A hard-soft microfluidic-based biosensor flow cell for SPR imaging application

An Ideal microfluidic-based biosensor flow cell should have not only a soft interface for high strength sealing with biosensing chips, but also hard macro-to-micro interface for tubing connection Since these properties are exclusive of each other, no one material can provide the advantages of both In this paper. we explore the application of a SiO2 thin film, deposited by plasma-enhanced chemical vapor deposition (PECVD) technology, as an intermediate layer for irreversibly adhering polydimethylsiloxane (PDMS) to plastic substrate, and develop a hard-soft, compact, robust microfluidic-based biosensor flow cell for the multi-array immunoassay application of surface plasmon resonance (SPR) imaging. This hard-soft biosensor flow cell consists of one rigid, computer numerically controlled (CNC)-machined poly(methyl methacrylate) (PMMA) base coated with a 200 nm thick SiO2 thin film, and one soft PDMS microfluidic layer This novel microfluidic-based biosensor flow cell does not only keep the original advantage of conventional PDMS-based biosensor flow cell such as the intrinsically soft interface, easy-to-fabrication, and low cost, but also has a rigid, robust, easy-to-use interface to tubing connection and can be operated up to 185 kPa in aqueous environments without failure. Its application was successfully demonstrated with two types of experiments by coupling with SPR imaging biosensor. the real-time monitoring of the immunoglobulin G (IgG) interaction, as well as the detection of sulfamethoxazole (SMOZ) and sulfamethazine (SMZ) with the sensitivity of 35 and 0.6 ng/mL, respectively This novel haid-soft microfluidic device is also useful for a variety of other biosensor flow cells (C) 2010 Elsevier B V All rights reserved