Hair follicles as a target structure for nanoparticles

Abstract

For at least two decades, nanoparticles have been investigated for their capability to deliver topically applied substances through the skin barrier. Based on¯ndings that nanoparticles are highly suitable for penetrating the blood-brain barrier, their use for drug delivery through the skin has become a topic of intense research. In spite of the research e®orts by academia and industry, a commercial product permitting the nanoparticle-assisted delivery of topically applied drugs has not yet been developed. However, nanoparticles of approximately 600 nm in diameter have been shown to penetrate e±ciently into the hair follicles, where they can be stored for several days. The successful loading of nanoparticles with drugs and their triggered release inside the hair follicle may present an ideal method for localized drug delivery. Depending on the particle size, such a method would permit targeting speci¯c structures in the hair follicles such as stem cells or immune cells or blood vessels found in the vicinity of the hair follicles.

Cellular Interactions and Formation of an Epithelial “Nanocoating-Like Barrier” with Mesoporous Silica Nanoparticles

“…In addition, the hair follicles in the porcine ear skin provided other routes for the accumulation of RITC-NPs, whereas they were not able to critically go across the follicular barrier into the underlying dermis (Figure S3). This finding supports the notion that hair follicles could be a potential target of the nanomaterials-based drug delivery vehicles [23]. Overall, a fairly even penetration and distribution of nanoparticles in the corneum layer were observed in the two selected epithelial structures, following 24 h treatment of RITC-NPs in the RHGE and porcine ear skin.…”

Dendritic Core-Multishell Nanocarriers in Murine Models of Healthy and Atopic Skin

“…Although hair follicle architecture is altered in the SKH-1 mouse, this is worth noting as hair follicles have been shown to be an important site of accumulation for certain nanoparticles [30]. …”

In vivo optical monitoring of transcutaneous delivery of calcium carbonate microcontainers

“…The stratum corneum (10-20 μm) and underlying living epidermis (75-150 μm) represent a barrier, which makes the delivery of medicaments into dermis a rather problematic [2]. It is possible to use micro-and nanoparticles as drug carriers for efficient localized delivery and storage of topically applied substances into skin appendages [3]. However, in dependence on anatomical sites and individuals, dimensions and density of these natural pathways vary widely [4].…”