Application Of Magnetic Bacterial Cellulose In Vascular Repair And Drug Release

Cardiovascular disease has globally become the leading cause of death in coming years.Developing new techniques have been evolved in providing effective treatment.Tissue engineering and repair,artificial blood vessels merged as an attractive field.However,synthetic materials are more prone to thrombosis and calcium deposition.Developing one kind of artificial blood vessels with small-diameter which can avoid thrombosis has becoming a promising field.Endothelialization is an effective method for artificial blood vessels to prevent thrombosis.Bacterial cellulose（BC）,a natural biocompatible polymer with good mechanical properties,has the potential to be implemented as artificial blood vessels.In this work,we have synthesized iron oxide nanoparticles（IONs）coated with carboxyl polyethylene glycol（HOOC-PEG-COOH）which were used to prepare magnetic bacterial cellulose（MBC）using in-situ and chemical modification methods then liked to RGD polypeptide.The vibration of polypeptide（RGD）was controlled by oscillating magnetic fields of different frequencies.We found that our composite promoted cells adhesion and growth,and the slow frequency magnetic field can promote the progress of endothelialization.The composites and the cells were characterized by SEM,TEM,AFM,FT-IR,TGA and immunofluorescence staining.The specific research results are as follows:（1）Magnetic Fe₃O₄ nanoparticles coated with carboxyl polyethylene glycol were synthesized by the method of thermo decomposition.The nanoparticles were monodispersed in aqueous solution with a particle size of about 20 nm.MBC1 was prepared by in-situ co-culture of nanoparticles in fermentation medium.Through characterization,it showed that the nanoparticles could be uniformly dispersed on the fibers,and the percentage of nanoparticles in MBC1 was about 5.06%,and MBC1 had a higher Young’s modulus than BC.Cell experiments showed that MBC1 had little cytotoxicity and promoted the adhesion and growth of mouse endothelial cells.（2）By changing the reaction conditions of nanoparticles,"nano-flower"were synthesized and MBC was prepared through the method of esterification.The MBC’s properties of drug loading and release were studied with or without magnetic field.It showed that the oscillating magnetic field can accelerate the release of doxorubicin hydrochloride to cure the cancer.RGD polypeptide was attached to the other site of the nanoparticle to prepare RMBC by the reaction of EDC/NHS.The movement of RGD can also be controlled by the external oscillating magnetic field.Compared with MBC1,MBC has a higher percentage of nanoparticles up to 17%,but young’s modulus is lower than BC.Compared with BC,C166 cells showed better adhesion on MBC,and showed the best on RMBC.Cells under slow oscillating magnetic field are more easily to form tight-junction.However,fast oscillating magnetic field inhibits cell adhesion on RMBC.