Preparation and Characterization of 2,2,6,6-Tetramethylpiperidine-1-oxyl (TEMPO)-Oxidized Cellulose Nanocrystal/Alginate Biodegradable Composite Dressing for Hemostasis Applications

Hemorrhage is common in surgery, and excessive bleeding is the main reason for trauma death. Effective control of bleeding is becoming more and more important in military and civilian trauma. In this work, oxidized cellulose nanocrystal/alginate composite films and sponges were successfully prepared and their usages as the hemostatic materials were investigated. Carboxyl functionalization on the cellulose nanocrystal surface not only played a fundamental role in the structural of composites, but also contributed to absorb plasma and stimulate erythrocytes and platelets. Fourier transform infrared (FTIR) and X-ray photoelectron spectroscopy (XPS) spectra showed that the carboxyl groups were successfully introduced on the cellulose nanocrystal surface by TEMPO-mediated oxidization. The oxidized cellulose nanocrystals (TOCN)/alginate (SA) composites were in the presence of Ca2+ solution cross-linking. Physical properties tests results indicated that the ultrahigh porosity (sponge), surface homogeneity (film), water absorption ability, and chemical stability of TOCN-30/SA composite sponge, as well as TOCN-30/SA composite film, were all increased after ionic cross-linking, compared to the SA sponge and film, respectively. In vitro evaluation of the hemostatic effect, hemostatic time, and the blood loss in two injury models exhibited that TOCN-30/SA composite sponge had the most excellent hemostatic efficiency and could be biodegraded completely without inflammatory reaction after three weeks. In addition, the potential hemostatic mechanism of TOCN/SA composites was discussed.