Laboratory of Advanced Materials, Department of Chemistry, Fudan University, Shanghai 200433, People's Republic of China.
Nano Lett. 2010 Aug 11;10(8):3179-83. doi: 10.1021/nl1020975.
We demonstrate a new protein detection methodology based upon frequency domain electrical measurement using silicon nanowire field-effect transistor (SiNW FET) biosensors. The power spectral density of voltage from a current-biased SiNW FET shows 1/f-dependence in frequency domain for measurements of antibody functionalized SiNW devices in buffer solution or in the presence of protein not specific to the antibody receptor. In the presence of protein (antigen) recognized specifically by the antibody-functionalized SiNW FET, the frequency spectrum exhibits a Lorentzian shape with a characteristic frequency of several kilohertz. Frequency and conventional time domain measurements carried out with the same device as a function of antigen concentration show more than 10-fold increase in detection sensitivity in the frequency domain data. These concentration-dependent results together with studies of antibody receptor density effect further address possible origins of the Lorentzian frequency spectrum. Our results show that frequency domain measurements can be used as a complementary approach to conventional time domain measurements for ultrasensitive electrical detection of proteins and other biomolecules using nanoscale FETs.
我们展示了一种新的蛋白质检测方法，基于使用硅纳米线场效应晶体管（SiNW FET）生物传感器的频域电测量。在缓冲溶液中或在不与抗体受体特异性结合的蛋白质存在下测量抗体功能化的 SiNW 器件时，偏置电流的 SiNW FET 的电压功率谱密度在频域中表现出 1/f 依赖性。在特异性识别抗体功能化 SiNW FET 的蛋白质（抗原）存在下，频谱呈现出具有几个千赫兹特征频率的洛伦兹形状。与同一器件作为抗原浓度函数进行的频率和传统时域测量显示，在频域数据中检测灵敏度增加了 10 多倍。这些浓度依赖性结果以及对抗体受体密度效应的研究进一步探讨了洛伦兹频谱的可能起源。我们的结果表明，频域测量可以作为传统时域测量的补充方法，用于使用纳米级 FET 进行超灵敏的蛋白质和其他生物分子的电检测。
