Study Of Application Of Mannose In Selective Recognition And Interaction Of Bacteria

Carbohydrate could selectively identify the lectin on the surface of bacteria,exploring the affinity between carbohydrate and bacteria was important to study the field of carbohydrate molecules uasd for bacteria,it was currently one of the hot research in field of carbohydrate chemistry.Carbohydrate non probes was prepared by combining non-toxic and cheap carbohydrate with nanoparticle,which had the advantages that both nanoparticle was large surface area and good photoelectric properties and carbohydrate was water soluble,good compatibility and biological,so that carbohydrate non probes was bettter suitable to research on interactions,recognition and detection between carbohydrate and bacteria.In this paper,mannose that could selectively recognized type I fimbriated bacteria was selected was reschearch object,carbohydrate nano probes were prepared combine with unique advantage of nanoparticles,to study interaction between mannose and bacteria.Combine with the technology and method of microfluidic chip,mannose was used as the recognition element to realize the on-line identification and capture of the type I fimbriated bacteria.The research had a clear significance in the study of the selective recognition of carbohydrate and bacteria and their interaction,and had a very good application prospect in screen the inhibition of the molecular skeleton of carbohydrate.The main research work and results are as follows: 1.Study of the interaction between mannose and bacteria based on Man-CQDsBased on abundant surface carboxyl on surface of CQDs,which was prepared using citric acid as carbon source,Man-CQDs was prepared in means that mannose modified amino covalently immobilized on the surface of CQDs.Combined with Scatchard model equation,the binding constants of mannose and bacteria were calculated and analyzed,the new method of research on affinity betwenn mannose and bacteria was developed.Escherichia coli and Salmonella used as the research object,the affinity of Man-CQDs and Escherichia coli JM109 were strong,and their binding was calculated,which were 2.39×103 L·mo L-1 and 1.17×105 L·mo L-1.and Man-CQDs and Escherichia coli DH5? was not effective combination.The developed method could be used to determine the binding constants between mannose and bacteria,and provided theoretical support for the study of the interaction between carbohydrate and bacteria.2.Study of the selective recognition of mannose and salmonella based on dual recognition of Man-Fe3O4 and Man-CQDsMannose was used as recognition element of salmonella,combined with magnetic nanoparticles and fluorescent nanoparticles prepared for carbohydrate nano-probe,using double recognition for selectively recognizing salmonella.Man-Fe3O4 nano-probes was added into the mixed bacteria to selectively capture Salmonella,and then Man-CQDs nano-probe was added to fluorescent label captured Salmonella,ultimately using fluorescence spectrometer tested the fluorescence signal of labeled Salmonella.Man-Fe3O4 and Man-CQDs could recogized salmonella,and Man-CQDs could efficiently labeled salmonella.There is a good linear relationship between the logarithm of the concentration of Salmonella and the corresponding fluorescence value,linear equation IFL=217.2Log(c)-758.8(R2=0.9874),the linear range was 104-107cfu·mL-1,the detection limit was 5 × 103cfu·mL-1.Using double recognition of magnetic and fluorescence nano probes to bacterial selective capture and fluorescence labeling,paved the way for further research on interactions of carbohydrate and bacteria.3.Study of selective recognition of mannose and bacteria based on microfluidic chipThe integrated 6 channels and the bottom modified mannose PDMS-Glass microfluidic bacterial recognition chip was designed,and build a small fluorescent micro-system and corresponding detection system of bacteria chip,and realized the selective recognition and capture of the expression of type I fimbriae of bacteria,established a detection system of microfluidic chip that selectively bacterial recognized and captured.High fluorescent quantum yield of acridine orange was seletced as labeling reagents to label five kinds of bacteria,in chip Salmonella S.123443,Escherichia coli W1485 and Escherichia coli JM109 were successfully recognized and captured,capture efficiency were 57.25%,43.69%,40.97%,respectively.Escherichia coli DH5? and Staphylococcus aureus cannot be recognized and captured.Mainly because the end of fimbriae of Salmonella S.123443,Escherichia coli W1485 and Escherichia coli JM109 had recognition sites of mannose,and Escherichia coli DH5? and Staphylococcus aureus had not recognition sites,which was coincident theory that bacteria of expression of type I pili could selectively recognized mannose.The method realized the recognition and capture bacteria of expression of type I fimbriae,avoided the tedious operation in a variety of modified bacterial recognition element in multiple channels,and had the advantages of fast,sensitive and simple operation,provided a new platform for the recognition of bacteria for carbohydrate.