Hydroxyapatite Growth on Poly(Dimethylsiloxane-Block-ε-Caprolactone)/Tricalcium Phosphate Coatings Obtained by Electrophoretic Deposition

REDONDO, FRANCO LEONARDO; GIAROLI, MARÍA CAROLINA; CIOLINO, ANDRÉS EDUARDO; NINAGO, MARIO DANIEL

Frontiers in Materials

Frontiers Boards

Año: 2022 vol. 8

For the first time, composite coatings based on poly(dimethylsiloxane-block-ε-caprolactone)copolymer and tricalcium phosphate were obtained on stainless steel plates by using theelectrophoretic deposition technique. The effect of different deposition times on the finalcharacteristics of the resulting coatings was also studied. Block copolymers were obtainedthrough a combination of anionic and ring-opening polymerization, with good homogeneityand chemical composition (Ð < 1.3 and wPCL 0.39). The composites obtained at differentelectrophoretic deposition times revealed a linear dependence between the deposited weightand time during assays. When immersing in simulated body fluid, a higher amount of residualsolids ( ∼ 20 %) were observed by thermogravimetric analysis after 7 days of immersion.Scanning electronmicroscopymicrographs revealed a porousmicrostructure over themetallicsubstrate and the absence of micro-cracks, and X-ray diffraction patterns exhibited diffractionpeaks associatedwith a hydroxyapatite layer. Finally, energy-dispersive X-ray analysis revealedvalues of the Ca/P ratio between 1.40 and 1.50 in samples, which are closer to thestoichiometric hydroxyapatite values reported in hard tissues. The results obtained in thisarticle confirm the usefulness of poly(dimethylsiloxane-block-ε-caprolactone) copolymer andcheaper tricalcium phosphate as precursors of compact and homogenous coatings obtainedby electrophoretic deposition, which yields useful substrates for hydroxyapatite growth.