Department of Electrical Engineering, KAIST, 291 Daehak-ro, Yuseong-gu, Daejeon 305-701, Republic of Korea.
Biosens Bioelectron. 2013 Mar 15;41:867-70. doi: 10.1016/j.bios.2012.08.036. Epub 2012 Aug 25.
The present work aims to improve the sensitivity of an electrical biosensor by simply changing a surface property of the passivation layer, which covers the background region except for the sensing site for electrical isolation among adjacent interconnection lines. The hydrophobic passivation layer dramatically enhances the sensitivity of the biosensor when compared with a hydrophilic passivation layer. A revamped metal oxide semiconductor field-effect transistor (MOSFET), which has a designed underlap region between a gate and a drain, is used as the electrical biosensor. A thin film of CYTOP(TM) and silicon nitride is used as the hydrophobic and hydrophilic passivation layers, respectively. The surface antigen and its specific antibody of the avian influenza virus were employed as the probe and target biomolecule, respectively, to confirm the enhanced sensitivity of the proposed biosensor. By using hydrophobic passivation, the limit of detection of the biosensor was improved up to 100-fold compared with that resulting from hydrophilic passivation. Therefore, a simple surface engineering to control surface wettability can notably improve the sensitivity of a biosensor without additional efforts, such as modifying the sensor structure, optimizing the bio-treatment protocol, or increasing the binding yield between a probe and its target, among other efforts.
本工作旨在通过简单地改变覆盖除传感区域以外的背景区域的钝化层的表面性质来提高电生物传感器的灵敏度，以实现相邻互连线之间的电隔离。与亲水性钝化层相比，疏水性钝化层极大地提高了生物传感器的灵敏度。使用具有在栅极和漏极之间设计的重叠区域的改良金属氧化物半导体场效应晶体管 (MOSFET) 作为电生物传感器。使用 CYTOP(TM) 和氮化硅薄膜分别作为疏水性和亲水性钝化层。禽流感病毒的表面抗原及其特异性抗体分别用作探针和靶生物分子，以确认所提出的生物传感器的增强灵敏度。通过使用疏水性钝化，与亲水性钝化相比，生物传感器的检测限提高了 100 倍。因此，通过简单的表面工程来控制表面润湿性，可以在不增加额外努力的情况下显著提高生物传感器的灵敏度，例如修改传感器结构、优化生物处理协议、或增加探针与其靶之间的结合产率等。
