Maxim E Darvin

Charité Universitätsmedizin Berlin | Charité · Department of Dermatology, Venerology and Allergology

Confocal Raman microscopy has a number of advantages in investigating the human stratum corneum (SC) in vivo and ex vivo. The penetration profiles of xenobiotics in the SC, as well as depth profiles of the physiological parameters of the SC, such as the concentration of water depending on the strength of hydrogen bonds, total water concentration, t...

Vibrational spectra of potassium antimonyl silicate (KSS) that may serve as a relaxor ferroelectric material and is assumed to be a reason for degradation of blue-green historical beads are obtained. Novel (Raman and low-frequency FTIR) spectroscopic data are obtained. Original calculations performed with the aid of the coupled-perturbed Hartree-Fo...

The quantitative determination of substance concentration in the stratum corneum (SC) is important for profiling of the skin barrier function‐related parameters and for investigating drug delivery through the SC. Hereby, confocal Raman microscopy (CRM) is a widely used method, which can be applied noninvasively and in vivo. Most analysis methods ar...

Preclinical studies frequently lack predictive value for human conditions. Human cell-based disease models that reflect patient heterogeneity may reduce the high failure rates of preclinical research. Herein, we investigated the impact of primary cell age and body region on skin homeostasis, epidermal differentiation, and drug uptake. Fibroblasts d...

Background Skin diseases can develop upon disadvantageous microclimate in relation to skin contact with textiles of supporting devices. Increased temperature, moisture, mechanical fracture, pressure, and inflammatory processes often occur mutually and enhance each other in their adverse effects. Therefore, the early prevention of skin irritations b...

Confocal Raman microscopy (CRM) has been used to measure depth‐dependent profiles of porcine skin ex vivo in the high wavenumber region after application of molecular optical clearing agents (OCAs). Glycerol (70%) and iohexol (100% Omnipaque™ (300)) water solutions were used as OCAs and topically applied to porcine ear skin for 30 and 60 min. Using...

A system for shifted excitation resonance Raman spectroscopy (SERRDS) suitable for the application in medical practice for the in vivo detection of carotenoids in human skin is presented. This system comprises a miniaturized (150 mm × 27 mm × 12 mm) handheld probe and a wavelength-tunable diode laser-based 488 nm SHG light source. The diode laser p...

Imaging Raman spectroscopy can be used to identify cancerous tissue. Traditionally, a step-by-step scanning of the sample is applied to generate a Raman image, which, however, is too slow for routine examination of patients. By transferring the technique of integral field spectroscopy (IFS) from astronomy to Raman imaging, it becomes possible to re...

In this work, resonance Raman spectroscopy was used for the first time to determine carotenoid values in common vegetables prior to and at different time points during boiling. Carrots, yellow peppers and Rosara potatoes demonstrated higher initial carotenoid levels which increased through cooking. The low initial carotenoid concentration of the re...

Confocal Raman microscopy (CRM) has been used to measure depth-dependent profiles of porcine skin ex vivo in the high wavenumber (HWN) region after application of molecular optical clearing agents (OCAs). Glycerol (70 %) and iohexol (100% Omnipaque™ (300)) water solutions were used as OCAs and topically applied to porcine ear skin for 30 and 60 min...

The skin is the biggest organ of human organism playing an important physiological function of barrier between the organism and environment. The main skin functions are regulation of the water loss, insulation and thermo-regulation as well as protection of the internal organs from external mechanical impact and penetration of pathogens. In this way...

Raman measurements applied on freshly tattooed porcine skin ex vivo showed a possibility of obtaining the ink pigment related information in the skin. Based on these results, confocal Raman microscopy was used to identify the tattoo ink pigments of different colors in multicolored tattooed human skin in vivo. The Raman signatures of tattoo ink pigm...

Two-photon excited fluorescence of red blood cells (RBC) has been reported to be applicable for their assessment in vitro and in vivo. The corresponding fluorescence emission was ascribed to hemoglobin (Hb), however, as Hb is essentially non-fluorescent at single-photon excitation, the mechanism of two-photon excited fluorescence of RBC remains deb...

Porcine skin is widely used as a human skin model in dermatology. For both, porcine stratum corneum (SC) ex vivo and human SC in vivo, the hydrogen bonding states of water, the secondary and tertiary structures of keratin, the natural moisturizing factor (NMF) concentrations and the intercellular lipids' (ICL) lateral organization are investigated...

Heart failure is among the socially significant diseases, involving over 2% of the adult population in the developed countries. Diagnostics of the HF severity remains complicated due to the absence of specific symptoms and objective criteria. Here we present an indicator of the HF severity based on the imaging tissue parameters around the nailfold...

The papillary dermis of human skin is responsible for its biomechanical properties and for supply of epidermis with chemicals. Dermis is mainly composed of structural protein molecules, including collagen and elastin, and contains blood capillaries. Connective tissue diseases, as well as cardiovascular complications have manifestations on the molec...

The secondary and tertiary structure of keratin and natural moisturizing factor (NMF) are of great importance regarding the water regulating functions in the stratum corneum (SC). In this in vivo study, the depth-dependent keratin conformation and its relationship to the hydrogen bonding states of water and its content in the SC, are investigated u...

Aiming to increase the probing depth, a comparative ex vivo study of optical clearing of porcine ear skin was performed by using two optical clearing agents (OCAs), i.e., glycerol and iohexol (OmnipaqueTM) at different concentrations, which exhibit different osmotic properties. The results show that a topical application of glycerol or OmnipaqueTM...

Background/aims: Extrinsic and intrinsic skin aging is subject to constant remodeling and degradation processes, primarily in components of the extracellular matrix. While collagen fibers thin out during the aging process, the amorphous elastin fibers accumulate. These are essential formative components of the dermis. So far, these processes have...

In this study, stratum corneum (SC) depth profiles of hydrogen bound water molecule types, intercellular lipid (ICL) ordering, concentration of natural moisturizing factor (NMF) and keratin folding/unfolding properties are investigated in vivo for older (mean 50 years old) and younger (mean 29 years old) human skin using confocal Raman microscopy....

Background: Topical glucocorticoids (GCs) are known to induce atrophy of human skin including thinning of epidermal and dermal compartments by influencing keratinocyte proliferation and synthesis of extracellular matrix proteins. GCs are also known to reduce skin barrier integrity but little is known about the changes in lipid composition in human...

Topical glucocorticoids (GC) are known to induce changes in human skin with the potential to develop skin atrophy. Here, atrophogenic effects and subsequent structural changes in the skin after topical application of GC were investigated in vivo. Sixteen healthy volunteers were topically treated daily on the forearms with clobetasol propionate, bet...

Background: Oxidative stress plays an important role in the pathogenesis of various skin diseases. Thus, the antioxidant network of the skin relies on the uptake of exogenous antioxidants to ensure cell protection against radical formation. Green tea is one of the main sources of polyphenolic antioxidant compounds, but only few data are available...

Two differently designed, spatially resolved reflectance spectroscopy-based scanners and two-photon tomography were used for noninvasive in vivo determination of cutaneous carotenoids, and collagen I/elastin aging index of dermis, respectively, in the skin of 29 healthy female volunteers between 40 and 56 years of age. The volunteers received a sup...

Confocal Raman microscopy (CRM) is employed to study the skin physiology, drug permeation and skin disease monitoring. In order to increase the depth of investigations, the effect of optical clearing was observed on porcine ear skin ex vivo. The optical clearing agents (OCAs) glycerol and iohexol (OmnipaqueTM) were applied to the porcine ear skin a...

e21664 Background: A potential pathomechanism for doxorubicin-associated hand-foot syndrome (HFS) was shown based in particular on radical formation in the skin. Topically applied antioxidants (AO) have a therapeutic effect on HFS. Here, radical formation of orally administered sorafenib (Nexavar), sunitinib (Sutent) and capecitabine (Xeloda) was i...

Background The intercellular lipids (ICL) of stratum corneum (SC) play an important role in maintaining the skin barrier function. The lateral and lamellar packing order of ICL in SC is not homogenous, but rather depth-dependent. Objective This study aimed to analyze the influence of the topically applied mineral-derived (paraffin and petrolatum)...

An unexpected effect – the generation of free radicals (mostly reactive oxygen species (ROS)) in human skin subsequent to the irradiation with solar infrared (IR) light – was shown in vivo using resonance Raman spectroscopy and confirmed in vitro using electron paramagnetic resonance spectroscopy (EPR). It could be demonstrated that the IRA part (7...

The papillary dermis of human skin is responsible for its biomechanical properties and for supply of epidermis with chemicals. Dermis is mainly composed of structural protein molecules, including collagen and elastin, and contains blood capillaries. Connective tissue diseases, as well as cardiovascular complications have manifestations on the molec...

Background/aim: The main reason for extrinsic skin aging is the negative action of free radicals. The formation of free radicals in the skin has been associated with ultraviolet (UV) exposure and also to visible (VIS) and near-infrared (NIR) irradiations. The aim of the present study was to evaluate the efficacy of a sunscreen in the whole solar r...

The literature claims that incorporation of antioxidants into sunscreens provides additional skin photoprotection by scavenging free radicals formed due to sun radiation, but there are limited in vivo studies that support this hypothesis. This study aims to examine whether addition of antioxidants to a broad-spectrum sunscreen increases its photopr...

Multiphoton tomography (MPT) is a prospective tool for imaging the skin structure. Aiming to increase the probing depth, a comparative ex vivo study of optical clearing of porcine ear skin was performed by using two optical clearing agents (OCAs), i.e., glycerol and iohexol (OmnipaqueTM) at different concentrations, which exhibit different osmotic...

It is known that the collagen and elastin fibre structures are changing with age. There is little knowledge about the influence of body area as these investigations have been limited for ethical reasons, so far. Thus, modified non-invasive two-photon microscopy was used providing vertical optical sections of second harmonic generation and autofluor...

Autofluorescence photobleaching describes the decrease of fluorescence intensity of endogenous fluorophores in biological tissue upon light irradiation. The origin of autofluorescence photobleaching is not fully understood. In the skin, the spatial distribution of various endogenous fluorophores varies within the skin layers. Most endogenous fluoro...

An improvement of the penetration efficiency combined with the controlled release of actives in the skin can facilitate the medical treatment of skin diseases immensely. Dexamethasone (Dx), a synthetic glucocorticoid, is frequently used for the treatment of inflammatory skin diseases. To investigate the penetration of nano-sized lipid particles (NL...

Die Dermatologie ist ein geeignetes Fachgebiet, um optische und spektroskopische Untersuchungen zur Analyse der Haut, aber auch zur Penetration topisch applizierter Substanzen durchzuführen. Der Penetration topisch applizierter Substanzen in Form von Arzneimitteln und Pflegeprodukten kommt hierbei eine besondere Bedeutung zu. Während laserscanmikro...

Organisms produce free radicals which are essential for various metabolic processes (enzymatic oxidation, cellular respiration, signaling). Antioxidants are important chemical compounds that specifically prevent the oxidation of substances by scavenging radicals, especially reactive oxygen species (ROS). Made up of one or two unpaired electrons, RO...

An unexpected effect – the generation of free radicals (mostly reactive oxygen species (ROS)) in human skin subsequent to the irradiation with solar infrared (IR) light – was shown in vivo using resonance Raman spectroscopy and confirmed in vitro using electron paramagnetic resonance spectroscopy (EPR). It could be demonstrated that the IRA part (7...

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