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Micro-machining of microcirculation model and a method for analyzing deformability and fluidity of blood cells

微循环模型微加工及血细胞变形性和流动性分析方法

基本信息

批准号：
11558112
负责人：
MINAMITANI Haruyuki
金额：
$ 7.94万
依托单位：
Keio University
依托单位国家：
日本
项目类别：
Grant-in-Aid for Scientific Research (B).
财政年份：
1999
资助国家：
日本
起止时间：
1999 至 2000
项目状态：
已结题

项目摘要

Mechanical properties of erythrocyte and blood platelet under diabetic and some other physico-chemical conditions were measured by using transparent micro-channel flow system to analyze the blood cell deformability and fluidity, and also by using atomic force microscope (AFM) to analyze microscopic elasticity of the cell membrane respectively. The micro-channel flow system was made of quartz glass plate and used as a capillary model. Flow channels of 50narrow ditches were straight cut on the glass plate by means of silicon micro-machining technology. Concentration of blood cell suspensions was adjusted with Krebs-Ringer solution that was poured into the flow system. Hydrostatic pressure of 10〜30 cmH_2O was applied to enable the blood flow smoothly through the channels. Local area images of the blood cells were observed under intra-vital microscope, recorded using a high-speed video camera and analyzed by an image processor of PC base. AFM was used in contact mode that gives the relation between deflection and displacement of the AFM cantilever. The spring constant and Young's modulus of erythrocyte was estimated by applying the Hooke's law and the Hertz model respectively on the data of force curve. As the result, deformability of diabetic erythrocytewas significantly lower than that of healthy controls, especially at higher shear rate. The spring constant and Young's modulus of diabetic erythrocytes were much higher than those of healthy controls. These erythrocytes were obviously stiffened to be hard to deform in the capillary flow passage that may follow to the growth of microangiopathy. Diabetic platelets showed the augmented inclination of their adhesion, aggregation and more acceleration of the thrombus formation. This suggested that the endothelial cell layer of micro blood vessel might be easy to be Injured and lead the platelets to form thrombus shortly.

用透明微通道流动系统分析血细胞的变形性和流动性，用原子力显微镜(AFM)分析细胞膜的微观弹性，分别测定糖尿病和其他物理化学条件下红细胞和血小板的力学性质。该微通道流动系统由石英玻璃板制成，作为毛细管模型。利用硅微加工技术，在玻璃板上直接切割出50条窄沟的流道。用倒入流动系统的Krebs-Ringer溶液调节血细胞悬液浓度。施加10~30cmH2O的静水压力，使血液流经通道。在活体显微镜下观察血细胞的局部图像，用高速摄像机记录，用PCBASE图像处理器进行分析。原子力显微镜在接触模式下使用，给出了原子力显微镜悬臂梁的挠度与位移的关系。根据测力曲线数据，分别应用胡克定律和赫兹模型估算了红细胞的弹性常数和杨氏模数。结果表明，糖尿病患者红细胞的变形性明显低于健康对照组，尤其是在较高的切变率下。糖尿病患者红细胞弹性常数和杨氏模数明显高于健康对照组。这些红细胞明显僵硬，难以在毛细血管流道中变形，这可能伴随着微血管病变的发展。糖尿病患者血小板粘附性、聚集性增强，血栓形成速度加快。提示微血管内皮细胞层易受损伤，导致血小板短时间内形成血栓。