Calcium ion-exchange cross-linked porous starch microparticles with improved hemostatic properties

Starch hemostatic agents have been clinically used in surgical hemostasis in recent years. Calcium ion (Ca²⁺)-exchange cross-linked porous starch microparticles (Ca²⁺CPSMs) were prepared as a new hemostatic agent to enhance the hemostatic efficacy. A series of Ca²⁺CPSMs with varying Ca²⁺ contents were prepared and characterized by Fourier-transform infrared spectroscopy (FT-IR), X-ray photoelectron spectroscopy (XPS), X-ray diffraction (XRD), scanning electron microscope (SEM), and ion content analysis. The XPS and FT-IR results indicated that the surface of Ca²⁺CPSMs was modified by Ca²⁺, which might form coordination bonds with oxygen atoms of starch molecules. Ca²⁺CPSMs revealed a porous surface structure and a lower crystallinity degree according to SEM and XRD, which facilitated the phosphate buffer saline (PBS) uptake rate and enzymatic degradation in vitro. The fast release of Ca²⁺ from Ca²⁺CPSMs accelerated the whole blood clotting rate, shortened the activated partial thromboplastin time, and promoted platelet adhesion. The physical hemostatic mechanism benefited from the rapid PBS uptake capacity and porous surface structure of Ca²⁺CPSMs, in addition to the chemical activation of coagulation process by Ca²⁺, thus achieving a significant hemorrhage control in the mouse tail amputation model.