The Study on Immunoassay Microchannel Chip by Ferrofluid Actuation

• Main Authors: Chu-Hsuan Lin, 林竹軒
• Other Authors: Yaw-Jen Chang
• Format: Others
• Language: en_US
• Published: 2010
• Online Access: http://ndltd.ncl.edu.tw/handle/14369086011834155985

碩士 === 中原大學 === 機械工程研究所 === 98 === Ferrofluid is usually used as actuation medium in micropump or microvalve where most microchannels were fabricated with Para-methoxymethamphetamine (PMMA) or silicon. The manufacturing is time-consuming and costly. In this paper, we present a novel microchip design and application based on the magnetic actuation of ferrofluid. The device contains plugs and pistons formed by a ferrofluid which is actuated by an external NdFeB permanent magnet. The ferrofluid used for this application is a colloidal suspension of nanosize Fe3O4 particles in a carrier fluid that is mixed with silicone oil and hexane. We used LABVIEW software (National Instruments, USA) to control the rotating speed of stepper motor. The microchannel was fabricated by Polydimethylsiloxane (PDMS) with four reaction zones. Four different of concentrations of biotin were immobilized in each zone respectively. To verify the performance of proposed device, the immunoassay reactions were carried out using nitrocellulose protein chips. Under constant temperature, the effect of flow speed on immunoassay reactions was investigated. It was discovered that flow at 4rpm and 6rpm speed of stepper motor was indeed contributive to enhance the immunoassay reactions. The result showed that different speeds had distinct effect on the immunoassay reactions. The experimental result shows that the ferrofluidic actuation of fluid in the PDMS microchannel was feasible. However, leakage and swelling in the PDMS microchannel might lead to fluid actuation problems. In order to enhance the resistance of PDMS microchannel to acid and alkali, we also make the surface modification by O2 plasma. The result also reveals that it has potential application in biochip.