Copper stress response of aspergillus niger spores and the implications for antifungal surface functionalization

Microbial life has been an enduring presence in various environments, prompting research into understanding the interactions between microorganisms and antimicrobial agents. Not only in terrestrial settings but even in human spaceflight related environments, Aspergillus niger has been identified alongside Penicillium ssp. as predominant species in HEPA filters and dust within the international space station. As especially fungal contaminations could have detrimental effects on built materials over an extended amount of time and negatively affect not only the structural integrity of a confined built environment, but cause negative effects on human health, it underscores the need to understand fungal responses to stress. Within this study we researched the fungal spore stress response from novel functionalized copper surfaces. The undertaken research focuses on the interaction between A. niger spores and innovative antimicrobial surfaces, that are made from copper and copper-alloys (brass) which have been micro-topographied through Ultrashort pulses Direct Laser Interference Patterning (USP-DLIP). The pulsed patterns show patterns of 3 µm or 9 µm depths which enhances the release of copper ions up on contact with microbial cells. The preliminary findings of contact – killing assays using spores from a wildtype and melanin deficient mutant strain of A.niger, reveal an unexpected heterogeneity in A. niger spore germination responses to copper stress, shedding light on the sophisticated regulation of copper homeostasis by this fungus. The results of those assays were further investigated using varied microscopy based methods like Fluorescence staining, SEM and Live - microscopic imaging of germinating spores under copper stress. For further analysis a detailed RNA profile analyses to discern the molecular mechanisms underlying any observed damage is planned, to gain deeper insights into the intricacies of A. niger's response to copper-induced stress. Understanding how A. niger reacts to copper stress is important for refining effective antimicrobial strategies with broader applications, addressing fungal contamination challenges across diverse settings.