A 3D porous polymer monolith-based platform integrated in poly(dimethylsiloxane) microchips for immunoassay

Abstract

In this work, we demonstrate the immunocapture and on-line fluorescence immunoassay of protein and virus based on porous polymer monoliths (PPM) in microfluidic devices. Poly(glycidyl methacrylate-co-ethylene glycol dimethacrylate) [poly(GMA-co-EGDMA)] monoliths were successfully synthesized in the polydimethylsiloxane (PDMS) microfluidic channels by in situ UV-initiated free radical polymerization. After surface modification, PPM provides a high-surface area and specific affinity 3D substrate for immunoassays. Combining with well controlled microfluidic devices, the direct immunoassay of IgG and sandwich immunoassay of inactivated H1N1 influenza virus using 5 μL sample has been accomplished, with detection limits of 4 ng mL(-1) and less than 10 pg mL(-1), respectively. The enhanced detection sensitivity is due to both high surface area of PPM and flow-through design. The detection time was obviously decreased mainly due to the shortened diffusion distance and improved convective mass transfer inside the monolith, which accelerates the reaction kinetics between antigen and antibody. This work provides a novel microfluidic immunoassay platform with high efficiency thereby enabling fast and sensitive immunoassay.

A new strategy for simultaneous synthesis and efficient anchorage of polymer monoliths in native PDMS microchips

“…Despite the extended use of PDMS, only a few PDMS microsystems integrating polymer MN have been reported up to now [28e34]. Most of them relied on hybrid PDMS/Glass systems [29,30,32,34]. Only three MN have been obtained on real PDMS/PDMS systems [28,31,33].…”

“…To overcome those problems, various approaches relying on the surface modification of PDMS/PDMS systems such as photografting [28], oxidation and silanization [33] or modification by intertwining monomers within the PDMS matrix [31] have been proposed to achieve successful MN synthesis and anchorage. Photografting with preadsorption of benzophenone (BP) has been up to now the most common strategy [35] to anchor the MN in PDMS/glass microsystems [29,30,32,34] but this method is long entailing numerous polymerization and rinsing steps and not suitable for an industrial application. Alternative methods of anchorage of MN should therefore be considered to overcome these major drawbacks and to allow further development in the field of monolith-based analytical microsystems.…”

Advances in monoliths and related porous materials for microfluidics

“…Kang et al 63 developed a PDMS microchip with a GMA-based monolith that had antibodies immobilized for a microfluidic immunoassay. The device was used to perform a direct immunoassay with model compounds and a sandwich immunoassay for the H1N1 virus, resulting in 4 ng/ml and 10 pg/ml limits of detection for IgG and H1N1, respectively.…”

Immune‐affinity monolithic array with chemiluminescent detection for mycotoxins in barley

“…PPMs have been extensively used as matrices for separating and purifying molecules, owing to the unique characterisation of simple preparation, easy modification, large surface area to volume ratio, and convective mass transmission . An affinity monolith obtained usually by immobilisation of antibodies or aptamers on the surface of the monolith has been used for separating and purifying proteins and cells from complicated samples.…”