The influence of corneocyte structure on the interpretation of permeation profiles of nanoparticles across skin

Pinheiro, Teresa; Pallon, Jan; Alves, L.C.; Veríssimo, A.; Filipe, Paulo; Silva, J.N.; Silva, R.

doi:10.1016/j.nimb.2007.02.014

Cited by 59 publications

(33 citation statements)

References 15 publications

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“…Biopsies were mounted in mounting medium for microscopy (OCT TM compound), guaranteeing that they would not become fully immersed; thus, preventing the non-immersed part to suffer from unacceptable temperature gradients that would facilitate cell disruption and ion displacement [24,25] . Sections were obtained from the non-immersed portion of the tissue, and sectioning was performed from inside to outside to avoid tissue contamination with the sunscreen at the skin surface.…”

Section: Skin Sample Preparationmentioning

confidence: 99%

Stratum Corneum Is an Effective Barrier to TiO<sub>2</sub> and ZnO Nanoparticle Percutaneous Absorption

Filipe

Silva

et al. 2009

Skin Pharmacol Physiol

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190

115

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Background: There is increasing concern over the local and systemic side effects of TiO₂ and ZnO coated nanoparticles widely used in sun blockers. Objective: To determine the localization and possible skin penetration of TiO₂ and ZnO nanoparticles, dispersed in 3 sunscreen formulations, under realistic in vivo conditions in normal and altered skin. Methods: Nuclear microscopy techniques provided spatially resolved quantitative analysis of Ti and Zn nanoparticle distributions in transversal cryosections of skin obtained by biopsy with no further treatment. A test hydrophobic formulation containing coated 20-nm TiO₂ nanoparticles and 2 commercial sunscreen formulations containing TiO₂ alone or in combination with ZnO were tried, taking into account realistic use conditions by consumers and compared with the recommended standard condition for the sun protection factor test. The protocols consisted of an open test. Results: Following a 2-hour exposure period of normal human skin to TiO₂- and ZnO-containing sunscreens, detectable amounts of these physical blockers were only present at the skin surface and in the uppermost stratum corneum regions. Layers deeper than the stratum corneum were devoid of TiO₂ or exogenous ZnO, even after 48 h of exposure to the sunscreen, under occlusion. Deposition of TiO₂ and ZnO nanoparticles in the openings of the pilosebaceous follicles was also observed, suggesting a preferential fixation area. Penetration of nanoparticles into viable skin tissue could not be detected. Conclusions: TiO₂ or ZnO nanoparticles are absent or their levels are too low to be tested under the stratum corneum in human viable epidermal layers. Therefore, significant penetration towards the underlying keratinocytes is unlikely.

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Section: Skin Sample Preparationmentioning

confidence: 99%

Stratum Corneum Is an Effective Barrier to TiO<sub>2</sub> and ZnO Nanoparticle Percutaneous Absorption

Filipe

Silva

et al. 2009

Skin Pharmacol Physiol

Self Cite

190

115

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“…These studies were able to demonstrate that TiO 2 NPs at a size of ≥30 nm do not penetrate the intact skin barrier and do not reach viable layers of the epidermis [21,22,23]. However, if the skin is damaged by interaction with chemical irritants or mechanical procedures, various amounts of TiO 2 NPs can be detected in the living tissue [6,15,24,25].…”

Section: Introductionmentioning

confidence: 99%

Safety Assessment by Multiphoton Fluorescence/Second Harmonic Generation/Hyper-Rayleigh Scattering Tomography of ZnO Nanoparticles Used in Cosmetic Products

Darvin

König

Kellner-Hoefer

et al. 2012

Skin Pharmacol Physiol

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Zinc oxide nanoparticles (ZnO NPs) are commonly used as UV filters in commercial sunscreen products. Their penetration into the skin is intensively discussed in the literature. In the present in vivo study, penetration of ZnO NPs (30 nm in size) into human skin was investigated by multiphoton tomography. Based on the non-linear effects of a second harmonic generation and hyper-Rayleigh scattering, the distribution of ZnO NPs in the horny layers of the epidermis, as well as the furrows, wrinkles and orifice of the hair follicles was analyzed. This method permitted distinguishing between the particulate and dissolved forms of Zn. A detection limit of 0.08 fg/µm³ was estimated. Taking advantage of this sensitivity, it was clearly shown that ZnO NPs penetrate only into the outermost layers of stratum corneum, furrows and into the orifices of the hair follicles and do not reach the viable epidermis.

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“…According to these results, the particles penetrate the stratum corneum and remain retained in the outermost corneocyte layers [38,41,138,140,142]. Permeation of the solubilized zinc form seems to be reduced in these studies.…”

Section: Titanium Dioxide or Zinc Oxide Nanoparticlesmentioning

confidence: 70%

Transport of Substances and Nanoparticles across the Skin and in Vitro Models to Evaluate Skin Permeation and/or Penetration

Contri

Fiel

Pohlmann

et al. 2011

Nanocosmetics and Nanomedicines

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Abstract. Nanotechnology can be used to modify the drug permeation/penetration of encapsulated substances, through the manipulation of many different factors, including direct contact with the skin surface and controlled release. In general, nanoparticles cannot cross the skin barrier, which can be explained by the cell cohesion and lipids of the stratum corneum, the outermost skin layer. The device most commonly used to study the transport of substances and nanoparticles across the skin is the Franz vertical diffusion cell, followed by the substance quantification in the receptor fluid or determination of the amount retained in the skin. Microscopy techniques have also been applied in skin penetration or permeation experiments. This chapter will present the fundamental considerations regarding the transport of encapsulated substances and/or nanoparticles across the skin, the experimental models applied in these studies and a review of the main studies reported in the literature in order to allow the reader to gain insight into the current knowledge available in this area.

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The influence of corneocyte structure on the interpretation of permeation profiles of nanoparticles across skin

Cited by 59 publications

References 15 publications

Stratum Corneum Is an Effective Barrier to TiO<sub>2</sub> and ZnO Nanoparticle Percutaneous Absorption

Stratum Corneum Is an Effective Barrier to TiO<sub>2</sub> and ZnO Nanoparticle Percutaneous Absorption

Safety Assessment by Multiphoton Fluorescence/Second Harmonic Generation/Hyper-Rayleigh Scattering Tomography of ZnO Nanoparticles Used in Cosmetic Products

Transport of Substances and Nanoparticles across the Skin and in Vitro Models to Evaluate Skin Permeation and/or Penetration

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