Functional Fluorinated Modifications on a Polyelectrolyte Coated Polydimethylsiloxane Substrate for Fabricating Antibody Microarrays

摘要

Fluorinated compounds exhibit hydrophobic, nonstick,nand self-cleaning properties, making them attractive fornuse as the coating material for biochips. In this study, wencopolymerized the fluorinated compound 1H,1H,2Hperfluoro-n1-decene (FD) with acrylic acid (AA) and bondednthe resulting copolymer with protein G on the surface ofnpolyelectrolyte coated polydimethylsiloxane (PDMS) tonform a functional surface that captures antibodies. Wendemonstrated that the modified PDMS surface remainednhydrophobic while becoming resistant to nonspecificnprotein binding. Thus, aqueous sample solutions formednthe droplets (4 μL) on the surface without spreading andndrying during the sample printing. Contact angle measurementsnshowed that this functionalized surface was asnhydrophobic as the native PDMS with a virtually constantncontact angle over seven days of the study under driedncondition at 4 °C. Spectroscopic measurements revealednthat FD/AA copolymerization formed a homogeneous andnhighly dense multilayer (50 mg/mm2) with a fluorinencoverage of 35.4%. Moreover, protein G was shown toncovalently bind to AA molecules on the surface at anbinding density of 0.24 μg/mm2. We demonstratednthat the fluorinated coating withstood nonspecificnbinding with extremely low background emission,nleading to bioassays that, without the need of blockingnagents, exhibited six times more sensitivity than PEGncoatings. The fluorinated PDMS antibody microarraysnwere further applied to accurately determine the absolutenconcentration of ERr in MCF-7 cells. In conclusion,nthe unique properties of fluorinated compounds,nsuch as withstanding wetting, nonspecific binding andncontamination, make them an excellent coating materialnfor use in sensitive and simple on-chip assays.