ORCID Profile
0000-0001-6044-9705
Current Organisation
University of South Australia
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Publisher: American Chemical Society (ACS)
Date: 16-10-2015
DOI: 10.1021/ACS.ANALCHEM.5B03183
Abstract: Internalized gold nanoparticles were quantified in large numbers of in idual prostate cancer cells using large area synchrotron X-ray fluorescence microscopy. Cells were also irradiated with a 6 MV linear accelerator to assess the biological consequence of radiosensitization with gold nanoparticles. A large degree of heterogeneity in nanoparticle uptake between cells resulted in influenced biological effect.
Publisher: MDPI AG
Date: 26-11-2021
Abstract: The MTT assay for cellular metabolic activity is almost ubiquitous to studies of cell toxicity however, it is commonly applied and interpreted erroneously. We investigated the applicability and limitations of the MTT assay in representing treatment toxicity, cell viability, and metabolic activity. We evaluated the effect of potential confounding variables on the MTT assay measurements on a prostate cancer cell line (PC-3) including cell seeding number, MTT concentration, MTT incubation time, serum starvation, cell culture media composition, released intracellular contents (cell lysate and secretome), and extrusion of formazan to the extracellular space. We also assessed the confounding effect of polyethylene glycol (PEG)-coated gold nanoparticles (Au-NPs) as a tested treatment in PC-3 cells on the assay measurements. We additionally evaluated the applicability of microscopic image cytometry as a tool for measuring intracellular MTT reduction at the single-cell level. Our findings show that the assay measurements are a result of a complicated process dependant on many of the above-mentioned factors, and therefore, optimization of the assay and rational interpretation of the data is necessary to prevent misleading conclusions on variables such as cell viability, treatment toxicity, and/or cell metabolism. We conclude, with recommendations on how to apply the assay and a perspective on where the utility of the assay is a powerful tool, but likewise where it has limitations.
Publisher: Elsevier BV
Date: 03-2018
DOI: 10.1016/J.TAAP.2018.02.012
Abstract: Zinc pyrithione is an active component incorporated in an extensive range of topically applied commercial products that are used worldwide. Despite its prevalence, no published study has investigated the penetration of zinc from the zinc pyrithione complex into human skin. Zinc is crucial for healthy skin function however an elevated concentration of labile zinc is toxic outside a narrow concentration range. Synchrotron X-ray fluorescence microscopy in conjunction with X-ray absorption near edge structure spectroscopy was used to map the deposition of zinc, quantitate the amount of zinc within the skin and to identify a change in the chemical form of zinc after application. This study has demonstrated a ~3.8 fold increase in zinc concentration within the viable epidermis (VE) after 24 h topical application of zinc pyrithione that increased significantly by ~250 fold after 48 h when compared to control skin. Confocal microscopy using a labile zinc specific dye, ZinPyr-1, showed that zinc pyrithione disrupted the skin cells zinc homeostasis and significantly increased the intracellular zinc concentration leading to cell toxicity. Overall, this study demonstrates that topical application of zinc pyrithione formulations leads to an increase in zinc penetration in human skin, consequently, raising concerns for potential localised toxicity to occur.
Publisher: Springer Science and Business Media LLC
Date: 11-2019
DOI: 10.1007/S00216-019-02154-W
Abstract: Quantification of intercellular heterogeneity in nanoparticle association is of paramount interest in research investigating applications of nanoparticles in the biomedical space. In this work, gold nanoparticle association (AuNP) in cell populations was quantified using synchrotron X-ray fluorescence microscopy (XRF) for 3 different cell lines (PC-3, Caco2 and MDA-MB-231) and 2 nanoparticle co-culture times (30 min and 10% of each respective cell lines' doubling time). Heterogeneity in association between single cells in the same population was dependant on cell line as well as co-culture time. AuNP association heterogeneity increased with co-culture time for 2 out of the 3 cell lines. Regardless of mean association quantity and measured intercellular heterogeneity, all data were best described by log normal distributions. Mean association between cell lines was statistically different at 30 min, yet indistinguishable at 10% doubling time. Heterogeneity between cell lines which demonstrated statistical differences in distribution can exist despite having statistically indistinguishable means.
Publisher: American Chemical Society (ACS)
Date: 22-04-2019
Publisher: American Chemical Society (ACS)
Date: 19-05-2020
Abstract: Zinc oxide nanoparticles (ZnO NPs) are a key constituent of many commercial broad-spectrum sunscreens. Studies have shown that these NPs are retained on the superficial layers of the skins' barrier layer, the stratum corneum, and solubilized zinc species from the ZnO NPs have been shown qualitatively to penetrate intact human skin. The cytotoxicity of zinc is concentration- and species-dependent however, to date, the amount of zinc permeating the skin strata is yet to be determined. Here, we applied commercial ZnO NPs to intact and impaired
Publisher: American Chemical Society (ACS)
Date: 26-08-2022
Publisher: MDPI AG
Date: 24-04-2022
DOI: 10.3390/IJMS23094707
Abstract: Aluminium (Al) compounds are used as adjuvants in human and veterinary prophylactic vaccines due to their improved tolerability compared to other adjuvants. These Al-based adjuvants form microparticles (MPs) of heterogeneous sizes ranging from ~0.5 to 10 µm and generally induce type 2 (Th2)-biased immune responses. However, recent literature indicates that moving from micron dimension particles toward the nanoscale can modify the adjuvanticity of Al towards type 1 (Th1) responses, which can potentially be exploited for the development of vaccines for which Th1 immunity is crucial. Specifically, in the context of cancer treatments, Al nanoparticles (Al-NPs) can induce a more balanced (Th1/Th2), robust, and durable immune response associated with an increased number of cytotoxic T cells compared to Al-MPs, which are more favourable for stimulating an oncolytic response. In this review, we compare the adjuvant properties of Al-NPs to those of Al-MPs in the context of infectious disease vaccines and cancer immunotherapy and provide perspectives for future research.
Publisher: MDPI AG
Date: 15-08-2023
Abstract: Nanoparticle-based therapeutics are being clinically translated for treating cancer. Even when thought to be biocompatible, nanoparticles are being increasingly identified as altering cell regulation and homeostasis. Antioxidant pathways are important for maintaining cell redox homeostasis and play important roles by maintaining ROS levels within tolerable ranges. Here, we sought to understand how a model of a relatively inert nanoparticle without any therapeutic agent itself could antagonize a cancer cell lines’ antioxidant mechanism. A label-free protein expression approach was used to assess the glutathione-thioredoxin antioxidative pathway in a prostate cancer cell line (PC-3) after exposure to gold nanoparticles conjugated with a targeting moiety (transferrin). The impact of the nanoparticles was also corroborated through morphological analysis with TEM and classification of pro-apoptotic cells by way of the sub-G0/G1 population via the cell cycle and annexin V apoptosis assay. After a two-hour exposure to nanoparticles, major proteins associated with the glutathione-thioredoxin antioxidant pathway were downregulated. However, this response was acute, and in terms of protein expression, cells quickly recovered within 24 h once nanoparticle exposure ceased. The impact on PRDX-family proteins appears as the most influential factor in how these nanoparticles induced an oxidative stress response in the PC-3 cells. An apparent adaptive response was observed if exposure to nanoparticles continued. Acute exposure was observed to have a detrimental effect on cell viability compared to continuously exposed cells. Nanoparticle effects on cell regulation likely provide a compounding therapeutic advantage under some circumstances, in addition to the action of any cytotoxic agents however, any therapeutic advantage offered by nanoparticles themselves with regard to vulnerabilities specific to the glutathione-thioredoxin antioxidative pathway is highly temporal.
Publisher: Cambridge University Press (CUP)
Date: 02-08-2017
DOI: 10.1017/S0885715617000719
Abstract: A robust analysis script was developed in MATLAB for cross-correlative quantification of internalised gold nanoparticle (AuNP) uptake in a large number of in idual cells with the corresponding number of DNA double-strand breaks (DSBs) in the same cells. The correlation of inorganic NP content with a biological marker at the single-cell level will aid in the elucidation of mechanisms of NP radiosensitisation. PC-3 cells were co-cultured with AuNPs and irradiated using an iridium-192 source. AuNP uptake was measured using synchrotron X-ray fluorescence (XRF) and DSBs imaged via confocal microscopy. MATLAB 2016a was used to develop a script to cross-correlate the two imaging modalities and quantify both DSBs and internalised AuNP content in the same cell. Various user-defined options written into the script give a high degree of versatility, which can account for a large number of variables in experimental parameters and data acquisition. The analysis procedure is flexible and robust, which gives consistent consideration to the wide spectrum of potential input image/data sets. Quantitative correlative microscopy was achieved with a custom MATLAB script used to correlate γH2AX foci (a marker of DNA DSBs) from confocal microscopy with AuNP content acquired using synchrotron XRF at the single-cell level. The script can be extended to a broad range of multi-modality imaging spectroscopies.
No related grants have been discovered for Tyron Turnbull.