This study was aimed at establishing a novel visual detection method for SARS-CoV-2 based on magnetic beads(MBs)enrichment and Au@Pt nanoparticles(Au@PtNPs)enzyme catalysis.According to the double-antibody sandwich method,MBs conjugated with SARS-CoV-2 antibody 1 enriched SARS-CoV-2 antigen in samples.After magnetic adsorption,separation,and washing,the enriched antigen reacted with Au@PtNPs labeled with SARS-CoV-2 antibody 2,thereby forming an immune com-plex.After another round of magnetic adsorption and washing,the color change was catalyzed by Au@PtNPs in the chromogenic solu-tion,and the results were determined through comparison of color changes:a blue color change indicated a positive result,whereas no obvious color change indicated a negative result.The sensitivity and specificity of this method were evaluated.This study successfully established a visual detection method based on MBs enrichment and Au@PtNPs enzyme catalysis for targeting SARS-CoV-2 antigens.The method was able to detect SARS-CoV-2 antigens within 30 minutes and SARS-CoV-2nucleocapsid protein samples with antigen concentrations above 3.125 ng/mL.The method showed no cross-reactivity with seasonal influenza(H1N1)or influenza B virus nu-cleoprotein.The visual detection method established in this study,based on Au@PtNPs enzyme catalysis and MBs enrichment,has high specificity and sensitivity,is simple and quick to operate,and provides a new approach for rapid viral detection.

This study was aimed at establishing a novel visual detection method for SARS-CoV-2 based on magnetic beads(MBs)enrichment and Au@Pt nanoparticles(Au@PtNPs)enzyme catalysis.According to the double-antibody sandwich method,MBs conjugated with SARS-CoV-2 antibody 1 enriched SARS-CoV-2 antigen in samples.After magnetic adsorption,separation,and washing,the enriched antigen reacted with Au@PtNPs labeled with SARS-CoV-2 antibody 2,thereby forming an immune com-plex.After another round of magnetic adsorption and washing,the color change was catalyzed by Au@PtNPs in the chromogenic solu-tion,and the results were determined through comparison of color changes:a blue color change indicated a positive result,whereas no obvious color change indicated a negative result.The sensitivity and specificity of this method were evaluated.This study successfully established a visual detection method based on MBs enrichment and Au@PtNPs enzyme catalysis for targeting SARS-CoV-2 antigens.The method was able to detect SARS-CoV-2 antigens within 30 minutes and SARS-CoV-2nucleocapsid protein samples with antigen concentrations above 3.125 ng/mL.The method showed no cross-reactivity with seasonal influenza(H1N1)or influenza B virus nu-cleoprotein.The visual detection method established in this study,based on Au@PtNPs enzyme catalysis and MBs enrichment,has high specificity and sensitivity,is simple and quick to operate,and provides a new approach for rapid viral detection.

Objective To synthesize a novel polymer POMs-CS/nano-HAP and study its biocompatibility and safety.Methods The biocompatibility was evaluated through the experiments including acute systemic toxicity test,pyrogen,intracutaneous test.Results The crystals of POMs-CS/nano-HAP were equal on sizes, which average diameter was 20 nm and length was 100 nm.By comparing,the polymer were better than those reported,which were closer to the natural bone.The material had no toxicity,no irritation to skin.(Conclusion The) POMs-CS/nano-HAP artificial bone possesses excellent biocompatibility.