Skin penetration and cellular uptake of amorphous silica nanoparticles with variable size, surface functionalization, and colloidal stability.
In this study, the skin penetration and cellular uptake of amorphous silica particles with positive and negative surface charge and sizes ranging from 291 ± 9 to 42 ± 3 nm were investigated. Dynamic light scattering measurements and statistical analyses of transmission electron microscopy images were used to estimate the degree of particle aggregation, which was a key aspect to understanding the results of the in vitro cellular uptake experiments. Despite partial particle aggregation occurring after transfer in physiological media, particles were taken up by skin cells in a size-dependent manner. Functionalization of the particle surface with positively charged groups enhanced the in vitro cellular uptake. However, this positive effect was contrasted by the tendency of particles to form aggregates, leading to lower internalization ratios especially by primary skin cells. After topical application of nanoparticles on human skin explants with partially disrupted stratum corneum, only the 42 ± 3 nm particles were found to be associated with epidermal cells and especially dendritic cells, independent of their surface functionalization. Considering the wide use of nanomaterials in industries and the increasing interest for applications in pharmaceutics and cosmetics versus the large number of individuals with local or spread impairment of the skin barrier, e.g., patients with atopic dermatitis and chronic eczema, a careful dissection of nanoparticle-skin surface interactions is of high relevance to assess possible risks and potentials of intended and unintended particle exposure.
Clinical Research Center for Hair and Skin Science, Department of Dermatology and Allergy, Charité-Universitätsmedizin Berlin, Berlin, Germany. fiorenza.rancan@charite.de
Fiorenza
F
Rancan
Qi
Q
Gao
Christina
C
Graf
Stefan
S
Troppens
Sabrina
S
Hadam
Steffen
S
Hackbarth
Cynthia
C
Kembuan
Ulrike
U
Blume-Peytavi
Eckart
E
Rühl
Jürgen
J
Lademann
Annika
A
Vogt
D002460:Cell Line; D003102:Colloids / Q000737:chemistry; D004355:Drug Stability; D006801:Humans; D066298:In Vitro Techniques; D015603:Keratinocytes / Q000737:chemistry* / Q000378:metabolism*; D008422:Materials Testing; D053758:Nanoparticles / Q000737:chemistry* / Q000648:ultrastructure*; D012822:Silicon Dioxide / Q000737:chemistry* / Q000493:pharmacokinetics*; D012869:Skin Absorption / Q000502:physiology*
D003102:Colloids; D012822:Silicon Dioxide