In vivo skin penetration and metabolic path of quantum dots

The skin is the largest organ of the body and is a potential route of exposure to sunscreens and cosmetics containing nanoparticles; however, the permeability of the skin to these nanoparticles is currently unknown. In this paper, we studied the transderreal delivery capacity through mouse skin of water-soluble CdSeS quantum dots （QDs） and the deposition of these QDs in the body. QD solution was coated onto the dorsal hairless skin of male ICR mice. Fluorescence microscopy and transmission electron microscopy （TEM） were used to observe the distribution of QDs in the skin and organs, and inductively coupled plasma-mass spectrometry （ICP-MS） was used to measure the 111Cd content to indicate the concentration of QDs in plasma and organs. Experimental results indicate that QDs can penetrate into the dermal layer and are limited to the uppermost stratum corneum layers and the hair follicles. Through blood circulation, QDs deposit mostly in liver and kidney and are difficult to clear, 111Cd concentration was greater than 14 ng g-1 in kidney after 120 h after 0.32 nmol QDs was applied to a mouse. These results suggest that QDs have in vivo transdermal delivery capacity through mouse skin and are harmful to the liver and kidney.

Skin Penetration of Inorganic and Metallic Nanoparticles

Nanotechnology is a rapidly growing science of producing and utilizing nano-sized particles. These nanomaterials are already having an impact on health care. Nowadays we are using nanoproducts in various fields,and this leads to direct and indirect exposure in human. Skin is the largest organ of the body and functions as the first-line barrier between the external environment and the internal organs of the human body. Then people worry about the nanoparticle(NP) small enough to penetrate the skin. The potential of solid NPs to penetrate the stratum corneum and to diffuse into underlying structures raises a considerable health and safety issue for their topical use. We review the current state of knowledge on the potential risk to human health presented by skin penetration of NPs nanotechnologies, and explore the robustness of current research strategies and directions to ensure the development of "safe" and publicly accepted nano-based products and technologies.

A Novel Facial Cream Based on Skin Penetrable Hemp Oil Microparticles

Objective: Hemp seed oil is perfect for most skin types;it moisturizes skin and protects it from inflammation, oxidation, and other causes of aging. The problem is that the Hemp oil-based products do not penetrate the skin;they remain on the skin’s surface. Recently researchers have been trying to prepare nano emulsions of hemp oil to facilitate its permeation to deep skin layers. In all techniques used today, surfactants are added to the emulsification process. These surfactants may cause unwanted skin side effects. In the present study, we prepare micronized Hemp (m-Hemp) without using any surfactants in the micronization process, thus avoiding the side effects associated with surfactant addition. Methods & Results: Particles size of m-Hemp was evaluated using electron microscopy. Various sizes of m-Hemp were found, the smallest being 100 nm in diameter. The antioxidation properties of m-Hemp were measured using the Electron Spin Resonance (ESR) technique and were found to be enhanced. Skin topography and morphology following a cream containing m-Hemp treatment were visualized by Optical Profilometry and ESEM respectively. The results show a marked improvement in skin topography in all measured parameters. In addition, human keratinocytes (HaCaT) were exposed to inflammatory conditions and were then treated using Hemp. As a result, one of the key inflammatory factors (IL-2) was significantly reduced after treatment with m-Hemp (p ≤ 0.0001). The skin penetration of the cream containing m-Hemp was tested on human skin using the IMOPE (Iterative Multi-plane Optical Property Extraction) system. The results indicate that m-Hemp penetrates both the stratum corneum and the deep epidermal layers towards the dermis. Conclusion: The new cream prepared with micronized Hemp shows significant anti-inflammatory and antioxidative effects and demonstrates the entrance of m-Hemp to the skin epidermal layer.

Topically applied hypericin exhibits skin penetrability on nude mice

OBJECTIVE Hypericin,a powerful naturally photosensitizer in photodynamic therapy(PDT),is suitable for treating skin diseases involving excess capillary proliferation.In the present study,we aimed to evaluate the skin penetrability of a topically applied hypericin,expecting reducing the risk of prolonged skin photosensitivity,which often occurs after systemic administration.METHODS The Franz diffusion cell assay was performed to evaluate different penetration enhancers.In vivo studies,fluorescence microscopy was performed to examine the distribution of hypericin in the skin,macroscopic and microscopic analyses were also carried out to detect pathological changes in the skin after topical hypericin-PDT treatment.Immunohistochemistry was used to determine the expression of PECAM-1 in the treated skin.RESULTS 5% menthol facilitated hypericin penetrate the skin of nude mice most.The results of in vivo assays revealed that hypericin penetrated nude mice skin,spread to the dermis,and resulted in obvious photosensitivity reaction on the dermal capillaries.Moreover,skin injured by the photosensitive reaction induced by hypericin was replaced by normal skin 7 d after hypericin-PDT treatment.CONCLUSION Topical hypericin could penetrate nude mouse skin well and be great potential in PDT treatment of skin diseases.