Probing skin interaction with hydrogen peroxide using diffuse reflectance spectroscopy

Antimicrobial Activity of Hydrogen Peroxide for Application in Food Safety and COVID-19 Mitigation: An Updated Review

Hydrogen peroxide (H2O2) is a well-known agent with a broad-spectrum antimicrobial activity against pathogenic bacteria, fungi, and viruses. It is a colorless liquid and commercially available in aqueous solution over a wide concentration range. It has been extensively used in the food industry by virtue of its strong oxidizing property and its ability to cause cellular oxidative damage in microbial cells. This review comprehensively documents recent research on the antimicrobial activity of H2O2 against organisms of concern for the food industry, as well as its effect against SARS-CoV-2 responsible for the COVID-19 pandemic. In addition, factors affecting the antimicrobial effectiveness of H2O2, different applications of H2O2 as a sanitizer or disinfectant in the food industry as well as safety concerns associated with H2O2 are discussed. Finally, recent efforts in enhancing the antimicrobial efficacy of H2O2 are also outlined.

Combining the use of two non-invasive instruments to confirm that a formula can improve skin luminance while respecting constitutive melanogenesis

INTRODUCTION

Skin radiance products achieve perceivable benefits with different sort of mechanism of action.

AIMS

To use two non-invasive instrumental devices to evaluate the effectiveness of a cosmetic formula designed to improve skin reflectance while respecting skin integrity.

PATIENTS AND METHODS

Subjects (N = 43) aged 18-50 years old had healthy skin of phototype V-VI and Individual Typology Angle between -10° and -50°. The treatment was applied twice weekly for 4 weeks on a delineated area of the back, and an adjacent area was left untreated. Instrumental and clinical scoring assessments of treated and untreated skin were performed at baseline and Day 26.

RESULTS

Between baseline and Day 26, reflectance (Delta L*) increased by 1.27 points and was considered as clinically relevant. Dermatologist clinical scoring of radiance significantly improved from 2.6 to 3.6 after 4 weeks of treatment and the Skin Color Chart Clarity level significantly decreased from a score of 15.5 to 14.3, representing a skin reflectance improvement. Conversely, the change between baseline and Day 26 in Mexameter Melanin Density was not clinically different for treated skin versus untreated skin (difference of 2.54). At Day 26, changes from baseline for Mexameter Melanin Density and Delta L* parameters appeared to be uncorrelated (r = -0.036).

CONCLUSIONS

This combination of two non-invasive devices can be useful to confirm that a product can modulate skin reflectance without modifying constitutive pigmentation. The formula tested in this study did not interfere with constitutive melanogenesis.

Dermatologic reactions to disinfectant use during the COVID-19 pandemic

Infection preventive practice of using disinfectants against SARS-CoV-2 has become the new normal due to the COVID-19 pandemic. Although disinfectants may not be applied directly to the human body, it remains at high risk of exposure including close skin contact on disinfected surfaces or during handling. This dermal contact, on a regular basis, can induce hazardous skin reactions like irritation, inflammation, and burning in severe conditions. Disinfectants are germicide chemicals that can penetrate the skin and create skin reactions that are usually regarded as irritant and allergic contact dermatitis. More importantly, disinfectants can react with skin components (proteins and lipids) to facilitate their skin penetration and disrupt the skin barrier function. Whereas the antimicrobial actions of disinfectants are well understood, much less is known regarding their dermatologic reactions, including but not limited to irritation and hypersensitivity. We reviewed the skin reactions created by those disinfectants against SARS-CoV-2 approved by the European Chemical Agency and the US Environmental Protection Agency.

The past, present, and prospective on UV-VIS-NIR skin photonics and spectroscopy-a wavelength guide

The study and applications of in vivo skin optics have been openly documented as early as the year 1954, or possibly earlier. To date, challenges in analyzing the complexities of this field remain, with wide scopes requiring more scrutiny. Recent advances in spectroscopic research and multivariate analytics allow a closer look into applications potentially for detecting or monitoring diseases. One of the challenges in this field is in establishing a reference for applications which correspond to certain bandwidths. This article reviews the scope on past research on skin spectroscopy, and the clinical aspects which have or may have applications on disease detection or enhancing diagnostics. A summary is supplied on the technicalities surrounding the measurements reported in literature, focused towards the wavelength-dependent applications in themes central to the respective research. Analytics on the topology of the papers' data cited in this work is also provided for a statistical perspective. In short, this paper strives to immediately inform the reader with possible applications via the spectroscopic devices at hand. Graphical Abstract .

Hydrogen peroxide and cutaneous biology: Translational applications, benefits, and risks

Hydrogen peroxide (H₂O₂) is an endogenous reactive oxygen species that contributes to oxidative stress directly as a molecular oxidant and indirectly through free radical generation. Topically applied 1% to 45% H₂O₂ can be used for a range of clinical purposes, which will be reviewed here in addition to its safety. In concentrations from 1% to 6%, H₂O₂ has antimicrobial properties and can act as a debriding agent through its effervescence, making low-concentration H₂O₂ useful for wound care. H₂O₂ has also been shown to promote venous insufficiency ulcer healing, but studies in other wound types are needed. In 1% formulations, H₂O₂ is used outside the United States to treat acne and has shown efficacy similar to or greater than benzoyl peroxide, with reduced side effects. In a concentration of 40%, H₂O₂ is US Food and Drug Administration-approved to treat seborrheic keratoses and may cause fewer pigmentary changes than cryotherapy, although elimination often requires 2 to 4 treatments. However, H₂O₂ should be used with caution, as exposure can cause adverse effects through its oxidant capabilities. Low H₂O₂ concentrations cause only transient symptoms (blanching and blistering), but exposure to 9% to 45% H₂O₂ can cause more severe skin damage, including epidermal necrosis leading to erythema and bullae. Overall, H₂O₂ has numerous therapeutic uses, and novel indications, such as treating actinic keratoses and skin cancers, continue to be explored.

Modeling diffuse reflectance from homogeneous semi-infinite turbid media for biological tissue applications: a Monte Carlo study

Diffuse reflectance spectroscopy is one of the simplest and widely used techniques for the non-invasive study of biological tissues but no exact analytical solution exists for the problem of diffuse reflectance from turbid media such as biological tissues. In this work, a general treatment of the problem of diffuse reflectance from a homogeneous semi-infinite turbid medium is presented using Monte Carlo simulations. Based on the results of the Monte Carlo method, simple semi-empirical analytical solutions are developed valid for a wide range of collection geometries corresponding to various optical detector diameters. This approach may be useful for the quick and accurate modeling of diffuse reflectance from tissues.

Noise and stray light characterization of a compact CCD spectrophotometer used in biomedical applications

In recent years, new generation spectrophotometers are increasingly used in biomedical applications. Handheld spectrophotometers, offering compactness, versatility, and low cost, have facilitated a broad array of applications in biomedical optics. However, despite the popularity and the diverse range of applications, a detailed characterization of many of these new spectrophotometers in terms of stray light and noise characteristics is missing from the literature. Such a popular instrument (USB2000) is characterized in detail with particular focus and emphasis on its noise and stray light characteristics. The results of the analysis may be useful to numerous users of this and other similar instruments in a diverse range of applications.

Advances in quantitative UV-visible spectroscopy for clinical and pre-clinical application in cancer

Methods of optical spectroscopy that provide quantitative, physically or physiologically meaningful measures of tissue properties are an attractive tool for the study, diagnosis, prognosis, and treatment of various cancers. Recent development of methodologies to convert measured reflectance and fluorescence spectra from tissue to cancer-relevant parameters such as vascular volume, oxygenation, extracellular matrix extent, metabolic redox states, and cellular proliferation have significantly advanced the field of tissue optical spectroscopy. The number of publications reporting quantitative tissue spectroscopy results in the UV-visible wavelength range has increased sharply in the past three years, and includes new and emerging studies that correlate optically measured parameters with independent measures such as immunohistochemistry, which should aid in increased clinical acceptance of these technologies.

Light scattering spectroscopy of human skin in vivo

We present an in vivo study of the reduced scattering coefficient of normal skin and of common melanocytic nevi in Caucasian subjects. The spectral shape of the reduced scattering coefficient is described well by a power-law dependence on the wavelength, in accordance with previous studies of light scattering by biological tissues. We investigate statistical variations in the scattering spectrum slope and also identify an inherent correlation between scattering intensity and scattering spectral slope, observed mainly in normal skin. In addition, we do not find any significant differences between the scattering properties of normal skin and common melanocytic nevi. Finally, we also provide a short review of previously published studies reporting on the light scattering properties of human skin both in vivo and in vitro.

Comparative evaluation of two simple diffuse reflectance models for biological tissue applications

We present a comparative evaluation of two simple diffuse reflectance models for biological tissue applications. One model is based on a widely accepted and used in biomedical optics implementation of diffusion theory, and the other one is based on a semiempirical approach derived from basic physical principles. We test the models on tissue phantoms and on human skin, utilizing a standard six-around-one optical fiber probe for light delivery and collection. We show that both models are suitable for use with an optical fiber probe and illustrate the potential, applicability, and validity range of the models.