Portable Multi-Immunosensing Lab-on-a-Chip (LOC) Triggered by Air Bladder

摘要

This paper presents a simple and reliable multi-immunosensing lab-on-a-chip detecting antibodies as multi-disease markers using electrochemical method suitable for a portable point-of-care system. Since multi-immunosensing LOCs are to be disposable and cheap, the complications associated with the liquid control need to be removed. The main complication arises from the active microfluidic part driven by the external electric power. In this paper, a multi-stacked PDMS LOC including PDMS passive valves is proposed. The sequential liquid driving by capillary attraction and the action of check valve provide a reliable immunosensing tool simply triggered by an air bladder push without an electrical power. The immunosensing-LOC with the size of "25mm × 20mm × 6 mm" is fabricated with PDMS using the replica molding and oxygen plasma bonding. The LOC consists of a PDMS valve, channel, and a glass substrate. The fluidic tests were performed using DI water. The liquids are controlled by two kinds of passive valve, one is capillary stop valve and the other is membrane type check valve. The capillary stop valve stops liquids using pressure barrier of expanded channel. The check valve stops the liquid triggered by an air bladder from flowing backward. The assembly of these two valves assures the well controlled liquid driving for the immunosensing. The model experiments were performed with anti-DNP antibody and anti-biotin antibody as target analytes. The antibodies conjugated with GOX are used as a signaling molecule for cyclic voltammetry. The different amplified signals show different target analyte affinities and make sure the multi-immunosensing.