Application Of Organic Conjugated Polymer Nanomaterials In Photothermal Antibacterial And Tumor Photothermal Therapy

Conjugated polymers is a special type of macromolecule with a large ?-? conjugated backbone.The high electron delocalization structure gives it a strong ability to absorb light energy and convert it into other energies.Conjugated polymer nanomaterials are often used in photothermal anti-tumor therapy due to their excellent photothermal conversion capabilities.However,the conjugated polymer nanoparticles themselves are usually unstable,easily dissociated,and difficult to modify with other biomolecules on their surface,which seriously hinders their further development in the biomedical field.In order to solve such problems,a general method for encapsulating conjugated polymer nanoparticles has been developed in this paper.The prepared PDA coated conjugated polymer nanoparticles have excellent photothermal properties for photoacoustic imaging and photothermal antitumor therapy.In addition,this paper combined with the excellent photothermal properties of nanoparticles and silver nanoparticle antibacterial to realize common antibacterial.Therefore,the specific research content of this paper mainly includes the following two aspects:(1)Preparation of organic conjugated polymer nanomaterials and their antitumor applications:PSBTBT NPs were first prepared by reprecipitation method.The PDA shell layers were fabricated on the surface of PSBTBT NPs by in-situ dopamine polymerization.The obtained PSBTBT@PDA NPs are uniform in size(~65 nm)and have the advantage of being purified by centrifugation.Biomolecules that can be modified on the surface of polydopamine(PDA)with functional groups such as catechol and amino groups.In this study,three representative biomolecules with different reactive groups including small molecule(folate,FA),polypeptide(cRGD)and polymer(SH-PEG)were selected.The experimental results show that three organisms molecules can be successfully modified to the PSBTBT@PDA NPs under mild conditions.More importantly,due to the strong absorption of dopamine itself and the fluorescence quenching effect on PSBTBT NPs,compared to the original PSBTBT NPs,the synthesized PSBTBT@PDA NPs showed excellent structural stability and significantly enhanced photoacoustic and photothermal performance,which can ablate tumors more effectively.(2)Preparation and application of polydopamine modified organic-inorganic hybrid antibacterial materials:PSBTBT NPs were first prepared via reprecipitation method.The PDA shell layers were fabricated on the surface of PSBTBT NPs by in-situ dopamine polymerization.The silver nanoparticles are loaded on the surface of PSBTBT@PDA NPs,combined photothermal antibacterial and silver nanoparticles antibacterial to achieve a common antibacterial effect.TEM and DLS show that the obtained dopamine-coated organic-inorganic hybrid PSBTBT@PDA-Ag NPs can form nanoparticles of uniform size(~80 nm)and has the advantage of rapid purification by centrifugation.Ag NPs loaded on the surface of PSBTBT@PDA NPs are uniform in size(~10 nm).PSBTBT@PDAAg NPs combines the excellent photothermal properties of organic semiconductor nanomaterials with the antibacterial properties of silver nanoparticles to get a high-efficiency antibacterial effect.