Intelligent And Convenient Fluorescent Imprinting Sensors For Sensitive Detection Of Viruses

Pathogenic viruses are highly contagious,and it is still difficult to control the virus immediately and effectively in today’s environment,but the virus is ubiquitous in our daily life.It is difficult to identify which virus is caused by clinical manifestations,so the specific identification and detection of the virus is the key to diagnosis and treatment.On the other hand,the detection of viruses is also challenging,because different viruses have similar structure and size,and most viruses also have the same functional groups,which may cause great interference in detection by conventional methods.The molecular imprinting technology can just imprint the shape and size of the template molecule,so as to realize the specific recognition of the target molecule.Therefore,we combined molecular imprinting technology to construct a thermosensitive viral molecularly imprinted fluorescent sensor for the detection of enterovirus 71（EV71）,and a paper-based fluorescent viral molecularly imprinted sensor for avian influenza virus detection.Visual detection of H5N1.The main research work is as follows:1.Using enterovirus 71（EV71）as the target virus,a thermosensitive imprinted hydrogel ratiometric fluorescent virus sensor was designed.A microwave method was used to rapidly synthesize carbon dot CDs with a quantum yield of up to 98%.In addition,rhodamine B hydrazide was synthesized as a fluorescent signal source for ratiometric detection,followed by EV71 as the imprinting template,N-isopropylacrylamide（NIPAm）is a thermosensitive monomer,acrylamide（AAm）is a comonomer,N,N’-methylenebisacrylamide（MBA）is a crosslinking agent,ammonium persulfate（APS）is an initiator,N,N,N’,N’-tetramethylethylenediamine（TEMED）was used as the promoter to prepare a temperature-responsive viral molecularly imprinted hydrogel MIP.Due to the introduction of NIPAm,it can respond to temperature.At 37 ^oC,the imprinted gel can recognize the bound target virus,and at 45 ^oC,the imprinted hydrogel bound to the target virus will shrink,and then the target virus will be released.The results showed that MIPs had good selectivity and sensitivity for the detection of EV71,with an imprinting factor of 3.25,a detection range of 0.5-6.0 U/m L,and a detection limit of 0.29 U/m L.The prepared temperature-sensitive virus-imprinted gel sensor shows significant advantages in the detection of EV71 virus,and has great potential in the practical application of virus detection.2.Using the avian influenza subtype virus H5N1 as the template virus,a paper-based virus imprinting fluorescence-visualization dual-mode detection sensor was constructed.Firstly,Fe₃O₄nanoparticles were synthesized by hydrothermal method,and then Fe₃O₄was loaded on qualitative filter paper.Then,TEOS and APTES were used to cross-link the surface of the filter paper and template virus to form an imprinted layer.After the template was eluted,the paper-based imprinted polymer WP@MIPs.The imprinted cavity of the as-prepared WP@MIP has exposed Fe₃O₄,which catalyzes H₂O₂to generate reactive oxygen species upon contact with H₂O₂,thereby oxidizing 3,3’,5,5’-tetramethylbenzidine（TMB）from colorless.It turns blue.Based on this color development mechanism,MIP can be used for fluorescent quantitative detection of target viruses,and can also be used for visual semi-quantitative detection of H5N1.The constructed paper-based virus imprinting sensor is sensitive to the detection of H5N1,has good selectivity,and can be used for visual semi-quantitative detection.These results indicate that the designed sensor can be used for the actual detection of virus.