Construction And Photodynamic Antimicrobial Performance Of Composite Surface Based On Micro-nano Structure

Photodynamic antibacterial hybrid membranes based on the micro-nano structures（RB@ZIF-8@PCL）were prepared by using photosensitizer Bengal rose red（RB）as bactericide,metal organic framework（ZIF-8）as drug carrier and polycaprolactone（PCL）as the polymer matrix.Firstly,RB loaded ZIF-8（RB@ZIF-8）was prepared by"one pot method"by simply mixturing RB,zinc nitrate and 2-methylimidazole in methanol.The chemical structure and morphology of the as-prepared nanoparticles were characterized by fourier infrared spectroscopy（FTIR）,ultraviolet and visible light analysis（Uv-Vis）,X-ray diffraction（XRD）,field emission scanning electron microscopy（SEM）,field emission transmission electron microscopy（TEM）and dynamic light scattering（DLS）,respectively.The RB loading of RB@ZIF-8 was measured by TGA and UV-Vis,respectively.The results show that the RB loading did not affect the morphology,structure,particle size and crystallinity of ZIF-8.The loading amount of RB@ZIF-8 is about 11 wt.%.Subsequently,RB@ZIF-8@PCL was prepared by co-electrospinning of RB@ZIF-8 and PCL suspensions.The chemical structure,surface morphology and surface wettability of RB@ZIF-8@PCL were characterized by attenuated total reflection FTIR,SEM and water contact angle（WCA）,respectively.The experimental results show that the surface micro-nano structure could be regulated by changing the loading amount of RB@ZIF-8 in the hybrid fiber membrane.ROS detection assay showed that RB@ZIF-8@PCL can effectively release singlet oxygen under visible light irradiation,of which amount was closely related to the load amount of RB@ZIF-8 and light irradiation time.In vitro bactericidal test proved that the ROS endowed the hybrid membrane with good broad-spectrum bacterial sterilization performances.In vivo animal experiments further proved that the hybrid nanofiber membranes can effectively inactivate bacteria at infected wound beds,thus accelerate healing of infected wounds.In addition,RB@ZIF-8 and PCL did not cause hemolysis and adverse tissue inflammation.Therefore,the hybrid nano-membrane showed potential applications in the field of anti-infection.A super-hydrophobic antibacterial surface with anti-adhesion and photodynamic bactericidal performances was prepared by using the electrostatic layer-by-layer self-assembly（LBL）technology to immobilization of SiO₂ nanoparticles with different sizes.In detail,by using tetraethyl orthosilicate（TEOS）and aqueous ammonia as a raw materials,SiO₂ nanoparticles with different diameters of approximately 1200 nm and 200 nm were initially prepared.Subsequently,the MB was loaded inside the MSN via electrostatic interaction to get the MB-loaded MSN（MB@MSN）.FTIR and UV-vis spectrometer spectrophotometer proved that the MB was successfully loaded inside the MSN,and the MB loading amount was about¹.4wt%measured by calculating.ROS detection and in vitro antibacterial experiments showed that MB@MSN can effectively produce singlet oxygen upon visible light irradiation,which can in turn result in the high inactivation efficiencies against Gram-positive Staphylococcus aureus and Gram-negative E.coli.Then,SiO₂ particles with a diameter of about 1200 nm were fixed on the material surface via surface spining coating and epoxy curing to prepare a single scale structure.Subsequently,MB@MSN was introduced onto the single scale structured surface through the particle electrostatic interaction between MB@MSN and surface SiO₂ particles to get the dual scale structured surface.Then,a fluorine-containing silane was used to endow the surface with low-surface energy.The preparation of dual scale structured surface was confirmed by SEM and its surface WCA was higher than 150℃.The synergetic anti-bacterial adhesion and bactericidal properties will be further explored.