Preparation And Structure-Activity Relationship Research Of A Biomimetic Antimicrobial Polymer

There are two parts in this thesis. In the first part a novel biomimetic antimicrobial polymer material is synthesized, and studied the antibacterial properties and mechanism, finally analysis of the impact of their structure on the antibacterial properties. In the second part, a nano-silver antibacterial composite film is prepared,and studied sort of physical and antibacterial properties.The first part: preparation and structure-activity relationship research of a biomimetic antimicrobial polymer.With the cross-depth study of the various scientific fields and disciplines, more and more broad-spectrum antimicrobial agent was found, extracted and synthesized,development of science and technology will improve human antimicrobial levels to new height. However, the emergence of a variety of drug-resistant and increasing drug resistance, means increasingly difficult to study and funding, and is the thorny issue of all antimicrobials researchers have to face.Mimic the structure of a class of natural antimicrobial peptides, this thesis prepared N-2-hydroxypropyl trimethyl ammonium chloride Chitooligosaccharide and Quaternary ammonium salt of cinnamoyl Chitooligosaccharide and explore the synthesis conditions and antibacterial properties of these antimicrobial agents, finally get two good antibacterial properties bionic antibacterial antimicrobial polymer materials.By adjusting the different reaction times and raw material ratio, obtained a series of different degree of substitution of N-2-hydroxypropyl trimethyl ammonium chloride Chitooligosaccharide and Quaternary ammonium salt of cinnamoyl Chitooligosaccharide. After the usual degree of substitution titration method is no longer applicable, use the results of UV-visible spectrophotometry, elemental analysis and 1HNMR to calculate the degree of deacetylation and the degree of substitution.The results indicate that, both increasing amount of raw materials or reaction times can improve the degree of quaternization of N-2-hydroxypropyl trimethyl ammoniumchloride Chitooligosaccharide; with the increase of the amount of cinnamic acid, the cinnamic acyl substitution degreeof Quaternary ammonium salt of cinnamoyl Chitooligosaccharidedeclined after reaching 22.76%.After N-2-hydroxypropyl trimethyl ammonium chloride Chitooligosaccharide and Quaternary ammonium salt of cinnamoyl Chitooligosaccharide antibacterial properties were tested, results of the minimum inhibitory concentration showed that,two antibacterial polymer drugs either S.aureus or E. coli have antibacterial resistance,and antibacterial against S.aureusis better than against E. coli. Particularly, there have been different results with previous studies: with the increase N-2-hydroxypropyl trimethyl ammonium chloride Chitooligosaccharide substitution degree, the antibacterial properties of the products decreased, which contrary to the past results of N-2-hydroxypropyl trimethyl ammonium chloride Chitosan, at the same time, the antibacterial results of Quaternary ammonium salt of cinnamoyl Chitooligosaccharidedose not accord with the theoretical speculation. The experimental results combined with early theoretical study, we can presume such amphiphilic polymer structure bionical antimicrobial drugs antimicrobial process, and summarize the amphiphilic molecule conformation is the most excellent critical performance factor in the antibacterial activity in such drugs.The second part: synthesis and antibacterial activity of synthetic nano-silver composite film.Due to complications caused by a bacterial infection, food poisoning, wound deterioration and countless other problems, make people eagerly to find more effective antibacterial agent. With the discovery and synthesis of more and more antibacterial agents, the new target of antibacterial agents are increasing durability and reducing Antibiotic resistance.As a effectively inorganic antibacterial agent, because of excellentsurfaceeffect,nano-silver’s antibacterial ability more than 200 times the micron-sized silver particles. By nano-silver composite with other organic materials, many new materials have more perfect properties. In this thesis, by alginate reduced silver ions to obtain stable alginate/nano-silver particles. Next composite alginate/nano-silver with HTCC,we obtained HTCC-Alg/Ag composite film.Performance test results show that because of HTCC, the composite film has excellentwater-absorbingquality, above 200%.The antibacterial experiments show that the film against S.aureus better than E.coli..The antibacterial persistentexperiments show that films can still be sustained release of silver ions on the seven day.