Production and Characterization of Silk Fibroin–<i>Aloe vera</i> Hydrogel: A Study on Extraction, Hydrogel Properties, and Release Mechanism

This work investigated the production and characterization of a silk fibroin (SF) hydrogel incorporated with an <i>Aloe vera</i> (AV) extract. Four extraction methods, ultrasound-assisted extraction with bath and probe, stirring, and Soxhlet, were tested, while the hydrogel was produced by a one-step freeze-thaw method. Besides the extraction yield, the antioxidant capacity of the extracts was accessed, which allowed to select the extract obtained by ultrasound-assisted extraction to be incorporated into the hydrogels. Hydrogels were characterized by scanning electron microscopy and Fourier transform infrared spectroscopy. Rheological assay, swelling behavior, and water uptake capacity were measured. The SF-AV hydrogel was submitted to release test, and the data were mathematically modeled. The hydrogels exhibited malleability, insolubility in water, interconnected pores, and thermal and physical stability. The SF-AV hydrogel released 37% extract over 330 min, with diffusion controlled by the Fickian mechanism. These promising results make the SF-AV hydrogel an attractive choice for wound dressing and other biomaterial-related applications.