Potential Protective Activity and Stability of Cornstarch/Chitosan Films Loaded with the Ctx(Ile²¹)-Ha Antimicrobial Peptide † ^†

The high mortality rate of different multi-resistant bacteria (MDR) has led to an immediate and urgent solution. Patients hospitalized for chronic diseases have a weakened immune system and are at high risk of contracting an opportunistic infection. Likewise, the WHO prioritized studies against a selected group of MDR bacteria for their control [1]. In this scope, the Ctx(Ile²¹)-Ha antimicrobial peptide (AMP) presented great potential and efficient biological activity against Acinetobacter baumannii and Pseudomonas aureginosa MDR bacteria [2,3,4]. Thus, the aim of this research was to design ultrasound-assisted micro-structured films loaded with the Ctx(Ile²¹)-Ha AMP, based on starch and chitosan, for its effective protective action. Gelling was performed for grain breaking and to expose the hydroxyls [5]. For this, 10 g of cornstarch was used as well as 300 mL of distilled water under agitation at 90 °C for 1 h. Then, 5 mL of the gelled starch was added and mixed with 50 mg of peptide. Then, it was stored in petri dishes at 50 °C for 5 h. Chitosan film was synthesized by free-radical polymerization in the presence of crosslinker [6]. Chitosan dispersion (CD) was prepared by dissolving 2% w/v chitosan in 2% v/v acetic acid solution. Ctx(Ile²¹)-Ha was placed on the CD with 0.3% w/v of glycerol and magnetic agitation at 150 rpm. For this, its properties were evaluated by DSC/TGA, FTIR, XRD, and SEM. The physicochemical stability studies of the AMP showed its structure unchanged for up to 3 months exposed to water and for up to one year in the form of a dry film. These results were confirmed by the LC/MS profile, in which XDR indicates a consistent semi-morpho phase. Finally, with these results, we check its stability and protective potential over time and, based on previously published results on their activity against MDR bacteria [2], we conclude that the new products based on AMPs could be potential anti-MDR bacterial agents, avoiding the exposure of critically ill patients in intensive care or post-surgery beds and preventing their dissemination.