Supercritical Solvent Impregnation Technique for the Development of Antimicrobial Starch-based Aerogels

Abstract

Natural compounds found in different plant extracts can show numerous biological activities and be used as health promoters. For instance, thymol, carvacrol, citronellol, and eugenol (found in extracts of thyme, oregano, lemongrass, and clove, respectively) can be used as anti-inflammatory, antiviral, and antimicrobial agents [1- 4]. The high volatility of the mentioned natural bioactive compounds (NBCs), which restricts their broader application, can be managed by the incorporation of NBCs into polymer matrices. Therefore, intending to develop devices that release antimicrobial substances in a controlled manner, this study tested the applicability of the supercritical solvent impregnation (SSI) technique for the incorporation of NBCs into starch aerogels. First, the hydrogels were prepared from corn starch. The water in the hydrogels was replaced by ethanol, and the obtained alcogels were dried using the supercritical drying (SCD) technique. The parameters of the aerogels` preparation were optimized previously [5].Later, SSI was performed at 150 bar and 35 °C for 2 h. The obtained materials were analyzed using FTIR, to determine the potential interactions between the NBCs and polymer that could determine the rate of controlled release and antimicrobial activity. Controlled release of NBCs from the aerogels was tested in phosphate-buffered saline solution at 37 °C. ...