Abstract
Using ammonium bicarbonate (AB) particles as a porogen, chitosan (CS)-based hemostatic porous sponges were prepared in supercritical carbon dioxide due to its low viscosity, small surface tension, and good compatibility with organic solvent. Fourier transform infrared spectroscopy (FTIR) spectra demonstrated that the chemical compositions of CS and poly-(methyl vinyl ether-co-maleic anhydride) (PVM/MA) were not altered during the phase inversion process. The morphology and structure of the sponge after the supercritical fluid (SCF) process were observed by scanning electron microscopy (SEM). The resulting hemostatic sponges showed a relatively high porosity (about 80%) with a controllable pore size ranging from 0.1 to 200 μm. The concentration of PVM/MA had no significant influence on the porosity of the sponges. Comparative experiments on biological assessment and hemostatic effect between the resulting sponges and Avitene® were also carried out. With the incorporation of PVM/MA into the CS-based sponges, the water absorption rate of the sponges increased significantly, and the CS-PVM/MA sponges showed a similar water absorption rate (about 90%) to that of Avitene®. The results of the whole blood clotting experiment and animal experiment also demonstrated that the clotting ability of the CS-PVM/MA sponges was similar to that of Avitene®. All these results elementarily verified that the sponges prepared in this study were suitable for hemostasis and demonstrated the feasibility of using SCF-assisted phase inversion technology to produce hemostatic porous sponges.
Highlights
Studies and applications of absorbable hemostatic material are meaningful to both hygiene and military [1]
It has been demonstrated that the morphology of the sponges could be reproduced accurately by the supercritical fluid (SCF) phase inversion process [15]
In the phase inversion process, the properties of the final porous structure were mainly controlled by the precipitation temperature, the pressure of the bath, the flow rate of CO2, the concentration of the casting solution, and the particle size of the porogen
Summary
Studies and applications of absorbable hemostatic material are meaningful to both hygiene and military [1]. Over the past few decades, supercritical fluid (SCF) technology has been developed and widely utilized in tissue engineering and biomedical applications It appears to be an interesting alternative to the traditional processing method [15,16]. Our previous study [15] produced a porous nanostructured poly-L-lactide (PLLA) scaffold with interconnected pores by phase inversion, using supercritical CO2 as an anti-solvent in the presence of ammonium bicarbonate (AB) particles. It confirmed the possibility of using supercritical fluid technology to produce porous material. We attempted to prepare CS-based hemostatic porous sponges by phase inversion, using supercritical CO2 as an anti-solvent in the presence of AB particles. A femoral artery hemorrhage mouse model was established to investigate the hemostatic effects
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