Synthesis and Evaluation of a Chitosan-Based Cationic Hydrogel with Strong Antifungal and Antibiofilm Activities Against Clinical Isolates of Candida auris.

Background

Candida auris is a significant global health concern, due to its rapid transmission, high mortality rate, and resistance to commonly available antifungal drugs. Methodology: During the current study, a cationic polymeric hydrogel was developed using chitosan (CS), polyethylene glycol (PEG), and methacrylic acid (MAA). The respective solutions were mixed in a volumetric ratio of 2:1:1. After characterization, the hydrogel was assessed using antifungal, antibiofilm, and hemocompatibility assays.

Results

The hydrodynamic radius of 554.7 ± 90.1 nm and zeta potential of 15.6 ± 1.09 mV indicate the ideal size and charge for topical applications and in vivo studies, respectively. The formulation exhibited improved thermal stability, enhanced swelling, and a drug release profile for non-Fickian diffusion. The hydrogel effectively inhibited fungal growth in agar plates (42 ± 7.31 mm zone of inhibition), with a mean IC50 of 15.17 ± 4.01 μg/mL and MIC of 29.30 ± 11.72 μg/mL. Calcofluor white (CFW) staining showed diffuse irregular yeast cells, suggesting increased membrane permeability, eventually leading to cell death. The hemocompatibility assay revealed no visible agglutination or hemolysis at the MIC value. The formulation exhibited significantly reduced biofilm formation compared to the growth control (p < 0.05). Additionally, in silico analysis revealed that MAA showed superior oral bioavailability, no inhibitory activity on cytochrome P450 enzymes, and low potential for toxicity through nuclear receptor signaling pathways.

Conclusions

Cationic hydrogels show promise as potential antifungal treatments. The development of cost-effective and improved therapeutic methods is crucial to combat this deadly pathogen and to improve patient outcomes.