Development and in vitro hemagglutination studies of chitosan/poly(ε-caprolactone) sponges produced by freeze-drying as topical hemostatic agents

The biological effects of natural polymers have been investigated as an attempt to create materials that can be used in tissue repair. Chitosan, a natural polymer with hemostatic properties, is among these materials. Sponges of chitosan (CS) and poly(ε-caprolactone) (PCL) were prepared by emulsion–solvent displacement for possible uses as a topical hemostatic agent. Chitosan solutions and PCL emulsions were prepared, respectively, in water containing 1% acetic acid and 2.5 wt.% PCL in acetone/Tween^® 80 (surfactant), and then mixed in proportions of 100:0; 75:25; 50:50; 25:75; 0:100, followed by freeze-drying to produce CS/PCL sponges. Samples were characterized by scanning electron microscopy (SEM), X-ray diffraction (XRD), thermogravimetric analysis (TGA) and Fourier-transform infrared spectroscopy (FTIR). Hemagglutination assay, absorbance and hemolysis tests were also carried out to study the interactions between sponges and blood tissue. It was observed that CS favored CS/PCL sponge formation while sponges were not produced when only PCL was used. Moreover, SEM images demonstrate that CS/PCL sponges have an interconnected porous morphology. XRD patterns showed that the individual morphologies of CS and PCL were maintained, which indicates a low interaction between the components in the mixture as can also be corroborated by FTIR, since there were no significant changes in the characteristic frequencies of functional groups in the sponges when compared to the spectra of pure polymers. Results also showed that sponges with up to 50% CS had a good hemagglutination capacity, demonstrating the potential of these blends as hemostatic materials for surgical purposes such as in dental surgeries.

Graphical abstract