基质胶对植入式葡萄糖传感器外膜材料壳聚糖生物相容性的影响

Effects of Matrigel on the Biocompatibility of Implantable Glucose Sensor Outer Materials Chitosan

异物反应的存在导致植入式葡萄糖传感器难以持续正常工作,壳聚糖具有无毒可降解、生物相容性良好等特性,可作为传感器外层的保护膜以提高设备的生物相容性,但尚不能满足实际需求,希望进一步提高膜材料的生物相容性,为此探究不同浓度的基质胶对多孔壳聚糖膜生物相容性的影响。利用模板浸取法,以硅胶作为致孔剂制作多孔壳聚糖膜(PCSM),在此膜的表面滴涂不同浓度的基质胶(matrigel),蛋白质浓度分别为10、15、20 mg/mL。将单独的PCSM(对照组)与滴涂基质胶的PCSM组(实验组)一同植入到SD大鼠背部的皮下组织。植入7、14、28、42、56、70 d后,取材制备常规石蜡切片并进行苏木精-伊红染色,利用组织形态学和统计学方法(主要运用单因素方差分析和Bonferroni法比较两组数据间的差异),对膜外炎性细胞比、纤维包膜厚度和血管密度等数据进行统计分析,评价材料的生物相容性。形态学观察,植入第7、14 d时,膜材料周围细胞核染色均较深。统计膜外炎性细胞比,滴涂不同浓度基质胶的PCSM组在第7 d时炎性细胞比整体上少于PCSM组,第14 d时这一数值略高于多孔壳聚糖膜组。方差分析结果显示,各组间无明显差异(P>0.05)。第28 d时,纤维包膜开始形成,膜材料周围的炎性细胞减少,一些胶原堆积在膜的表面,并随着时间的延长纤维包膜变得致密;第56和70 d时,纤维包膜厚度降低得较明显,各滴涂基质胶的PCSM组纤维包膜厚度均小于PCSM组。方差分析结果表明,各实验组与对照组间差异显著(P<0.05),运用Bonferroni法进行两两比较后,第42、56、70 d时,对照组与实验组中滴涂基质胶浓度为20 mg/mL的PCSM组差异明显,膜材料靠近皮肤端数据两两组比较的P值分别为0.01、0.035、0.024,靠近肌肉端数据P值分别为0.036、0.047、0.210,其他各组之间两两比较后的差异不显著(P>0.05)。膜外血管密度各浓度组大体随着时间的延长呈现增加的趋势,各实验组与对照组间比较差异不大,但个别数据差异明显,滴涂基质胶的PCSM周围血管密度有的值低于PCSM。整体来看,基质胶能提高多孔壳聚糖膜的生物相容性,进一步提高膜材料的性能。

Currently implantable glucose sensors cannot attain normally work.Chitosan has the characteristics of non-toxic,biodegradable and biocompatible,allowing a good candidate for uses as protective films of the outer layer of the sensors.However,it still cannot meet the requirements in clinical practice The aim of this study was to investigate the effects of Matrigel with different concentrations on the biocompatibility of porous chitosan membranes.We used a template leaching technique to prepare porous chitosan membranes(PCSMs).Silica gel was used as the porogen.PCSMs were coated with Matrigel,by dropping different concentrations of Matrigel(10,15,20 mg/mL).The PCSMs coated with or without Matrigel were implanted into the back subcutaneous tissues of male SD rats.The implanted membranes with surrounding tissues were taken out at 1,2,4,6,8,10 weeks.Paraffin section was made with routine procedure.Inflammatory reaction,fibrous capsule thickness and vascular density around the membrane were analyzed by using morphological method and statistical method,comprehensively discussed the biological compatibility of membrane materials were evaluated comprehensively.Morphological observation:nuclei around the membranes were obvious at day 7 and day 14.The number of the inflammatory cells around the PCSMs with different concentrations of Matrigel was less than those of the PCSMs(control group)at the first 7 days.Then the inflammatory cells of the experimental group(with Matrigel)were higher than that of the porous chitosan membrane(control group)at day 14.Variance analysis showed no significant differences between the two groups.Fibrous capsule began to form at day 28,accompanying inflammatory cells decreased,and some collagen accumulated on the surface of membranes.The fibrous capsule became dense over time,the thickness of fibrous capsule decreased obviously at day 56 and day 70.The thickness of fibrous capsule thickness of the experimental group was less than the control group.Variance analysis results showed that the significant difference between experimental group and control group(P<0.05).Using Bonferroni method,the difference between the control group and experimental group with the 20 mg/mL Matrigel was significantly different at day 42,day 56 and day 70.Near the skin,the P values were 0.01,0.035 and 0.024;near muscle the p values were 0.036,0.047 and 0.210.No obvious difference between the other groups(P>0.05).Vascular density around the membranes of each group increased overtime.The general difference between the experimental group and control group was not significant.However differences among the individual data were obvious.Vascular density of some of the PCSM coated with Matrigel was lower than that of the PCSM group.In general,Matrigel can improve the biocompatibility of the porous chitosan membranes to some degree.This can be reflected by the animal experiments.