Nanocrystalline bioactive apatite coatings

Dip coated silicon-substituted hydroxyapatite films

“…, which may appear as a consequence of the Ca/P ratio increase with the silicon substitution. Moreover, these results indicate that the introduction of silicon into the precursor sol does not alter the deposition conditions in such a way that compounds like calcite may appear together with or instead of apatite, as has been observed after minimal variations in these parameters in the deposition of pure HA films [30,31]. However, some differences on the XRD patterns can be appreciated with increasing silicon content, namely a progressive broadness of the apatite maxima; in fact, from x = 0.5 the maxima attributable to the (0 0 2), (3 0 0) and (2 0 2) reflections can be hardly distinguished from the background.…”

“…From previous experience of the sol-gel deposition of HA coatings [30,31], a compromise can be established between temperatures and times of sol aging. Briefly, the higher the temperature, the shorter the aging period to obtain pure HA coatings and, unfortunately, also the stability of the sol decreases.…”

“…These conditions were chosen according to previous results obtained for HA coatings deposited by sol-gel using these precursors [30,31].…”

“…In this sense, sol-gel technology has been employed by several authors to prepare hydroxyapatite layers onto different types of substrates [16][17][18][19][20][21][22][23][24][25][26][27][28][29][30][31], where the influence of parameters such as the nature of the precursors, sol temperature, aging time and temperature, extraction rate, etc. have been studied in order to optimize the deposition conditions of pure HA films.…”

Apatite coating on anionic and native collagen films by an alternate soaking process

“…The surface of HAp must be exposed to the surrounding environment in order for its biological properties to act [7]. HAp coating has been widely used in orthopedics and dentistry in order to improve the bone bonding and tissue compatibility of various substrates [8,9]. A variety of methods have been reported in the literature for coating a HAp layer onto organic polymer substrates.…”