叶酸-聚乙烯亚胺复合碳点的跨膜机制和胞内分布

摘要

目的:探讨以叶酸和聚乙烯亚胺(PEI)为原料合成的荧光碳点跨 MC3T3-E1细胞膜转运途径、胞内分布其对细胞的影响,并阐明其机制.方法:以叶酸和 PEI为原料,通过水热法合成具有细胞成像功能的荧光碳点,采用 MTT法筛选碳点的最佳使用浓度.将 MC3T3-E1细胞分为空白对照组、叶酸组和碳点组,通过细胞周期、细胞凋亡和细胞活性氧(ROS)水平检测评估碳点的生物相容性;通过胞膜窖途径抑制剂制霉菌素、巨胞饮途径抑制剂诺考达唑的使用,探讨细胞摄取碳点的途径;利用碳点在紫外光激发下发射蓝色荧光的特点,通过各种细胞器探针进行荧光共定位以观察碳点在细胞内的分布.结果:与空白对照组比较,24 h 时100~450 mg·L-1碳点组细胞增殖率明显升高(P0.05);与空白对照组比较,叶酸组和碳点组细胞凋亡率无明显改变(P>0.05),但细胞内 ROS水平明显降低(P0.05);at 48 h,the cell proliferation rate was reduced to 68.4% of blank control group when the concentration of CDs reached 350 mg · L -1(P0.05).Compared with blank control group,the apoptotic rates of the cells in folic acid group and CDs group had no significant differences(P>0.05). Compared with blank control group,the intracellular ROS levels in folic acid group and CDs group were significantly decreased(P<0.05).Compared with blank control group,the uptake amount of CDs in the cells was decreased in nystatin group(P<0.05).The blue fluorescence of CDs overlapped with the red fluorescence of mitochondria under an inverted fluorescence microscope,the blue fluorescence of CDs overlapped with the red fluorescence of lysosomes;they didn't overlap completely with the red fluorescence of the endoplasmic reticulum;the blue fluorescence of CDs overlapped poorly with the red fluorescence of Golgi apparatus.Conclusion:CDs perform well in biocompatibility and they can be distributed to different organelles after taken in by the cells.They can be used as a kind of gene carrier in transgenic therapy.