Hydroxyapatite/tannic acid coating (HA/TA) were prepared on AZ31 magnesium alloys (AZ31) via chemical conversion and biomimetic methods. The characterization and properties of the coating were studied by scanning electron microscopy (SEM), X-ray diffraction (XRD), Fourier transform infrared spectroscopy (FTIR), corrosion testing, MC3T3-E1 cell proliferation assay, and MC3T3-E1 cell morphology observation. The results showed that tannic acid as an inducer increased the number of nucleation centers of hydroxyapatite and rendered the morphology more uniform. Compared to bare AZ31 magnesium (Mg) alloys (E corr = −1.462 ± 0.006 V, I corr = (4.8978 ± 0.2455) × 10 −6 A/cm 2 ), the corrosion current density of the HA/TA-coated magnesium alloys ((5.6494 ± 0.3187) × 10 −8 A/cm 2 ) decreased two orders of magnitude, and the corrosion potential of the HA/TA-coated Mg alloys (E corr = −1.304 ± 0.006 V) increased by about 158 mV. This indicated that the HA/TA coating was effectively protecting the AZ31 against corrosion in simulated body fluid (SBF). Cell proliferation assays and cell morphology observations results showed that the HA/TA coating was not toxic to the MC3T3-E1 cells.

In this study, we evaluate the effect of co-doping with TiO2 nanoparticles and sisal cellulose nanocrystals (CNCs) on the physical and biological properties of a conventional glass-ionomer cement (GIC). Test samples were characterized by scanning electron microscopy, and Fourier-transform infrared spectroscopy, and subjected to mechanical tests to evaluate the mechanical performances. Antimicrobial activity was evaluated against Candida albicans, and cytotoxicity experiments were conducted using L-929 cells. Unmodified GIC served as a control. Compared with the control group, the co-doped group demonstrated an increased compressive strength of 18.9%, an increased shear bond strength of 51%, the dissolution decreased by 18.3%, the volume wear rate was reduced by 5%. The antifungal effect against C. albicans was increased by 22%. In cytotoxicity experiments, the co-doped group had a slightly negative effect on the viability of L-929 cells.

Abstract:The purpose of this work is to improve the cytocompatibility and corrosion resistance of magnesium alloy in the hope of preparing a biodegradable medical material. The aminated hydroxyethyl cellulose-induced biomimetic hydroxyapatite coating was successfully prepared on AZ31 magnesium alloy surface with a sol-gel spin coating method and biomimetic mineralization. Potentiodynamic polarization tests and electrochemical impedance spectroscopy showed that the hydroxyapatite/aminated hydroxyethyl cellulose (HA/AHEC) coating can greatly improve the corrosion resistance of AZ31 magnesium alloy and reduce the degradation speed in simulated body fluid (SBF). The MTT [3-(4,5-dimethylthiazol-2-yl)-2,5-Diphenyltetrazolium bromide] method and cell morphology observation results showed that the HA/AHEC coating on AZ31 magnesium alloy has excellent cytocompatibility and biological activity.

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