Detection of SARS-CoV-2 S protein based on FRET between carbon quantum dots and gold nanoparticles.

The COVID-19 pandemic caused by SARS-CoV-2 virus brings nasty crisis for public health in the world. Until now, the virus has caused multiple infections in many people. Detecting antigen to SARS-CoV-2 is a powerful method for the diagnosis of COVID-19 and is helpful for controlling and stopping the pandemic.

Rational design of three-in-one Pt/MnO/GO hybrid nanozyme with enhanced catalytic performance for colorimetric detection of ascorbic acid and cysteine.

In this work, a novel three-in-one Pt/MnO/GO hybrid nanozyme with wide pH and temperature working range was rational prepared using simple hydrothermal and reduction strategy. The prepared Pt/MnO/GO displayed enhanced catalytic activity than single active component due to the excellent conductivity of GO, the increased active sites, the increased electron transfer capacity, the synergistic effect between each component and the decreased binding energy for adsorbed intermediates. Combing chemical characterization and theoretical simulation calculations, the O reduction process on the Pt/MnO/GO nanozymes and the generated reactive oxygen species in the nanozyme-TMB system were thoroughly illustrated.

A novel sensitive DNAzyme-based optical fiber evanescent wave biosensor for rapid detection of Pb in human serum.

We describe here a portable DNAzyme-based optical fiber evanescent wave biosensor (OFEWB) for the rapid and sensitive detection of Pb in human serum. Unlike other biosensors, the OFEWB dispensed with the complicated process of attaching biometric elements to the optical fiber, and the optical fiber directly acted as a transducer to transmit the excitation light and simultaneously collected the fluorescence, which could simplify the detection process, avoid the susceptibility to interference from complex environments and strengthen the reusability of the biosensor. The fluorescence (Cy3) labelled substrate sequence (GR-5S-Cy3) could be cleaved under the catalysis of the GR-5 DNAzyme sequence (GR-5E-BHQ2) in the presence of Pb; then the released fluorescence labelled fragments could be directly excited and detected by the OFEWB due to the high transmission efficiency of the excitation light and fluorescence in the OFEWB.