Brewery spent grain derived carbon dots for metal sensing

Engineering of Green Carbon Dots for Biomedical and Biotechnological Applications

Carbon dots (CDs) are attracting increasing research attention due to their exceptional attributes, including their biocompatibility, water solubility, minimal toxicity, high photoluminescence, and easy functionalization. Green CDs, derived from natural sources such as fruits and vegetables, present advantages over conventionally produced CDs, such as cost-effectiveness, stability, simplicity, safety, and environmental friendliness. Various methods, including hydrothermal and microwave treatments, are used to synthesize green CDs, which demonstrate strong biocompatibility, stability, and luminescence. These properties give green CDs versatility in their biological applications, such as bioimaging, biosensing, and drug delivery. This review summarizes the prevalent synthesis methods and renewable sources regarding green CDs; examines their optical features; and explores their extensive biological applications, including in bioimaging, biosensing, drug/gene delivery, antimicrobial and antiviral effects, formatting of mathematical components, cancer diagnosis, and pharmaceutical formulations.

Nitrogen-doped carbon dots as fluorescent probes for sensitive and selective determination of Fe3

At present, the contamination of water resources by heavy metal ions has posed a significant threat to human survival. Therefore, it is particularly critical to develop low-cost, easy-to-use, and highly efficient heavy metal detection technologies. In this work, a fast and cost-effective fluorescent probe for nitrogen-doped carbon dots (N-CDs) was prepared using one-step hydrothermal method with citric acid (CA) as carbon source, and melamine as nitrogen source. The structural and optical characterizations of the resulting N-CDs were investigated in details. The results showed that the quantum yield of the prepared fluorescent probe was as high as 45 %, and an average fluorescence lifetime was about 7.80 ns. N-CDs have excellent water solubility and dispersibility, with an average size of 2.58 nm. N-CDs exhibited excellent specific responsiveness to Fe3+ and can be used as an effective method for detecting Fe3+ at low-concentrations (the concentrations of N-CDs as low as 0.24 μg/mL) using fluorescent probes. The linear response of the fluorescent probe N-CDs to Fe3+ was formed in the concentration range of 20-80 μM, and the detection limit was 3.18 μM. In addition, in the actual water samples analysis, the recovery rate reached 97.05-100.58 %. The prepared of N-CDs provide available Fe3+ fluorescent probes in the environment.

Microwave synthesized novel biomass carbon dots applied in the fluorescent detection of crystal violet

To establish a new method for detecting crystal violet (CV), a harmful dye, herein, a genre of novel biomass carbon dots (CDs) was synthesized via a microwave method and employed as a fluorescent probe, in which water spinach and polyethylene glycol (PEG) performed as raw materials. Based on the inner filter effect (IFE) between the luminescent CDs and CV, the blue emission of this probe at 430 nm could be quenched by CV. Hence, a new strategy was proposed to selectively determine CV in aquaculture ambient. Moreover, under the optimal experiment conditions, this method showed a good linearity between the concentration of CV (c) and fluorescence quenching rate (ΔF/F0) in the concentration range of 4-200 μmol/L with the corresponding correlation coefficient (r) and the detection limit of 0.997 and 710 nmol/L, respectively. With advantages of environmental protectivity, sensitivity, affordability, and user-friendliness, the facilely fabricated CDs could be successfully applied in detecting CV in aquaculture samples, providing a technical foundation for monitoring the pollution of CV and ensuring the quality and safety of aquatic products.

Revealing the synergetic interaction between amino and carbonyl functional groups and their effect on the electronic and optical properties of carbon dots

Nitrogen and oxygen-based functionalized carbon dots (CDs) surfaces have attracted significant attention due to their ability to tailor the optical and electronic properties of CDs.