Novel Coronavirus N Protein Detection By Lateral Flow Assay Based On Colorimetric Fluorescent Nanospheres

Since the outbreak of the novel coronavirus,the seventh coronavirus after SARS,there has been a great deal of public panic.Until April 21 of 2022,more than 500 million novel coronavirus infections and over 6.2 million deaths have been reported worldwide.The novel coronavirus is a highly pathogenic and infectious type of coronavirus,which is 80% similar to the genetic sequence of the SARS virus in 2003.A variety of detection methods for the virus have been reported,all of which have their advantages,but are still not fully adequate for the current complex situation of the epidemic.In this paper,combined with the advantages of novel coronavirus real-time detection by lateral chromatography,and further improved on the basis of current lateral chromatography,the following work is done.A multifunctional nanosphere with colorimetric and fluorescence properties was prepared.A layer of polyethylene imine was assembled on the fluorescent nanospheres of quantum dots with carboxyl group on the surface,and the gold nanoparticles were adsorbed by electrostatic action.By silanization reagent,the fluorescent nanospheres adsorbed with Au NPs were coated with a silicon shell to obtain the marker used in this paper,colorimetric fluorescent nanospheres.The multifunctional nanospheres have stable properties,strong anti-photobleaching ability,colorimetric and fluorescence detection functions,as well as signal amplification function,which can be used for antibody labeling,This is the biggest innovation of the method.Then the test platform of the sample was prepared.As a carrier of liquid sample detection,test strip has the advantages of simplicity,speed and low cost.CN140 nitrocellulose film(NC film)was used.This model of NC film has a fast flow rate,which can guarantee the presence of signals with less background adsorption,and can stably detect signals in the lateral chromatography process.A novel coronavirus N protein lateral chromatography method based on dipstick is developed.The concentration of the blocking reagent,the concentration of the colorimetric fluorescent nanospheres and the chromatography time were optimized.The specificity,anti-interference ability and stability of the method were investigated.The linear working range of the method is 8.9-180.0 nmol/L,and the detection limit is 2.1 nmol/L(1.3 ?g/m L).The reagent in this method is easy to obtain,simple to operate,and is not limited by the environment and technical ability of personnel.The method has good specificity,anti-interference ability and stability(the coefficient of variation within the group is 4.7%,the coefficient of variation between the groups is 7.5%).The detection result can be obtained visually within 25 minutes,which greatly improve the detection efficiency.