R&D on a Multi-functional Phase Detection Biomedical Instrument and an Electrochemical Biochip Tool for Glucose Detection
Date Issued
2005
Date
2005
Author(s)
Chen, Yiwen
DOI
zh-TW
Abstract
Surface plasmon resonance (SPR) phenomenon for sensing application has been developed for almost two decades. When a light beam impinges onto the interface between the dielectric media and metal media, a surface plasmon wave is produced. The surface plasmon wave is also an evanescent wave and the intensity that is perpendicular to the interface is exponentially decayed. At the SPR angle, the intensity of the reflective light beam will appear to have a minimum value and the phase will present a phase delay phenomenon. The value of the SPR angle and phase delay correlate with the permittivity of the media. By applying this principle, there are four optical configurations developed which are wavelength modulation, intensity modulation, angular modulation and phase modulation. These four methods have been widely used in measuring the thickness variation of thin film, the reflective index change of liquid or gas samples and the biomolecular interaction. During the course of this study, we extend our research team’s many years optical system design experience and employ a paraboloidal mirror, a spherical mirror, and a precision servomotor control. The 0.001 degrees accuracy incident angle can be easily achieved. By rotating an analyzer and five steps phase shift method, a small volume and low cost optical system is presented. This system has angular modulation function which has large dynamic measuring range and phase modulation function which has high theoretical resolution at the same time. Although the instability of the small volume laser diode module decreases the resolution of the system, by using mathematical analysis and different concentrations alcohol experiments, the system has been proved to have 10-4 resolution in measuring reflective indices. By measuring different glucose concentrations standard solutions, the study verify the system has the ability of glucose detection which is even better than angular modulation mode SPR instrument. In order to expand the biomedical detection ability of this system, the study also proves the capability of ELISA experiment of the system successily. A novel electro-chemistry method is another issue discussed in this study. Extending the research of our research team, externally applied sine wave voltage was adopted in this study. With enzymatic strip and different glucose concentrations standard solutions, the new voltage applied method was proved to have high repeatability and even better current performance than that of the traditional method. By modulating the frequency and the amplitude of the externally applied sine wave voltage, a higher linearity and current to concentration relation can be obtained. By integrating the current, another newly developed glucose concentration relation is also developed, which found to have better performance than that of the traditional method. With an attempt to expand the application of this newly developed optical system, the newly developed biosensor presented in this dissertation is tested to pursuer glucose concentration as well.
Subjects
表面電漿共振
電化學檢測
血糖
干涉術
surface plasmon resonance
electro-chemistry
glucose
interferometry
Type
thesis