Journal of Functional Biomaterials (Dec 2022)

In Vitro Degradation and Photoactivated Antibacterial Activity of a Hemin-CaP Microsphere-Loaded Coating on Pure Magnesium

  • Lixin Long,
  • Yang Song,
  • Xiaoyi Tian,
  • Lanyue Cui,
  • Chengbao Liu,
  • Shuoqi Li,
  • Yu Wang,
  • Rongchang Zeng

DOI
https://doi.org/10.3390/jfb14010015
Journal volume & issue
Vol. 14, no. 1
p. 15

Abstract

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Photoactivated sterilization has received more attention in dealing with implant-associated infections due to its advantages of rapid and effective bacteriostasis and broad-spectrum antibacterial activity. Herein, a micro-arc oxidation (MAO)/polymethyltrimethoxysilane (PMTMS)@hemin-induced calcium-bearing phosphate microsphere (Hemin-CaP) coating was prepared on pure magnesium (Mg) via MAO processing and dipping treatments. The morphology and composition of the coating were characterized via scanning electron microscopy, Fourier transform infrared spectrometer, X-ray diffractometer and X-ray photoelectron spectrometer. Corrosion behavior was evaluated through electrochemical and hydrogen evolution tests. The release of Fe3+ ions at different immersion times was measured with an atomic absorption spectrophotometer. Antibacterial performance and cytotoxicity were assessed using the spread plate method, MTT assay and live/dead staining experiment. The results showed that the corrosion current density of the MAO/PMTMS@(Hemin-CaP) coating (4.41 × 10−8 A·cm−2) was decreased by two orders of magnitude compared to that of pure Mg (3.12 × 10−6 A·cm−2). Photoactivated antibacterial efficiencies of the Hemin-CaP microspheres and MAO/PMTMS@(Hemin-CaP) coating reached about 99% and 92%, respectively, which we attributed to the photothermal and photodynamic properties of hemin with a porphyrin ring. Moreover, based on the release of Fe3+ ions, the MC3T3-E1 pre-osteoblasts’ viability reached up to 125% after a 72 h culture, indicating a positive effect of the coating in promoting cell growth. Thus, this novel composite coating holds a promising application as bone implants.

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