Nanotoxicology in the Skin: How Deep is the Issue?

Abstract

Nanotoxicology is a concern. While skin exposure is generally perceived as less hazardous than inhalation or ingestion of engineered nanoparticles, there remain signi¯cant knowledge gaps in the topic to suggest greater caution in making a conclusion. Penetration of nanoparticles across an intact skin barrier is low. However, the verdict is still out on how this will change in situations where the skin barrier is compromised. Many studies on the interaction of nanoparticles with biological systems including skin cells have been reported. Under di®erent scenarios, nanoparticles commonly found in topical skin products have been shown to be capable of exerting a variety of toxicological in°uences. These in°uences include causing cell death, stress, in°am-mation and damage to DNA. While alarming, it should also be noted that there remains much confusion and contradiction in the literature due to the complexity of studying cell-nanoparticle interactions. This review aims to provide a concise perspective on our current understanding of nanotoxicology in the skin, and identify the knowledge gaps where research e®orts may be focused to help clarify the uncertainties in the¯eld.

Poly[acrylonitrile-co-(N-vinyl pyrrolidone)] nanoparticles – Composition-dependent skin penetration enhancement of a dye probe and biocompatibility

“…Nanotoxicity can be roughly classified into acute and chronic effects. Acute toxicity includes immediate cell death, reduction in metabolic activity and inflammation, whereas chronic toxicity generally refers to genotoxicity and carcinogenesis [37], besides enhanced efficacy because of accumulation of the substance. To assess the potential interaction of the nanoparticles of interest with cutaneous cells in relation to concentration and exposure time, we first performed MTT assay on primary NHK and NHDF ( Fig.…”

Oxidative stress by inorganic nanoparticles

“…As a result, there is increased exposure to humans through the testing of these applications. For this reason, any accompanying detrimental health effects arising from the same exposure cannot be undermined . Like any xenobiotics and in particular their chemical reactivities, exposure to metallic NPs presents the potential to generate toxicity such as oxidative stress and inflammation, which may in turn lead to cellular injury and death in biological systems .…”

Titanium dioxide and zinc oxide nanoparticles induce autophagy associated with toxicity effects in primary human keratinocytes : a dose relevance study

“…For nanotoxicity study, it has been accepted that nanoparticle-aggregates also can provide stable suspensions for a relatively correct dose. Additionally, TiO2 nanoparticles form aggregates in sunscreen formulations as well [8,10]. Therefore, it is biologically relevant to observe toxicity caused by TiO2 aggregates in the interaction with skin keratinocytes.…”

“…Human skin is the body's largest defense system that prevents external injuries and hazards. The stratum corneum, the outer layer of human epidermis, plays the main function of skin protection [10]. Physical properties of TiO2 and ZnO nanoparticles make them highly mobile, which may lead to skin penetration of these small particles through small cuts or wounds, for example.…”