Preparation of porous clitosan membrane and observation of its subcutaneously implanted histology

Abstract

Objective To analyze the impact of glutaraldehyde crosslinker on porosity and pore size of porous chitosan membrane (PCSM) and to explore the feasibility of PCSM as the protective membrane of glucose sensor.Methods The PCSM was prepared by particle leaching method using silica gel and different amounts of glutaraldehyde.Density method and slice method were used to analyze the structural parameters of PCSM such as porosity and pore size and its surface morphology was observed with scanning electron microscope (SCM). Thereafter, the uncrosslinked porous membranes were subcutaneously transplanted into 9 SD rats and extracted to observe their histomorphological changes by section staining at the 7th,17th and 45th day after transplantation.Quantitative analysis was then performed on collagen deposition inside and outside of the porous membranes and vascular proliferation density.Results The glutaraldehyde could increase the PCSM porosity that could reach the maximum of 76.2％/73.0％ with 5％ degree of crosslinking (density method vs slice method),but it could also decrease the pore size of porous membrane.The uncrosslinked porous membranes with the largest pore size (38.5 μm) were used and subcutaneously transplanted,which resulted in an increase of intramembranous collagen deposition content from 6.74％ at the 7th day to 22.5％ at the 45th day.Moreover,the intramembranous proliferated capillary density was increased from 0.37％ to 2.56％ using Masson staining,which was consistent with the measured outcomes using HE staining (ranged from 0.11％ to 1.65％ ).At the 45th day,the content of collagen deposition outside of the membrane was 38.3％ that was 1.7 times of the intramembranous collagen deposition content.Conclusions PSCM may decrease the compactness fibrous composition of material-tissue interface but increase vascular proliferation,with favorable histocompatibility.Thus,PCSM appears promising in application in transplanted glucose sensor. Key words: Chitosan; Porous; Histocompatibility; Fibrous capsule; Angiogenesis