生物传感器
石墨烯
场效应晶体管
分析物
膜
灵敏度(控制系统)
材料科学
电化学
晶体管
化学
分析化学(期刊)
纳米技术
电极
物理化学
电压
色谱法
电子工程
生物化学
物理
量子力学
工程类
作者
Decarle S. Jin,Moses Nnaji,Hilena F. Gezahagne,Katherine T. Young,Eleanor L. Brightbill,Eric M. Vogel
摘要
Theoretical models have predicted that pH-responsive surface groups can reduce the sensitivity of field-effect transistor biosensors. However, attempts to prove this experimentally have shown conflicting results. In this work, a graphene field effect transistor (gFET) biosensor is used, which, without modification, is pH insensitive. The surface of the graphene is then functionalized using 1-hydroxypyrene to modulate the pH sensitivity of the gFET. A pH sensitivity ranging from 3.9 to 36.8 mV/pH was demonstrated. The biosensitivity of the gFETs was tested using streptavidin–biotin as a model system. The experimental results showed no correlation between biosensitivity and pH sensitivity. An electrochemical membrane model was used to determine the expected relationship between biosensitivity and pH sensitivity. The model results show that biosensitivity does not decrease until a certain threshold pH sensitivity is reached. This threshold is dependent on factors such as the acid dissociation constants of the surface hydroxyl groups and ion concentration. Furthermore, the differences between the simulation and experiment suggest that the effect of screening is greatly reduced when the analyte binds within a membrane.
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