Toward the development of polydimethylsiloxane (PDMS) microfluidic capillary biosensors

초록

Immunoassays are commonly used to measure the concentration of a variety of viruses and bacteria in surroundings. Immunosensors developed in the previous studies, however, have limited capabilities regarding sensitivity, selectivity, visibility and portability. Especially, portability of biosensors becomes more important due to the Point-Of-Care paradigm in health care. In this work, we demonstrate a novel concept of a microfluidic immunosensor, in which the thickness differences of immobilized layers due to the selected conjugate reaction are amplified by capillary action of silicone oil in a polydimethylsiloxane (PDMS) microchannel, resulting in the difference of a meniscus height. PDMS is selected as the microchannel material since its hydrophobic property improves the surface adhesion of antibody and it is easily formed as portable sensor devices. We use silicone oil into the PDMS microchannels to achieve upward meniscus analogous to the case of water into the glass tube. In the immobilization process, Bovine Serum Albumin (BSA) and Protein A are employed to improve selectivity and arrangement of antibody. Geometry of our microfluidic immunosensor device is designed to make the naked eye measurement possible by calculating meniscus height with the properties (density of silicon oil, interfacial tension between silicone oil and air, contact angle of silicone oil with PDMS). © 2012 American Scientific Publishers All rights reserved.

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