Surface Modification Of Polymeric Short Fibers As Drug Delivery Carriers

Cancer is a disease that poses a serious threat to human health and the incidence of this disease continues to rise.At present,the treatment of tumors is mainly based on surgical resection combined with postoperative radiotherapy and chemotherapy,but these methods have their own obvious defects.When chemotherapeutic drugs are intravenously injected into the human body,they are always faced with a problem that the metabolism of the drugs is too rapid and the bioavailability becomes very low.At the same time,there are problems such as excessive toxic side effects on the normal tissues of the body,and controlled release and targeting of antitumor drugs.Research on transportation is increasingly valued by researchers.The nano drug delivery system can entrap the drug in the carrier for targeted delivery.At present,there is a certain degree of progress in improving the bioavailability of drugs and reducing the toxic and side effects of drugs.However,in vivo circulation time,tumor tissue accumulation,tumor cell phagocytosis,etc.are still not ideal.This dissertation designed and synthesized polymer-modified short fibers with different ligands.Using a non-degradable material(styrene-maleic anhydride copolymer)with good stability as a carrier,the target ligand and long-cycle ligand grafting were used to examine the phagocytosis of cells.The impact of organizational distribution.In this paper,short-fibers containing coumarin-6 were prepared by electrospinning combined with freeze-cutting techniques.The targeting ligands(folic acid,biotin,and their combination)were used to increase the tumor cell phagocytosis of the short fibers.Increasing the in vivo circulation time of short fibers is performed by long circulating ligands(amphiphilic ionic polymers).The long-circulating ligands are grafted onto the fibers via acid-sensitive linkages for the purpose of achieving both long circulation and cell targeting.The tumor cell phagocytosis experiment not only obtained the optimal targeting ligand density of short fibers,but also confirmed in the phagocytosis inhibition experiment that folic acid and biotin mainly achieved the capture of short fibers by promoting clathrin-mediated endocytosis of tumor cells.Amphiphilic ionic polymer modified macrophages phagocytosed significantly less than blank fibers,indicating that it can indeed reduce the possibility of mononuclear macrophage system clearance,the results of in vivo distribution experiments showed amphiphilic ions Polymers reduce the ability of polymer staple fiber blood clearance to achieve longer cycle times.Responsive to the tumor's slightly acidic environment,long-circulating ligands are detached,which can promote cell targeting and phagocytosis and increase the amount of drug accumulation in tumors.The above studies show that ligand-modified short fibers have better potential for tumor-targeted drug delivery.