Biological interactions of quantum dot nanoparticles in skin and in human epidermal keratinocytes
ABSTRACT Quantum dots nanoparticles have novel optical properties for biomedical applications and electronics, but little is known about their skin permeability and interaction with cells. QD621 are nail-shaped nanoparticles that contain a cadmium/selenide core with a cadmium sulfide shell coated with polyethylene glycol (PEG) and are soluble in water. QD were topically applied to porcine skin flow-through diffusion cells to assess penetration at 1 microM, 2 microM and 10 microM for 24 h. QD were also studied in human epidermal keratinocytes (HEK) to determine cellular uptake, cytotoxicity and inflammatory potential. Confocal microscopy depicted the penetration of QD621 through the uppermost stratum corneum (SC) layers of the epidermis and fluorescence was found primarily in the SC and near hair follicles. QD were found in the intercellular lipid bilayers of the SC by transmission electron microscopy (TEM). Inductively coupled plasma-optical emission spectroscopy (ICP-OES) analysis for cadmium (Cd) and fluorescence for QD both did not detect Cd nor fluorescence signal in the perfusate at any time point or concentration. In HEK, viability decreased significantly (p<0.05) from 1.25 nM to 10 nM after 24 h and 48 h. There was a significant increase in IL-6 at 1.25 nM to 10 nM, while IL-8 increased from 2.5 nM to 10 nM after 24 h and 48 h. TEM of HEK treated with 10 nM of QD621 at 24 h depicted QD in cytoplasmic vacuoles and at the periphery of the cell membranes. These results indicate that porcine skin penetration of QD621 is minimal and limited primarily to the outer SC layers, yet if the skin were damaged allowing direct QD exposure to skin or keratinocytes, an inflammatory response could be initiated.
Archives des Maladies Professionnelles et de l Environnement 11/2013; 74(5):488-498. DOI:10.1016/j.admp.2013.05.003 · 0.09 Impact Factor
Chapter: Chapter 11 - Skin[Show abstract] [Hide abstract]
ABSTRACT: The role of the skin as a potential route of exposure to nanomaterials is described in the present chapter. Most studies suggest minimal skin penetration and little to no systemic exposure. However, they also show that nanoparticle (NP) size, shape, charge, surface properties, and vehicle as well as animal species are very important determinants as to whether or not NP can traverse through the rate-limiting lipid barrier of the stratum corneum. Long-term in vivo studies in humans or animals are desperately needed because in vitro cell systems and differences in animal species present several limitations to a complete understanding of NP penetration through the skin. This will be a major challenge in understanding the safety of nanomaterials.Adverse Effects of Engineered Nanomaterials, Edited by Shvedova, Bengt FadeelAntonio PietroiustiAnna A, 01/2012: pages 185-207; Academic Press., ISBN: 9780123869401
[Show abstract] [Hide abstract]
ABSTRACT: Toxicity of nanoparticles (NPs) is often correlated with the physicochemical characteristics of the materials. However, some discrepancies are noted in in-vitro studies on quantum dots (QD) with similar physicochemical properties. This is partly related to variations in cell type. In this study we show that epithelial (BEAS-2B), fibroblast (HFF-1) and lymphoblastoid (TK6) cells show different biological responses following exposure to QDs. These cells represented the three main portals of NP exposure; bronchial, skin, and circulatory. The uptake and toxicity of negatively and positively charged CdSe:ZnS QDs of the same core size but with different surface chemistries (carboxyl or amine polymer coatings) were investigated in full and reduced serum containing media following 1 and 3 cell cycles. Following thorough physicochemical characterisation, cellular uptake, cytotoxicity and gross chromosomal damage were measured. Cellular damage mechanisms in the form of reactive oxygen species and the expression of inflammatory cytokines IL8 and TNFα were assessed. QDs uptake and toxicity significantly varied in the different cell lines. BEAS-2B cells demonstrated the highest level of QDs uptake yet displayed a strong resilience with minimal genotoxicity following exposure to these NPs. In contrast, HFF-1 and TK6 cells were more susceptible to toxicity and genotoxicity respectively as a result of exposure to QDs. Thus, this study demonstrates that in addition to nanomaterial physicochemical characterisation, a clear understanding of cell type dependent variation in uptake coupled to the inherently different capacities of the cell types to cope with exposure to these exogenous materials are all required to predict genotoxicity. © The Author 2015. Published by Oxford University Press on behalf of the Society of Toxicology.