Plasma Nanoengineering of Bioresource-Derived Graphene Quantum Dots as Ultrasensitive Environmental Nanoprobes

Construction of a three-mode sensor based on gold nanoparticles and carbon quantum dots as probes for the detection of thiosemicarbazone

In this study, ginkgo leaves were used as a carbon source to synthesize carbon quantum dots (CQDs) with uniform particle size, high fluorescence (FL) intensity and strong stability, using a hydrothermal method. FL could be quenched by the FL resonance energy transfer effect between CQDs and gold nanoparticles (AuNPs), an important FL quenching agent. The electrostatic attraction between thiosemicarbazone (TSC) and citrate on the surface of AuNPs and the formation of a stable Au-S bond between TSC and AuNPs led to the aggregation of AuNPs and thus weakened the quenching effect on CQDs and partly recovered the FL. A sensor in FL mode for the detection of TSC was constructed based on the above-mentioned FL "off" and "on" phenomena. The results showed a good linear correlation in the concentration range 0-1.75 μM, and the limit of detection was as low as 0.05 μM. In addition, the aggregation of AuNPs caused by TSC also led to a change in the absorbance curve and color of the solution; colorimetric and chrominance detection modes were also constructed using these two types of changes, with sensitive responses ranging 0-2.25 μM and 0-1.60 μM and the limits of detection of 0.03 μM and 0.08 μM, respectively. More importantly, these three detection modes obtained satisfactory recovery rates in the detection of the TSC content in river water, liquor and wheat samples, and the detection results were mutually verified (95.18% to 104.96%).

Advances in Structural Modifications and Properties of Graphene Quantum Dots for Biomedical Applications

Graphene quantum dots (GQDs) are carbon-based, zero-dimensional nanomaterials and unique due to their astonishing optical, electronic, chemical, and biological properties. Chemical, photochemical, and biochemical properties of GQDs are intensely being explored for bioimaging, biosensing, and drug delivery. The synthesis of GQDs by top-down and bottom-up approaches, their chemical functionalization, bandgap engineering, and biomedical applications are reviewed here. Current challenges and future perspectives of GQDs are also presented.

Functional Carbon from Nature: Biomass-Derived Carbon Materials and the Recent Progress of Their Applications

Biomass is considered as a promising source to fabricate functional carbon materials for its sustainability, low cost, and high carbon content. Biomass-derived-carbon materials (BCMs) have been a thriving research field. Novel structures, diverse synthesis methods, and versatile applications of BCMs have been reported. However, there has been no recent review of the numerous studies of different aspects of BCMs-related research. Therefore, this paper presents a comprehensive review that summarizes the progress of BCMs related research. Herein, typical types of biomass used to prepare BCMs are introduced. Variable structures of BCMs are summarized as the performance and properties of BCMs are closely related to their structures. Representative synthesis strategies, including both their merits and drawbacks are reviewed comprehensively. Moreover, the influence of synthetic conditions on the structure of as-prepared carbon products is discussed, providing important information for the rational design of the fabrication process of BCMs. Recent progress in versatile applications of BCMs based on their morphologies and physicochemical properties is reported. Finally, the remaining challenges of BCMs, are highlighted. Overall, this review provides a valuable overview of current knowledge and recent progress of BCMs, and it outlines directions for future research development of BCMs.