Application Of Aptamers In Detection And Targeted Therapy Of SARS-CoV-2

In recent years,with the acceleration of globalization in all walks of life,the communication between human beings has become increasingly frequent.In this process,the spread speed of some pathogenic viruses has obviously accelerated,for example,Severe Acute Respiratory Syndrome Coronavirus 2（SARS-CoV-2）,Ebola virus,monkeypox,and Middle East respiratory syndrome,etc.These viruses will not only affect the development of society,but also cause irreversible harm to the physical and mental health of human beings.In particular,the SARS-CoV-2 that is currently raging around the world has not only brought many troubles to people’s lives,but also disrupted the normal development order of society.Facing the challenge brought by the virus,the most effective way is to screen patients from the healthy people as soon as possible and treat them promptly and efficiently.Aptamers have been widely used because of their specific recognition targets.In this thesis,we propose to use the aptamer of nucleocapsid protein（N protein）,an important component protein of SARS-CoV-2,as a probe for treatment and detection.The research ideas were as follows:（1）Remdesivir is a specific drug for treating coronavirus,but as a new drug,whether it will have some negative effects while treating diseases requires a certain clinical observation period.It is of great significance to save medical resources and reduce the negative impact of excessive drug use on human body while ensuring the therapeutic effect.In this experiment,mesoporous silica nanoparticles based on N-protein-triggered aptamers were used as gating to release remdesivir and treat novel coronavirus（2019-nCoV）in a targeted way.Through a series of experiments,it can be concluded that this experimental method can specifically recognize N protein and release remdesivir.By analyzing the data of actual samples,the average recovery rate was 90.4%～113.1%,and the RSD was 3.6%～6.7%.（2）Development of a photodriven renewable N protein Electrochemical aptamer sensor based on N protein aptamer.The 5’modification of the N protein aptamer has azobenzene.The aptamer modified by azobenzene will form a hairpin structure when it binds to N protein under visible light.Under ultraviolet light,azobenzene will be transformed into a polar and non-planar cis structure,which will lead to the reopening of the aptamer forming the hairpin structure.The aptamer with the primary structure will form the hairpin state of the secondary structure after binding with N protein,and the sensor can be reused by using this property.The experimental results show that the sensor can realize 5 times of regeneration detection,and the signal value is more than 90%.The logarithm of N protein concentration at 100 fM-100 nM has a linear relationship with the peak current generated by the sensor(ΔIp=0.051log C_{N protein}/fM-0.042,R²=0.994),limit of detection was 4.9 fM（S/N=3）.