Time-Correlated Single Photon Counting For Simultaneous Monitoring Of Zinc Oxide Nanoparticles And NAD(P)H In Intact And Barrier-Disrupted Volunteer Skin
- 634 Downloads
There is a lack of relevant, non-animal alternatives for assessing exposure and toxicity of nanoparticle-containing cosmetics, e.g. sunscreens. Our goal was to evaluate timecorrelated single photon counting (TCSPC) for simultaneous monitoring of zinc oxide nanoparticles (ZnO-NP) and the metabolic state of volunteer skin.
We separated the fluorescence lifetime signatures of endogenous fluorophore signals (i.e. nicotinamide adenine dinucleotide phosphate, NAD(P)H and keratin) and the ZnO-NP signal using advanced TCSPC to simultaneously determine ZnO-NP penetration profiles and NAD(P)H changes in subjects with altered barrier function, including tape-stripped skin and in psoriasis or atopic dermatitis lesions.
We detected no ZnO-NP penetration into viable human skin in any group. ZnO-NP signal was significantly increased (p < 0.01) on the surface of tape-stripped and lesional skin after 4 and 2 h of treatment, respectively. Free NAD(P)H signal significantly increased in tape-stripped viable epidermis treated for 4 h of ZnO-NP compared to vehicle control. No significant NAD(P)H changes were noted in the lesional study.
TCSPC techniques enabled simultaneous, real-time quantification of ZnO-NP concentration and NAD(P)H via non-invasive imaging in the stratum corneum and viable epidermis of volunteers.
KEY WORDShuman skin metabolism multiphoton microscopy sunscreen zinc oxide nanoparticle
atomic absorption spectroscopy
fluorescence lifetime imaging microscopy
inductively coupled plasma-optical emission spectroscopy
instrument response function
potassium di-hydrogen phosphate
multiphoton tomography with fluorescence lifetime imaging microscopy
nicotinamide adenine dinucleotide phosphate
second harmonic generation
time-correlated single photon counting
transmission electron microscope
transepidermal Water Loss
zinc oxide nanoparticles
ACKNOWLEDGMENTS & DISCLOSURES
We would like to thank the National Health and Medical Research Council of Australia (ID# 569694) and the United States Air Force Asian Office of Aerospace Research and Development for funding. We also thank Corinne Yoong for recruiting volunteers for the lesion studies.
- 1.DIRECTIVE 2003/15/EC OF THE EUROPEAN PARLIAMENT AND OF THE COUNCIL. Official Journal of the European Union 2003;46:26–35, .Google Scholar
- 2.Regulation (EC) No 1223/2009 of the European Parliament and of the Council of 30 November 2009 on cosmetic products Official Journal of the European Union. 52:59–209 (2009).Google Scholar
- 15.Kortingand HC, Schafer-Korting M. Carriers in the topical treatment of skin disease. Handb Exp Pharmacol :435–468 (2010).Google Scholar
- 16.Prow TW, Grice JE, Lin LL, Faye R, Butler MK, Becker W, Wurme EMT, Yoong Y, Robertsona TA, Soyer HP, Roberts MS. Nanoparticles and Microparticles for Skin Drug Delivery. Adv Drug Del Rev:In press. (2011).Google Scholar
- 21.Bian SW, Mudunkotuwa IA, Rupasinghe T, Grassian VH. Aggregation and Dissolution of 4 nm ZnO Nanoparticles in Aqueous Environments: Influence of pH, Ionic Strength, Size, and Adsorption of Humic Acid. Langmuir (2011).Google Scholar
- 25.Sanchez WY, Prow TW, Sanchez WH, Grice JE, Roberts MS. Analysis of the metabolic deterioration of ex vivo skin from ischemic necrosis through the imaging of intracellular NAD(P)H by multiphoton tomography and fluorescence lifetime imaging microscopy. J Biomed Opt. 2010;15:046008.PubMedCrossRefGoogle Scholar
- 29.Prow TW, Monteiro-Riviere NA, Inman AO, Grice JE, Chen X, Zhao X, Sanchez WH, Gierden A, Kendall MA, Zvyagin AV, Erdmann D, Riviere JE, Roberts MS. Quantum dot penetration into viable human skin. Nanotoxicology 2011.Google Scholar