Preparatioin And Research Of Acid-sensitive Photothermal-chemotherapy Cooperative Nano-drug Carriers

In developing countries,the incidence of female breast cancer has been ranked first,and the conventional treatment method is mainly surgery combined with radiotherapy and chemotherapy.However,common chemoradiotherapy methods often have great toxic side effects on normal human tissues.Therefore,increasing the targeting of drugs,achieving the controlled release of drugs,and developing alternative therapeutic methods have become the main targets for the development of nano drug carriers.Polymer nano-carriers have the characteristics of clear structure,simple preparation and adjustable control,and can be enriched in functional modification.Therefore,they have become an important choice for many anti-cancer drug carriers.According to the bio-characteristics of the acidity of the tumor,we prepared a tumor drug carrier with an acid response and GA ve it a pHotothermal effect based on chemotherapy.Starting from the small molecular chain transfer agent,a three-arm polymer is prepared through a variety of polymerization reactions.This polymer has a better biocompatible PEG hydropHilic end,with acid-responsive C7A and pHotothermally-reactive Cy 7.5 two hydropHobic ends.In aqueous solution,the polymer can self-assemble,the hydropHobic end can form a stable hydropHobic core with the hydropHobic drug GA mbogic acid through hydropHobic interaction,and PEG acts as the hydropHilic end to externally enclose the inner hydropHobic part in the blood circulation.The drug-loaded micelles can be well hidden from clearance by the reticuloendothelial system.After the polymer micelles enter the tumor tissue through the EPR effect,C7A changes from a hydropHobic segment to a hydropHilic segment due to a decrease in the pH value,and at the same time,the particle size of the nanoparticles increases,so that it is difficult to escape from the tumor tissue site,and the unidirectional pH is passed through.Responsive enrichment can increase the total amount of nanomedicine enriched in tumor tissue.After entering the tumor tissue,the chemotherapeutic drugs released can effectively kill cancer cells.At the same time,the pHotothermal effect of the hydropHobic terminal Cy 7.5 can be used to further consolidate the curative effect.To verify the effect of pH response,a linear polymer without a C7A segment was constructed for comparative studies.4T1 cells were used for cell experiments and animal models were constructed to verify the efficacy of the two polymers.