a modified version of the 'single step hydrothermal carbonization'. C-dots having blue emission were obtained with this method and we further evaluated the effect of metal ions interactions on c-dots, as a sharp decrease in photoluminescence was observed. The synthesized c-dots were found bioactive against B.subtilis, M. smegmatis and S. aureus as determined by the well diffusion assay. We also explored nanotheranostic applications of c-dots as biosensor matrix in DNA hybridization sensor for pancreatic cancer and in bioimaging of cancer cells. This study demonstrated that c-dots can be explored for numerous biomedical and environmental applications in a variety of fields owing to the cost effective synthesis, biocompatibility and excellent physico-chemical properties.
Carbon Dots as Nontoxic and High-Performance Fluorescence Imaging Agents
Fluorescent carbon dots (small carbon nanoparticles with the surface passivated by oligomeric PEG molecules) were evaluated for their cytotoxicity and in vivo toxicity and also for their optical imaging performance in reference to that of the commercially supplied CdSe/ZnS quantum dots. The results suggested that the carbon dots were biocompatible, and their performance as fluorescence imaging agents was competitive. The implication to the use of carbon dots for in vitro and in vivo applications is discussed.
Bio-Derived Fluorescent Carbon Dots: Synthesis, Properties and Applications
Molecules
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 concen...
Hemoglobin detection using carbon dots as a fluorescence probe
Biosensors and Bioelectronics, 2015
Herein, we have described the application of high fluorescent carbon dots (CDs) without any surface modification as a simple and fast responding fluorescence probe for sensitive and selective determination of hemoglobin (Hb) in the presence of H 2 O 2. Although Hb itself was able to quench the fluorescence of CDs, based on the inner filter effect (IFE) of the protein that affects both the excitation and emission spectra of CDs, the presence of H 2 O 2 resulted in further improvement of the sensitivity of Hb detection. The assay is based on the reaction of Hb with H 2 O 2 that generates reactive oxygen species including hydroxyl ( OH) and superoxide (2 O) radicals under heme degradation and/or iron release from Hb and the subsequent reaction of hydroxyl radicals, as strong oxidizing agents, with CDs resulting in high fluorescence quenching. The proposed probe was used for determination of Hb in concentration range of 1-100 nM with a detection limit of 0.4 nM. The method was successfully applied to the determination of Hb in human blood samples.
Recent advance of carbon dots in bio-related applications
Journal of Physics: Materials, 2020
Carbon dots (CDs) is a kind of carbon nanoparticles with a plentiful of surface functional groups and tunable emission with different excitation wavelength. Broadly speaking, CDs include carbon nanodots, carbon quantum dots, graphene quantum dots, carbonized polymer dots. Due to the unique nature, they are explored for various applications in the bio-related fields such as bioimaging, sensor for ion and (bio)molecules, catalyst, LED and other fields. They are viewed as great alternative tracers to the current fluorescent biomarkers in personalized nanomedicine and surgery operation monitoring. In this review, we summarized the recent progress in the development of CDs, including improvement in fluorescence properties, two-photon fluorescence, and integration with other modalities as theragnostic agents. Specifically, we discussed the preparation of dual-modal imaging agents to improve the accuracy of diagnosis, the combination of imaging and targeting functionality for the effective...
Advances in fluorescent carbon dots for biomedical applications
Advances in Physics: X
Carbon Dots are an emerging class of carbon-based nanoparticles, which since their discovery have attracted tremendous attention because of their exceptional fluorescent, chemical and mechanical properties as well as high photostability and biocompatibility. This unique combination of outstanding characteristics, together with the ease with which they can be synthesized, qualify carbon dots as highly promising materials for applications in electronics and biology, in particular, for biosensing, bioimaging, biotherapy and drug delivery. In this review, we present some of the most recent applications of carbon dots in biology and medicine, concentrating on their fluorescence properties, biocompatibility and efficiency; we also discuss how improvements could prompt their use in human studies. We illustrate how carbon dots, prepared through several facile and costeffective methods by either the bottom-up or the top-down route, can be used for imaging cells and bacteria and as sensing probes of metal cations. Moreover, we explain how their astonishing versatility has given rise to new biotherapy methods especially in the field of cancer theranostics.