15 research outputs found
Modelling the human epidermis in vitro: tools for basic and applied research
Get PDFCulture models of tissues and organs are valuable tools developed by basic research that help investigation of the body functions. Modelling is aimed at simplifying experimental procedures in order to better understand biological phenomena, and consequently, when sufficiently characterized, culture models can also be utilized with high potential in applied research. In skin biology and pathology, the development of cultures of keratinocytes as monolayers has allowed the elucidation of most functional and structural characteristics of the cell type. Beside the multiple great successes that have been obtained with this type of culture, this review draws attention on several neglected characteristics of monolayer cultures. The more sophisticated models created in order to reconstruct the fully differentiated epidermis have followed the monolayers. The epidermal reconstruction produces all typical layers found in vivo and thus makes the model much less simple, but only this kind of model allows the study of full differentiation in keratinocyte and production of the cornified barrier. In addition to its interest in basic research, the reconstructed epidermis is currently gaining a lot of interest for applied research, particularly as an alternative to laboratory animals in the chemical and cosmetic industry. Today several commercial providers propose reconstructed skin or epidermis, but in vitro assays on these materials are still under development. In order to be beneficial at long term, the validation of assays must be performed on a material whose availability will not be interrupted. We warn here providers and customers that the longevity of in vitro assays will be guaranteed only if these assays are done with well-described models, prepared according to published procedures, and must consider having a minimum of two independent simultaneous producers of similar material
Non-invasive, transdermal, path-selective and specific glucose monitoring via a graphene-based platform
Get PDFCurrently, there is no available needle-free approach for diabetics to monitor glucose levels in the interstitial fluid. Here, we report a path-selective, non-invasive, transdermal glucose monitoring system based on a miniaturized pixel array platform (realized either by graphene-based thin-film technology, or screen-printing). The system samples glucose from the interstitial fluid via electroosmotic extraction through individual, privileged, follicular pathways in the skin, accessible via the pixels of the array. A proof of principle using mammalian skin ex vivo is demonstrated for specific and ‘quantized’ glucose extraction/detection via follicular pathways, and across the hypo- to hyper-glycaemic range in humans. Furthermore, the quantification of follicular and non-follicular glucose extraction fluxes is clearly shown. In vivo continuous monitoring of interstitial fluid-borne glucose with the pixel array was able to track blood sugar in healthy human subjects. This approach paves the way to clinically relevant glucose detection in diabetics without the need for invasive, finger-stick blood sampling
In vivo skin absorption and distribution of the nerve agent VX (O-ethyl-S-[2(diisopropylamino)ethyl] methylphosphonothioate) in the domestic white pig
No full textThe purpose of this study was to characterize the skin absorption and distribution of VX (O-ethyl-S-[2 (diisopropylamino)ethyl] methylphosphonothioate) in the domestic pig in order to evaluate the animal as a potential model for assessing pretreatments against toxic anti-cholinesterase compounds. A liquid droplet (equivalent to a 2 x LD50 dose) of radiolabelled VX was applied to the inner ear-skin of each anaesthetized animal. Blood and tissue samples (liver, lung, kidney, heart and skin exposure sites) were obtained post-mortem. The amount of radioactivity in each sample was measured by liquid scintillation counting, from which the skin absorption rate and dose distribution of VX were calculated. A substantial proportion (22 +/- 3%) of the applied dose remained within the skin at the site of application. It is conceivable that strategies to minimize or remove this reservoir may be of benefit in the early treatment of VX-exposed casualties. Image analysis of autoradiographs of exposed skin sites indicated that each milligram of radioactive VX covered an area of 1.2 +/- 0.5 cm(2). The average skin absorption rate of C-14-VX was 661 +/- 12 6 mu g/cm(2) per hour. Comparison of these data with previous studies suggests that human skin is less permeable to VX than pig skin, but VX spreads over a greater surface area when applied to human skin. Thus, paradoxically, while pig-ear skin is more permeable than human skin, the difference in skin surface spreading may lead to the absorption of an equivalent systemic dose.Peer reviewe
A micro-bioimpedance meter for monitoring insulin bioavailability in personalized diabetes therapy
No full textFollicular Penetration: Development of a Method to Block the Follicles Selectively against the Penetration of Topically Applied Substances
No full textUtility of Göttingen minipigs for Prediction of Human Pharmacokinetic Profiles After Dermal Drug Application
No full textA Drug-in-Adhesive Matrix Based on Thermoplastic Elastomer: Evaluation of Percutaneous Absorption, Adhesion, and Skin Irritation
No full textBioadhesive Films Containing Benzocaine: Correlation Between In Vitro Permeation and In Vivo Local Anesthetic Effect
No full textNon-invasive, transdermal, path-selective and specific glucose monitoring via a graphene-based platform
No full text
