Hydrogel based sensor arrays (2 × 2) with perforated piezoresistive diaphragms for metabolic monitoring (in vitro).
Hydrogel based sensor arrays (2 × 2) with perforated piezoresistive diaphragms for metabolic monitoring (in vitro).
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DOI：
10.1016/j.snb.2010.01.063
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发表时间：
2010-03-19
影响因子：
8.4
通讯作者：
Solzbacher, F.
中科院分区：
文献类型：
--
作者：
Orthner, M. P.;Lin, G.;Avula, M.;Buetefisch, S.;Magda, J.;Rieth, L. W.;Solzbacher, F.
本报告详细介绍了新型水凝胶传感器阵列 (2 × 2) 的第一个实验结果，该阵列将分析物扩散孔合并到压阻隔膜中，用于检测水凝胶膨胀压力，从而检测化学浓度。传感器组件由三个组件组成，即有源四个传感器、HPMA/DMA/TEGDMA（甲基丙烯酸羟丙酯（HPMA）、甲基丙烯酸 N,N-二甲氨基乙酯（DMA）和交联剂二甲基丙烯酸四乙二醇酯（TEGDMA））水凝胶和背板。阵列中的每个单独的传感器都可以与各种水凝胶一起使用，用于测量多种刺激的存在，包括 pH、离子强度和葡萄糖浓度。理想情况下，未来这些传感器将用于连续代谢监测应用并植入皮下。在本文中，为了正确表征传感器组件，使用甲基丙烯酸羟丙酯（HPMA）、甲基丙烯酸N,N-二甲氨基乙酯（DMA）和交联剂二甲基丙烯酸四乙二醇酯（TEGDMA）合成了对离子强度变化敏感的水凝胶，并将其插入传感器组件中。当放置在离子强度范围为 0.025 至 0.15 M 的生理缓冲溶液 (PBS) 环境中时，这种水凝胶会快速、可逆地膨胀，使其成为概念验证测试和初始表征的理想选择。该组件通过引线键合到印刷电路板上，并使用化学气相沉积 (CVD) 涂有 3 ± 0.5 μm 的聚对二甲苯-C，以在离子强度湿测试期间保护传感器和电气连接。为了进行比较，制造了两种版本的传感器，第一种将扩散孔合并到隔膜中，第二种使用带有穿孔背板的实心隔膜。当与水凝胶结合时，这种新设计（穿孔隔膜）的灵敏度比具有单独扩散背板的固体隔膜传感器稍高。 1 mm × 1 mm、1.25 mm × 1.25 mm、1.5 mm × 1.5 mm 穿孔隔膜传感器的灵敏度分别为 53.3 ± 6.5、171.7 ± 8.8 和 271.47 ± 27.53 mV/V-M。这些结果表明，隔膜中的穿孔不仅可用于允许分析物扩散到腔中，还可用于增加压阻隔膜中的机械应力，从而增加传感器输出信号。通过将传感器输出半周期拟合到指数增长函数来计算膨胀 (τswelling) 和收缩 (τcontracting) 的时间常数。我们发现传感器的响应最初在水凝胶初步调节期间延迟，然后在 3-5 个循环后得到改善，τ 膨胀和 τ 收缩的值约为 9 和 7 分钟。对于所有测试的传感器，τswelling > τcontracting。这可能是由于膨胀过程中隔膜对水凝胶的负载增加所致。在收缩过程中，隔膜通过可逆地施加机械压力来帮助水凝胶，从而减少τ收缩。长期稳定性测试表明，传感器在测试磷酸盐缓冲溶液 (PBS) 中保持功能长达 2 周以上。
This report details the first experimental results from novel hydrogel sensor array (2 × 2) which incorporates analyte diffusion pores into a piezoresistive diaphragm for the detection of hydrogel swelling pressures and hence chemical concentrations. The sensor assembly was comprised of three components, the active four sensors, HPMA/DMA/TEGDMA (hydroxypropyl methacrylate (HPMA), N,N-dimethylaminoethyl methacrylate (DMA) and crosslinker tetra-ethyleneglycol dimethacrylate (TEGDMA)) hydrogel, and backing plate. Each of the individual sensors of the array can be used with various hydrogels used to measure the presence of a number of stimuli including pH, ionic strength, and glucose concentrations. Ideally, in the future, these sensors will be used for continuous metabolic monitoring applications and implanted subcutaneously. In this paper and to properly characterize the sensor assembly, hydrogels sensitive to changes ionic strength were synthesized using hydroxypropyl methacrylate (HPMA), N,N-dimethylaminoethyl methacrylate (DMA) and crosslinker tetra-ethyleneglycol dimethacrylate (TEGDMA) and inserted into the sensor assembly. This hydrogel quickly and reversibly swells when placed environments of physiological buffer solutions (PBS) with ionic strengths ranging from 0.025 to 0.15 M, making it ideal for proof-of-concept testing and initial characterization. The assembly was wire bonded to a printed circuit board and coated with 3 ± 0.5 μm of Parylene-C using chemical vapor deposition (CVD) to protect the sensor and electrical connections during ionic strength wet testing. Two versions of sensors were fabricated for comparison, the first incorporated diffusion pores into the diaphragm, and the second used a solid diaphragm with perforated backing plate. This new design (perforated diaphragm) was shown to have slightly higher sensitivity than solid diaphragm sensors with separate diffuse backing plates when coupled with the hydrogel. The sensitivities for the 1 mm × 1 mm, 1.25 mm × 1.25 mm, 1.5 mm × 1.5 mm perforated diaphragm sensors were 53.3 ± 6.5, 171.7 ± 8.8, and 271.47 ± 27.53 mV/V-M, respectively. These results show that perforations in the diaphragm can be used not only to allow the diffusion of analyte into the cavity but to increase mechanical stress in the piezoresistive diaphragm, thereby increasing sensor output signal. The time constants for swelling (τswelling) and contracting (τcontracting) were calculated by fitting the sensor output half cycles to an exponential growth function. We found that the sensors' response was initially retarded during the preliminary hydrogel conditioning period then improved after 3–5 cycles with values of approximately 9 and 7 min for τswelling and τcontracting. For all sensors tested τswelling > τcontracting. This may be due to the increased loading on the hydrogel from the diaphragm during the swelling process. During contraction the diaphragm aids the hydrogel by reversibly applying mechanical pressure and therefore reducing τcontracting. Long term stability testing showed the sensors remained functional for upwards of 2 weeks in the test phosphate buffer solution (PBS).
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DOI：
10.1016/j.msec.2003.11.002
发表时间：
2004-06-01
期刊：
MATERIALS SCIENCE & ENGINEERING C-BIOMIMETIC AND SUPRAMOLECULAR SYSTEMS
影响因子：
--
作者：
Johnson, BD;Beebe, DJ;Crone, W
通讯作者：
Crone, W
影响因子：
6.2
作者：
Han, IS;Han, MH;Magda, JJ
通讯作者：
Magda, JJ
影响因子：
2.8
作者：
Herber, S;Bomer, J;van den Berg, A
通讯作者：
van den Berg, A
影响因子：
7.4
作者：
Sorber, Joerg;Steiner, Gerald;Arndt, Karl-Friedrich
通讯作者：
Arndt, Karl-Friedrich
影响因子：
2.2
作者：
ter Steege, Rinze W F;Herber, Sebastiaan;Kolkman, Jeroen J
通讯作者：
Kolkman, Jeroen J