Study On The Structure Control And Hemostatic Application Of Biodegradable Ploymer Microspheres

Biodegradable aliphatic polyesters have been widely used in biomedical field due to their good biocompatibility,adjustable degradable rate and physical and chemical properties.Because of their big specific surface area,porous structure,chemical structure,controllable surface and degradable rate,the microspheres of aliphatic polyesters show great potentiality in hemostasis.The work of this paper mainly discuss the effect of changing chemical composition,preparation conditions and degradation conditions of aliphatic polyester microspheres.Discover the influence of the physical and chemical structure of the microspheres on the hemostatic ability,especially structural factors affecting the hemostatic effect are elucidated.This paper provides a theoretical basis for the application of degradable polymeric microspheres in the field of hemostasis.The specific research content is as follows:1.A series of polycaprolactone homopolymers with adjustable structure and adjustable composition and amphiphilic block copolymers containing different functional groups are prepared by the ring-opening polymerization of caprolactone which is initiated by ethylene glycol,amino-terminated and terminal methoxy polyethylene oxide macromolecules as initiators and stannous octoate as a catalyst.The structure of the obtained polymer was characterized by 1HNMR and GPC.2.PCL porous microspheres were prepared by modified double emulsion solvent evaporation method.Study on the effect of microsphere preparation conditions(such as solvent,ammonium bicarbonate concentration,initial emulsion strength,external water phase stirring speed,etc.)on the microstructure of microspheres.Discuss formation mechanism of different structure microspheres.Through the ammonolysis experiment of microspheres,the functional groups on the surface of the microspheres were controlled.At the same time,a series of microspheres with different pore structures on the surface were prepared through the control of the degradation time.3.The study compares the hemostatic ability of seven different materials:PCL10k-b-PEO1k-OCH3?PCL20k-b-PEO1k-OCH3?PCL40k-b-PEO1k-OCH3?PCL10k-b-PEO1k-NH2?PCL20k-b-PEO1k-NH2?PCL40k-b-PEO1k-NH2?PCL25K.Combining two systems for evaluation of hemostasis in vitro and evaluation of hemostasis in living organisms,study on the influence of microsphere dryness,pore structure,chemical composition of microspheres,and surface chemical structure on the hemostatic properties of microspheres.The paper explains the hemostatis principle of microspheres.