Silver Nanoparticle-Functionalised Nitrogen-Doped Carbon Quantum Dots for the Highly Efficient Determination of Uric Acid

Abstract

The fabrication of efficient fluorescent probes that possess an excellent sensitivity and selectivity for uric acid is highly desirable and challenging. In this study, composites of silver nanoparticles (AgNPs) wrapped with nitrogen-doped carbon quantum dots (N-CQDs) were synthesised utilising N-CQDs as the reducing and stabilising agents in a single reaction with AgNO3. The morphology and structure, absorption properties, functional groups, and fluorescence properties were characterised by transmission electron microscopy, X-ray photoelectron spectroscopy, Fourier transform infrared spectroscopy, ultraviolet spectroscopy, fluorescence spectroscopy, and X-ray diffraction spectroscopy. In addition, we developed a novel method based on AgNPs/N-CQDs for the detection of uric acid using the enzymatic reaction of uric acid oxidase. The fluorescence enhancement of the AgNPs/N-CQDs composite was linear (R2 = 0.9971) in the range of 2.0–60 μmol/L, and gave a detection limit of 0.53 μmol/L. Trace uric acid was successfully determined in real serum samples from the serum of 10 healthy candidates and 10 gout patients, and the results were consistent with those recorded by Qianxinan Prefecture People’s Hospital. These results indicate that the developed AgNP/N-CQD system can provide a universal platform for detecting the multispecies ratio fluorescence of H2O2 generation in other biological systems.

Nitrogen‐Doped Carbon Quantum Dots on Graphene for Field‐Effect Transistor Optoelectronic Memories

“…On both samples, different vibrations can be observed and attributed to OH, CH, CO, and CO stretching according to previous reports. [ 34,57–60 ] In comparison to undoped CQDs, N‐doped CQDs exhibit additional vibrations which can be assigned to CNHC asymmetric stretching, NH bending, and/or CN stretching, and possibly also to the CN stretching, confirming the nitrogen‐doping in the N‐doped CQDs. X‐ray photoelectron spectroscopy (XPS) results confirm well that the present N‐CQDs mainly composed of C, N, and O ( Figure a).…”

Target-triggered ‘colorimetric-fluorescence’ dual-signal sensing system based on the versatility of MnO2 nanosheets for rapid detection of uric acid

“…The analysis methods of UA have evolved from the phosphotungstic reduction method to diversified methods, including fluorescence, 9 colorimetric, 10 electrochemical, 11 chemiluminescence, 12 and chromatography. 13 Among the above-mentioned methods, fluorescence, colorimetric, and electrochemical methods that are rapid and sensitive are the most attractive to researchers, and they are easy to operate and achieve real-time visualizing and more advisable in daily monitoring.…”

Improvement of Dynamic Performance and Detectivity in Near-Infrared Colloidal Quantum Dot Photodetectors by Incorporating Conjugated Polymers

“…Among these, CQDs are regarded as promising candidates for flexible NIR PDs. They can be deposited by a solution process under ambient conditions, and their bandgaps and energy levels can be easily tuned by the particle size, ligand exchange treatment, and/or surface modification [ 16 , 17 , 18 , 19 , 20 , 21 ]. Wei et al reported lateral bilayer CQD PDs (QPDs) composed of PbS CQDs and p - n bulk heterojunction (BHJ) organic layers.…”