Study On Construction And Photo-Induced Antibacterial Activity Of Bioactive Phthalocyanine Polymers

The phthalocyanine photosensitizer has the advantages of stable chemical properties,simple synthesis and easy modification,which is expected to be used in novel photodynamic therapy.The solubility and photosensitive activity of phthalocyanine are crucial to the photodynamic antibacterial performance.However,highly conjugated phthalocyanine with high singlet oxygen generation efficiency tends to aggregate in aqueous environments,leading to poor solubility and photodynamic antibacterial activity.In this paper,a novel photodynamic antibacterial polymer based on the phthalocyanine photosensitizer was designed and synthesized according to the characteristics of the microenvironment of bacterial infection site.The main contents of this paper are as follows:(1)The polymeric phthalocyanine photosensitizer was synthesized using phthalocyanine chain transfer agent and water-soluble monomers by the reversible addition-fragmentation chain transfer polymerization.The positive charge surface of the polymer was obtained by quaternization reaction,which can interact with the bacteria by electrostatic attraction.The phthalocyanine cationic polymer showed excellent photodynamic antibacterial effect,which can kill both gram-positive and gram-negative bacteria under the 680 nm light irradiation.The phthalocyanine polymer had low cytotoxicity and can be used for the rapid healing of the bacterial infected wounds.(2)Based on the characteristics of the microenvironment of the bacterial infection site,a p H-sensitive phthalocyanine polymer was designed and synthesized.The p H-sensitive polymer presented neutral or negative in normal physiological environment.However,the potential of the polymer changed from negative to positive when it reached the location of infection.The affinity of polymer and bacterial surface has been enhanced,which was beneficial to the enrichment of antibacterial polymer at the location of bacterial infection.Therefore,the charge-reversed phthalocyanine polymer-silver nanocomposites were prepared.With triple antibacterial effect of photodynamic antibacterial,photothermal antibacterial and cationic antibacterial activity under 808 nm light irradiation,this nanocomposite can effectively kill the bacteria.(3)An excellent water-soluble polymyxin B-functionalized phthalocyanine photosensitizer was designed and synthesized for photodynamic antibacterial treatment.Combined with the photodynamic activity of phthalocyanine and the antibacterial ability of polymyxin B,the photosensitizer could target to the surface of bacteria and rapidly produce singlet oxygen,killing Gram-positive bacteria and Gram-negative bacteria under 680 nm light irradiation.Antibacterial mechanism result showed that the phthalocyanine photosensitizer can destroy the integrity of the bacterial cell membrane by binding with Ca²⁺and Mg²⁺on the bacterial surface.The photosensitizer has excellent biocompatibility and can effectively promote the rapid healing of bacterial infected wounds,providing a new development idea for the combination of photodynamic antimicrobial therapy and chemotherapy.