Biocomposites based on SBA-15 and papain: Characterization, enzymatic activity and cytotoxicity evaluation

Papain has bacteriostatic and anti-inflammatory properties and has been shown to be effective in the healing process of wounds, injuries, and ulcers by breaking down fibrinous material into necrotic tissue. However, papain is unstable and easily denatures or deactivates preventing their broad industrial application. In this work, papain was incorporated into SBA-15 ordered mesoporous silica, with the aim of improving its stability, as well as its encapsulation yield and influence of the reaction time on its stability and enzymatic activity. By small-angle X-ray scattering it was possible to verify that the papain is a globular and slightly elongated protein, likely dimeric, with a maximum size of ~6.0 nm, which favors its inclusion in the SBA-15 mesopores (~10 nm). The biocomposites (SBA-15:papain) were characterized by several physical-chemical techniques. The results indicated that the papain was incorporated into the SBA-15 mesopores. The biocomposites exhibited higher thermal degradation temperature than pure papain and did not show cytotoxic potential. The papain enzymatic activity was maintained, with the best performance for the samples prepared with 30 wt% of papain. The results also showed that the 3D cell culture system is better suited for biocomposites that present a cell disruption mechanism.