In vitro cytocompatibility and antibacterial studies on biodegradable Zn alloys supplemented by a critical assessment of direct contact cytotoxicity assay

Abstract

In vitro cytotoxicity assessment is indispensable in developing new biodegradable implant materials. Zn, which demonstrates an ideal corrosion rate between Mg-and Fe-based alloys, has been reported to have excellent in vivo biocompatibility. Therefore, modifications aimed at improving Zn's mechanical properties should not degrade its biological response. As sufficient strength, ductility and corrosion behavior required of load-bearing implants has been obtained in plastically deformed Zn-3Ag-0.5Mg, the effect of simultaneous Ag and Mg additions on in vitro cytocompatibility and antibacterial properties was studied, in relation to Zn and Zn-3Ag. Direct cell culture on samples and indirect extract-based tests showed almost no significant differences between the tested Zn-based materials. The diluted extracts of Zn, Zn-3Ag, and Zn-3Ag-0.5Mg showed no cytotoxicity toward MG-63 cells at a concentration of ≤12.5%. The cytotoxic effect was observed only at high Zn 2+ ion concentrations and when in direct contact with metallic samples. The highest LD 50 (lethal dose killing 50% of cells) of 13.4 mg/L of Zn 2+ ions were determined for the Zn-3Ag-0.5Mg. Similar antibacterial activity against Escherichia coli and Staphylococcus aureus was observed for Zn and Zn alloys, so the effect is attributed mainly to the released Zn 2+ ions exhibiting bactericidal properties. Most importantly, our experiments indicated the limitations of water-soluble tetrazolium salt-based cytotoxicity assays for direct

Biocompatibility Assessment of Zinc Alloys as a New Potential Material for Bioabsorbable Implants for Osteosynthesis

“…Furthermore, the measurements are in a similar range compared to previous studies on biomaterials [50,51]. W ątroba et al hypothesized that a surface roughness of 0.22 µm is adequate for MG-63 cells [52]. According to Andrukhov et al [53], even a surface roughness of 1-2 µm is suitable for osteoblastic cells.…”

Noninvasive biosensing 3D scaffold to monitor degradation: The potential of fluorescent PCL and PLGA for tissue engineering

“…After that time, this cell culture media containing the degradation products of each sample (conditioned media) were administered to cultured cells (20,000 cells per well) seeded in a 24‐well plate. The cells were kept under incubation with the conditioned media for 24 h. This in‐direct cytotoxicity method was followed as recommended by the ISO 10993‐5: 2009 and widely employed in the literature for cytotoxicity assays 40 . To measure the metabolic activity the samples were submitted to a colorimetric assay.…”

“…The cells were kept under incubation with the conditioned media for 24 h. This in-direct cytotoxicity method was followed as recommended by the ISO 10993-5: 2009 and widely employed in the literature for cytotoxicity assays. 40 To measure the metabolic activity the samples were submitted to a colorimetric assay. The samples were treated with CellTiter Blue following the manufacturer protocols.…”

Synergistic effects of calcium silicate/zinc silicate dual compounds and in-situ interconnected pores on promoting bone regeneration of composite scaffolds

“…% Zn exhibited the best osteogenetic effect. However, some studies have shown that Zn ion at concentration of 13.4 mg l −1 kill 50% of human osteosarcoma (MG-63) cells [34]. It was evident that cells were less tolerant to Zn ions than to Si ions.…”