Preparation and hemostatic performance of composites using tourmaline and shells as main raw materials

Controlling blood loss is crucial for saving lives during trauma. Based on the current application of solid waste in hemostatic materials, this study reports the synthesis of a hydroxyapatite/tourmaline composite material (referred to as ST) and a hemostatic sponge (referred to as STS). These materials were synthesized through hydrothermal processes and lyophilization techniques using seashells, tourmaline, and chitosan as precursors. The phase analysis and microstructure characterization were performed using XRD, SEM, TEM, and HRTEM. Owing to the spontaneous polarization of tourmaline attracting free ions in the system, the shells were deposited on the surface of tourmaline particles in the form of hydroxyapatite (HA) through dissolution and recrystallization during the hydrothermal process. HA can release free Ca²⁺, an important component in the coagulation system, while tourmaline can enhance cell metabolism by reducing water molecular clusters, thereby altering the permeability of cell membranes. ST particles were incorporated into the chitosan sponge matrix to prevent particle shedding. Through orthogonal design experiments on the preparation process of ST, the optimal preparation conditions were determined as follows: a hydrothermal temperature of 180 °C, a hydrothermal time of 12 h, a pH value of 8, and a shell-to-tourmaline ratio of 8 : 1. The composite materials were evaluated for their adsorption capacity, clotting time, hemolysis rate, antibacterial rate, and cytotoxicity. The results demonstrated a higher liquid adsorption rate, significantly reduced clotting time, a hemolysis rate of <5.0%, an antibacterial capacity of 88.5%, and lower cytotoxicity. These findings suggest that STS has the potential to be a safe, effective, and cost-efficient hemostatic agent.