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82. "Rapid Gel Formation and Adhesion in Photocurable and Biodegradable Block Copolymers with High DOPA Content" Lee, B.P.; Chao, C.-Y.; Nunalee, F.N.; Motan, E.; Shull, K.R.; Messersmith, P.B., Macromolecules, 39, 1740 (2006).
Marine mussels anchor to a variety of surfaces in turbulent intertidal zones
through the use of adhesive plaques formed from hardened mussel adhesive proteins
(MAPs). It is believed that 3,4-dihydroxyphenylalanine (DOPA) imparts both water-resistant
adhesive characteristics and rapid curing ability to MAPs. In this paper, DOPA-modified
triblock copolymers were synthesized and used to form adhesive hydrogels. Amphiphilic
block copolymers with DOPA content as high as 10 wt % were prepd., and aq. solns.
of the polymers rapidly (<1 min) formed hydrogels by photopolymn. of methacrylate
end groups attached to the hydrophobic segments. Contact mechanics adhesion
tests were performed on the photocured hydrogels, and it was shown that incorporating
DOPA into the polymer structure significantly enhanced work of adhesion to titanium
surfaces submerged in an aq. medium. Work of adhesion values as high as 410
mJ/m2 were recorded for polymers contg. 10 wt % DOPA, although the introduction
of Lys in the form of a DOPA-Lys copolypeptide reduced the work of adhesion.
Oxidn. of DOPA was shown to reduce work of adhesion to Ti, confirming earlier
studies suggesting that the catecholic form of DOPA is largely responsible for
adhesion to metal oxide surfaces. The DOPA-contg. block copolymers described
in this study are candidates for use as adhesive biomaterials for medical applications.
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