A microfluidic based Interstitial Fluid (ISF) transdermal extraction tool made from polydimethylsiloxane (PDMS) was designed to the application of continuous glucose monitoring. Four layers of PDMS fabricated by replica molding process were bonded together using oxygen plasma to construct the device, including a Venturi tube for vacuum generation, chambers for the introduction of ISF and normal saline solution, pneumatic valves for fluid control, and interconnected microchannels. Then,the output vacuum of Venturi tube and the close pressure of pneumatic valve were measured. Finally,the ISF extraction and collection function was tested. Results show that the vacuum pressure is used for fluid manipulation and a 92 kPa (absolute pressure) vacuum is achieved, when 220 kPa (absolute pressure) external pressure is applied to the Venturi tube. Moreover, the normally open pneumatic valves can be closed under the operating pressure.less than 65 kPa (relative pressure). Under the control of pneumatic valves, the normal saline injection, ISF extraction and collection function of the tool are implemented by using the vacuum generated from the Venturi tube.%为了在连续血糖监测中实现微量组织液的透皮抽取和收集,采用微流体技术,利用聚二甲基硅氧烷(Polydimethylsiloxane,PDMS)设计加工了组织液透皮抽取装置.首先,采用模塑法加工得到组成装置的4层PDMS.接着,采用氧等离子体键合方法键合PDMS获得能够产生真空负压的文氏管,用于注入生理盐水、抽取组织液和收集组织液的腔体,控制流体传输的气动阀以及连接各部分的微管路4部分装置.然后,测量文氏管的输出负压和气动阀的关闭压强.最后,检验了装置抽取和收集组织液的功能实现情况.结果显示,将220 kPa(绝对压强)的氮气通入文氏管的输入端口,在文氏管的喉部端口获得了92 kPa(绝对压强)的真空负压.另外,只需低于65 kPa(相对压强)的压强就可以关闭采用PDMS薄膜加工的常开型气动阀.该装置可在气动阀的控制下,利用文氏管产生的真空负压,自动完成生理盐水的注入、组织液的抽取和收集.
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