Physicochemical, antibacterial and biocompatibility assessments of silver incorporated nano-hydroxyapatite synthesized using a novel microwave-assisted wet precipitation technique

Abstract

This current work highlights the synthesis of hydroxyapatite incorporated with silver (Ag-HA) bioceramic material using microwave-assisted wet precipitation method for the first time. This method is relatively convenient and cost effective to produce Ag-HA composite. Apart from physicochemical characterization, antibacterial and biocompatibility analyses are also crucial to validate the bioceramics prior to biomedical applications. Ag-HA nanoparticles were prepared with different Ag concentrations (HA, 3Ag-HA, 6Ag-HA and 9Ag-HA) and its physicochemical characterization was performed using XRD, FTIR, XPS, FESEM, HR-TEM, BET and surface wettability. The antibacterial activity of the nanoparticles was evaluated against Staphylococcus aureus and Streptococcus mitis. The biocompatibility analysis was assessed based on the cell attachment and viability/proliferation of the human bone marrow derived mesenchymal stromal cells (hBMSCs). The elemental and functional group analyses confirmed the presence of Ag and HA in nanoparticles. The crystallinity degree of the Ag-HA decreased while the hydrophilicity increased with increasing Ag concentration. Ag-HA disks indicated a significant zone of inhibition to S. aureus (3Ag-HA: 14.29 ± 0.12 mm; 6Ag-HA: 14.84 ± 0.36 mm, 9Ag-HA: 15.12 ± 0.10 mm, p<0.01) and S. mitis (3Ag-HA: 13.59 ± 0.44 mm; 6Ag-HA: 14.23 ± 0.42 mm, 9Ag-HA: 14.75 ± 0.45 mm, p<0.01) when compared with HA. Biocompatibility tests demonstrated an excellent cell attachment and significant viability/proliferation of hBMSCs on day 7 (p<0.01) for 3Ag-HA disk when compared to day 1 or 3, however the observed result was comparable to HA. This study showed that microwave-assisted wet precipitation method could produce a superior Ag-HA composite for biomedical applications.