Sialic Oxazolidine For Visual Detection Of Influenza Viruses

Influenza is a acute infectious disease caused by influenza viruses,which has brought heavy losses to human beings in history.Nowadays influenza is still a high-incidence disease,threatening human life and health.Rapid and effective detection methods are important in the prevention and treatment of influenza viruses.Current influenza virus detection methods mainly include virus isolation and culture,PCR,ELISA,colloidal gold method,etc.However,the existing methods are time-consuming,high cost and highly specialized.Neuraminidase(NA)is a major protein on the surface of influenza virus,which has the ability to recognize and cut off sialic acid glycoside bonds.Neuraminidase can remove sialic acid residues from respiratory mucosa and help newly assembled influenza viruses release from host cells.It plays a key role in the transmission and replication of influenza viruses.Sialic oxazolidine was synthesized as a probe for influenza virus.Sialic oxazolidine can be recognized by influenza virus neuraminidase and hydrolyze its oxygen glycoside bond.The hydrolysate N-hydroxyethyl indole derivative shows red color when observed with naked eyes.At the same time,it can emit fluorescence with a maximum absorption wavelength of 558 nm at a specific excitation wavelength.These two optical properties can be used to detect influenza virus.In this study,sialic acid was used as the starting material for methyl esterification of carboxyl group,acetylation of hydroxyl group,chlorination of 2-position carbon atoms of sialic acid,glycoside bond was formed between hydroxyl group of p-hydroxybenzaldehyde and sialic acid,alkene bond was formed between aldehyde group and indole oxazole,and the final product was obtained through seven steps.The compound was used to detect influenza viruses with different hemagglutination units(HAU).The detection limits under naked eye examination and fluorescence detection were 21 HAU and 2-2 H AU,respectively.The experimental results show that the detection limit of the influenza virus probe is comparable with the commercial kit,and the preparation is simpler,the cost is lower and the operation is easier.With the help of the detection instrument such as microplate spectrophotometer,higher detection efficiency and lower detection limit can be achieved.Aiming at the characteristics of resistance of mutant influenza virus NA to some neuraminidase inhibitors,we designed an experiment to distinguish drug-resistant influenza viruses by combining sialic oxazolidine with neuraminidase inhibitor oseltamivir carboxylate.The experimental results show that this method can effectively distinguish drug-resistant NA and can be applied to the detection of drug-resistant influenza viruses.