Study On Chiral Borneols And Their Interfacial Antibacterial Performances

In recent years, the prevention of bacterial adhesion on material surfaces is an important research topic, as the adhesion of bacteria is the first step in bacterial colonization or proliferation as well as the formation of bacterial biofilms, which are responsible for numerous human healthcare (i.e., infections and diseases) and environmental problems. Various strategies have been explored based on the immobilization or release of bactericidal substances. However, these strategies have different limitations, so the researchers take more attention on the new effective antibacterial strategy. In the field of antibacterial material, the research on chiral molecule of material surface is still less. So relationship between the surface chiral stereochemistry and antibacterial performance by developing new antibacterial materials is urgent.Borneol is known as a natural chiral drug, it has a variety of chiral stereochemistry structure. In this study, borneol monomers with three different chiral configurations (endo-L-(-)-borneol, endo-D-(+)-borneol and exo-Iso-(±)-borneol) were used as raw material. Then the polyborneolacrylates (PBAs) were synthesized, which were proved by using GC-MS,1H-NMR, GPC, CD and CA etc characterizations. Then "prison break" experiment, bacteria coincubation experiment, optical density (OD) and the plate count method etc methods were used to evaluate the antimicrobial activity of the PBAs. At the same time, the cytotoxicity, biological capacitive of materials were evaluated. Further, the isoborneol acrylate monomer (IBA) and the methyl methacrylate monomer (MMA) were mixed in different ratios, and then the poly(borneolacrylate-methyl methacrylate) [P(IBA-MMA)] copolymers were successfully synthesized, and their antibacterial performance were evaluated. The main research results are listed in below:1.Three chiral PBA polymers have been synthesized successfully.2.The antimicrobial test showed that PBAs have wide antimicrobial properties; they could inhibit the adhesion of Escherichia coli (E. coli), Staphylococcus aureus (S. aureus) and Mucor racemosus (M. racemosus).3.Particularly, PLBA and PIBA displayed more resistance to bacteria than PDBA.4.Meanwhile, these PBAs were found to be non-cytotoxic and non-inflammatory implant. They can be used as an antibacterial material in medicine, food and environmental protection filed, with an enormous potential for development.5.For copolymer materials, the antibacterial activity of the copolymers enhanced with the increase of the content of IBA nomomer. When the IBA monomer content reached 50%, the antibacterial properties of copolymer material close to the PIBA’s. So, by adding IBA nomomer, the antibacterial activity of P(IBA-MMA) copolymer materials were enhanced, demonstrating better potential for biomedical applications.The research result showed, the antibacterial mechanism of PBA is that, the PBA possess dense pendants of camphane-type bicyclic structures, which have three chiral centers. It can significantly influence bacteria adhesion mainly through surface stereochemistry structure. From the point of view of biology, bacteria don’t tend to adhesive on the surface that has complex stereochemistry structure. The stereochemistry mechanism is a kind of new antibacterial strategy.