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Recently, PDMS-based application systems have been gaining popularity due to their distinct advantages, such as inexpensive, nontoxicity, easy fabrication, practical scalability, optical transparency, and gas permeability, impermeable to water. However, due to the inherent hydrophobicity of PDMS materials, biological samples easily interact strongly with the PDMS surface when it is present in a biological environment. Moreover, it always prevents the immediate use of PDMS-based microfluidic or bio-and molecular material without any surface processing. Therefore, various surface modification methods have been performed to change the hydrophobicity and biomolecule-adhesion of PDMS surfaces.In this paper, the synthesis of dendronized Poly(3,4,5-tris(2-(2-(2-hydroxyl ethoxy)ethoxy)ethoxy)benzy lmethacrylate) (PEG methacrylate) brushes using surface initiated atom transfer radical polymerization (ATRP) on PDMS substrate was reported. In this approach, the PDMS substrates were first oxidized in H2SO4/H2O2 solution to transform the Si-CH3 groups into Si-OH groups on their surfaces. Then an initiator for ATRP was immobilized onto the PDMS surface, and PG was grafted onto the surface of PDMS via copper-mediated ATRP. Various characterization techniques, including contact angle measurements (CA), attenuated total reflection infrared spectroscopy (ATR-IR), X-ray photoelectron spectroscopy (XPS) ascertained the successful grafting of PG brush at the PDMS surface. Furthermore, the wetability and stability of the PDMS-PolyPG surface were examined by contact angle measurements. The protein adsorption was examined by protein adsorption studies using three fluorophore-labeled protein (Alexa 594-labeled BSA, Alexa 594-labeled Chicken egg albumin, FITC labeled Lysozyme). The ability of these PG brushes to control bacteria adhesion by bacteria adhesion studies using two bacterial species (Gram-positive S. aureus and Gram-negative E.coli). The cell adhesion study of fibroblast cells (NIH/3T3) was used to test the cell adhesion of the PDMS-PolyPG surface. Studies suggest that the PDMS-PolyPG surface exhibited the durable wetability, stability and significantly resist nonspecific protein adsorption, bacteria adhesion and cell adhesion as compared to unmodified PDMS surface. This activity results from its main structural features: a highly flexible aliphatic polyether, hydrophilic surface groups, and branched architecture. The results show that the PDMS-PolyPG surface is probably applicable as an adhesion barrier, antifouling or functional surface in biomedical.
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