Skin Imaging

Public health concerns continue to exist over the safety of zinc oxide nanoparticles that are commonly used in sunscreen formulations. In this work, we assessed the effects of two conditions which may be encountered in everyday sunscreen use, occlusion and a compromised skin barrier, on the penetration and local toxicity of two topically applied zinc oxide nanoparticle products. Caprylic/capric triglyceride (CCT) suspensions of commercially used zinc oxide nanoparticles, either uncoated or with a silane coating, were applied to intact and barrier impaired skin of volunteers, without and with occlusion for a period of six hours. The exposure time was chosen to simulate normal in-use conditions. Multiphoton tomography with fluorescence lifetime imaging was used to noninvasively assess zinc oxide penetration and cellular metabolic changes that could be indicative of toxicity. We found that zinc oxide nanoparticles did not penetrate into the viable epidermis of intact or barrier impaire...

Public health concerns continue to exist over the safety of zinc oxide nanoparticles that are commonly used in sunscreen formulations. In this work, we assessed the effects of two conditions which may be encountered in everyday sunscreen use, occlusion and a compromised skin barrier, on the penetration and local toxicity of two topically applied zinc oxide nanoparticle products. Caprylic/capric triglyceride (CCT) suspensions of commercially used zinc oxide nanoparticles, either uncoated or with a silane coating, were applied to intact and barrier impaired skin of volunteers, without and with occlusion for a period of six hours. The exposure time was chosen to simulate normal in-use conditions. Multiphoton tomography with fluorescence lifetime imaging was used to noninvasively assess zinc oxide penetration and cellular metabolic changes that could be indicative of toxicity. We found that zinc oxide nanoparticles did not penetrate into the viable epidermis of intact or barrier impaire...

10 years and always been there for me. Most importantly, I would like to sincerely thank one of my best friends, Pradeep who has been there as a constant source of support every step of the way. Our refreshing and thought-provoking conversations and discussions about any subject, be it science or otherwise, have made the last 6 years a very memorable ride. I never felt far away from home because of my wonderful extended family in the US-I would like to acknowledge my cousins and sisters-in-law, Ramkumar, Vidya, Revathy, Karthik, Sivakumar and Subha. Right from cooking tips to my first credit card, they've helped me settle down in this country and were my home away from home during my PhD. Lastly, I would like to thank my parents Murali and Lakshmi and my sister Divya who are my source of motivation, and encouragement in everything I do. They provide a strong backbone and are always behind my every successful project. vii

Objective: Cutaneous relief analysis is crucial in the development of new skincare products, as well as in the evaluation of dermatological treatments. The analysis can be performed by qualitative or quantitative methods. We propose a new algorithm to detect wrinkles and quantify skin roughness by image processing from a dermatoscope. Methods: A clinical study was carried out with 33 research participants, and images were collected with the dermatoscope and PRIMOS equipment for wrinkle evaluation at two different times: Day 0 (D0) and 45 days (D45) after the use of a dermocosmetic product. Later, a new algorithm was developed to detect wrinkles in the acquired images by applying filters and image transformations that generate a segmented image highlighting the wrinkles. A roughness calculation method is proposed from the pixels belonging to wrinkles. Results: Correlation between the values obtained by the PRIMOS equipment and the proposed system was verified. No correlation was found for data obtained at D0; however, there was correlation at time D45 by Spearman's similarity coefficient. By comparing roughness between times D0 and D45, the treatment was statistically significant for both PRIMOS and the proposed methodology data. Conclusion: The wrinkle detection algorithm, in addition to the roughness calculation, demonstrated a sensitivity comparable to the PRIMOS system in evaluating the effectiveness of the dermocosmetic treatment. Significance: Considering the simplicity of the dermatoscope design compared to other established devices such as PRIMOS, the proposed system is promising as an alternative for dermatological evaluations.

10 years and always been there for me. Most importantly, I would like to sincerely thank one of my best friends, Pradeep who has been there as a constant source of support every step of the way. Our refreshing and thought-provoking conversations and discussions about any subject, be it science or otherwise, have made the last 6 years a very memorable ride. I never felt far away from home because of my wonderful extended family in the US-I would like to acknowledge my cousins and sisters-in-law, Ramkumar, Vidya, Revathy, Karthik, Sivakumar and Subha. Right from cooking tips to my first credit card, they've helped me settle down in this country and were my home away from home during my PhD. Lastly, I would like to thank my parents Murali and Lakshmi and my sister Divya who are my source of motivation, and encouragement in everything I do. They provide a strong backbone and are always behind my every successful project. vii

Public health concerns continue to exist over the safety of zinc oxide nanoparticles that are commonly used in sunscreen formulations. In this work, we assessed the effects of two conditions which may be encountered in everyday sunscreen use, occlusion and a compromised skin barrier, on the penetration and local toxicity of two topically applied zinc oxide nanoparticle products. Caprylic/capric triglyceride (CCT) suspensions of commercially used zinc oxide nanoparticles, either uncoated or with a silane coating, were applied to intact and barrier impaired skin of volunteers, without and with occlusion for a period of six hours. The exposure time was chosen to simulate normal in-use conditions. Multiphoton tomography with fluorescence lifetime imaging was used to noninvasively assess zinc oxide penetration and cellular metabolic changes that could be indicative of toxicity. We found that zinc oxide nanoparticles did not penetrate into the viable epidermis of intact or barrier impaire...

Skin is the largest organ of the human body and during aging it shows easily modifications caused by the senescence. Hydration, pH, pigmentation, sebum and skin texture may undergo modifications, above all in centenaries. We can find some papers that analyse the modifications induced by aging (Marrakchi et al., 2007); but no one of these studies people in the range 90-110 years old. Thus, our work has the aim to verify how these parameters can change. In our study we recruited 80 volunteers of Sardinian population divided in two groups: young and old people. We analyzed levels of sebum, hydration, pigmentation and pH with instruments of Courage + Khazaka electronic GmbH. Then we prepared the imprint that must be observed at SEM. The microscope used was a FEI INSPECT S, wherewith we took some photos of each imprint. The modifications are: hydration and sebum decrease significantly in centenaries; pigmentation and pH levels were higher in the old volunteers like demonstrated by other authors (Stucker et al., 2002). Studying skin texture, we found a diminution of furrows in old people. We can say that decrease of hydration and sebum is mainly linked to low level of hormones, such as estrogens and androgens, while the augmentation of pigmentation is due to the thinness of skin; the higher values of pH have probably a relation with a minor presence of sebum and water in cutaneous surface. Furthermore, accuracy of the pictures taken with SEM demonstrates that the study of skin texture associated with analysis of pH, sebum, pigmentation and hydration can help the comprehension of skin aging. references Marrakchi et al. (2007) Biophysical parameters of skin: map of human face, regional, and age-related differences. Contact dermatitis 57(1): 28-34. Stucker et al. (2002) The cutaneous uptake of atmospheric oxygen contributes significantly to the oxygen supply of human dermis and epidermis.

Public health concerns continue to exist over the safety of zinc oxide nanoparticles that are commonly used in sunscreen formulations. In this work, we assessed the effects of two conditions which may be encountered in everyday sunscreen use, occlusion and a compromised skin barrier, on the penetration and local toxicity of two topically applied zinc oxide nanoparticle products. Caprylic/capric triglyceride (CCT) suspensions of commercially used zinc oxide nanoparticles, either uncoated or with a silane coating, were applied to intact and barrier impaired skin of volunteers, without and with occlusion for a period of six hours. The exposure time was chosen to simulate normal in-use conditions. Multiphoton tomography with fluorescence lifetime imaging was used to noninvasively assess zinc oxide penetration and cellular metabolic changes that could be indicative of toxicity. We found that zinc oxide nanoparticles did not penetrate into the viable epidermis of intact or barrier impaire...

Nonlinear optical imaging of human skin and of differently colored microspheres was carried out to compare and evaluate the imaging properties of three different excitation femtosecond lasers: a spectrally
tunable 80 MHz Ti:sapphire oscillator that produced 100 fs pulses (spectral width ~10 nm) and two ultrabroadband Ti:sapphire oscillators with repetition rates of 85 MHz and 1 GHz. The latter of these two and the 100 fs laser
were combined with a laser scanning microscope Tau-Map. The intensities of images of the polychromatic microsphere samples obtained with both lasers are in accordance with the usual dependence of two-photon processes on laser pulse parameters, .e. the intensity is proportional to the square of the mean laser power and the reciprocal pulse duration. In contrast to that, skin images measured with all three different excitation sources with mean powers of each laser adjusted to the particular pulse length and repetition rate exhibited discrepancies from this relation. For characterization of the ultrabroadband GHz laser, the measurements are supplemented by spectra of second-harmonic-generation signals of urea and collagen.

Multiphoton imaging offers unique, high-resolution insights into the composition of the epidermal and upper dermal skin. The noninvasive technique can be readily performed in vivo since it relies on endogenous fluorophores which are excited by harmless NIR-laser pulses1. The fluorescence lifetime can provide, in addition to the signal intensity, information on the molecular signal origin and local metabolic activity. Its spatial distribution, depicted in pseudo- colors, is represented in so-called FLIM images2. These images are used for identification of the skin composition, to evaluate healthy and diseased skin and to follow the penetration of substances and particles into tissues. In particular, the equipment of clinical multiphoton tomographs with FLIM capability enhances their application capabilities. It enables dermatological FLIM imaging which gives insight into skin conditions like inflammations as well as the state of skin cancer and is used in cosmetic research to evaluate the effect of anti-ageing products3. We give an overview of the technical possibilities and limitations of clinical in vivo multiphoton FLIM imaging for dermatological applications based on our own data as well as literature examples.

Laser microscopy provides a non-invasive view of the surface and inside of the skin. In particular by using near infrared laser radiation to excite signals from endogenous skin molecules and structures, detailed, high-contrast, and substance-specific in-vivo imaging is possible even without any labelling. With simultaneous two-wavelength excitation, even non-fluorescent molecules can be detected because they specifically scatter the incoming light, a process which is associated with the generation of new wavelengths. This so-called Raman scattering is caused by the light interaction with the molecular bonds which enables in particular the detection of lipids and water which are invisible to solely fluorescence imaging. The extension of optical imaging by including Raman techniques, for label-free detection of non-fluorescent molecules, has been an active area of research in the last decades. However, in contrast to multiphoton tomography, which has been utilized in many medical studies for in vivo as well as ex vivo imaging, the combination with Raman imaging and its variants, like coherent anti-Stokes Raman scattering (CARS) 1 , has only recently found its way into clinical practice 2 , although, a manifold of excitation setups and light sources has been described in the literature and the method has technically matured. However, costs and complexity are intrinsically higher than for sole fluorescence imaging which still limits a widespread use by non-imaging experts. We present multimodal skin imaging, including fluorescence, second harmonic generation and CARS imaging with a commercial skin imaging device and discuss possibilities and limitations. Microscopic label-free autofluorescence and CARS imaging provides complementary information on the skin composition in vivo. Scale bar: 30 µm.

The MPTcompact is a multiphoton tomograph based on femtosecond laser technology. It is able to perform five imaging modalities: The autofluorescence (AF) of biomolecules such as NAD(P)H, flavins, porphyrins, elastin, and melanin is imaged with submicron resolution. The extracellular matrix protein collagen can be identified by its second harmonic generation (SHG). An integrated module provides confocal reflection microscopy (RCM) images.

Johann Wilhelm Ritter at age 24 discovered the ultraviolet radiation in 1801. Becoming increasingly in the crossfire of critical opinions, he lost his reputation as a genius of physics and electrochemistry and died aged 33 as a poor man.
Johann Wilhelm Ritter started to study medicine at the University of Jena but focused more on self-experiments on galvanic phenomena. He became the pioneer of scientific electrochemistry.
Ritter was a member of the German Romantic movement. Influenced by its philosophy of “polarities and symmetries in nature” and after the discovery of „heat rays“ (infrared radiation) by Herschel in 1800, Ritter started to search for opposite rays beyond the violet. He found in 1801 that silver chloride was transformed into black when it was placed beyond the violet end of the visible part. This was the discovery of „chemical rays“, later on called ultraviolet radiation.

The Abstracts from all over the world about:
Emerging Trends in Skin Science
Skin in its environment
Skin Imaging
Skin Biophysics : Methods&Models
Biophysics: Methods & Clinics
Skin Sensory Responses & Treatments
Skin, Brain & Perception

Skin is a widely used route of delivery for local and systemic drugs and is potentially a route for their delivery as nanoparticles. The skin provides a natural physical barrier against particle penetration, but there are opportunities to deliver therapeutic nanoparticles, especially in diseased skin and to the openings of hair follicles. Whilst nanoparticle drug delivery has been touted as an enabling technology, its potential in treating local skin and systemic diseases has yet to be realised. Most drug delivery particle technologies are based on lipid carriers, i.e. solid lipid nanoparticles and nanoemulsions of around 300 nm in diameter, which are now considered microparticles. Metal nanoparticles are now recognized for seemingly small drug-like characteristics, i.e. antimicrobial activity and skin cancer prevention. We present our unpublished clinical data on nanoparticle penetration and previously published reports that support the hypothesis that nanoparticles N 10 nm in diameter are unlikely to penetrate through the stratum corneum into viable human skin but will accumulate in the hair follicle openings, especially after massage. However, significant uptake does occur after damage and in certain diseased skin. Current chemistry limits both atom by atom construction of complex particulates and delineating their molecular interactions within biological systems. In this review we discuss the skin as a nanoparticle barrier, recent work in the field of nanoparticle drug delivery to the skin, and future directions currently being explored.

We assessed the effects of flexing and massage on human skin penetration and toxicity of topically applied coated and uncoated zinc oxide nanoparticles (∼75 nm) in vivo. Materials & methods: Noninvasive multiphoton tomography with fluorescence lifetime imaging was used to evaluate the penetration of nanoparticles through the skin barrier and cellular apoptosis in the viable epidermis. Results: All nanoparticles applied to skin with flexing and massage were retained in the stratum corneum or skin furrows. No significant penetration into the viable epidermis was seen and no cellular toxicity was detected. Conclusion: Exposure of normal in vivo human skin to these nanoparticles under common in-use conditions of flexing or massage is not associated with significant adverse events.

New multiphoton and confocal microscope technologies and fluorescence lifetime imaging techniques are now being used to non-invasively image, in space (three dimensions),in time, in spectra, in lifetime and in fluorescence anisotropy (total of 7 dimensions), fluorescent molecules in in situ and in vivo biological tissue, including skin. The process involves scanning a 2D area and measuring fluorescence at a given tissue depth below the surface after excitation by a laser beam with a wavelength within the one-photon or two-photon absorption band of the fluorophores followed by the stacking together of a series of 2D images from different depths to reconstruct the full spatial structure of the sample. Our aim in this work is to describe the principles, opportunities, limitations and applications of this new technology and its application in defining skin morphology, disease and skin penetration in vitro and in vivo by drugs, chemicals and nanoparticles. A key emphasis is in the use of fluorescence lifetime imaging to add additional specificity and quantitation to the detection of the various exogenous chemicals and nanoparticles that
may be applied to the skin as well as endogenous fluorescent species in the skin. Examples given include equipment configuration; components in skin autofluorescence in various skin strata; imaging and quantification
of coexisting drugs and their metabolites; skin pH; nanoparticle zinc oxide skin penetration; liposome delivery of drugs to deeper tissues; and observations in skin ageing and in various skin diseases.

Public health concerns continue to exist over the safety of zinc oxide nanoparticles that are commonly used in sunscreen formulations. In this work, we assessed the effects of two conditions which may be encountered in everyday sunscreen use, occlusion and a compromised skin barrier, on the penetration and local toxicity of two topically applied zinc oxide nanoparticle products. Caprylic/capric triglyceride (CCT) suspensions of commercially used zinc oxide nanoparticles, either uncoated or with a silane coating, were applied to intact and barrier impaired skin of volunteers, without and with occlusion for a period of six hours. The exposure time was chosen to simulate normal in-use conditions. Multiphoton tomography with fluorescence lifetime imaging was used to noninvasively assess zinc oxide penetration and cellular metabolic changes that could be indicative of toxicity. We found that zinc oxide nanoparticles did not penetrate into the viable epidermis of intact or barrier impaired skin of volunteers, without or with occlusion. We also observed no apparent toxicity in the viable epidermis below the application sites. These findings were validated by ex vivo human skin studies in which zinc penetration was assessed by multiphoton tomography with fluorescence lifetime imaging as well as Zinpyr-1 staining and toxicity was assessed by MTS assays in zinc oxide treated skin cryosections. In conclusion, applications of zinc oxide nanoparticles under occlusive in-use conditions to volunteers are not associated with any measurable zinc oxide penetration into, or local toxicity in the viable epidermis below the application site.

Prurigo pigmentosa (PP) is a rare idiopathic inflammatory dermatosis that typically presents as pruritic erythematous papulovesicles in a reticular pattern predominantly on the trunk of young women. The lesions then resolve with residual hyperpigmentation. The pathogenesis of PP is not completely clear. However, it has mainly been associated with ketotic states such as those seen in dieting, fasting, diabetes mellitus, and soft-drink ketosis. Herein we report the first case to our knowledge of PP occurring after bariatric surgery, which provides further evidence of a possible role of ketosis in PP pathogenesis.