A rigorously simple quantitative model for free radical behavior in aerobic biological systems.

Background Human life is based on oxygen respiration and an enzymatic, free radical-dependent water chemistry, whose billions of parallel reactions take place at pH ∼7.4 and a temperature of 37°C, in accordance with the laws of chemistry. The cellular metabolic processes occur over time periods covered by the half-lives of ROS (reactive oxygen species) for °OH to over 10 s for LOS (lipid oxygen species), indicating that mixtures of free radicals form the basic components for these processes.

Radical formation in skin and preclinical characterization of a novel medical plasma device for dermatology after single application.

Cold atmospheric plasma (CAP) enables painless tissue treatment by producing reactive species including excited molecules and charged particles and is of great interest for medical applications. Medical CAP sources work in contact with air at ambient pressure, resulting in the generation of substantial amounts of reactive oxygen and nitrogen radicals. These radicals have a significant influence on cellular biochemistry, are crucial components of the immune system, and play a central role in wound therapy.

Dual Role of Stratum Corneum Carotenes/Lycopene Against the Development of Chemotherapy-induced PPE in Patients With Cancer.

Palmar-plantar erythrodysaesthesia (PPE) is a common side effect of chemotherapy treatment in patients with cancer. The exact pathophysiologic mechanisms of the development of PPE remain unclear. Here, we report two important physiological functions of carotenoids without hydroxyl groups (α-carotene, β-carotene, γ-carotene, ξ-carotene, lycopene, phytoene, phytofluene and their isomers) in the stratum corneum (SC) of glabrous skin: The powerful antioxidant protection of the integrity of the SC components against the destructive action of free radicals and maintaining the skin barrier function by the creation of an orthorhombic organization of intercellular lipids within lamellae using carotenoids as a skeleton.

Atopic Dermatitis: Molecular Alterations between Lesional and Non-Lesional Skin Determined Noninvasively by In Vivo Confocal Raman Microspectroscopy.

Atopic dermatitis (AD)/atopic eczema is a chronic relapsing inflammatory skin disease affecting nearly 14% of the adult population. An important pathogenetic pillar in AD is the disrupted skin barrier function (SBF). The atopic stratum corneum (SC) has been examined using several methods, including Raman microspectroscopy, yet so far, there is no depth-dependent analysis over the entire SC thickness.

Altered structure indicating reduced barrier function of lesional compared to non-lesional psoriatic skin-A non-invasive in vivo study of the human stratum corneum with confocal Raman micro-spectroscopy.

Psoriasis, one of the most common skin diseases affecting roughly 2%-3% of the world population, is associated with a reduced skin barrier function (SBF) that might play an important role in its pathophysiology. The SBF is provided primarily by the stratum corneum (SC) of the skin. Previous studies have revealed a higher trans-epidermal water loss, lower hydration, abnormal concentration and composition of intercellular lipids, as well as alterations in secondary keratin structure in the psoriatic SC.

Contributions towards variable temperature shielding for compact NMR instruments.

The application of compact NMR instruments to hot flowing samples or exothermically reacting mixtures is limited by the temperature sensitivity of permanent magnets. Typically, such temperature effects directly influence the achievable magnetic field homogeneity and hence measurement quality. The internal-temperature control loop of the magnet and instruments is not designed for such temperature compensation.

Spectroscopic biofeedback on cutaneous carotenoids: A powerful tool for primary prevention in advanced age.

Antioxidants exhibit a powerful defense mechanism against aging and chronic disease. The human skin reflects the overall antioxidant status of the body. The cutaneous carotenoid concentration is a biomarker for individual nutritional intake of antioxidants, as it correlates with the overall antioxidant status.

Tattoo Pigments Are Localized Intracellularly in the Epidermis and Dermis of Fresh and Old Tattoos: In vivo Study Using Two-Photon Excited Fluorescence Lifetime Imaging.

Background: The knowledge about the location and kinetics of tattoo pigments in human skin after application and during the recovery is restricted due to the limitation of in vivo methods for visualizing pigments. Here, the localization and distribution of tattoo ink pigments in freshly and old tattooed human skin during the regeneration of the epidermis and dermis were investigated in vivo.

Methods: Two-photon excited fluorescence lifetime imaging (TPE-FLIM) was used to identify tattoo ink pigments in human skin in vivo down to the reticular dermis.

Lycopene, but not zeaxanthin, serves as a skeleton for the formation of an orthorhombic organization of intercellular lipids within the lamellae in the stratum corneum: Molecular dynamics simulations of the hydrated ceramide NS bilayer model.

Carotenoids play an important role in the protection of biomembranes against oxidative damage. Their function depends on the surroundings and the organization of the lipid membrane they are embedded in. Carotenoids are located parallel or perpendicular to the surface of the lipid bilayer.

Label-free imaging of M1 and M2 macrophage phenotypes in the human dermis in vivo using two-photon excited FLIM.

Macrophages (ΜΦs) are important immune effector cells that promote (M1 ΜΦs) or inhibit (M2 ΜΦs) inflammation and are involved in numerous physiological and pathogenic immune responses. Their precise role and relevance, however, are not fully understood for lack of noninvasive quantification methods. Here, we show that two-photon excited fluorescence lifetime imaging (TPE-FLIM), a label-free noninvasive method, can visualize ΜΦs in the human dermis in vivo.

Penetration Depth of Propylene Glycol, Sodium Fluorescein and Nile Red into the Skin Using Non-Invasive Two-Photon Excited FLIM.

The stratum corneum () forms a strong barrier against topical drug delivery. Therefore, understanding the penetration depth and pathways into the is important for the efficiency of drug delivery and cosmetic safety. In this study, TPT-FLIM (two-photon tomography combined with fluorescence lifetime imaging) was applied as a non-invasive optical method for the visualization of skin structure and components to study penetration depths of exemplary substances, like hydrophilic propylene glycol (), sodium fluorescein () and lipophilic Nile red () into porcine ear skin ex vivo.

Quantitative determination of concentration profiles of skin components and topically applied oils by tailored multivariate curve resolution-alternating least squares using in vivo confocal Raman micro-spectroscopy.

The main components of the stratum corneum (SC), water, lipids, and proteins, are non-homogeneously distributed throughout the depth. The quantitative determination of their concentration profiles and penetration depth of topically applied substances are urgent topics of dermatological and cosmetic research. Confocal Raman micro-spectroscopy has distinct advantages when determining semi-quantitative concentrations of SC components and topically applied substances non-invasively and in vivo.

Carotenoids in Human SkinIn Vivo: Antioxidant and Photo-Protectant Role against External and Internal Stressors.

The antioxidant system of the human body plays a crucial role in maintaining redox homeostasis and has an important protective function. Carotenoids have pronounced antioxidant properties in the neutralization of free radicals. In human skin, carotenoids have a high concentration in the stratum corneum (SC)-the horny outermost layer of the epidermis, where they accumulate within lipid lamellae.

Cosmetic Formulations with Melaleuca alternifolia Essential Oil for the Improvement of Photoaged Skin: A Double-Blind, Randomized, Placebo-Controlled Clinical Study.

This aim of this study was to evaluate the penetration depth, antioxidant capacity and the clinical efficacy of Melaleuca alternifolia pure essential oil and in a nanoemulsion to prevent skin photoaging. For this, 2% of pure essential oil or 2% of this essential oil in a nanoemulsion were vehiculated in a formulation. The skin penetration was evaluated using confocal Raman microspectroscopy.

Current Views on Noninvasive in vivo Determination of Physiological Parameters of the Stratum Corneum Using Confocal Raman Microspectroscopy.

Confocal Raman microspectroscopy is widely used in dermatology and cosmetology for analysis of the concentration of skin components (lipids, natural moisturizing factor molecules, water) and the penetration depth of cosmetic/medical formulations in the human stratum corneum (SC) in vivo. In recent years, it was shown that confocal Raman microspectroscopy can also be used for noninvasive in vivo depth-dependent determination of the physiological parameters of the SC, such as lamellar and lateral organization of intercellular lipids (ICLs), folding properties of keratin, water mobility, and hydrogen bonding states. The results showed that the strongest skin barrier function, which is primarily manifested by the orthorhombic organization of ICLs, is provided at ≈20-40% SC depth, which is related to the maximal bonding state of water with surrounding components in the SC.

Safety and efficacy of combined essential oils for the skin barrier properties: In vitro, ex vivo and clinical studies.

Objective: To evaluate the safety and the synergistic effects of tea tree, lavender, eucalyptus and tangerine essential oils in combination on the skin using in vitro, ex vivo and clinical studies.

Methods: The phototoxicity was predicted using 3T3 neutral red uptake phototoxicity test (OECD TG 432). Skin penetration was evaluated by confocal Raman microspectroscopy using direct application of essential oils to pig ears.

Relations between the Raman spectra and molecular structure of selected carotenoids: DFT study of α-carotene, β-carotene, γ-carotene and lycopene.

Using the density functional theory (DFT), we calculated the structures and Raman spectra of trans-isomers of α-carotene, β-carotene, γ-carotene and lycopene as well as trans-isomers of modified β-carotene and lycopene molecules with substituted end or/and side groups. The DFT calculations showed that the position of the CC stretching band depends mainly on the number of conjugated CC bonds and decreases with an increase in the conjugation length. The weak dependence of the position of the CC stretching band on the structure of the carotenoid side and end groups suggests that this band can be used to evaluate the conjugation length for trans-isomers of various molecules containing polyene chains.

Microdialysis on Ex Vivo Porcine Ear Skin Can Validly Study Dermal Penetration including the Fraction of Transfollicular Penetration-Demonstrated on Caffeine Nanocrystals.

Common ex vivo methods for penetration investigations often fail to monitor transfollicular penetration appropriately. In the present investigation, the validity of dermal microdialysis on the ex vivo porcine ear skin to investigate penetration kinetics, including transfollicular penetration, was studied. In setup A, a caffeine nanocrystal formulation was compared to a non-particular caffeine gel formulation.

In vivo Skin Penetration, Radical Protection, and Structural Changes after Topical Application of a Herbal Oil Cream Compared to Topical Calcipotriol in Mild to Moderate Psoriasis.

Background: The chronicity of psoriasis often requires continuous topical treatment.

Materials And Methods: Here, the radical protection of a cream containing various herbal oils was evaluated in vivo by electron paramagnetic resonance (EPR) spectroscopy and its skin penetration by Raman microscopy in intact and barrier-disturbed skin. Changes in skin barrier properties were evaluated after 4 weeks of daily topical application using in vivo laser scanning microscopy (LSM) and transepidermal water loss in 26 healthy volunteers.

Eco-friendly sunscreen formulation based on starches and PEG-75 lanolin increases the antioxidant capacity and the light scattering activity in the visible light.

Most modern sunscreens contain physical filters, which scatter the sunlight, increasing the photons' pathway in the upper stratum corneum. This effect can lead to a better efficacy of the UV filters and improve the diffuse reflection. However, the addition of nanosized inorganic UV filters reduces the antioxidant capacity of sunscreen formulations.

Influence of nanocrystal size on the in vivo absorption kinetics of caffeine after topical application.

The absorption of topically applied substances is challenging due to the effective skin barrier. Encapsulation of substances into nanoparticles was expected to be promising to increase the bioavailability of topically applied products. Since nanoparticles cannot traverse the intact skin barrier, but penetrate into the hair follicles, they could be used to deliver substances via hair follicles, where the active is released and can translocate independently transfollicularly into the viable epidermis.

Blind source separation of molecular components of the human skin in vivo: non-negative matrix factorization of Raman microspectroscopy data.

Determination of the molecular composition of the skin is crucial for numerous tasks in medicine, pharmacology, dermatology and cosmetology. Confocal Raman microspectroscopy is a sensitive method for the evaluation of molecular depth profiles in the skin in vivo. Since the Raman spectra of most of the skin constituents significantly superimpose, a spectral decomposition by a set of predefined library components is usually performed to disentangle their contributions.