Study on the "intelligent mosquito"

为了减少采血带来的痛苦，开发了一种模仿蚊子的小型分析系统。该系统由微型葡萄糖传感器、取样机构和显微针组成。采用聚N-异丙基丙烯酰胺和丙烯酸共聚凝胶，构建了一种缓慢抽取样品溶液的机构。使用11 mm × 11 mm × 4 mm的凝胶，通过改变温度、改变温度和pH以及使用由葡萄糖氧化酶的酶促反应引起的pH变化来引起体积变化。对于负载酶的凝胶，凝胶收缩最慢，跨越近10小时。在硅橡胶膜片的帮助下，凝胶的体积变化可以转化为流道中的压力变化。因此，该机构可以将外部溶液抽入流动通道中。该葡萄糖传感器由铂工作电极组成，铂工作电极上覆盖有分别作为选择性渗透膜和扩散限制膜的Nafion膜和polyHEMA膜。在两层之间形成酶固定化层。标准曲线的线性范围扩大到30 mM，对L-抗坏血酸和尿酸的响应可降低到葡萄糖的1%左右。外部葡萄糖标准溶液可以通过开启凝胶体积变化而自主地引入系统中。当在硅胶管中流动的外部溶液的葡萄糖浓度任意改变并且通过显微镜针对溶液进行取样时，可以使用芯片上微型葡萄糖传感器连续监测葡萄糖浓度。

In order to minimize pain accompanying blood sampling, a miniaturized analysis system that imitates a mosquito was developed. The system consisted of a micro glucose sensor, a sampling mechanism, and a microscopic needle. A copolymerized gel composed of poly(N-isopropylacrylamide) and acrylic acid was used to construct a mechanism that withdrew sample solution slowly. A gel of 11mm×11mm×4mm was used and a volume change was caused by changing the temperature, changing the temperature and pH, and using a pH change caused by the enzymatic reaction of glucose oxidase. With the enzyme-loaded gel, the gel shrank most slowly spanning nearly 10h. The volume change of the gel could be converted into a pressure change in a flow channel with the help of a silicone rubber diaphragm. As a result, the mechanism could withdraw an external solution into the flow channel. The glucose sensor consisted of a platinum working electrode covered with a Nafion membrane and a polyHEMA membrane which worked as a perm-selective membrane and a diffusion-limiting membrane, respectively. An enzyme-immobilized layer was formed between the two layers. The linear range of the calibration curve was expanded up to 30mM and the responses to L-ascorbic acid and uric acid could be reduced to about 1% of that to glucose. An external glucose standard solution could be introduced into the system autonomously by switching on the gel volume change. When the glucose concentration of an external solution flowed in a silicone tube was changed arbitrarily and the solution was sampled through the microscopic needle, the glucose concentration could be monitored continuously using an on-chip micro glucose sensor.