Center for International Research on Micronano Mechatronics (CIRMM), Institute of Industrial Science (IIS), the University of Tokyo, 4-6-1 Komaba Meguro, Tokyo, 153-8505, Japan.
Lab Chip. 2012 Oct 21;12(20):4115-9. doi: 10.1039/c2lc40232g.
Here we describe the application of a recently developed high-resolution microcantilever biosensor resonating at the air-liquid interface for the continuous detection of antigen-antibody and enzyme-substrate interactions. The cantilever at the air-liquid interface demonstrated 50% higher quality factor and a 5.7-fold increase in signal-to-noise-ratio (SNR) compared with one immersed in the purified water. First, a label-free detection of a low molecular weight protein (insulin, 5.8 kDa) in physiological concentration was demonstrated. The liquid facing side of the cantilever was functionalized by coating its surface with insulin antibodies, while the opposite side was exposed to air. The meniscus membrane at the micro-slit around the cantilever sustained the liquid in the microchannel. After optimizing the process of surface functionalization, the resonance frequency shift was successfully measured for insulin solutions of 0.4, 2.0, and 6.3 ng ml(-1). To demonstrate additional application of the device for monitoring enzymatic protein degradation, the liquid facing microcantilever surface was coated with human recombinant SOD1 (superoxide dismutase 1) and exposed to various concentrations of proteinase K solution, and the kinetics of the SOD1 digestion was continuously monitored. The results showed that it is a suitable tool for sensitive protein detection and analysis.
在这里，我们描述了一种最近开发的高分辨率微悬臂梁生物传感器在气液界面的应用，用于连续检测抗原-抗体和酶-底物相互作用。与浸入纯水中的微悬臂梁相比，气液界面上的微悬臂梁的品质因数提高了 50%，信噪比（SNR）提高了 5.7 倍。首先，我们演示了对生理浓度下低分子量蛋白质（胰岛素，5.8 kDa）的无标记检测。微悬臂梁的液侧通过用胰岛素抗体涂覆其表面来功能化，而另一侧暴露在空气中。微悬臂梁周围微缝隙处的弯月面膜将液体维持在微通道中。在优化表面功能化过程后，成功测量了 0.4、2.0 和 6.3 ng ml(-1)胰岛素溶液的共振频率位移。为了进一步证明该设备在监测酶蛋白降解方面的应用，将液侧微悬臂梁表面涂覆有人重组 SOD1（超氧化物歧化酶 1），并暴露于不同浓度的蛋白酶 K 溶液中，连续监测 SOD1 消化的动力学。结果表明，它是一种用于灵敏蛋白质检测和分析的合适工具。
