title: Solution-phase surface modification in intact poly(dimethylsiloxane) microfluidic channels.
abstract: An improved approach composed of an oxidation reaction in acidic H2O2 solution and a sequential silanization reaction using neat silane reagents for surface modification of poly(dimethylsiloxane) (PDMS) substrates was developed. This solution-phase approach is simple and convenient for some routine analytical applications in chemistry and biology laboratories and is designed for intact PDMS-based microfluidic devices, with no device postassembly required. Using this improved approach, two different functional groups, poly(ethylene glycol) (PEG) and amine (NH2), were introduced onto PDMS surfaces for passivation of nonspecific protein absorption and attachment of biomolecules, respectively. X-ray electron spectroscopy and temporal contact angle experiments were employed to monitor functional group transformation and dynamic characteristics of the PEG-grafted PDMS substrates; fluorescent protein solutions were introduced into the PEG-grafted PDMS microchannels to test their protein repelling characteristics. These analytical data indicate that the PEG-grafted PDMS surfaces exhibit improved short-term surface dynamics and robust long-term stability. The amino-grafted PDMS microchannels are also relatively stable and can be further activated for modifications with peptide, DNA, and protein on the surfaces of microfluidic channels. The resulting biomolecule-grafted PDMS microchannels can be utilized for cell immobilization and incubation, semiquantitative DNA hybridization, and immunoassay.
authors.affiliation: Crump Institute for Molecular Imaging and Department of Molecular & Medical Pharmacology, David Geffen School of Medicine at UCLA, 700 Westwood Plaza, Los Angeles, California 90095, USA.
authors.forename: Guodong
authors.initials: G
authors.lastname: Sui
authors.forename: Jinyi
authors.initials: J
authors.lastname: Wang
authors.forename: Chung-Cheng
authors.initials: CC
authors.lastname: Lee
authors.forename: Weixing
authors.initials: W
authors.lastname: Lu
authors.forename: Stephanie P
authors.initials: SP
authors.lastname: Lee
authors.forename: Jeffrey V
authors.initials: JV
authors.lastname: Leyton
authors.forename: Anna M
authors.initials: AM
authors.lastname: Wu
authors.forename: Hsian-Rong
authors.initials: HR
authors.lastname: Tseng
mesh_terms: D000588:Amines / Q000737:chemistry; D002448:Cell Adhesion; D045744:Cell Line, Tumor; D004247:DNA / Q000032:analysis; D004129:Dimethylpolysiloxanes / Q000737:chemistry*; D006801:Humans; D006861:Hydrogen Peroxide / Q000737:chemistry*; D007118:Immunoassay; D046210:Microfluidic Analytical Techniques / Q000295:instrumentation / Q000379:methods*; D015394:Molecular Structure; D010084:Oxidation-Reduction; D010455:Peptides / Q000032:analysis; D011092:Polyethylene Glycols / Q000737:chemistry; D011506:Proteins / Q000032:analysis; D012680:Sensitivity and Specificity; D012828:Silicones / Q000737:chemistry*; D012996:Solutions / Q000737:chemistry; D013499:Surface Properties; D013997:Time Factors
chemical_list: D000588:Amines; D004129:Dimethylpolysiloxanes; D010455:Peptides; D011506:Proteins; D012828:Silicones; D012996:Solutions; D011092:Polyethylene Glycols; C013830:baysilon; D004247:DNA; D006861:Hydrogen Peroxide