Herbal Architectures in Strontium Phosphosilicate: A Comparative Microstructure–Biointerface Study of Tulsi-, Moringa-, and Aloe Vera-Doped Bio Ceramics

Abstract

Strontium phosphosilicates are promising bioceramics in bone-repair materials but their blood biocompatibility and lack of antibacterial activity require improvement. In this study, SrPS samples were prepared by sol–gel synthesis and modified with plant aqueous extracts of Ocimum sanctum, Moringa oleifera, and Aloe barbadensisMiller. Phase analysis confirmed the preservation of the core SrPS lattice with an apatite-like framework in all samples, as evidenced by XRD, FT-IR, and Raman spectroscopy. SEM and particle size analysis revealed particles in the submicron range and a clear increase in agglomerate size from Pure SrPS ≈ Moringa-SrPS < Tulsi-SrPS ≪ Aloe vera-SrPS. The elemental ratio of natural bone is close to 1.67; meanwhile, EDAX confirmed that the Sr/P ratios for pure SrPS, as well as for SrPS samples doped with tulsi, moringa, and aloe vera, are 1.60, 1.59, 1.62, and 1.65, respectively. Eventually, Vickers microhardness assessment revealed that dried biodoped SrPS performed better than natural bone and hydroxyapatite, and it followed the order pure SrPS (sintered) < aloe vera-doped < moringa-doped < tulsi-doped SrPS. Antibacterial activity showed improved ZOI in aloe vera (18 and 16 mm), moringa (17 and 13 mm), tulsi (16 and 15 mm) for the bacterial strains (S. aureus and E. coli), while pure SrPS was inactive. Hemolysis ratios remained under 5% for all compositions, ranging from 1.81% to 3.86%; notably, Aloe vera-SrPS showed a hemolysis value of 2.90%, which indicates excellent hemocompatibility. Synergistically, these results corroborate that medicinal-plant-extract tuning converted SrPS into an antibacterial, mechanically robust, and blood-biocompatible material. Among the three biodopants, Aloe vera-SrPS outperformed the other two biodoped systems and emerged as the most balanced formulation.