School of Engineering, University of British Columbia, Kelowna, BC, Canada; Department of Bioengineering, McGill University, Montreal, QC, Canada.
School of Engineering, University of British Columbia, Kelowna, BC, Canada.
Anal Chim Acta. 2022 Aug 22;1222:340177. doi: 10.1016/j.aca.2022.340177. Epub 2022 Jul 19.
Aptamer-based electrolyte-gated graphene field-effect transistor (EGFET) biosensors have gained considerable attention because of their rapidity and accuracy in terms of quantification of a wide range of biomarkers. Functionalization of the graphene channel of EGFETs with aptamer biorecognition elements (BREs) is a crucial step in fabrication of EGFET aptasensors. This paper presents a comprehensive comparison of commonly used biochemical functionalization approaches applied for preparation of sensing films in EGFET aptasensors, namely indirect and direct immobilization of BREs. This study is the first of its kind to experimentally compare the two BREs immobilization approaches in terms of their effects on the carrier mobility of the monolayer graphene channel and their suitability for sensing applications. Both approaches can preserve and even improve the carrier mobility of bare graphene channel and hence the sensitivity of the EGFET; however, the direct BREs immobilization method was selected to develop an aptameric EGFET biosensor as this method enables simpler and more efficient preparation of the graphene-based aptameric sensing film. The utility of the prepared EGFET aptasensor is demonstrated through detection of tumor necrosis factor-α (TNF-α), an important inflammatory biomarker. The direct BREs immobilization approach is applied to develop an EGFET aptasensor to measure TNF-α in a detection range from 10 pg/ml to 10 ng/ml, representative of its physiological level in human sweat, as a non-invasively accessible biofluid. The outstanding sensing performance of the developed TNF-α EGFET aptasensor based on direct BREs immobilization can pave the way for development of graphene biosensors.
适体基电解质门控石墨烯场效应晶体管（EGFET）生物传感器因其在定量检测多种生物标志物方面的快速性和准确性而受到广泛关注。在 EGFET 中，石墨烯沟道的功能化是制备 EGFET 适体传感器的关键步骤。本文全面比较了常用于制备 EGFET 适体传感器传感膜的生化功能化方法，即适体生物识别元件（BRE）的间接和直接固定化。这项研究首次在实验上比较了这两种 BRE 固定化方法对单层石墨烯沟道载流子迁移率的影响及其在传感应用中的适用性。这两种方法都可以保留甚至提高裸石墨烯沟道的载流子迁移率，从而提高 EGFET 的灵敏度；然而，选择了直接 BRE 固定化方法来开发适体 EGFET 生物传感器，因为这种方法可以更简单、更有效地制备基于石墨烯的适体传感膜。通过检测肿瘤坏死因子-α（TNF-α），一种重要的炎症生物标志物，证明了制备的 EGFET 适体传感器的实用性。直接 BRE 固定化方法被应用于开发一种 EGFET 适体传感器，以在 10 pg/ml 至 10 ng/ml 的检测范围内测量 TNF-α，这代表了其在人汗中生理水平的检测范围，因为汗是一种非侵入性的可访问生物流体。基于直接 BRE 固定化的开发的 TNF-α EGFET 适体传感器具有出色的传感性能，为石墨烯生物传感器的发展铺平了道路。
