MEMS Sensors and Actuators Laboratory (MSAL), Department of Electrical and Computer Engineering, Institute for Systems Research, University of Maryland, College Park, MD 20742, USA.
Biosens Bioelectron. 2012 Oct-Dec;38(1):114-20. doi: 10.1016/j.bios.2012.05.009. Epub 2012 May 16.
DNA hybridization detection in microfluidic devices can reduce sample volumes, processing times, and can be integrated with other measurements. However, as device footprints decrease and their complexity increase, the signal-to-noise ratio in these systems also decreases and the sensitivity is thereby compromised. Device miniaturization produces distinct properties and phenomena with greater influence at the micro-scale than at the macro-scale. Here, a diffusion-restriction model was applied to a miniaturized biochip nanovolume reactor to accurately characterize DNA hybridization events that contribute to shifts in both charge transfer resistance and diffusional resistance. These effects are shown to play a significant role in electrochemical impedance spectroscopy (EIS) analyses at these length scales. Our highly functional microfluidic biosensor enables the detection of ssDNA targets selectively, with a calculated detection limit of 3.8 nM, and cross-reactivity of 13% following 20 min incubation with the target. This new biosensing approach can be further modeled and tested elucidating diffusion behavior in miniaturized devices and improving the performance of biosensors.
在微流控装置中进行 DNA 杂交检测可以减少样品量、处理时间，并可以与其他测量方法集成。然而，随着器件足迹的减小和复杂性的增加，这些系统中的信噪比也会降低，从而影响灵敏度。器件的小型化会产生独特的特性和现象，这些特性和现象在微观尺度上比在宏观尺度上的影响更大。在这里，扩散限制模型被应用于小型化的生物芯片纳米体积反应器中，以准确描述导致电荷转移电阻和扩散电阻变化的 DNA 杂交事件。这些效应在这些长度尺度的电化学阻抗谱（EIS）分析中起着重要作用。我们的高性能微流控生物传感器能够选择性地检测 ssDNA 靶标，在 20 分钟与靶标孵育后，计算出的检测限为 3.8 nM，交叉反应率为 13%。这种新的生物传感方法可以进一步建模和测试，阐明小型化设备中的扩散行为，并提高生物传感器的性能。
