Patterning microbeads inside poly(dimethylsiloxane) microfluidic channels and its application for immobilized microfluidic enzyme reactors

Abstract

We propose a convenient and reliable approach for immobilizing microbeads on poly(dimethylsiloxane) (PDMS) microchips. It is built upon a simple fabrication procedure of PDMS chip through directly printing the master with an office laser printer which was described in our previous work (J. Chromatogr. A 2005, 1089, 270-275). On the printed toners used as the positive relief of the master, microbeads were immobilized by a thermal treatment and then transferred to the surface of the microchip by direct molding of the prepolymer on the master. With this approach, the region-selective immobilization of microbeads and the fabrication of PDMS microchips can be accomplished at the same time. Then, using these microbeads as supports, further modification with enzyme was achieved. Surface characteristics of the microbeads-modified PDMS microchannels were investigated with scanning electron microscope, atomic force microscope, and inverse fluorescence microscope. The electrokinetic properties of the native PDMS and the modified PDMS chips were also compared. Based on this approach, an immobilized glucose oxidase (GOD) reactor was constructed and the reaction using glucose as substrate was studied. All these experiments aim to show that the proposed approach may have a good potential in the study of biochemistry and other related areas.

A photoelectrochemical sensor based on CdS-polyamidoamine nano-composite film for cell capture and detection

“…Different from PL, the obtained CdS-PAMAM nano-composite film showed enhanced photocurrent compared with CdS alone. Moreover, the large amount of -NH 2 in PAMAM could be used as functional groups for further covalent coupling ConA which was reported to have an ability of recognizing and binding mannosyl groups on cell surface Ding et al, 2008), via glutaraldehyde bridges (Zhang et al, 2006). Thus, the ConA/CdS-PAMAM film bearing both good photoelectrochemical property and the cell capture ability was employed for cell-based photoelectrochemical sensing.…”

Silicones for Microfluidic Systems

“…• Immobilization of biomolecules for biomolecular detection using immunoassays [35,75,[177][178][179][180] and enzymatic microreactors [181,182]. • Cell culture under controlled fl ow conditions on surfaces modifi ed with ligands important for cell adhesion and proliferation [35,73,76,105].…”

Development of microfluidic devices incorporating non-spherical hydrogel microparticles for protein-based bioassay

“…Microspheres, also known as microbeads, have recently been incorporated into microfluidic devices as protein supports, since they can provide a large surface area onto which various proteins can be immobilized, contributing to an overall higher sensitivity of the system (Peterson 2005;Verpoorte 2003;Zhang et al 2006). Microbeads are available in several different materials such as polymer, glass, or magnetic microsphere, and proteins are covalently immobilized on the surface-modified microbeads through the use of protein-binding ligands.…”