Anti Inflammatory Properties of Terbium Doped Hydroxyapatite Crystals for Biomedical Applications - In Vitro Study

Abstract

Objective: This study aimed to evaluate the anti-inflammatory properties of terbium-doped hydroxyapatite (Tb-HAp) in vitro, with the goal of determining its ability to attenuate inflammation and improve the biocompatibility of HA-based biomaterials for bone and dental applications.

Materials and Methods: Tb-HAp was synthesized using the coprecipitation method with varying concentrations of terbium (0%–10%). Anti-inflammatory activity was assessed through three assays: protein denaturation inhibition, heat-induced hemolysis (membrane stabilization), and trypsin inhibition, with aspirin used as the positive control.

Results: In the protein denaturation inhibition assay, Tb-HAp exhibited a dose-dependent increase in inhibition. At 100 µg/mL, inhibition was 36.15%, which rose to 85.95% at 500 µg/mL. The IC50 value was calculated to be 259.67±1.47 µg/mL, indicating that higher concentrations were required to inhibit 50% of protein denaturation. In comparison, aspirin at 100 µg/mL showed a higher inhibition of 95.69%. The heat-induced hemolysis assay showed a similar dose-dependent response. At 100 µg/mL, inhibition was 39.24%, which increased to 81.74% at 500 µg/mL, with an IC50 of 194.41±1.83 µg/mL. Aspirin at 100 µg/mL achieved 94.43% inhibition, indicating superior membrane stabilization. Lastly, the trypsin inhibition assay revealed a dose-dependent increase in inhibition, starting at 16.46% at 100 µg/mL and reaching 70.05% at 500 µg/mL. The IC50 for this assay was 350.14±1.56 µg/mL, while aspirin showed 94.01% inhibition at 100 µg/mL, outperforming Tb-HAp at the same concentration.

Conclusion: Tb-HAp demonstrated significant anti-inflammatory activity in all three assays, showing a dose-dependent response. While it was less potent than aspirin, it displayed potential for improving the biocompatibility of hydroxyapatite-based biomaterials. These findings suggest that Tb-HAp could be an effective material for reducing inflammation and enhancing tissue integration in biomedical and dental applications