In this study we utilised an in vitro model system to gain insight into the potential cellular interactions that quantum dot (QD) nanoparticles may experience while transiting the viable skin epidermis, and we consider the effects of UVB exposure. UVB skin exposure is known to induce a skin barrier defect that facilitates QD stratum corneum penetration. Primary human keratinocytes were cultured in low and high calcium to induce basal and differentiated phenotypes, respectively. Results suggest that differentiation state plays a role in keratinocyte response to UVB exposure and exposure to negatively charged CdSe/ZnS core/shell QD. QD cell uptake increased with QD dose but association with differentiated cells was significantly lower than the basal keratinocyte phenotype. Differentiated keratinocytes were also less sensitive to the cytotoxic effects of UVB exposure. We did not observe an effect of UVB preexposure on QD cytotoxicity level despite the fact that fluorescent microscopy and flow cytometry data suggest that UVB may slightly increase QD uptake in the basal cell phenotype. The implications of these findings for assessing potential risk of human skin exposure are discussed.

中文翻译：

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UVB 暴露和原代角质形成细胞分化状态对其与量子点相互作用的影响。

在这项研究中，我们利用体外模型系统深入了解量子点 (QD) 纳米粒子在通过活的皮肤表皮时可能经历的潜在细胞相互作用，并考虑了 UVB 暴露的影响。众所周知，UVB 皮肤暴露会导致皮肤屏障缺陷，促进 QD 角质层渗透。原代人角质形成细胞在低钙和高钙中培养，分别诱导基础表型和分化表型。结果表明，分化状态在角质形成细胞对 UVB 暴露和暴露于带负电荷的 CdSe/ZnS 核/壳 QD 的反应中起作用。QD 细胞摄取随 QD 剂量而增加，但与分化细胞的关联显着低于基底角质形成细胞表型。分化的角质形成细胞对 UVB 暴露的细胞毒性作用也不太敏感。尽管荧光显微镜和流式细胞术数据表明 UVB 可能会略微增加基底细胞表型中的 QD 摄取，但我们没有观察到 UVB 预暴露对 QD 细胞毒性水平的影响。讨论了这些发现对评估人类皮肤暴露的潜在风险的意义。