Piezoelectric cantilever sensors with asymmetric anchor exhibit picogram sensitivity in liquids

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• 作者：Harsh Sharma^a ; Ramji S. Lakshmanan^a ; Blake N. Johnson^a ; Raj Mutharasan ; ^a ; ^{mutharasan@drexel.edu} [Author vitae]
• 关键词：Resonant frequency ; Mass-change sensitivity ; In-liquid ; Biosensor
• 刊名：Sensors and Actuators B: Chemical
• 出版年：2011
• 出版时间：31 March 2011
• 年：2011
• 卷：153
• 期：1
• 页码：64-70
• 全文大小：904 K

文摘

We show for the first time that self-exciting and self-sensing piezoelectric cantilevers consisting only of lead zirconate titanate (PZT) measure resonance only if they are asymmetrically anchored. Symmetric-anchoring did not give rise to electrically measurable bending resonant modes in the 0–100 kHz range. Sensitivity of first and second bending mode resonances was characterized in a flow apparatus using small density changes in liquid (0.003–0.01 g/cm³) and by dodecanethiol chemisorption at 30 pM. Density change results were consistent with existing models of submerged cantilevers, and yielded mass-change sensitivity of 33 ng/Hz and 217 pg/Hz for the first two modes. In chemisorption experiments, where binding was localized to 1 mm² distal tip of the PZT cantilever, sensitivity improved by an order of magnitude to 2 pg/Hz and 414 fg/Hz for the same two resonant modes.