Synthesis And Antibacterial Property Of Photodynamic Enhanced Nanocomposite Membrane

The bacterial resistance caused by traditional antibacterial methods is becoming more and more serious,and the related infectious diseases have caused serious medical risk and increased the economic burden.In comparison,photodynamic therapy?PDT?,as a non-specific antibacterial method that does not easily cause bacterial resistance,has received particular research interests.Generally,PDT requires ultraviolet or visible light to induce photosensitizer for reactive oxygen species?ROS?generation.However,the penetrability of visible light is relatively weak,and the irradiation of ultraviolet light may cause unnecessary damage to healthy tissue,which largely limit the therapeutic effects and further applications.In addition,ROS has extremely short release distance?tens to hundreds of nm?and lifetime?a few microseconds?,heavily limiting its bactericidal effect.In this respect,we proposed and developed several strategies to enhance the antibacterial effect and expand the further application of PDT,mainly as follows:1.An upconversion nanoparticles?UCNPs?doped antibacterial nanocomposite membrane was prepared by electrospinning.This nanocomposite membrane itself does not possess bactericidal performance,but exhibits excellent antibacterial ability under the irradiation of near-infrared?NIR?light.The UCNPs in the nanocomposite membrane could indirectly sensitize the photosensitizer upon the NIR irradiation,and then trigger the release of ROS.The antibacterial experiments showed that the nanocomposite membrane could effectively kill both Staphylococcus aureus and Escherichia coli upon NIR irradiation?980 nm?.In addition,the bactericidal properties of this nanocomposite membrane remained effective even after 4 cycle operations.Cytotoxicity experiment showed that the nanocomposite membrane had no obvious cytotoxicity to mammalian cells.This nanocomposite membrane could potentially be used in fields such as anti-infection and wound healing,and the study provided a new strategy for the design of PDT antibacterial materials.2.Using the mixture of biodegradable zein and polycaprolactone?PCL?as polymer matrix and functionalized MSNF@MB as the co-doped nanoparticles for electrospinning to prepare the nanocomposite membrane.After perfluorination treatment,the surface energy of MSNF@MB was largely reduced,and these nanoparticles tended to be enriched on the surface of nanofiber during the electrospinning.Based on the self-aggregation of the MSNF@MB on the surface,the resulting nanocomposite membrane could increase the ROS yield upon visible light?660 nm?irradiation and exhibit the significantly enhanced surface hydrophobicity,realizing the effective bacterial repellency and PDT synergistic efficacy.This strategy could overcome the uncontrollability of powdered antibacterial materials and the limitation of low ROS production in the nanoparticle-doped matrix,and it provided a novel method for improving the PDT antibacterial effect of nanocomposite materials,which has the potential application in various fields.3.A nanocomposite membrane with synergistic antibacterial effect of PDT and photothermal therapy?PTT?triggered by a single NIR light has been developed.First,a hierarchically structured nanoparticle?UCNPs@TiO₂?with NaYF₄:Yb,Tm nanorods as core and TiO₂ nanoparticles as shell was synthesized.Then,nanoscale graphene oxide?GO?as a photothermal agent was doped into UCNPs@TiO₂ to obtain the tertiary structured nanoparticle UCNPs@TiO₂@GO.Finally,UCNPs@TiO₂@GO and polyvinylidene fluoride?PVDF?were composited by electrospinning to obtain the nanocomposite membrane?UTG-PVDF?.Under a single NIR?980 nm?irradiation,this nanocomposite membrane could simultaneously produce ROS and moderate photothermal effect,which can achieve the high antibacterial efficacy of synergistic PDT and PTT.In addition,the nanocomposite membrane can effectively inhibit the inflammatory response and accelerate wound healing,so it offers a potential in the treatment of infectious complications during the wound healing process.4.An antibacterial nanocomposite membrane with synergistic effect of PDT and NO therapy was synthesized.In experiment,hierarchically structured nanoparticles?UCNP@PCN?consisting of the UCNPs and porphyrin MOFs?Metal-organic frameworks,PCN224?were synthesized.Under NIR irradiation?980 nm?,the fluorescence resonance energy transfer from UCNPs to MOFs was achieved,which then triggered the ROS generation.In addition,L-arginine?LA?was compounded with UCNP@PCN by electrostatic interaction to achieve the controllable release of NO in the presence of ROS.Then,the UCNP@PCN@LA nanoparticles were introduced into polyvinylidene fluoride?PVDF?by electrospinning to get the nanocomposite membrane UCNP@PCN@LA-PVDF.Upon NIR irradiation,this membrane could achieve the synergistic antibacterial performances on the basis of the controllable PDT and NO-releasing.The long release distance of NO could make up for the short distance of ROS transmission,significantly enhancing the antibacterial efficacy.In addition,this membrane can be used for disinfection of dermal wounds in vivo,and has potential applications in treating infectious diseases for antimicrobial resistance.