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, 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]. Thus, the aim of this research was to design ultrasound-assisted microstructured films loaded with the Ctx(Ile²¹)-Ha AMP, based on starch and chitosan, for its effective protective action. Gelling was done, for grain breaking and exposing the hydroxyls [3]. For this, it was used 10 g cornstarch and 300 mL distilled water under agitation at 90°C for 1 h. Then, added 5 mL of the gelled starch and mixed with 50 mg of peptide and stored in petri dishes, at 50°C for 5 h. Chitosan film was synthesizing by free radical polymerization in the presence of crosslinker [4]. 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 indicate a consistent semi-morpho phase. Finally, with these results, we show that 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.