Application of a new microcantilever biosensor resonating at the air–liquid interface for direct insulin detection and continuous monitoring of enzymatic reactions

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

研究速報 : Making five atomic force microscope for 200,000yen each : A student project

特集2 日仏マイクロメカトロニクス国際共同研究組織(LIMMS

特集6 : 研究速報 : Some Problems Related to Detection of Displacement of an Object by a Tunneling Current

Due to its very high sensitivity to tunneling distance, the tunneling current has the potential of being used for detecting small displacements. Moreover, the target with which the displacement is to be measured need only be a few nanometers or less in size, which makes the detection technique a strong candidate for application to displacement measurement of nano to micrometric objects. In this paper, I will report on an experiment carried out to measure the displacement of a conventional scanning force microscopy cantilever, with an aim of applying the technique to vibration excitation and detection of a nanometric oscillator.小特集 マイクロマシ

特集17 : 研究速報 : Two Dimensional Positioning Control using a Crystal as the Reference

特集 先進プロダクションテクノロジ