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The antimicrobial efficacy of hypoxia mimicking cobalt oxide doped phosphate-based glasses against clinically relevant Gram positive, Gram negative bacteria and a fungal strain

DOI: 10.1021/acsbiomaterials.8b01045 DOI Help

Authors: Farah N. S. Raja (Aston University) , Tony Worthington (Aston University) , Mark A. Isaacs (University College London) , Louis Forto Chungong (Aston University) , Bernard Burke (Coventry University; University of Birmingham School of Dentistry) , Owen Addison (University of Birmingham School of Dentistry; University of Alberta) , Richard Martin (Aston University)
Co-authored by industrial partner: No

Type: Journal Paper
Journal: Acs Biomaterials Science & Engineering

State: Published (Approved)
Published: November 2018
Diamond Proposal Number(s): 16079

Abstract: Bioactive phosphate glasses are of considerable interest for a range of soft and hard tissue engineering applications. The glasses are degradable and can release biologically important ions in a controlled manner. The glasses can also potentially be used as an antimicrobial delivery system. In the given study, novel cobalt doped phosphate-based glasses, (P2O5)50(Na2O)20(CaO)30-x(CoO)x where 0 ≤ x (mol%) ≤ 10, were manufactured and characterised. As the cobalt oxide concentration increased the rate of dissolution was observed to decrease. The antimicrobial potential of the glasses was studied using direct and indirect contact methods against both Escherichia coli (NCTC 10538) Staphylococcus aureus (ATCC 6538) and Candida albicans (ATCC 76615). The results showed a strong, time dependent and strain specific, antimicrobial activity of the glasses against microorganisms when in direct contact. Antimicrobial activity (R) ≥ 2 was observed within 2 hours against Escherichia coli whereas similar effect was achieved in 6 hours against Staphylococcus aureus and Candida albicans. However, when in indirect contact, the dissolution products from the bioactive glasses failed to show antimicrobial effect. Following direct exposure to the glasses for 7 days, osteoblast-like SAOS-2 cells showed a 5-fold increase in VEGF mRNA whilst THP-1 monocytic cells showed a 4-fold increase in VEGF mRNA expression when exposed to 10% CoO doped glass compared with the cobalt free control glass. Endothelial cells stimulated with conditioned medium taken from cell cultures of THP-1 monocytes exposed to 10% CoO doped glass showed clear tube–like structure (blood vessel) formation after 4 hours

Journal Keywords: Bioactive glass; antibacterial; vascularisation; VEGF; Hypoxia Inducible Factor-1 α (HIF-1α)

Subject Areas: Biology and Bio-materials, Chemistry


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