Nano Copper‐chelate Triggers Cuproptosis‐like Death in Fungi and Synergizes with Microneedles for Enhanced Biofilm Removal

The study demonstrates that the synthesized nano-chelate Cu(DDC)₂@BSA exhibits antifungal activity against Candida albicans by inducing mitochondrial dysfunction, as evidenced by copper ions overload, decreased ATPase activity, reduced mitochondrial membrane potential, and changes in two key proteins involved in cuproptosis. Additionally, the combination of Cu(DDC)₂@BSA with quaternary ammonium chitosan microneedles enhances the antifungal effect and provides a novel treatment strategy for fungal infections.

Abstract

Fungal infections pose a significant global public health threat, particularly candidemia and biofilm formation. Current antifungal drugs have limitations due to their toxicity and drug resistance. Ion interference therapy, particularly cuproptosis, shows significant potential for disease treatment. Herein, nano copper-chelate Cu(DDC)₂@BSA (CDB) is synthesized for antifungal research and the mechanism of cuproptosis-like death is investigated. Initially, CDB demonstrates a strong inhibitory effect on multiple fungi and exhibits strong antifungal activity against two fluconazole-resistant clinical isolates. The decrease in ATPase activity and mitochondrial membrane potential indicates that the antifungal mechanism may involve mitochondrial dysfunction. Subsequently, transcriptome analysis reveals significant alterations in genes related to copper ions transport and regulation, oxidative phosphorylation, and mitochondrial function. Additionally, copper ions overload is observed, along with an increase in heat shock protein 70 levels and a decrease in lipoic acid synthetase protein expression. Given that biofilms hinder drug penetration, quaternary ammonium chitosan microneedles are employed in combination with CDB to penetrate the biofilm barrier and enhance the antifungal effect. Overall, this study provides new insight into the cuproptosis-like death mechanism in fungi and presents a promising strategy for fungal infection treatment through the combination of nano copper–chelate and microneedle delivery system.