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Mangion SE, Sandiford L, Mohammed Y, Roberts MS, Holmes AM. Multi-Modal Imaging to Assess the Follicular Delivery of Zinc Pyrithione. Pharmaceutics 2022; 14:pharmaceutics14051076. [PMID: 35631659 PMCID: PMC9145647 DOI: 10.3390/pharmaceutics14051076] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/04/2022] [Revised: 05/12/2022] [Accepted: 05/14/2022] [Indexed: 02/04/2023] Open
Abstract
Zinc pyrithione (ZnPT) is a widely used antifungal, usually applied as a microparticle suspension to facilitate delivery into the hair follicles. It then dissociates into a soluble monomeric form that is bioactive against yeast and other microorganisms. In this study, we use multiphoton microscopy (MPM) and fluorescence lifetime imaging microscopy (FLIM) to characterise ZnPT formulations and map the delivery of particles into follicles within human skin. To simulate real-world conditions, it was applied using a massage or no-massage technique, while simultaneously assessing the dissolution using Zinpyr-1, a zinc labile fluorescent probe. ZnPT particles can be detected in a range of shampoo formulations using both MPM and FLIM, though FLIM is optimal for detection as it allows spectral and lifetime discrimination leading to increased selectivity and sensitivity. In aqueous suspensions, the ZnPT 7.2 µm particles could be detected up to 500 µm in the follicle. The ZnPT particles in formulations were finer (1.0–3.3 µm), resulting in rapid dissolution on the skin surface and within follicles, evidenced by a reduced particle signal at 24 h but enhanced Zinpyr-1 intensity in the follicular and surface epithelium. This study shows how MPM-FLIM multimodal imaging can be used as a useful tool to assess ZnPT delivery to skin and its subsequent dissolution.
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Affiliation(s)
- Sean E. Mangion
- Therapeutics Research Centre, UniSA—Clinical and Health Sciences, University of South Australia, Adelaide, SA 5000, Australia; (S.E.M.); (L.S.); (M.S.R.)
- Basil Hetzel Institute for Translational Health Research, Woodville South, SA 5011, Australia
- Sydney Medical School, University of Sydney, Camperdown, NSW 2006, Australia
| | - Lydia Sandiford
- Therapeutics Research Centre, UniSA—Clinical and Health Sciences, University of South Australia, Adelaide, SA 5000, Australia; (S.E.M.); (L.S.); (M.S.R.)
- Basil Hetzel Institute for Translational Health Research, Woodville South, SA 5011, Australia
| | - Yousuf Mohammed
- Therapeutics Research Group, The University of Queensland Diamantina Institute, Faculty of Medicine, University of Queensland, Brisbane, QLD 4102, Australia;
| | - Michael S. Roberts
- Therapeutics Research Centre, UniSA—Clinical and Health Sciences, University of South Australia, Adelaide, SA 5000, Australia; (S.E.M.); (L.S.); (M.S.R.)
- Basil Hetzel Institute for Translational Health Research, Woodville South, SA 5011, Australia
- Therapeutics Research Group, The University of Queensland Diamantina Institute, Faculty of Medicine, University of Queensland, Brisbane, QLD 4102, Australia;
| | - Amy M. Holmes
- Therapeutics Research Centre, UniSA—Clinical and Health Sciences, University of South Australia, Adelaide, SA 5000, Australia; (S.E.M.); (L.S.); (M.S.R.)
- Basil Hetzel Institute for Translational Health Research, Woodville South, SA 5011, Australia
- Correspondence: ; Tel.: +61-449-020-795
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Xiao J, Li H, Zhao W, Cai C, You T, Wang Z, Wang M, Zeng F, Cheng J, Li J, Duan X. Zinc-metal–organic frameworks with tunable UV diffuse-reflectance as sunscreens. J Nanobiotechnology 2022; 20:87. [PMID: 35183191 PMCID: PMC8858458 DOI: 10.1186/s12951-022-01292-1] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/19/2021] [Accepted: 02/02/2022] [Indexed: 11/10/2022] Open
Abstract
Abstract
Background
UV exposure continues to induce many health issues, though commercial sunscreens are available. Novel UV filters with high safety and efficacy are urgently needed. Metal–organic frameworks (MOFs) could be a suitable platform for UV filter development, due to their tunable optical, electrical, and photoelectric properties by precise controlled synthesis.
Results
Herein, four zinc-based MOFs with various bandgap energies were chose to investigate their optical behaviors and evaluate their possibility as sunscreens. Zeolitic imidazolate framework-8 (ZIF-8) was found to possess the highest and widest UV reflectance, thereby protecting against sunburn and DNA damage on mouse skin and even achieving a comparable or higher anti-UV efficacy relative to the commercially available UV filters, TiO2 or ZnO, on pig skin, a model that correlates well with human skin. Also, ZIF-8 exerted appealing characteristics for topical skin use with low radical production, low skin penetration, low toxicity, high transparency, and high stability.
Conclusion
These results confirmed ZIF-8 could potentially be a safe and effective sunscreen surrogate for human, and MOFs could be a novel source to develop more effective and safe UV filters.
Graphical Abstract
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Khabir Z, Holmes AM, Lai YJ, Liang L, Deva A, Polikarpov MA, Roberts MS, Zvyagin AV. Human Epidermal Zinc Concentrations after Topical Application of ZnO Nanoparticles in Sunscreens. Int J Mol Sci 2021; 22:12372. [PMID: 34830253 PMCID: PMC8618668 DOI: 10.3390/ijms222212372] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/24/2021] [Revised: 11/09/2021] [Accepted: 11/11/2021] [Indexed: 12/11/2022] Open
Abstract
Zinc oxide nanoparticle (ZnO NP)-based sunscreens are generally considered safe because the ZnO NPs do not penetrate through the outermost layer of the skin, the stratum corneum (SC). However, cytotoxicity of zinc ions in the viable epidermis (VE) after dissolution from ZnO NP and penetration into the VE is ill-defined. We therefore quantified the relative concentrations of endogenous and exogenous Zn using a rare stable zinc-67 isotope (67Zn) ZnO NP sunscreen applied to excised human skin and the cytotoxicity of human keratinocytes (HaCaT) using multiphoton microscopy, zinc-selective fluorescent sensing, and a laser-ablation inductively coupled plasma-mass spectrometry (LA-ICP-MS) methodology. Multiphoton microscopy with second harmonic generation imaging showed that 67ZnO NPs were retained on the surface or within the superficial layers of the SC. Zn fluorescence sensing revealed higher levels of labile and intracellular zinc in both the SC and VE relative to untreated skin, confirming that dissolved zinc species permeated across the SC into the VE as ionic Zn and significantly not as ZnO NPs. Importantly, the LA-ICP-MS estimated exogenous 67Zn concentrations in the VE of 1.0 ± 0.3 μg/mL are much lower than that estimated for endogenous VE zinc of 4.3 ± 0.7 μg/mL. Furthermore, their combined total zinc concentrations in the VE are much lower than the exogenous zinc concentration of 21 to 31 μg/mL causing VE cytotoxicity, as defined by the half-maximal inhibitory concentration of exogenous 67Zn found in human keratinocytes (HaCaT). This speaks strongly for the safety of ZnO NP sunscreens applied to intact human skin and the associated recent US FDA guidance.
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Affiliation(s)
- Zahra Khabir
- Department of Physics and Astronomy & Earth and Planetary Sciences & Clinical Medicine, Macquarie University, Sydney 2109, Australia; (Z.K.); (Y.-J.L.); (L.L.); (A.D.)
- ARC Centre of Excellence for Nanoscale BioPhotonics, Sydney 2109, Australia
| | - Amy M. Holmes
- Clinical Health Sciences and Basil Hetzel Institute for Translational Health Research, University of South Australia, Adelaide 5000, Australia;
| | - Yi-Jen Lai
- Department of Physics and Astronomy & Earth and Planetary Sciences & Clinical Medicine, Macquarie University, Sydney 2109, Australia; (Z.K.); (Y.-J.L.); (L.L.); (A.D.)
| | - Liuen Liang
- Department of Physics and Astronomy & Earth and Planetary Sciences & Clinical Medicine, Macquarie University, Sydney 2109, Australia; (Z.K.); (Y.-J.L.); (L.L.); (A.D.)
- ARC Centre of Excellence for Nanoscale BioPhotonics, Sydney 2109, Australia
| | - Anand Deva
- Department of Physics and Astronomy & Earth and Planetary Sciences & Clinical Medicine, Macquarie University, Sydney 2109, Australia; (Z.K.); (Y.-J.L.); (L.L.); (A.D.)
| | | | - Michael S. Roberts
- Clinical Health Sciences and Basil Hetzel Institute for Translational Health Research, University of South Australia, Adelaide 5000, Australia;
- Diamantina Institute, University of Queensland, Brisbane 4072, Australia
| | - Andrei V. Zvyagin
- Department of Physics and Astronomy & Earth and Planetary Sciences & Clinical Medicine, Macquarie University, Sydney 2109, Australia; (Z.K.); (Y.-J.L.); (L.L.); (A.D.)
- Centre of Biomedical Engineering, Sechenov University, Moscow 119991, Russia
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