Browsing by Author "Penman, R"

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    Biochemical interaction of few layer black phosphorus with microbial cells using synchrotron macro-ATR-FTIR
    (Materials Australian and The Australian Ceramic Society, 2022-06-01) Shaw, ZL; Cheeseman, S; Huang, LZY; Penman, R; Ahmed, T; Bryant, SJ; Bryant, G; Christofferson, AJ; Orwell-Twigg, R; Dekiwadia, C; Truong, VK; Vongsvivut, JP; Walia, S; Elbourne, A
    In the fight against drug-resistant pathogenic microbial cells, low dimensional materials are emerging as a promising alternative treatment. Specifically, few-layer black phosphorus (BP) has demonstrated its effectiveness against a wide range of pathogenic microbial cells with studies suggesting low cytotoxicity towards healthy mammalian cells. However, the antimicrobial mechanism of action of BP is not well understood and further in-depth investigations are required. In this work, the complex biochemical interaction between BP and a series of microbial cells is investigated using advanced, high-resolution microscopy techniques to provide a greater understanding of the antimicrobial mechanism. Synchrotron macro-attenuated total reflection–Fourier transform infrared (ATR-FTIR) micro-spectroscopy is used to elucidate the chemical changes occurring outside and within the cell of interest after exposure to BP nanoflakes. The ATR-FTIR data, coupled with microscopy, reveals chemical changes to the cellular phospholipids, proteins, structural polysaccharides and nucleic acids when compared to untreated cells. These changes can be attributed to the physical interaction combined with the oxidative stress induced by the degradation of the BP nanoflakes. This study provides an insight into the biochemical interaction of BP nanoflakes with microbial cells, allowing for a better understanding of the antimicrobial mechanism of action.
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    Gold nanoparticle adsorption alters the cell stiffness and cell wall bio-chemical landscape of Candida albicans fungal cells
    (Elsevier, 2024-01-15) Penman, R; Kariuki, R; Shaw, ZL; Dekiwadia, C; Christofferson, AJ; Bryant, G; Vongsvivut, JP; Bryant, SJ; Elbourne, A
    Hypothesis Nanomaterials have been extensively investigated for a wide range of biomedical applications, including as antimicrobial agents, drug delivery vehicles, and diagnostic devices. The commonality between these biomedical applications is the necessity for the nanoparticle to interact with or pass through the cellular wall and membrane. Cell-nanomaterial interactions/uptake can occur in various ways, including adhering to the cell wall, forming aggregates on the surface, becoming absorbed within the cell wall itself, or transversing into the cell cytoplasm. These interactions are common to mammalian cells, bacteria, and yeast cells. This variety of interactions can cause changes to the integrity of the cell wall and the cell overall, but the precise mechanisms underpinning such interactions remain poorly understood. Here, we investigate the interaction between commonly investigated gold nanoparticles (AuNPs) and the cell wall/membrane of a model fungal cell to explore the general effects of interaction and uptake. Experiments The interactions between 100 nm citrate-capped AuNPs and the cell wall of Candida albicans fungal cells were studied using a range of advanced microscopy techniques, including atomic force microscopy, confocal laser scanning microscopy, scanning electron microscopy, transmission electron microscopy, and synchrotron-FTIR micro-spectroscopy. Findings In most cases, particles adhered on the cell surface, although instances of particles being up-taken into the cell cytoplasm and localised within the cell wall and membrane were also observed. There was a measurable increase in the stiffness of the fungal cell after AuNPs were introduced. Analysis of the synchrotron-FTIR data showed significant changes in spectral features associated with phospholipids and proteins after exposure to AuNPs. © 2023 The Author(s). Published by Elsevier Inc. This is an open access article under the CC BY license.