title: Functionalized 3D-hydrogel plugs covalently patterned inside hydrophilic poly(dimethylsiloxane) microchannels for flow-through immunoassays.
abstract: Integration of a hydrogel and polydimethylsiloxane (PDMS)-based microfluidic device can greatly reduce the cost of developing channel-based devices. However, there are technical difficulties including the hydrophobic and inert surface properties associated with PDMS as well as back pressure and fragile material associated with the use of hydrogel in microchannels. In this study, a strategy to covalently photopattern 3-D hydrogel plugs with functionalized protein G inside microfluidic channels on a hydrophilic PDMS substrate coated with polyelectrolyte multilayers (PEMS) is presented. In this process, a UV-light microscope is applied to initiate the protein G-poly(acryl amide) copolymerization from the bulk substrate to solution areas via the deeply implanted photoinitiator (PI), resulting in sturdy 3D plugs covalently bonded to the upper and lower channel wall, while leaving open spaces in the channel width for the fluid to flow through. In addition, the long-term hydrophilicity and low nonspecific binding property associated with PEMS surface can be conserved for the nonpatterned area, leading to hydrogel plugs in extremely hydrophilic and permeable environment in a restricted channel space for bubble-free fluid transport and affinity interaction. By immobilization of well-oriented antibodies via protein G on the hydrogel plugs in the channel, estrogen receptor alpha (ERalpha) is demonstrated to be captured quantitatively with high loading capacity and high specificity.
authors.affiliation: Department of Chemistry, National Cheng Kung University, No. 1, College Road, Tainan 701, Taiwan.
authors.forename: Wang-Chou
authors.initials: WC
authors.lastname: Sung
authors.forename: Huang-Han
authors.initials: HH
authors.lastname: Chen
authors.forename: Honest
authors.initials: H
authors.lastname: Makamba
authors.forename: Shu-Hui
authors.initials: SH
authors.lastname: Chen
mesh_terms: D000911:Antibodies, Monoclonal / Q000276:immunology / Q000378:metabolism; D004129:Dimethylpolysiloxanes / Q000737:chemistry*; D004573:Electrolytes / Q000737:chemistry; D047628:Estrogen Receptor alpha / Q000032:analysis; D020136:Hydrogel, Polyethylene Glycol Dimethacrylate / Q000737:chemistry*; D055767:Immobilized Proteins / Q000737:chemistry / Q000378:metabolism; D007118:Immunoassay / Q000379:methods*; D046210:Microfluidic Analytical Techniques / Q000295:instrumentation* / Q000379:methods; D009419:Nerve Tissue Proteins / Q000737:chemistry; D011485:Protein Binding
chemical_list: D000911:Antibodies, Monoclonal; D004129:Dimethylpolysiloxanes; D004573:Electrolytes; D047628:Estrogen Receptor alpha; C029152:G-substrate; D055767:Immobilized Proteins; D009419:Nerve Tissue Proteins; D020136:Hydrogel, Polyethylene Glycol Dimethacrylate; C013830:baysilon