Assessing Cellular Viability, Cytotoxicity, and Antimicrobial Susceptibility of Magnesium-Doped Hydroxyapatite Nanofibers in Primary Fibroblast Cultures: A Biological Characterization.

Hydroxyapatite (HAp) is a bioceramic material of great interest in the field of tissue engineering and bone regeneration, given its high biocompatibility and bioactivity in the human body. HAp has been doped with different elements, including magnesium, strontium, silver, and others. Particularly, magnesium-doped HAp (Mg-HAp) appears to have high potential in biomedical applications. Therefore, it is relevant to characterize their biocompatibility. In this study, an in vitro model of fibroblasts obtained from chicken embryos was used to evaluate the effect of HAp-Mg on cell viability. HAp doped with 5% and 10% magnesium was synthesized by the Microwave hydrothermal-assisted method in a Monowave 300 [Anton Paar]. Subsequently, X-ray diffraction analysis was performed to characterize the HAp-Mg samples. The morphological and microstructural characterization of HAp-Mg was carried out using scanning electron microscopy (SEM). Additionally, chemical analysis was conducted using energy-dispersive X-ray spectroscopy (EDS) and FTIR-ATR spectroscopy. To evaluate the effect of HAp-Mg on cell viability, primary fibroblast cultures were obtained from 10-day-old chicken embryos. Cultures were maintained in DMEM medium supplemented with 10% FBS and incubated for 3 days in 5% CO₂ at 37°C. For the treatments, 5% and 10% HAp-Mg were diluted in DMSO at different concentrations (0.1-100 µg/ml) and added to the fibroblast cultures for 24 hours. Subsequently, cell viability was assessed using the MTT and AlamarBlue assays. Antimicrobial susceptibility tests were performed using the disk diffusion method to determine the antimicrobial activity against <i>Escherichia coli, Staphylococcus aureus, Enterococcus faecalis</i>, and <i>Candida albicans</i>. This helped determine its ability to inhibit microbial growth and prevent the formation of biofilms. In conclusion, this study explored the biocompatibility of HAp-Mg, an important material in biomedical applications. Using a fibroblast model, it characterized HAp-Mg samples and assessed their impact on cell viability. Additionally, the antimicrobial activity of HAp-Mg was evaluated against various pathogens. These findings have significant implications for tissue engineering and bone regeneration applications.