A novel low‐friction surface for biomedical applications: Modification of poly (dimethylsiloxane)(PDMS) with polyethylene glycol (PEG)‐DOPA‐lysine

K Chawla, S Lee, BP Lee, JL Dalsin, PB Messersmith, ND Spencer
September 9, 2009
Journal of Biomedical Materials Research Part A 90 (3), 742-749, 2009.
Abstract:

Aqueous biocompatible tribosystems are desirable for a variety of tissue-contacting medical devices. L-3,4-dihydroxyphenylalanine (DOPA) and lysine (K) peptide mimics of mussel adhesive proteins strongly interact with surfaces and may be useful for surface attachment of lubricating polymers in tribosystems. Here, we describe a significant improvement in lubrication properties of poly (dimethylsiloxane) (PDMS) surfaces when modified with PEG-DOPA-K. Surfaces were characterized by optical and atomic force microscopy, contact angle, PM-IRRAS, and X-ray photoelectron spectroscopy. Such surfaces, tested over the course of 200 rotations (∼8 m in length), maintained an extremely low friction coefficient (μ) (0.03 ± 0.00) compared to bare PDMS (0.98 ± 0.02). These results indicate the potential applications of PEG-DOPA-K for the modification of device surfaces. Extremely low μ values were maintained over relatively long length scales and a range of sliding speeds without the need for substrate pre-activation and in the absence of excess polymer in aqueous solution. These results were only obtained when DOPA was bound to lysine (modification with PEG-DOPA did not have an effect on μ) suggesting the critical role of lysine in obtaining a lowered friction coefficient. © 2008 Wiley Periodicals, Inc. J Biomed Mater Res, 2009

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