Hydrogel-actuated capacitive transducer for wireless biosensors
Hydrogel-actuated capacitive transducer for wireless biosensors
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DOI：
10.1023/a:1014627029818
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发表时间：
2002-05-01
影响因子：
2.8
通讯作者：
McConaghy, CF
中科院分区：
文献类型：
--
作者：
Strong, ZA;Wang, AW;McConaghy, CF
本文介绍了一种新型的传感器，结合电容式压力传感技术与生物敏感水凝胶，使用一个适应性强的MEMS制造平台。响应于分析物浓度的水凝胶溶胀在可变形导电隔膜上施加接触压力，从而产生电容变化。初步结果报告测试设备的可行性。测试未交联的PHEMA水凝胶响应于硝酸钙四水合物的溶胀压力。在NiTi基隔膜上测量由于施加的空气压力引起的隔膜偏转，并将其与相同隔膜的水凝胶致动偏转进行比较，以确定水凝胶的压力产生特性。PHEMA样品在0-0.5 M的浓度范围内表现出最大的灵敏度，产生110 mN/M/穆尔的平均值。该装置被纳入一个无源LC谐振电路。在水凝胶溶胀产生的压力范围内，测量共振频率作为施加的空气压力的函数。在0-32 kPa的压力范围内，共振频率从66 MHz偏移到33 MHz，对应于在0-0.5 M的范围内，每μ mol硝酸钙四水合物的估计平均灵敏度为66 Hz。
This article introduces a new type of transducer that combines capacitive pressure sensing techniques with biosensitive hydrogels, using an adaptable MEMS fabrication platform. Hydrogel swelling in response to analyte concentration exerts contact pressure on a deformable conducting diaphragm, producing a capacitance change. Initial results are reported for testing device feasibility. Uncrosslinked PHEMA hydrogel was tested for swelling pressure in response to calcium nitrate tetrahydrate. Diaphragm deflection due to applied air pressure was measured on NiTi-based diaphragms and compared with hydrogel-actuated deflections of the same diaphragms to determine the pressure generating characteristics of the hydrogel. The PHEMA sample exhibited greatest sensitivity in the concentration range 0-0.5 M, generating an average of 110mN/M/mul. The device was incorporated into a passive LC resonant circuit. Resonance frequency was measured as a function of applied air pressure, in the range of pressures generated by hydrogel swelling. Resonance frequency shifted from 66 MHz to 33 MHz over the pressure range 0-32 kPa, corresponding to an estimated average sensitivity of 66 Hz per mumol of calcium nitrate tetrahydrate over the range 0-0.5 M.