Ultrasonic irradiation in the synthesis of nanohydroxyapatite: a chemically friendly technique for improving hemocompatibility and antibiofilm applications.

This study explores the synthesis of nanohydroxyapatite (nHA) using high-frequency ultrasonic irradiation (UI), a chemically friendly technique aligned with green chemistry principles. Synthesis was achieved by varying the UI time (15, 30, 45, and 60 min) and the reaction medium. Water-based mixtures were used, that is, water/acetone (W/ACET), water/tetrahydrofuran (W/THF), and water/ethanol (W/ETOH). The resulting nHA was characterized structurally using FTIR, XRD, TGA, FESEM, and specific surface area determination. These analyses revealed the formation of carbonated nHA similar to biological apatite, with distinct morphologies and particle sizes dependent on the solvent system used. All synthesized materials exhibited high thermal stability and yields exceeding 80%. Hemocompatibility studies showed that nHA samples obtained in the W/THF mixture presented very low hemotoxicity (hemolysis < 2%), and did not affect platelet ADP aggregation processes. Microbiological assays showed a significant reduction in Pseudomonas aeruginosa biomass production (p < 0.05) after 24 h, particularly for nHA synthesized with the W/ETOH mixture. There was also a less bacterial colonization, cellular aggregates, or formation of specialized structures after treatment with this bioceramic, compared to the commercial hydroxyapatite, suggesting potential antibiofilm properties. This research presents an original and efficient method for producing nHA as a promising biomaterial for tissue engineering.