Current Progress of Ratiometric Fluorescence Sensors Based on Carbon Dots in Foodborne Contaminant Detection

Carbon dots (CDs) are widely used in the detection of foodborne contaminants because of their biocompatibility, photoluminescence stability, and ease of chemical modification. In order to solve the interference problem of complexity in food matrices, the development of ratiometric fluorescence sensors shows great prospects. In this review, the progress of ratiometric fluorescence sensors based on CDs in foodborne contaminant detection in recent years will be summarized, focusing on the functionalized modification of CDs, the fluorescence sensing mechanism, the types of ratiometric fluorescence sensors, and the application of portable devices. In addition, the outlook on the development of the field will be presented, with the development of smartphone applications and related software helping to better enable the on-site detection of foodborne contaminants to ensure food safety and human health

The Applications of Electrochemical Immunosensors in the Detection of Disease Biomarkers: A Review

Disease-related biomarkers may serve as indicators of human disease. The clinical diagnosis of diseases may largely benefit from timely and accurate detection of biomarkers, which has been the subject of extensive investigations. Due to the specificity of antibody and antigen recognition, electrochemical immunosensors can accurately detect multiple disease biomarkers, including proteins, antigens, and enzymes. This review deals with the fundamentals and types of electrochemical immunosensors. The electrochemical immunosensors are developed using three different catalysts: redox couples, typical biological enzymes, and nanomimetic enzymes. This review also focuses on the applications of those immunosensors in the detection of cancer, Alzheimer’s disease, novel coronavirus pneumonia and other diseases. Finally, the future trends in electrochemical immunosensors are addressed in terms of achieving lower detection limits, improving electrode modification capabilities and developing composite functional materials

Synergistic Effect of Zn–Co Bimetallic Selenide Composites for Lithium–Sulfur Battery

Compared with monometallic selenides, heterogeneous bimetallic selenides have rich phase boundaries and superior electrical conductivity. ZnSe/CoSe2 composites were prepared by introducing Zn metal and using ZIF-8/67 as the precursor through the synergistic effect between Zn and Co after selenification. The electrocatalytic conversion of polysulfide is accelerated by ZnSe through chemical adsorption and the catalytic effect. The conductive CoSe2 surface provides a rapid diffusion path for lithium ions, accelerating the conversion of the polysulfide. On the basis of their individual strengths, ZnSe and CoSe2 can jointly promote the smooth adsorptive–diffuse–catalytic conversion process of polysulfide and induce the growth of lithium sulfide around its heterogeneous interface, thus enhancing the electrochemical performance of the lithium–sulfur battery cathode materials. The ZnSe/CoSe2–S electrode, at the optimal Zn-to-Co ratio of 1:1, has a 790.06 mAh g−1 initial specific capacity at 0.2 C and excellent cycling stability at 1 C. After 300 cycles, the final capacity is 300.85 mAh g−1, and the capacity retention rate reaches 82.71%