Article,
Sol-gel hybrid coatings with strontium-doped 45S5 glass particles for enhancing the performance of stainless steel implants: Electrochemical, bioactive and in vivo response
JOURNAL OF NON-CRYSTALLINE SOLIDS, (October 2015)
DOI: {10.1016/j.jnoncrysol.2015.05.024}
Abstract
The protection of stainless-steel implants by applying a hybrid
organic-inorganic coating generates a barrier for ion migration and a
potential holder for functional particles. Chemical composition of
bioactive silicate-glasses (BG) can be varied to tailor their rate of
dissolution in the biological environment. The substitution of calcium
by strontium (Sr) generates a locally-controlled release of Sr-ions to
the media. Strontium is known to reduce bone resorption and stimulate
bone formation.
This work presents coatings made by sol-gel method containing
tetraethoxysilane, methyl-tiethoxysilane and silica nanoparticles as
precursors, and functionalized either with BG or Sr-substituted BG
particles onto surgical grade stainless steel. The coated implants were
tested in vitro for corrosion resistance and bioactivity, and in vivo to
analyze bone formation.
The applied coating system provided an excellent protection to
aggressive fluids, even after 30 days of immersion. The presence of
hydroxyapatite is shown, as a first evidence of bioactivity. The
evaluation of in vivo tests in Wistar-Hokkaido rat femur 4 or 8 weeks
after the implantation showed slight differences in the thickness of
newly formed bone measured by ESEM, and remarkable changes in bone
quality characterized with Raman microscopy. The in vivo response of the
coatings containing Sr-substituted bioglass is better at early times of
implantation as regards the bone morphology and quality making this
functionalized coatings a very promising option for implant protection
and bone regeneration. (C) 2015 Elsevier B.V. All rights reserved.
