Design,Synthesis And Antibacterial Application Of Donor-Acceptor Typed Photoactive Conjugated Polymers

Infectious diseases caused by antibiotic-resistant pathogenic microorganisms are seriously threatening human health.Photothermal therapy（PTT）uses photothermal agents to convert the absorbed light energy into high heat under laser irradiation,resulting in protein degeneration and cell wall destruction,so as to kill tumor cells or microorganisms.It is an emerging treatment method with high selectivity,little adverse effect,non-invasive and no drug resistance.The development of photothermal reagents with high photothermal conversion efficiency（PTCE）and good biocompatibility is the key to the clinical application of PTT.Conjugated polymers（CPs）exhibit strong light absorption due to their uniqueπ-conjugated structure.The energy levels can be easily regulated through main chain or side chain engineering,and then the absorption wavelength range can be regulated,and are a kind of potential photothermal reagent materials.In this paper,two kinds of donor（D）-acceptor（A）conjugate polymer photothermal reagents were designed and synthesized,and their applications in PTT antibacterial were explored.The main research contents are as follows:（1）Design and synthesis of donor-acceptor cationic conjugate polymer and its antibacterial properties.Conjugated polymer Poly（TP-T）with cations on side chains was synthesized by direct arylation polymerization,and its nanoparticles TPTNPs were prepared by nano precipitation method.TPTNPs are uniform spherical with a hydration diameter of about 79 nm and Zeta potential of 24 m V,indicating that they have positive surface charge and can be bonded to negatively charged bacterial surfaces by electrostatic interaction.Under the continuous irradiation of 808 nm laser for 20 min,TPTNPs aqueous solution showed obvious photothermal effect and PTCE reached48.7%.In the range of 0-200μM TPTNPs,the activity of He La cells incubated with TPTNPS was more than 97%,indicating good biocompatibility.The results of antibacterial experiment showed that after 10 min irradiation with 808 nm laser（1.0W/cm²）,TPTNPs could significantly damage the surface of E.coli and S.aureus cells,and inhibited the colony growth significantly.The antibacterial rate reached 100%when the concentration was 150μM.It showed excellent antibacterial activity.（2）Design and synthesis of donor-acceptor diketopyrrolopyrrole conjugated polymer and its antibacterial properties.Conjugated polymer PDPP-TP containing diketopyrrolopyrrole（DPP）was synthesized by direct arylation polymerization.PDPP-TP nanoparticles（PTNPs）with amphiphilic polymer DSPE-m PEG₂₀₀₀ coating were prepared by nano precipitation method.PTNPS were spherical with hydration diameter of about 120 nm.Under the continuous irradiation of 880 nm laser（15 min）,PTNPs showed excellent photothermal conversion ability,PTCE up to 52.8%.In the range of0-120μM,the activity of He La cells incubated with PTNPs was above 95%,indicating that PTNPS has good biocompatibility.The results of antibacterial experiment showed that after 6 min irradiation with 880 nm laser（0.7 W/cm²）,PTNPs could significantly damage the surface of E.coli and S.aureus cells,and the colony growth was significantly inhibited.The antibacterial rate reached 100%at 100μM of PTNPs.It showed excellent antibacterial activity.