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 (Ca)-exchange cross-linked porous starch microparticles (CaCPSMs) were prepared as a new hemostatic agent to enhance the hemostatic efficacy. A series of CaCPSMs with varying Ca 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 CaCPSMs was modified by Ca, which might form coordination bonds with oxygen atoms of starch molecules. CaCPSMs 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 Ca from CaCPSMs 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 CaCPSMs, in addition to the chemical activation of coagulation process by Ca, thus achieving a significant hemorrhage control in the mouse tail amputation model.