The study of Hydrophilic treated Micro Channel applied on physiological enzyme test

• Main Authors: Jia-Shiuan Tsuei, 崔家軒
• Other Authors: Der-Chi Shye
• Format: Others
• Language: zh-TW
• Published: 2011
• Online Access: http://ndltd.ncl.edu.tw/handle/65858322769679170441

碩士 === 明志科技大學 === 電子工程研究所 === 99 === This thesis describes the study of hydrophilic treated surface, applied onto the micro-channel chip, to implement the velocity control of the biological sample during the two-step enzyme reaction. The upper channel cover was made from PDMS (polydimethylsiloxane) using the technology of the MEMS (Micro Electro Mechanical System), and then sealed with glass substrate to form a siphonic micro-channel chip in this work. Photometric Method and Polymer Material Coating were individually used to enhance the hydrophilic properties of these micro-channel chips. As denoted in “Photometric Method”, the RF sputtered TiO2 thin film, post treated by ultra-vacuum (UV) irradiation (wave length: 360-400nm, intensity: 12mJ/cm2), deposits on the glass substrate of the micro-channel chip. The experimental results show the contact angle (34°, 11.1°, 7.3°) of the test fluid on the TiO2 film reduces as the time period (10, 20, 40 minutes) of UV-irradiation treatment increases. Obviously, the UV-irradiation treatment increases the oxygen vacancies and the density of hydroxide bond on the channel surface, and thus both of the hydrophilicity and flow speed enhance. Furthermore, the hydrophility of UV treated TiO2 film as exposure time increases, because the humidity compensates the oxygen vacancies and hydroxide bond on the surface. However, the hydrophility-degradation saturates after 20 Hrs exposure, and the contact angle with UV-irradiation is still better than the one without the UV-irradiation. On the other hand, the Polymer Material Coating Method uses PEI (Polyethleneimine) coating on the PDMS to improve the hydrophilicity, and the coating geometrical pattern was designed to control the fluid flow rate. As the result shows, the contact angle of PEI surface usually keeps 10°, so its hydrophilicity is difficult to change via process control. Hence, the geometrical gap of PEI coating is applied to control the fluid velocity in the channel. Finally, the chips, treated by both of Photometric Method and Polymer Material Coating, were verified for the bio effectiveness, and different concentrations (100 ~ 500 mg/dl ) of cholesterol were also tested. However, the enzymes of cholesterol oxidase and peroxidase were individually deposited on the variant sites of the micro-channel, which carried out the enzyme-optochemical reaction in two steps. As the results indicate, the ionized cholesterol successfully forms at the first reaction site for the cholesterol oxidase acting, and the photovoltaic versus the cholesterol concentration behaves very high linearity (R2=0.97) and low statistical variance (CV~1%) in the 2nd reaction site. Therefore, this study successfully realizes the controllable flow-speed with passive device using hydrophilic treated micro-channel chip, which is promising for the applications of two-step enzyme reaction.