A Silicon Resonant Micro-Cantilever Biosensor with Closed-Loop Self-Excitation System for Biomacromolecular Detection

Abstract

A silicon resonant micro-cantilever biosensor was introduced to detect biomacromolecular based on the relationship between the cantilever resonant frequency and the cantilever equivalent mass. A closed-loop self-excitation system was designed to acquire the resonant frequency of micro-cantilever. Two groups of resonant micro-cantilever sensors with different resonant frequencies of 18.192 kHz and 17.688 kHz respectively were tested. The result showed that the detection system can automatically search the resonant frequency of micro-cantilever and locked quickly. To demonstrate the feasibility of this approach, human immunoglobulin G(IgG) as model target biomacromolecular was employed, different concentration of IgG was detected by the resonant micro-cantilever sensors, the mass effect of micro-cantilever was adept and the micro-cantilever was drive by closed-loop circuit. The linearity of micro-cantilever biosensor was very well and the experimental result of sensitivity of micro-cantilever biosensor was about 6.6×106. All the results showed that sensitivity of the presented immunoassay significantly increased by one-order of magnitude and offered great application promises in providing a sensitive, specific, and potent method for real-time detection of biological detection.