Browsing by Author "Ahmed, T"

Now showing 1 - 2 of 2
  • Thumbnail Image
    Item
    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.
  • No Thumbnail Available
    Item
    Poly(ethylene glycol)-modulated cellular biocompatibility of polyhydroxyalkanoate films
    (Wiley-Blackwell, 2013-06-01) Chan, RTH; Marçal, H; Ahmed, T; Russell, RA; Holden, PJ; Foster, LJR
    Polyhydroxybutyrate (PHB) and its copolymer with hydroxyvalerate, P(HB-co-HV), are widely used biomaterials. In this study, improvements of their biological properties of degradability and compatibility were achieved by blending with low-molecular-weight poly(ethylene glycol) (PEG106) approved for medical use. Surface morphology and chemistry are known to support cell attachment. Attachment and proliferation of neural olfactory ensheathing cells increased by 17.0 and 32.2% for PHB and P(HB-co-HV) composite films. Cell attachment was facilitated by increases in surface hydrophilicity, water contact angles decreased by 26 ± 2° and water uptake increased by 23.3% depending upon biopolymer and PEG loading. Cells maintained high viability (>95%) on the composite films with no evidence of cytotoxic effects. Assays of mitochondrial function and cell leakage showed improved cell health as a consequence of PEG loading. The PEG component was readily solubilised from composite films, allowing control of degradation profiles in the cell growth medium. Promotion of biopolymer compatibility and degradability was not at the expense of material properties, with the extension to break of the composites increasing by 5.83 ± 1.06%. Similarly, crystallinity decreased by 36%. The results show that blending of common polyhydroxyalkanoate biomaterials with low-molecular-weight PEG can be used to promote biocompatibility and manipulate physiochemical and material properties as well as degradation. © 2013, Wiley-Blackwell.