engleski

Novel polyelectrolyte multilayers: amorphous calcium phosphate coatings for bone implants

Multilayer (ML) films formed by alternated adsorption of anionic and cationic polyelectrolytes (PE) have proven to be an efficient way to prepare functionalized surfaces [1]. Recently, it has been indicated that PE multilayers could induce calcium phosphate nucleation [2] and that crystalline calcium phosphate could grow on them [3, 4]. These findings prompted us to attempt to develop novel organic-inorganic coatings for artificial bone implants consisting of PE multilayers and “ in-situ” grown calcium phosphate crystals [4]. PE multilayers, consisting of poly-l-lysine (PLL) and poly-l-glutamic acid (PGA), (PLL/PGA)nPLL, (n number of layers) were deposited on glass and titanium plates. On the top of the multilayers, amorphous calcium phosphate (ACP) particles were deposited as seeds, from which calcium phosphate crystals were grown “ in situ” . The precipitates were observed by scanning electron microscopy and characterized by X-ray powder diffraction. It was demonstrated that multilayers uniformly cover the surfaces of the investigated substrates. Also, in the experimental systems, good coverage with partially oriented calcium phosphate crystals was obtained. The above results point to a novel method for the preparation of PE multilayer – calcium phosphate composite coatings for biomedical applications. The PE multilayers provide a polymer matrix, which may be designed to increase cell activity. The “ in situ” grown calcium phosphate component additionally increases the osteoinductive properties of the system.

amorphous calcium phosphate; bone implants; polyelectrolytes

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