A novel low-friction surface for biomedical applications: modification of poly(dimethylsiloxane) (PDMS) with polyethylene glycol(PEG)-DOPA-lysine.
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 ( approximately 8 m in length), maintained an extremely low friction coefficient (mu) (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 mu 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 mu) suggesting the critical role of lysine in obtaining a lowered friction coefficient.
Department of Biomedical Engineering, Northwestern University, Evanston, Illinois 60208, USA.
Kanika
K
Chawla
Seunghwan
S
Lee
Bruce P
BP
Lee
Jeffrey L
JL
Dalsin
Phillip B
PB
Messersmith
Nicholas D
ND
Spencer
D001672:Biocompatible Materials / Q000737:chemistry*; D004295:Dihydroxyphenylalanine / Q000737:chemistry; D004129:Dimethylpolysiloxanes / Q000737:chemistry; D054327:Lubricants / Q000737:chemistry*; D008239:Lysine / Q000737:chemistry; D008422:Materials Testing; D011092:Polyethylene Glycols / Q000737:chemistry; D013499:Surface Properties
D001672:Biocompatible Materials; D004129:Dimethylpolysiloxanes; D054327:Lubricants; D011092:Polyethylene Glycols; D004295:Dihydroxyphenylalanine; D008239:Lysine