Preparation Of Responsive Antibacterial Composite Nanoparticles And Study Of Targeted Anti-biofilm

Pathogenic bacteria bring many inconveniences to people’s lives.Moreover,free bacteria easily accumulate on the surface of biological tissues or materials to form mature biofilms.Most stubborn bacterial colonies are associated with the formation of bacterial biofilms.In addition to bacteria inside the biofilm,it also contains a large amount of extracellular polymers secreted by bacteria,making it difficult for traditional antibiotics and antibacterial agents to penetrate the biofilm,which greatly increases the difficulty of removing the biofilm.With the continuous development of nano-antibacterial materials,stimulus-responsive antibacterial nanomaterials have attracted widespread attention of scholars.In this paper,ZIF-8 or Fe3O4 were used as carriers to load antibacterial components and targeting folic acid(FA).Further,a responsive antibacterial composite nanoparticle with targeted anti-biofilm activity was prepared using the responsiveness of the carrier or assembly layer.The specific research content is as follows:1、In this study,firstly,the antibacterial carbon quantum dots and the targeting molecule FA were assembled into the ZIF-8 framework by a one-pot method to prepare acid-responsive antibacterial composite nanoparticles with targeting effect.Then the morphology and structure of the composites were characterized,which acid sensitivity,antibacterial activity,anti-biofilm activity,and biocompatibility were comprehensively evaluated.The results show that the prepared composites maintain the stable ZIF-8 framework.Under acidic conditions,the ZIF-8framework easily disintegrates and exposes the internal antibacterial agent to achieve acidresponsive antimicrobials.In addition,the anti-biofilm experiments prove that the targeting effect of folic acid effectively promotes the penetration of antibacterial nanocomposites into the biofilm to destroys the biofilms thoroughly.2、In order to further enhance the anti-biofilm activity of the antibacterial agents,Using magnetic ferric oxide nanoparticles as carriers,the antibacterial component gentamicin / carbon quantum dots,the responsive substance hyaluronic acid HA and the targeting molecule FA were self-assembled on the surface of the magnetic nanoparticles through the electrostatic interaction.The results show that the assembly layer of the composite nanoparticle has the effect of releasing the antibacterial component in response to the acid.In addition,the hydrolysis process of the HA layer has the response to acid and hyaluronidase at the same time,thereby achieving a dual responsive release of the antibacterial components.In the anti-biofilm experiment,the dual targeting effect of magnetic field and FA significantly enhanced the penetration of composite nanoparticles in biofilm.Compared with the previous chapter,the dual antibacterial component,dual response mechanism,and dual targeting effect give the magnetic antibacterial composite nanomaterial excellent anti-biofilm activity.