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In the last decade, cutaneous carotenoid measurements have become increasingly popular, as carotenoids were found to be a biomarker of nutrition rich in fruits and vegetables, permitting monitoring of the influence of various stress factors. For such measurements, in addition to the specific and selective resonance Raman spectroscopy (RRS), newly developed low expensive small and mobile sensors that are based on spatially resolved reflectance spectroscopy (SRRS) are used for cutaneous carotenoid measurements. Human volunteers of different age exhibiting skin types I to III were investigated using RRS and two SRRS-based sensors to determine the influence of these parameters on the measuring results. In two studies on volunteers of either the same age or skin type, however, the respective other parameter being varied and no significant influences of age or skin type could be detected. Furthermore, the kinetic changes resulting from the intake and discontinued intake of a vegetable extract rich in carotenoids showed a good correlation among the three sensors and with the detected blood carotenoids. This illustrates that the SRRS-based sensors and RRS device provide reliable cutaneous carotenoid values independent of age and skin types I to III of the volunteers.

Background: Inappropriate hair removal increases the risk of surgical site infections which are associated with a higher morbidity and mortality of surgical patients. Here, the effects of a clipping device and a disposable razor on the skin barrier, microbial burden and surface structure were compared. Methods: Changes in bacterial colonization, transepidermal water loss, antioxidant status and the skin surface structure were investigated on the calves of 12 healthy volunteers. Measurement time points were at baseline (t base ) and 24 hours after hair removal (t 24 ). Results: Both, the disposable razor and the clipper showed a decrease in log colony-forming units count from t base (mean(t base ) ± standard deviation = 2.6 ± 1.27, median ± standard error = 2.6 ± 0.37) to t 24 at p razo r = 0.05 and p clipper = 0.06 respectively. At t 24 clipping resulted in a higher reduction of log colony-forming units (mean(t 24 ) = 1.76 ± 0.8, median = 1.69 ± 0.23) compared to the use of the disposable razor (mean(t 24 ) = 1.84 ± 0.85, median = 1.91 ± 0.24). Furthermore, the razor-treated group showed an increase in colony-forming units from t 0 to t 24 , whereas clipping lead to a continuous decrease in colony-forming units from t 0 to t 24 . An enhanced appearance of microlesions and a significant increase of transepidermal water loss after shaving using the disposable razor (p = 0.005) were found indicating skin barrier disruptions. Clipping showed no significant effect on transepidermal water loss. Conclusion: Hair removal using the clipping device results in less disruption of the skin barrier compared to the razor, avoiding the development of microlesions. This could be favorable for the prevention of surgical side infections and postoperative wound management.

Herd health programs for the maintenance of welfare and productivity in cattle need efficient tools for monitoring the health of individual animals. Recent reports demonstrate that the oxidative status is related to various stress conditions in dairy cows. Biomarkers, among other carotenoids, could serve as indicators of stress originating from the environment (e.g., heat stress or sun radiation) or from the animal itself (e.g., disease). To date, only invasive in vitro tests are available to assess the oxidative status in cattle. The present study compares the results of optical noninvasive in vivo measurements of dermal carotenoids in cattle udder skin using an LED-based miniaturized spectroscopic system (MSS) with those obtained by photometric analysis of beta carotene in whole blood samples using a portable device. Correlations between the concentrations of dermal and blood carotenoids were calculated under consideration of the nutritional status of the animals. Significant correlation (R = 0.86) was found for cattle with a moderate to obese body condition. Thus, the blood and skin concentrations of the marker substance beta carotene are comparable under stable stress conditions of the cattle. This demonstrates that the MSS is suitable for noninvasive assessment of dermal carotenoid concentrations in cattle.

Noninvasive diagnostic tools, such as Trichoscan®, reflectance confocal microscopy (RCM), and optical coherence tomography (OCT), are efficient methods of hair shaft and growth evaluation. The aim of this study was to carry out a comparative assessment of these three medical procedures by measuring the hair shaft and hair growth after hair removal for a defined period of five days. The application of these techniques was demonstrated by measuring hair growth on the lower leg of six female volunteers. After removal of the hair shaft with a shaving system, the hair follicle infundibula and the length of the growing hairs were measured with the Trichoscan®, RCM, and OCT method. All three methods are reliable hair measuring tools after hair removal. Trichoscan® is best suited in the implementation of hair growth measurement and RCM in the analysis of hair follicles, whereas the OCT system can be consulted as an additional measurement for the evaluation of the hair follicle and length.

The structure, composition and photocatalytic activity of TiO 2 nanoparticles annealed in various gas atmospheres (N 2, NH 3 and H 2) were studied in this work. The effect of treatment on crystal structure, particle size, chemical composition and optical absorbance were assessed by means of x-ray diffraction, transmission electron microscopy, x-ray photoelectron spectroscopy and diffuse optical reflectance/transmittance measurements, respectively. Photocatalytic properties of the materials were evaluated by three different methods: degradation of methyl orange in water, killing of Staphylococcus aureus bacteria and photogeneration of radicals in the presence of 3-carboxy-2,2,5,5-tetramethyl pyrrolidine-1-oxyl (PCA) marker molecules. The results indicate that the correlation between pretreatment and the photocatalytic performance depends on the photocatalytic processes and cannot be generalized.

The efficacy of topically applied drugs is determined by their action mechanism and their potential capacity of passing the skin barrier. Nanoparticles are assumed to be efficient carrier systems for drug delivery through the skin barrier. For flexible nanoparticles like liposomes, this effect has been well demonstrated. The penetration properties of solid nanoparticles are currently under intensive investigation. The crucial advantage of nanoparticles over non-particulate substances is their capability to penetrate deeply into the hair follicles where they can be stored for several days. There is no evidence, yet, that solid particles ≥40 nm are capable of passing through the healthy skin barrier. Therefore and in spite of the long-standing research efforts in this field, commercially available solid nanoparticle-based products for drug delivery through the healthy skin are still missing. Nevertheless, the prospects for the clinical use of nanoparticles in drug delivery are tremendous. They can be designed as transport systems delivering drugs efficiently into the hair follicles in the vicinity of specific target structures. Once deposited at these structures, specific signals might trigger the release of the drugs and exert their effects on the target cells. In this article, examples of such triggered drug release are presented.

Nutrition rich in carotenoids is well known to prevent cell damage, premature skin aging, and skin cancer. Cutaneous carotenoids can be enriched in the skin by nutrition and topically applied antioxidants have shown an increase in radical protection after VIS/NIR irradiation. In this paper, it was investigated whether orally administered carotenoids increase the radical scavenging activity and the radical protection of the skin using in vivo electron paramagnetic resonance spectroscopy and the skin lipid profile was investigated applying HPTLC on skin lipid extracts. Furthermore, in vivo Raman resonance spectroscopy was used to measure the cutaneous carotenoid concentration. A double blind placebo controlled clinical study was performed with 24 healthy volunteers, who have shown a slow but significant and effective increase in cutaneous carotenoids in the verum group. The enhancement in carotenoids increases the radical scavenging activity of the skin and provides a significant protection against stress induced radical formation. Furthermore, the skin lipids in the verum group increased compared to the placebo group but only significantly for ceramide [NS]. These results indicate that a supplementation with dietary products containing carotenoids in physiological concentrations can protect the skin against reactive oxygen species and could avoid premature skin aging and other radical associated skin diseases.

The objective of the present investigation was to examine the utilization of optical and spectroscopic methods for the noninvasive characterization of Anthelios XL Fluide Extreme (SPF 50+), an exemplary sunscreen, concerning its homogeneity of distribution on the skin, its spectroscopic properties and its overall protective efficacy. The homogeneity of the distribution of the sunscreen on the skin was investigated with a multiphoton tomography microscope. Additionally, the sum transmission spectrum was determined using tape stripping and spectroscopic measurements. The results revealed a very homogeneous distribution of the sunscreen on the skin surface and also in the deep furrows. The sum transmission spectrum reflects a high protective efficacy of the sunscreen in both the UVA and UVB ranges. The sunscreen Anthelios XL Fluide Extreme (SPF 50+) generates a comfortable feeling on the skin and can be easily distributed. The presented optical methods have been shown to be suitable to investigate the overall protective efficacy of sunscreen products objectively, noninvasively and quickly.

In this study, we compared the UV-protective abilities of the europium complex compared to titanium dioxide, which represents the most common physical filter for ultraviolet light in the broad-band spectral range. The UV absorption and light transformative capacities of the europium complex were evaluated using a spectrometer with a double-integrating sphere showing that the europium complex does not only absorb and reflect UV light, but transforms it into red and infrared light. It was found that the europium complex binds to the surface of Jurkat cells in vitro. Cells incubated with the europium complex showed a significantly higher viability after UVA and UVB irradiation as compared to untreated cells and cells incubated with titanium dioxide pointing out its photoprotective properties. The europium complex and titanium dioxide show similar penetration capacities into the stratum corneum as tested in human and porcine skin using tape stripping analysis. The europium complex has proved to be an efficient UV filter with a low cyto- and phototoxic profile and therefore represents a potential candidate for use in sunscreen formulations.

Dissociative electron attachment (DEA) processes have been observed and characterized for submonolayer and multilayer quantities of CCl4, CDCl3, CD2Cl2, CH3Cl, and CH3Br adsorbed on metallic substrates and submonolayer quantities adsorbed onto Kr spacer layers. Anion yields (Br−, Cl−, H−, D−) are reported for incident electron energies from 0 to 12 eV; no desorbing polyatomic anion fragments were detected. The results are compared to the gas‐phase DEA analogs and demonstrate the perturbations on the DEA process that are introduced by the presence of the highly polarizable environment (molecular solid+metal substrate). We also report the first observation of H−(D−) produced by DEA of halomethanes containing hydrogen (deuterium).

Zinc oxide nanoparticles (ZnO NPs) are commonly used as UV filters in commercial sunscreen products. Their penetration into the skin is intensively discussed in the literature. In the present in vivo study, penetration of ZnO NPs (30 nm in size) into human skin was investigated by multiphoton tomography. Based on the non-linear effects of a second harmonic generation and hyper-Rayleigh scattering, the distribution of ZnO NPs in the horny layers of the epidermis, as well as the furrows, wrinkles and orifice of the hair follicles was analyzed. This method permitted distinguishing between the particulate and dissolved forms of Zn. A detection limit of 0.08 fg/µm3 was estimated. Taking advantage of this sensitivity, it was clearly shown that ZnO NPs penetrate only into the outermost layers of stratum corneum, furrows and into the orifices of the hair follicles and do not reach the viable epidermis.

The application of tissue tolerable plasma (TTP) is well suited for ­disinfection of living tissue. In particular, when treating chronic wounds, it has ­several advantages in comparison to the classical application of antiseptics, which do not penetrate sufficiently into the tissue or inhibit wound regeneration. The mode of action of the plasma is mainly based on synergetic effects between temperature increase and the formation of free radicals, which destroy the bacteria and fungi.

Hyperforin, a major constituent of St. John's Wort (Hypericum perforatum, HP), provides anti-inflammatory, anti-tumor, and anti-bacterial properties. Previous studies have shown anti-oxidative properties of St. John's Wort extracts; however, its free radical scavenging activity in skin cells or skin has not been assessed in detail so far. Therefore, the free radical scavenging activity of hyperforin was tested in the H(2)DCFDA-assay in vitro in HaCaT keratinocytes irradiated with solar simulated radiation. Hyperforin (EC(50) 0.7 μM corresponding to 0.42 μg/ml) was much more effective compared to Trolox (EC(50) 12 μg/ml) and N-acetylcysteine (EC(50) 847 μg/ml) without showing phototoxicity. The radical protection factor of a cream containing 1.5%w/w of a hyperforin-rich HP extract was determined to be 200 × 10(14) radicals/mg, indicating a high radical scavenging activity. The cream was further applied ex vivo on porcine ear skin and significantly reduced radical formation after infrared irradiation. Finally, the UV-protective effect of the HP cream was tested on 20 volunteers in a randomized, double-blind, vehicle-controlled study. HP cream significantly reduced UVB-induced erythema as opposed to the vehicle. Occlusive application of HP cream on non-irradiated test sites did not cause any skin irritation. Taken together, these results demonstrate that hyperforin is a powerful free radical scavenger.

Background Curcumin is known for its anti-inflammatory, antioxidative, and anticarcinogenic properties. However, the strong lipophilic compound is not easily applicable, neither in water, nor directly in o/w formulations. So far, loading of nano or micro scaled carriers has enabled only an uptake up to 30% of curcumin. Method In the present article, curcumin was successfully encapsulated into two different safe and inexpensive polymers, ethyl cellulose and methyl cellulose blended ethyl cellulose with a loading capacity of ~ 46–48%. In addition, the in vitro skin penetration of the two curcumin encapsulated particular systems, which were applied each in three different formulations, an o/w, w/o lotion, and water suspension, was investigated on porcine ear skin using Laser scanning microscopy. Results It was found that in comparison to water suspensions, o/w and w/o lotions enhanced, especially the follicular penetration of the encapsulated curcumin particles into porcine skin, whereas the w/o enhanced the penetration better than the o/w lotion. Furthermore, the application of ethyl cellulose blended with methyl cellulose improved the penetration of curcumin in all formulations. Conclusion High loaded encapsulated curcumin systems, prepared from a simple and highly efficient encapsulation system can be used to transport curcumin effectively into the skin.

The surface profile of human skin influences characteristically the distribution pattern of topically applied formulations and consequently the efficacy of sunscreens. The volumes of furrows and the spectroscopically determined factors of inhomogeneity are investigated for three sunscreens. A clear correlation between both measurands exists. The average values for younger (

Various nanometer scaled transport systems are used in pharmaceutics and cosmetics to increase penetration or storage of actives. Nanostructured lipid carriers (NLCs) are efficient drug delivery systems for dermatological applications. Electron paramagnetic resonance (EPR) spectroscopy was used for the determination of TEMPO (2,2,6,6-tetramethyl-1-piperidinyloxy) distribution within the carrier and to investigate the dynamics of skin penetration. Results of ex vivo penetration of porcine skin and in vivo data - forearm of human volunteers - are compared and discussed to previously obtained results with invasomes under comparable conditions. W-band measurements show 35% of TEMPO associated with the lipid compartments of the NLC. Application of TEMPO loaded NLC to skin ex vivo increases the observation time by 12min showing a stabilisation of the nitroxide radical. Moreover, stabilisation is also seen with data generated in vivo. Thus, same as invasomes NLCs are a suitable slow release depot system.

BACKGROUND The efficacy of sunscreens depends decisively on the homogeneity of its distribution on the skin surface, which is sensitively reflected by two spectroscopic data - the factor of inhomogeneity and the sum transmission - measured after tape stripping. The aim of this study was to investigate the influence of a skin pre-treatment with body lotion on the layout of the formulations. METHODS Six healthy volunteers were pre-treated using the body lotion, Nivea Body (Beiersdorf AG, Hamburg, Germany). The sunscreen was an oil/water (o/w) emulsion, Roc SPF 8 (RoC SA, Paris, France). The tape stripped tesa films were measured with a modified UV/VIS spectrometer Lambda 5 (PerkinElmer, Frankfurt/Main, Germany), the data of which were used to calculate both measurands. RESULTS The obtained results made clear that the original spectroscopic data must be corrected taking into account the changed amounts of horny layer particles removed with the individual tape strips after pre-treatment. As a consequence of the correction, the factors of inhomogeneity as well as the sum transmissions confirm a more homogeneous distribution of the applied sunscreen. CONCLUSION The findings confirm that the applied method is well suited to obtain information on the distribution of topically applied substances, and furthermore that the influence of the pre-treatment of the skin with the body lotion enhances the homogeneity of distribution and thus the sunscreen efficacy.

Resonance Raman spectroscopic measurements are suited to analyze the concentration of carotenoid antioxidants in biological samples. Previously, it has been shown that the carotenoid concentration of nutritional egg yolks has a direct influence on the carotenoid content of human skin in vivo. In the present study, resonance Raman spectroscopy was used to analyze the carotenoid concentration in the yolks of hen eggs, which were housed in battery cages or alternatively on free-range grassland. The egg yolks of hens, which had access to grassland, contained approximately double the amount of carotenoid concentration than the egg yolks of hens housed in battery cages (p < 0.001). The kinetics of the carotenoid concentration in the egg yolks, depending on fodder, housing and weather conditions, were investigated. (© 2012 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim)

The skin is not only the largest organ of the human body, but it is also a barrier to the environment. The major part of the human skin is in constant contact with textile materials. The objective of this study was to characterize textile materials and to investigate their influence on the skin properties. For this purpose, two different textile materials (polyamide and polyester) were objectively characterized by optical coherence tomography and surface structure 3D-profilometry. In addition, subjective textile properties like haptic sensation and stiffness, as tactile characteristics felt by volunteers, were analyzed. The objective textile characteristics and subjective parameters were compared to the barrier properties measured by in vivo laser scanning microscopy . Comparable results were achieved between barrier properties and subjective assessment in relation to the textile characteristics in favor of the polyester fabric. Consequently, the optical method used in dermatology for the analysis of the skin can be applied to characterize and evaluate textile fabrics and their interaction with human skin in vivo.

Most treatments in dermatology and cosmetology are based on the penetration of topically applied drugs into the skin or through the skin barrier to the target structure in the living tissue. In the case of healthy skin, scarcely 1% of the applied drugs pass the skin barrier, depending on their chemical properties. Therefore, different physical and chemical methods have been developed to stimulate the penetration process. All these methods are based on the partial destruction of the barrier. In this study, an electrical tissue-tolerable plasma (TTP) was used to increase the penetration of a topically applied model drug (fluorescent dye) through the skin barrier. Using laser scanning microscopy, the distribution of the model drug in different depths of the skin was investigated. It was found that the plasma treatment of the skin is a very efficient process to deliver topically applied substances into the living tissue. In the case of the non-plasma-treated skin, it was found that the fluorescent dye could be detected exclusively on the skin surface. If the dye was applied to the TTP-treated skin, it could be observed in high concentration also in deeper parts of the skin extending down to the stratum basale and the papillary structure.

Non-invasive measurements are of major interest for investigating the effects of stress, nutrition, diseases or pharmaceuticals on the antioxidative capacity of the human skin. However, only a few non-invasive methods are available.The resonance Raman spectroscopy is well established to monitor carotenoids in the skin, but correlations with other antioxidants have not yet been described. Electron paramagnetic resonance spectroscopy used for measurements of free radicals has already been used elsewhere to investigate the reduction of applied long-living nitroxide radicals, caused by skin antioxidants and UV irradiation, but only a single or up to four volunteers were included in these studies. Therefore, in this study, the two methods were applied in parallel on 17 volunteers, and the rate constant of the nitroxide decrease was correlated with the cutaneous carotenoid concentration.A correlation with R = 0.65 was found, supporting the thesis that different antioxidants protect each other and build an antioxidative network in the skin. The results also give first indications that the carotenoids serve as marker substances for the antioxidative capacity, if the nutrition is well balanced.

The interaction of free radicals with antioxidants is a topic of increasing interest in the development of prevention strategies against skin ageing. Carotenoids can serve as marker substances for the complete antioxidative network of human skin. Recently, it has become possible to measure the carotenoids non-invasively and online using resonance Raman spectroscopy. This method has been used in various studies to investigate the interaction of carotenoid antioxidants and free radicals in human skin. In this review, the results of the selected studies are summarized and compared. It could be demonstrated that the carotenoid concentration of the skin reflects the lifestyle of individuals. A high level of carotenoids can be achieved with a healthy diet rich, for instance, in fruit and vegetables. Stress factors such as illness, UV and IR radiation of the sun, and smoking and alcohol consumption reduce the concentration of the carotenoids in the skin. It could be demonstrated that premature skin ageing was less in people with a high level of antioxidants in their tissue. Consequently, the furrows and wrinkles were not so deep and dense as in the skin of individuals with a low antioxidant level. The measurements are highly suited for the development of anti-ageing strategies and can be efficiently used in the medical diagnostics and therapy control.

Objectives Esthetic restorations require that dental restorative materials have similar optical properties to teeth. To improve the color perception, the inhomogeneous morphology of the native tooth can be imitated by layering two optically different restorative materials. However until now the benefit of this method has not been satisfactorily demonstrated. Methods The optical parameters, absorption coefficient μa, scattering coefficient μs, anisotropy factor g and effective scattering coefficient μ ′ s , were determined for the enamel and dentin material of the restorative material systems Artemis® and Herculite XRV®. This was carried out for each material system in the wavelength range between 400 and 700 nm using integrating sphere measurements followed by inverse Monte Carlo simulations. Results Using the optical parameters and a forward Monte Carlo simulation, the color perception of layered samples could be predicted with a sufficient degree of accuracy. The total color impression was shown to be dependent on the sample thickness and the transparency/translucency of the single layers of enamel and dentin materials. Conclusion The study demonstrated that the use of two materials is well-suited for the restoration of front teeth with their relatively high proportion of enamel. This study will continue further with the compilation of a data pool of optical parameters which will enable the application of calculation models to optimize the optical approximation of the natural tooth.

The detection of the antioxidative capacity of the skin is of great practical relevance since free radicals are involved in many skin damaging processes, including aging and inflammation. The nitroxide TEMPO (2,2,6,6-tetramethyl-1-piperidinyloxyl) in combination with electron paramagnetic resonance spectroscopy was found suitable for measuring the antioxidative capacity since its reaction with reducing agents is considerably fast. Yet, in order to achieve longer measurement times, e.g. in inflammatory skin diseases, the stabilizing effect of an invasome (ultraflexible vesicle/liposome) suspension with TEMPO was investigated ex vivo on porcine skin and in vivo on human skin. Invasomes increased the measurement time ex vivo 2-fold and the reduction was significantly slowed down in vivo, which is due to membrane-associated and therefore protected TEMPO. Furthermore, TEMPO accumulation in the membrane phase as well as the decreasing polarity of the ultimate surroundings of TEMPO during skin penetration explains the stabilizing effect. Thus, an invasome suspension with TEMPO exhibits stabilizing effects ex vivo and in vivo.

The influence of stress factors on human skin induces the production of free radicals. Free radicals react immediately with antioxidants contained in the skin, giving rise to their depletion and with the surrounding molecules, resulting in their damage, disorganization and even destruction. High amounts of free radicals are produced in the upper skin layers, i.e. mainly in the epidermis, subsequent to sun irradiation. Irradiation of the skin in the infra-red (IR) range of the spectra, applied at physiological doses, can produce free radicals. The magnitude of destruction of antioxidants, such as carotenoids, can serve as a marker of the extent of the stress factor, characterized by the quantity of produced free radicals. In this study, measurements on the degradation of cutaneous carotenoids following IR skin irradiation of 12 healthy volunteers (skin type II), with two IR sources (standard infrared radiator = SIR and water filter infrared = wIRA) were taken using resonance Raman spectroscopy. Topical application of the antioxidant beta-carotene (2 mg/cm(2) ) provided protection for the human skin when exposed to IR radiation. The magnitude of the degradation of dermal carotenoids after IR irradiation was significantly higher for SIR than for wIRA irradiation, for both non-treated and cream-treated skin areas. The amount of destroyed carotenoids after IR irradiation was higher in the case of pretreatment with beta-carotene than for the untreated skin, indicating that the superficial part of antioxidants is most important for protecting against external stressors. The direct comparison of beta-carotene content was significantly higher for the cream-treated compared to untreated areas for all pairs: baseline, wIRA, after wIRA, baseline SIR and after SIR. Additionally, topically applied carotenoids as a single antioxidant component are less stable than the carotenoids in the skin incorporated by nutrition and accumulated in a mixture with different antioxidant substances. Resonance Raman spectroscopy can be used for the non-invasive measurements of carotenoids, which can be rated as marker substances of redox processes.

Anion formation following electron impact to CF3I is studied in the energy range 0–15 eV. The experiments include gas phase CF3I in the effusive molecular beam under single collision conditions, clusters in a supersonic molecular jet and CF3I condensed in the UHV in multilayer amounts onto a cold metallic substrate. In isolated molecules fragment anions are formed via dissociative attachment (DA) and dipolar dissociation (DD). The DA resonances are located at 0.0 and 3.8 eV and are assigned as single particle and two particle resonance, respectively. The low energy resonance exhibits an exceedingly high cross section for I− formation, while the higher energy resonance decomposes into CF3−, F−, and FI− with comparatively low intensity. Both resonances possess significant C–I antibonding character as apparent from their decomposition dynamics. In clusters the stabilized molecular anion CF3I− and larger complexes of the form (CF3I)n− and (CF3I)n⋅I− are observed. At higher energies anion formation is affected...

The pros and cons of the systemic and topical application of antioxidant substances are a subject of intense discussion among experts, with resulting confusion for consumers and producers. The objective of the present article is to clarify the various uncertainties relating to the use of antioxidant substances in dermatology. Whereas inappropriate application of antioxidant substances (concerning their concentration and composition) might induce harmful effects, the consumer will definitively benefit from physiological concentrations and compositions of antioxidants. The most suitable method is the consumption of natural antioxidants in the form of fruit and vegetables, for example. In addition, the skin, which also accumulates antioxidant substances, may profit from a sufficient antioxidative level, as damage induced by sun radiation in addition to skin aging is reduced.

The hair follicles could be a reservoir for topically applied substances. They are not only surrounded by a close network of blood capillaries, which makes them interesting for drug delivery, but they are also the host of dendritic cells, which are important for immunomodulation. Previously, pollen allergens were shown to penetrate into the hair follicles. The application of barrier-enhancing formulations might represent an effective strategy to prevent pollen protein penetration into the hair follicle. In the present study, porcine skin areas were pretreated with 4 barrier-enhancing emulsions. One skin area served as control and remained without pretreatment. Afterwards, fluorescein-isothiocyanate-labeled grass pollen proteins were applied to the porcine skin samples, and their penetration was investigated via fluorescent laser scanning microscopy. It was shown that the barrier-enhancing formulations were able to significantly reduce the penetration of exogenous proteins into the hair follicles, the extent of such reduction depending on the formulation.

Environmental factors like air pollutants, radiation of the sun and stress factors such as illness, smoking, or alcohol abuse produce free radicals in the human tissue as well as in the skin. Free radicals serve as the main cause for premature skin aging. Additionally, they also contribute towards immunosuppression and the formation of skin diseases including cancer. The human organism has developed a protection system against the destructive action of free radicals by means of the antioxidant network. In the present study, the interaction of free radicals and carotenoid antioxidants in the human skin under in vivo conditions was investigated and summarized. The measurement of carotenoids in human skin was performed in vivo using resonance Raman spectroscopy.

Cross sections and O− kinetic energy measurements are reported for the dissociative electron attachment to O2(1Δg) via the 2Πu and 2Σ+g negative ion states of O−2.

Long-lived (autodetachment lifetimes > 10−6 s) parent negative ions of a number of polycyclic aromatic hydrocarbons (M) have been observed when the electron affinity (EA) of M exceeds a few tenths of an electronvolt. For the larger hydrocarbons with EA (M) ⩾ 0.5 eV the long-lived parent negative ion was found to form via as many as three negative ion states above 0.0 eV. The production of long-lived parent negative ions at electron energies well above 0.0 eV and with much larger cross sections than at 0.0 eV is attributed to electron-excited Feshbach resonances (i.e., two-electron negative ion states). Results are also reported on the formation of (MH)− from M; (MH)− is the only dissociative attachment negative ion observed.

Reactions in negatively charged clusters following resonant electron attachment have been studied in a supersonic beam experiment. The results are discussed with respect to the correspondent processes from single molecules in the gas phase and from condensed molecules. It is shown that electron capture by oxygen clusters allows the population of electronic states in O2− not accessible in the single-electron-molecule frame of reference (violation of the σ− selection rule). Clusters composed of O2/CF2Cl2 yield ionic products composed of both constituents. They are generated along a complex scattering process within the ionized aggregate. The resonance profiles of their ion yields contain information on their genesis, i.e. the initial step of electron capture by the electrophore in the cluster. Since these reactions occur predominantly at low energies, sometimes at zero eV, we consider them as highly relevant in any environment (gaseous or condensed) where low energy electrons are present.

Production of free radicals in the human skin subsequent to IR irradiation has been demonstrated by means of two different methods. The first technique, based on resonance Raman spectroscopy, enables the non-invasive measurements of the kinetics of cutaneous carotenoid antioxidants beta-carotene and lycopene, subsequent to IR irradiation. Obtained degradation of the cutaneous carotenoids was a hint but not evidence that IR irradiation can produce free radicals in the skin. Therefore, the direct observation sustaining the production of free radicals subsequent to IR irradiation in the skin was performed in-vitro by electron paramagnetic resonance spectroscopy. Enzymatic processes as well as heat shock-induced radicals in the human skin are presumably involved in the energy transfer from IR irradiation into the molecules of the skin. Protection strategy for human skin against IR-induced free radicals based on the increase in the concentration of antioxidants by means of antioxidant-rich supplementation is discussed.

It has recently been demonstrated by the utilization of different techniques, such as differential stripping and laser scanning microscopy, that the hair follicles represent an efficient long-term reservoir for topically applied substances. In the present paper, the different in vivo techniques are compared to those of in vitro analysis. It was found that in vitro measurements on pig ear skin are highly superior for the analysis of follicular penetration, as compared to in vitro investigations on excised human skin, mainly due to the fact that the human skin contracts after removal. Restretching of the skin to its original size mainly stretches the interfollicular fibres, whereas the fibres around the hair follicles remain contracted. In contrast to excised human skin, pig ear tissue does not contract when the cartilage is not removed. Moreover, it has an intact barrier on both sides of the ear. Regardless of the fact that the hair follicles on pig ear skin are larger than those of humans, the porcine ear skin represents a more suitable in vitro model for the analysis of the penetration and storage of topically applied substances in the hair follicles than excised human skin.

The influence of the ultraviolet (UV) irradiation of the sun on the formation of free radicals in human skin is well investigated. Up to now, only small amounts of data are available stating that infrared (IR) irradiation can produce free radicals in the skin. In the present study, the formation of free radicals in human skin, subsequent to IRA irradiation (600–1,500 nm), has been demonstrated by means of two different methods. Firstly, the radical formation was detected indirectly by the degradation of the cutaneous carotenoid antioxidants β-carotene and lycopene, which was investigated in vivo by resonance Raman spectroscopic measurements. Secondly, the direct observation of produced radicals subsequent to IRA irradiation of the skin was performed in vitro by electron paramagnetic resonance spectroscopy. Taking into account the results of the present study and previous UV light studies, it can be expected that also solar irradiation in the visible spectral range will produce free radicals in the human skin. Therefore, the current sun protection strategies should be reconsidered. Furthermore, it was shown in the present study that the side effect in the form of radical formation could be significantly reduced by increasing the protection system of the human organism in form of the antioxidant network.

The penetration of topically applied substances in and through the human skin is of special interest for the development and optimization of topically applied drugs and cosmetic products. In the present study, the efficacy of barrier emulsions in the prevention of the penetration of pollen allergens into the hair follicles was investigated. Because of the sensitising potential of the used pollen allergens, the study was carried out under in vitro conditions. Therefore, excised human skin and porcine ear skin were used as tissue models. Applying laser-scanning microscopy and fluorescent-labeled grass pollen allergens, we found that the preventive efficacy of the barrier emulsions could be significantly better investigated on porcine ear skin than on excised human skin. This might be due to the contraction of the elastic fibres around the hair follicles in excised human skin after its removal. In contrast to the excised human skin, the porcine ear skin remains on the cartilage during the experiment. Therefore, contraction of the tissue can be avoided. The results give further indication that in vitro studies based on membranes of excised skin are not suitable for the investigation of the follicular penetration pathway of topically applied substances.

The amount of textile dye migration from the textile and penetration into the skin is relevant when assessing the risk of textile dyes. In this paper, in vivo methods were developed using a harmless textile dye with a strong fluorescence and were then compared with in vitro methods. For the in vivo method, the textile was applied to the lower back of six volunteers wearing the textile 12 h and to the lower back of 12 volunteers during 30 min active sport. The maximum skin absorption of 55 +/- 17 ng/cm(2) was obtained in the group engaged in sports. The in vitro methods, which involved the application of the textile to the pig ear skin, was shown to yield similar results to the 12 h in vivo group (31.2 +/- 9.6 ng/cm(2) vs 27 +/- 14 ng/cm(2)). The migration of the textiles into artificial sweat resulted in approximately 20 microg/cm(2). The disadvantage of such textile extract applications on pig ear skin is discussed. It could be demonstrated that the absorption of the dye is strongly correlated to the amount of sweat, whereas the contact time was less important.

Titanium dioxide TiO2 nanoparticles are extensively used today in sunscreens and coatings as protective compounds for human skin and material surfaces from UV radiation. In this paper, such par- ticles are investigated by electron paramagnetic resonance spectros- copy as sources of free radicals under UV irradiation. The surface density of a placebo with embedded particles corresponds to the rec- ommendations of dermatologists 2m g cm �2 . It is revealed that if applied onto glass, small particles 25 nm in diameter produce an increased amount of free radicals compared to the larger ones of 400 nm diam and the placebo itself. However, if applied onto porcine skin in vitro, there is no statistically distinct difference in the amount of radicals generated by the two kinds of particles on skin and by the skin itself. This proves that although particles as part of sunscreens produce free radicals, the effect is negligible in comparison to the production of radicals by skin in vitro. © 2009 Society of Photo-Optical Instru

Carotenoids, naturally occurring lipophilic micronutrients, possess an antioxidant activity associated with protection from damage induced by free radicals. The present study investigated an innovative non-invasive method to measure cutaneous levels of lycopene and beta-carotene and to monitor the distribution of orally administered lactolycopene in human skin and plasma. A double-blind placebo-controlled randomized study was performed in 25 volunteers, who were under a lycopene-deprived diet (4 weeks prior to study until end of the study) and orally received either lactolycopene or placebo for 12 weeks. Skin and plasma levels of lycopene and beta-carotene were monitored monthly using Raman spectroscopy and HPLC, respectively. Cutaneous levels of lycopene and beta-carotene monitored by resonance Raman spectroscopy showed high reliability. Irrespective of the investigated area, cutaneous levels were sensitive to lycopene deprivation and to oral supplementation; the forehead showed the closest correlation to lycopene variation in plasma. Plasma and skin levels of lycopene were both sensitive to oral intake of lactolycopene and, interestingly, also skin levels of beta-carotene. Thus, oral supplementation with lycopene led to an enrichment of beta-carotene in human skin, possibly due to the fact that carotenoids act in the skin as protection chains, with a natural protection against free radicals.

To develop a fast and easy clinical method for glucose measurements on whole blood samples, changes in glucose spectra are investigated varying temperature, glucose concentration, and solvent using attenuated total reflection Fourier transform infrared (ATR- FTIR) measurements. The results show a stability of the spectra at different temperatures and wavelength shifts of the absorption bands when water is replaced by blood. Because the ATR measurements are influenced by sedimentation of the red blood cells, a two-wavelength CO2 laser is used to determine the glucose concentration in whole blood samples. For this purpose, the first laser wavelength lambda(1) is tuned to the maximum of the glucose absorption band in blood at 1080 cm(-1), and the second laser wavelength lambda 2 is tuned to 950 cm(-1) for background measurements. The transmitted laser power through the optical cell containing the whole blood sample at lambda 1 and lambda 2 is used to determine the ratio. This signal correlates well with the glucose concentration in the whole blood samples. The CO2 laser measurement is too fast to be influenced by the red blood cell sedimentation, and will be a suitable method for glucose determination in whole blood.

The absorption coefficient, scattering coefficient, and effective scattering phase function of human red blood cells (RBCs) in saline solution were determined for eight different hematocrits (Hcts) between 0.84% and 42.1% in the wavelength range of 250-1100 nm using integrating sphere measurements and inverse Monte Carlo simulation. To allow for biological variability, averaged optical parameters were determined under flow conditions for ten different human blood samples. Based on this standard blood, empirical model functions are presented for the calculation of Hct-dependent optical properties for the RBCs. Changes in the optical properties when saline solution is replaced by blood plasma as the suspension medium were also investigated.

Regina Fölster-Holst,1 Jagoda Galecka,1 Sigo Weißmantel,1 Ute Dickschat,2 Frank Rippke,3 Kerstin Bohnsack,3 Thomas Werfel,4 Katja Wichmann,4 Matthias Buchner,1 Thomas Schwarz,1 Annika Vogt,5 Jürgen Lademann,5 Martina C Meinke5 1Department of Dermatology, Venerology and Allergy, University of Kiel, 2Wörth, 3Beiersdorf AG, Hamburg, 4Department of Dermatology, Venerology and Allergy, Division of Immunodermatology and Allergy Research, Hannover Medical School, Hannover, 5Department of Dermatology, Venerology and Allergology, Charité – Universitätsmedizin Berlin, Berlin, Germany Abstract: There is little clinical evidence for a correlation between the severity of atopic eczema (AE) and pollen exposition. To obtain more data, we performed a clinical cohort pilot study about the influence of pollen on AE between sensitized and nonsensitized subjects and an experimental study addressing the cutaneous penetration of pollen into the skin. Fifty-five patients were monitored during birch pollen season. To study the cutaneous penetration, grass pollen allergens were applied on excised skin and the uptake in CD1c-expressing dendritic cells was investigated. The correlation between environmental pollen load and severity of the Scoring Atopic Dermatitis (SCORAD) score and pruritus was observed, regardless of the status of sensitization. The sensitized group recovered significantly worse after the birch pollen season. Remarkably higher amounts of pollen allergens taken up by CD1c cells were detected in epidermal cells derived from skin explants with a disturbed epidermal barrier. These findings suggest an exacerbating role of pollen in AE utilizing the epidermal route. Keywords: aeroallergens, atopic eczema, seasonality, skin antigen-presenting cells, skin barrier penetration

The optical biopsy could be a quick and painless support or alternative to a punch biopsy. In this letter the first in vivo vertical wide field two photon microscopy (2PM) images of healthy volunteers are shown. The 2PM images are fused images of two photon excited auto fluorescence (AF) and second harmonic generation (SHG) signals given as false-color images of 200 μm × 7 mm in size. By using these two nonlinear effects, the epidermis can be easily distinguished from the dermis at a glance. The auto fluorescence provides cellular resolution of the epidermal cells, and elastin fibers are partly visible in the dermis. Collagen, visible by SHG signal, is the dominant structure in the dermis. As contact agent water was evaluated to increase the AF signal, especially in the deeper layers of epidermis and dermis. For further improvement any terminal hairs should be removed by shaving and by taking tape strips of the first five layers of the stratum corneum. The first images illustrated that young skin compared to aged skin shows remarkably different dermal elastin and collagen signals in the dermis.

For at least two decades, nanoparticles have been investigated for their capability to deliver topically applied substances through the skin barrier. Based on findings 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 efforts 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 efficiently 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 specific structures in the hair follicles such as stem cells or immune cells or blood vessels found in the vicinity of the hair follicles.

The absorption coefficient mu(a), scattering coefficient mu(s), and anisotropy factor g of diluted and undiluted human blood (hematocrit 0.84 and 42.1%) are determined under flow conditions in the wavelength range 250 to 1100 nm, covering the absorption bands of hemoglobin. These values are obtained by high precision integrating sphere measurements in combination with an optimized inverse Monte Carlo simulation (IMCS). With a new algorithm, appropriate effective phase functions could be evaluated for both blood concentrations using the IMCS. The best results are obtained using the Reynolds-McCormick phase function with the variation factor alpha = 1.2 for hematocrit 0.84%, and alpha = 1.7 for hematocrit 42.1%. The obtained data are compared with the parameters given by the Mie theory. The use of IMCS in combination with selected appropriate effective phase functions make it possible to take into account the nonspherical shape of erythrocytes, the phenomenon of coupled absorption and scattering, and multiple scattering and interference phenomena. It is therefore possible for the first time to obtain reasonable results for the optical behavior of human blood, even at high hematocrit and in high hemoglobin absorption areas. Moreover, the limitations of the Mie theory describing the optical properties of blood can be shown.

The topical application of drugs, such as nicotinates, affects cutaneous blood flow. Such a biological response, which is dependent on the drug and the individual, can be measured noninvasively using laser Doppler flowmetry. We illustrate the kinetics of vasodilation caused by topically applied benzyl nicotinate using a new frequency-selective laser Doppler flowmeter. This flowmeter measures the blood flow in the superficial dermal plexus and the deeper lying larger capillaries simultaneously and indirectly by determining the flow velocity. Both sets of data are compared with the skin temperature and redness. Four biological parameters are measured consecutively on a skin area treated with gel containing benzyl nicotinate and on an untreated control area. A linear relationship between both blood flows is observed. However, no correlation is obtained between the microcirculation with either the cutaneous temperature or the redness. These results indicate the transport of the drug in the blood from the upper to the deeper capillaries. Cutaneous temperature and redness are unsuitable parameters to measure the kinetics of the blood flow after topical application of drugs.

Visible and near-infrared (NIR) integrating sphere spectroscopy and chemometric multivariate linear regression were applied to determine hematocrit (HCT) and oxygen saturation (SatO2) of circulating human blood. Diffuse transmission, total transmission, and diffuse reflectance were measured and the partial least squares method (PLS) was used for calibration considering different wavelength ranges and selected optical measurement parameters. HCT and SatO2 were changed independently. Each parameter was adjusted to different levels and four designs with blood from different donors were carried out for the calibration with PLS. The calibration included the changes in hemolysis as well as inter-individual differences in cell dimensions and hemoglobin content. At a sample thickness of 0.1 mm the HCT and SatO2 were predicted with a root mean square error (PRMSE) of 1.4% and 2.5%, respectively, using transmission and reflectance spectra and the full Vis-NIR range. Using only diffuse NIR reflectance spectroscopy and a sample thickness of 1 mm, HCT and SatO2 could be predicted with a PRMSE of 1.9% and 2.8%, respectively. Prediction of hemolysis was also possible for one blood sample with a PRMSE of 0.8% and keeping HCT and SatO2 stable with a PRMSE of 0.03%.

In this paper the real and imaginary part of the refractive index of hemoglobin solutions were measured in the wavelength range of 250 to 1100 nm using Fresnel reflectance and transmittance measurements.