Highly sensitive, selective and label-free protein detection in physiological solutions using carbon nanotube transistors with nanobody receptors
Highly sensitive, selective and label-free protein detection in physiological solutions using carbon nanotube transistors with nanobody receptors
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DOI：
10.1016/j.snb.2017.08.164
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发表时间：
2018-02-01
影响因子：
8.4
通讯作者：
Tarasov, Alexey
中科院分区：
文献类型：
--
作者：
Filipiak, Marcin S.;Rother, Marcel;Tarasov, Alexey
基于纳米材料的场效应晶体管（FET）已被提议用于各种生物种类的实时、无标记检测。然而，两个主要挑战限制了它们在生理样本中的应用：电解质离子对分析物电荷的屏蔽（德拜屏蔽）以及非特异性吸附。在此，通过将基于单壁半导体碳纳米管（SWCNT）网络的高度稳定的FET与一种新型表面功能化相结合，克服了这些挑战，这种功能化包括：1）短纳米抗体（VHH）受体，以及2）聚乙二醇（PEG）层。纳米抗体是稳定的、易于生产的生物受体，其非常小（约2 - 4纳米），因此能够使分析物在更靠近传感器表面的位置结合。尽管纳米抗体具有独特的性质，但它们尚未被用作基于FET的生物传感器中的受体。PEG的添加在高离子强度环境中极大地增强了信号。以绿色荧光蛋白（GFP）作为模型抗原，在生理溶液中展示出了高选择性以及亚皮摩尔检测限，动态范围超过5个数量级。此外，长期稳定性测量显示SWCNT的低漂移为0.05 mV/小时。所提出的免疫测定快速、无标记，不需要任何样品预处理或清洗步骤。（C）2017爱思唯尔有限公司。保留所有权利。
Nanomaterial-based field-effect transistors (FETs) have been proposed for real-time, label-free detection of various biological species. However, two major challenges have limited their use in physiological samples: screening of the analyte charge by electrolyte ions (Debye screening) and non-specific adsorption. Here, these challenges are overcome by combining highly stable FETs based on single-walled semiconducting carbon nanotube (SWCNTs) networks with a novel surface functionalization comprising: 1) short nanobody (VHH) receptors, and 2) a polyethylene glycol (PEG) layer. Nanobodies are stable, easy-to-produce biological receptors that are very small (similar to 2-4 nm), thus enabling analyte binding closer to the sensor surface. Despite their unique properties, nanobodies have not been used yet as receptors in FET based biosensors. The addition of PEG strongly enhances the signal in high ionic strength environment. Using green fluorescent protein (GFP) as a model antigen, high selectivity and sub-picomolar detection limit with a dynamic range exceeding 5 orders of magnitude is demonstrated in physiological solutions. In addition, long-term stability measurements reveal a low drift of SWCNTs of 0.05 mV/h. The presented immunoassay is fast, label-free, does not require any sample pretreatment or washing steps. (C) 2017 Elsevier B.V. All rights reserved.