Tape Stripping Research Articles

Optimisation of the sampling method for skin microbiome studies in healthy children: a pilot cohort study

IntroductionRecent interest in the diverse ecosystem of bacteria, fungi and viruses that make up the skin microbiome has led to numerous studies investigating the skin microbiome in healthy skin and in dermatological conditions. However, skin microbiome analysis is challenging due to relatively low numbers of skin microorganisms compared to mucosal sites, such as the respiratory or gastrointestinal tracts. Microbiome results are heavily influenced by sampling methods. Previous sampling methods include that of cotton swabs, tape stripping, patch sampling and punch biopsies. It is essential to have a standardised sampling method for microbiome studies to have comparable results between studies. Two non-invasive methods of sampling the skin microbiome; a skin scraping versus a flocked swab were chosen as methodologies likely to be efficient, effective, and easy to access for future skin microbiome studies in children. Here we compare the two sampling methods to describe the composition of the skin microbiome in healthy children.MethodSamples were collected from six healthy children aged three to nine years from the skin overlying the cubital fossa, cheek and axilla using (i) flocked swabs and (ii) skin scrapings with a glass slide. Samples were collected from the left and right sides of the body at two separate time points, one week apart. Quantitative PCR of the gene encoding 16S ribosomal ribonucleic acid (rRNA) was performed to compare the bacterial load collected by each sampling method. Full-length 16S rRNA gene amplicon sequencing was performed to compare the relationship of sampling method and time with the diversity and ecology of bacteria between different body sites.ResultsFrom six children, 78 flocked swabs and 78 skin scraping samples were collected, along with details of their overall health and skin care practices. qPCR results indicated higher total bacterial load from flocked swabs compared with skin scrapings. Flocked swabs and skin scraping methods had very similar bacterial compositional profiles. The skin microbiome was diverse between individuals and remained relatively stable within individuals over time.DiscussionOverall, results were similar between sample types, however bacterial DNA yield was higher for flocked swab samples (compared to skin scraping methods) and with a simpler protocol is the preferred sampling method for future studies.

Scalp condition improvement with botanical extracts possessing chemical and physical antioxidant activity

AbstractObjectiveOxidative stress is implicated in scalp and hair health manifesting in several ways, including skin barrier, hair retention, healthy hair appearance and scalp sensation. We previously linked markers of oxidative damage to dandruff and skin barrier impairment and have linked key anti‐dandruff technologies to the resolution of these issues. Here we expand the therapeutic space demonstrating many botanical extracts offer protective benefits against ROS stress via both chemical and biological antioxidant mechanisms.MethodsChemical antioxidant activity of 10 botanical extracts was measured using oxygen radical absorbance capacity (ORAC) and biological antioxidant activity was measured using a Nrf‐2 cell assay. A three‐dimensional human keratinocyte skin equivalent model from MatTek was used to measure efficacy of reducing reactive oxygen species (ROS) from both the botanicals added as a solution and from a shampoo product. A 4‐week consumer study with 56 panels was conducted with a leave‐on treatment containing a botanical extract. Measurement of the oxidized lipids (9 and 13‐Hydroxy‐10E 12Z‐octadecadienoic acid, HODE) extracted from scalp tape strips was made using gradient reversed‐phase high‐performance liquid chromatography with tandem mass spectrometry (HPLC/MS/MS).ResultsWe demonstrated in vitro that many botanical extracts exert antioxidant activity by quenching radicals in ORAC testing as well as activating biological antioxidant pathways via nrf‐2 up‐regulation in a cellular reporter system. Furthermore, we demonstrate these antioxidant activities for these botanicals in 3D skin models and ultimately show the reduction of lipid oxidation products in a consumer use context with a rosemary extract.ConclusionImproved scalp condition can be achieved with incorporation of botanicals having the potential to exert antioxidant activity in hair/scalp care products.

Development and Optimization of Transferosomal Gel for Efficient Topical Delivery of Berberine Hydrochloride

Background: Berberine is an isoquinoline alkaloid with potent anti-inflammatory effects. However, its therapeutic efficacy is often restricted by its poor solubility, absorption, and permeability, especially in topical applications. Transferosomes are elastic vesicular carriers with high skin permeability values and retention, making them suitable for encapsulating hydrophilic and lipophilic actives. Objective: The objective of this research was to develop a transferosome-based topical gel formulation of Berberine hydrochloride (BER) to improve its skin permeability and anti-inflammatory efficacy. Method: The thin film hydration method was used to formulate the BER transferosomes. The effects of independent variables, amount of BER in lipid phase (X1), and lipid (Phospholipon 90G) to surfactant ratio (X2) on BER entrapment and vesicle size were studied using face-centered central composite design. The characterization was performed using differential scanning calorimetry, transmission electron microscopy, and X-ray diffraction. The optimized batch (F5) was incorporated in Carbopol gel and further investigated for viscosity, in vitro and ex-vivo diffusion, skin retention by tape stripping, and in-vivo anti-inflammatory efficiency. Results: The formulation optimized with 50 mg of drug and a 5:1 lipid-to-surfactant ratio (F5) demonstrated higher drug entrapment efficiency (72.11%) and lower vesicle size (77.9 nm). TEM validated the spherical vesicle morphology, whereas DSC and XRD analysis confirmed the molecular entrapment of BER within the phospholipid vesicles. The transferosomal gel demonstrated improved BER diffusion (0.63 mg/cm2) confirmed by in vitro and ex-vivo diffusion experiments that revealed a 6-fold increase in flux and permeability coefficient (0.1053 mg. cm-2.h-1). The drug release from transferosome gel was non-Fickian in nature (n = 0.6575), indicating an integration of diffusion and erosion processes. Furthermore, BER transferosomal gel displayed substantial anti- inflammatory activity in rats (p < 0.001). result: The independent variables exerted a substantial impact on drug entrapment and transferosome vesicle size. The optimized batch (F5) exhibited 72.11 % of BER entrapment and 77.9 nm vesicle size. DSC studies indicated molecular dispersion of BER in phospholipon G. The change in BER crystalline state was indicated by the XRD study. In vitro, diffusion study of Transferosome gel formulation indicated the sustained release by a non-fickian mechanism. Ex vivo skin permeation revealed significant improvement in BER permeation (p< 0.05). Further, the tape-stripping method revealed higher BER skin permeability. In-vivo anti-inflammatory efficacy of BER transferosome gel was significantly higher as compared to plain BER gel. Conclusion: The findings demonstrated the potential of transferosomal gel as a promising approach for efficient drug delivery and therapeutic efficacy.

Superior bendability enabled by inherent in-plane elasticity in Bi2Te3 thermoelectrics

With the rapid development of modern wearable electronics, powerful and deformable thermoelectric generators have become an urgent need as the power units that convert environmental or body heat into electricity. Existing efforts mostly focused on the assistance for deformability by substrates/additives, the resultant devices usually output much less power and showed very poor power retainment. Elasticity is inherent to all solids, which therefore offers an intrinsic solution for making thermoelectrics deformable without compromise in power output because of its full recoverability. This work demonstrates this in best-performing (Bi, Sb)2(Te, Se)3 thermoelectrics near room temperature, ending up in the film devices with both extraordinary power density and robust recoverable bendability. This originates from the inherent large elasticity for the in-plane orientation, which is enabled by an easy tape stripping approach for the Van der Waals layered structure, allowing the realization of both powerfulness and bendability that are equally important for wearable thermoelectrics.

Differential Diagnosis of Irritant Versus Allergic Contact Dermatitis Based on Noninvasive Methods

Introduction: Irritant contact dermatitis (ICD) is characterized by direct injury to the epidermal cells, activating the innate immune response. Allergic contact dermatitis (ACD), in contrast, is delineated by a delayed hypersensitivity reaction of type IV. Despite the distinct etiopathogenic mechanisms underpinning each condition, the differentiation between them presents a significant diagnostic challenge. Objective: This study aims to determine whether a combination of clinical evaluation and noninvasive measurements—encompassing oxidative stress, erythema, hydration, melanin content, transepidermal water loss (TEWL), hemoglobin concentration, and skin texture and volume—can distinguish ICD from ACD. Methods: Two cohorts, each comprising 21 patients, were evaluated: one diagnosed with ICD and the other with ACD. All participants underwent biophysical and clinical assessments, along with Antera® 3D evaluations. Tape strips were utilized for skin sampling, and oxidative stress levels were measured via fluorescence assessments. Results: ICD prompts an almost immediate inflammatory reaction (peaking at 24 hours), whereas ACD incites a delayed response (72 hours). Noninvasive evaluated parameters as hemoglobin concentration, skin texture and volume, melanin content, erythema, and TEWL showed significant differences between the ICD and ACD cohorts (p < 0.05). The allergens amcinonide, nickel sulphate, cobalt chloride, budesonide, PPD, and thiuram mix were found to induce elevated levels of oxidative stress. Conclusions: The evaluation of patients with noninvasive parameters, including transepidermal water loss (TEWL), hemoglobin concentration, and skin texture and volume, could markedly aid in distinguishing irritant contact dermatitis from allergic contact dermatitis (ACD). Nevertheless, the study is constrained by a limited sample size.

Combining RNA tape stripping with dermoscopic features for melanoma identification

AbstractBackgroundA noninvasive, accurate diagnostic method for melanoma is needed to improve early detection and decrease number of excisions. Gene expression as measured by RNA levels uses tape strips to directly assesses genetic markers from skin lesions. Commercial RNA assays show varying diagnostic accuracy in melanoma detection. Combining dermoscopic features with RNA tape strips could reduce unnecessary removal of benign lesions by increasing specificity.ObjectivesTo test an RNA‐based rule‐out test and integrate dermoscopic features with RNA analysis to improve diagnostic accuracy of malignant melanoma (MM). Furthermore, we explore the association between RNA profiles and dermoscopic features.MethodsSeventy patients with pigmented skin lesions suspected of being melanoma were imaged with dermoscopy and tape stripped for RNA analysis before surgical excision. The images were evaluated for seven dermoscopic features, and RNA levels of 11 genes were analyzed. A combined test using both gene expression and dermoscopic features was developed. Associations between RNA profiles and dermoscopic features were explored.ResultsHistopathology revealed 19 malignant lesions (17 MM and two basal cell carcinomas) and 51 benign lesions. The combined dermoscopy and RNA test identified all malignant lesions (100% sensitivity) based on PRAME expression, blotch and regression structures and patient age. This combined model increased specificity to 35%, compared to 24% with the original RNA rule‐out test, without missing any malignant lesions. Significant differences in RNA profiles were observed for lesions expressing atypical network and regression structures.ConclusionsCombining RNA tape stripping with dermoscopic features can reduce the removal of benign lesions by over one‐third while maintaining 100% sensitivity. We found specific RNA profiles to be strongly associated with dermoscopic features, presenting a promising opportunity to integrate molecular and morphological information and provide valuable guidance for dermatologists managing atypical pigmented lesions.

Topical Antioxidant Cocoa Polyphenol Skin Penetration.

Cocoa powder derived from the Theobroma cacao plant is rich in polyphenols, such as catechin and epicatechin. These polyphenols are strong antioxidants when consumed orally; however, their ability to enter the stratum corneum following the topical application has never been demonstrated. The objective of this study was to demonstrate the deposition of catechin and epicatechin in the stratum corneum following the topical application of 6% aqueous cocoa powder 1 and 2 h after application. Five healthy female subjects aged 25-60 years were enrolled. A 6% aqueous cocoa powder solution was prepared and applied to two randomized designated spots on the left forearm. 2 cc of the solution was applied under a ¼-inch gauze square covered with plastic wrap and held in place with a Coban dressing. The 15 d-squame 7/8-inch circular tape strips were applied to the predetermined area on the forearm 1 h and 2 h after application of the 6% cocoa powder solution. The tape strips were immediately placed in a -80°C freezer for storage until extraction in preparation for LC-MS evaluation for catechin and epicatechin levels. More catechin and epicatechin were detected at 2 h than 1 h for both compounds, although the difference was not statistically significant. Higher epicatechin levels than catechin levels were detected from the cocoa powder at both time points. This is consistent with published data from food-grade cocoa powder. It is detected that 6% aqueous cocoa powder delivers the antioxidants catechin and epicatechin to the stratum corneum 1 h and 2 h after topical application.

The chronic wound characterisation study and biobank: a study protocol for a prospective observational cohort investigation of bacterial community composition, inflammatory responses and wound-healing trajectories in non-healing wounds

IntroductionChronic wounds affect 1%–2% of the global population, with rising incidence due to ageing and lifestyle-related diseases. Bacterial biofilms, found in 80% of chronic wounds, and scattered single-cell bacteria may...

Transdermal Drug Delivery Systems: Different Generations and Dermatokinetic Assessment of Drug Concentration in Skin.

Transdermal drug delivery systems (TDDS) are a highly appealing and innovative method of administering drugs through the skin, as it enables the drugs to achieve systemic effects. A TDDS offers patient convenience, avoids first-pass hepatic metabolism, enables local targeting, and reduces the toxic effect of drug. This review details several generations of TDDS and the advancements made in their development to address the constraints associated with skin delivery systems. Transdermal delivery methods of the first generation have been consistently growing in their clinical application for administering small, lipophilic, low-dose drugs. Second-generation TDDS, utilizing chemical enhancers and iontophoresis, have led to the development of clinical products. Third-generation delivery systems employ microneedles, thermal ablation, and electroporation to specifically target the stratum corneum, which is the skin's barrier layer. Dermatokinetics is the study of the movement of drugs and formulations applied to the skin over a period of time. It provides important information regarding the rate and extent to which drugs penetrate skin layers. Several dermatokinetic techniques, including tape stripping, microdialysis, and laser scanning microscopy, have been used to study the intricate barrier properties and clearance mechanisms of the skin. This understanding is essential for developing and improving effective TDDS.

A Highly Efficient and User-Friendly Sensitive Skin Model on the Forearm.

Sensitive skin is a worldwide skin problem, and its assessment of therapeutic efficacy traditionally relies on the facial stinging test. However, this test possesses certain limitations due to its restrictive application site, intense pain sensation, and adverse effects on physical appearance. This study aimed to develop and evaluate a highly efficient and user-friendly sensitive skin simulation model, which combines tape stripping and capsaicin testing on the forearm (FA-TS-CAT), as an alternative to the facial stinging test. A randomized, double-blind, placebo-controlled clinical trial was conducted involving 74 subjects. Skin redness (a* value), transepidermal water loss (TEWL), and self-assessment questionnaires were collected at different time points for analysis. Tape stripping 5 times and 10 min application of capsaicin test were identified as the optimal conditions for the FA-TS-CAT model. Consistent stimulation and natural recovery trends of a* value and TEWL were observed on both the FA-TS-CAT and facial capsaicin test (F-CAT) models within 50 min. After the 4-t-butylcyclohexanol complex emulsion was applied, the a* value in the FA-TS-CAT model exhibited a soothing trend similar to the F-CAT model, with a significantly reduced by 3.99-fold and 3.28-fold at T3 and T4 (p < 0.001), compared to the placebo. Notably, the test efficiency of the FA-TS-CAT model was threefold higher than that of the F-CAT model, and subjects showed more willingness to participate in the FA-TS-CAT test (95.95% vs. 4.05%). These results indicated the FA-TS-CAT is a highly efficient and user-friendly model for sensitive skin, providing a reliable and valid method for clinical research in sensitive skin treatment.

Optimization of skin sampling based on tape stripping for lipidome analysis by nanoflow ultrahigh performance liquid chromatography-tandem mass spectrometry

In this study, skin sampling by tape stripping for lipid analysis was optimized by examining the lipid profiles of the stratum corneum (SC), focusing on the composition and levels of ceramides (Cer), diacylglycerols (DG), and triacylglycerols (TG), using nanoflow ultrahigh performance liquid chromatography-tandem mass spectrometry. Significant variations in the number and composition of the identified lipids, particularly Cer and neutral lipid species, were observed across different skin locations, including the forearm, forehead, cheek, and neck. Analysis of the layer-to-layer lipid profiles of the seven consecutive layers revealed a gradual decrease in DG and TG levels from the outermost to the innermost layers, with certain Cer subclasses showing increases in the second to fourth layers and subsequent decreases. Comparative analysis of lipid profiles from adjacent spots demonstrated statistical consistency and persistent differences between spots. Pooling layers were evaluated as an alternative method for representing SC layers, and their efficiencies were assessed by varying the number of pooled layers. We found that pooling five consecutive layers was effective in terms of the number and levels of identified lipids. Additionally, investigations into the matrix effect and extraction efficiency upon pooling layers indicated that pooling up to five layers did not significantly affect ionization suppression or reduce extraction recovery.

Stability-enhanced (Cu-, Zn-)MOFs via (Cu, Zn)S composite strategy: A promising approach for oil-water separation

The application of metal-organic frameworks (MOFs) in the field of oil-water separation is developing rapidly, but the challenges of poor water stability, poor scalability and durability still limit its practical application. In this study, two environmentally friendly and non-toxic superhydrophobic (Cu, Zn)S/(Cu-, Zn-)MOFs@stearic acid (CuS/Cu-MOFs@SA and ZnS/Zn-MOFs@SA) coatings were successfully prepared by hydrothermal method combined with dip coating method, with a water contact angle (WCA) of >165°. Through the synergistic effect with stearic acid (SA), the (Cu-, Zn-)MOFs coating composited with CuS and ZnS exhibits excellent durability in extreme environments. This synergistic effect significantly improves the mechanical stability and durability of the coating, allowing it to maintain a WCA of >155° after friction, kneading, tape stripping and ultrasonic treatment. However, CuS/Cu-MOFs@SA coating is significantly superior to ZnS/Zn-MOFs@SA coating in terms of chemical stability (acid-base-salt environment) and self-cleaning ability due to the different ligands used in the preparation process and the formation of particle structure. Significantly improved its durability and reliability in oil-water separation. The separation efficiency of the coating is as high as 98.7 %, and it remains above 97.8 % after 12 times of repeated use. This study provides a new strategy and important reference for the development of superhydrophobic MOFs coatings and oil-water separation materials with high stability, wear resistance and corrosion resistance.

Enhancing durability of superhydrophobic surfaces via nanoparticle-induced bipolar interface effects and micro-nano composite structures: A femtosecond laser and chemical modification approach

Superhydrophobic coatings are vital in energy, aerospace, and chemical engineering, while their complex preparation and limited durability hinder widespread application. Therefore, inspired by the unique structures of hydrophobic cotton surfaces and mosquito eyes in nature, a durable aluminum alloy superhydrophobic surface is developed using a combination of femtosecond laser and chemical modification methods. Initially, porous microneedle micro-nanostructures are ablated on the surface of the aluminum alloy via femtosecond laser technology. Then, epoxy resin modified with γ-aminopropyl triethoxysilane (KH550) forms a covalently bonded intermediate layer. Finally, biphasic silicon dioxide (BP-SiO2) nanoparticles modified by hexadecyltrimethoxysilane (HDTMS) are used to construct the top hydrophobic layer. The covalent interface interactions between the aluminum alloy substrate and the intermediate layer, as well as between the intermediate layer and the top layer, significantly enhance the durability of the superhydrophobic surface. The prepared F-M@KH-EP/BP-SiO2 coating exhibits outstanding superhydrophobic properties, with a water contact angle (CA) as high as 168.56° and a sliding angle (SA) as low as 1.52° More encouragingly, the composite coating maintains its excellent water resistance even when subjected to harsh mechanical durability damage, including sandpaper wear, tape stripping tests, water drop and sand impact tests. Moreover, the prepared coatings maintain distinguished non-wettability in harsh operating conditions such as corrosive liquid environments, ultraviolet radiation, ultrasonic vibration, etc. Additionally, the coating demonstrates remarkable self-cleaning properties. Superhydrophobic surface durability is significantly enhanced by combining nanoparticle-induced bipolar interface effect and micro-nano structures. These findings provide theoretical reference for the design and application of durable superhydrophobic coatings.

A facile preparation of durable superhydrophobic PFA coatings with superior anti-icing, anti-corrosion and self-cleaning performance

The potential of superhydrophobic coatings for various applications has been widely recognized. However, preparing durable superhydrophobic coatings on metal surfaces remains a significant challenge. Perfluoroalkoxy Alkane (PFA), a fluorine-rich material, has recently emerged as a promising candidate for constructing superhydrophobic coatings. In this study, a mechanically stable superhydrophobic PFA coating was prepared using a simple combination of electrodeposition and annealing. The prepared PFA coating displays excellent water repellency, as evidenced by a water contact angle of 171 ± 0.3° and a sliding angle of 1.0 ± 0.4° The water contact angle of the coating only decreases by 0.6°after undergoing 400 tape stripping tests, indicating the remarkable stability. The PFA coating significantly prolongs the freezing time of water droplets on a cool surface at temperatures of -6 °C, -8 °C, and -10 °C, with improvements of 19.4, 72.5, and 47.8 times respectively. The corrosion current density on the coated surface is reduced by four orders of magnitude compared to bare aluminum alloy, and the PFA coating exhibits a high inhibition corrosion efficiency of 99.995 %. Furthermore, the coating possesses exceptional self-cleaning performance by repelling dirt particles and maintaining a clean surface. Consequently, the developed superhydrophobic PFA coating holds significant promise for long-lasting anti-icing, anti-corrosion and self-cleaning applications.

Development and performance evaluation of green superhydrophobic coating for fouling and corrosion protection

In this paper, a simple and environmentally friendly superhydrophobic stearic acid-modified zinc-nickel-cobalt composite coating (SA@ZNC) is presented. The zinc-nickel-cobalt (ZNC) coating with petal-like micro/nano-rough structure was constructed on the metal surface by combining electrodeposition and chemical substitution techniques. Subsequently, the coating was modified with low surface energy by adding stearic acid, and the SA@ZNC coating with excellent superhydrophobicity (water contact angle of 161.08 ± 0.31° and rolling angle of 3.50 ± 0.54°) was prepared. The coating is self-cleaning against a wide range of simulated contaminants and can remain superhydrophobic in air for over a year. Changes in pH do not significantly affect the superhydrophobicity and at low temperatures, the freezing time of water droplets on the coating was extended by 2.1 times compared to a blank steel sheet. Furthermore, the SA@ZNC coating demonstrated remarkable robustness, withstanding 30 minutes of water impact, a wear mass of 0.2 % after rubbing with weights over 2400 mm and retaining its superhydrophobicity after 80 tape stripping cycles. The results of the corrosion protection tests demonstrated that the SA@ZNC coating provided excellent corrosion protection for N80 steel, exhibiting a current density two orders of magnitude lower than that of the blank sample. Furthermore, the coating exhibited a corrosion inhibition rate of 95.75 ± 0.33 % and excellent charge transfer resistance. The multiple protection mechanisms and homogeneous micro/nanostructure of the coatings resulted in significantly better corrosion resistance than most of the reported zinc-nickel based coatings. The use of low-energy consumption methods and environmentally friendly modifiers positions this coating for large-scale production and potential applications in sectors like food and medicine, with promising implications for corrosion protection in various industries.

Tape Stripping Method in Dermatological and Pharmacological Research: Evaluating Fresh and Frozen-Thawed Porcine Skin.

Background The stratum corneum (SC) plays a crucial role in protecting the skin and regulating water loss. Tape stripping is a well-established method for studying skin barrier function and evaluating topical treatments. However, the behavior of fresh versus frozen-thawed skin during tape stripping has not been extensively compared. Objective This study aims to compare the removal of the stratum corneum from fresh and frozen-thawed porcine skin using tape stripping. It also aims to assess the reliability of tape weighing versus histological methods in quantifying SC removal. Methods Fresh and frozen-thawed porcine ears were obtained, cleaned, and subjected to tape stripping at varying numbers of strips from zero to 40. Tape weight and histological measurements were used to quantify SC removal. Statistical analyses were conducted to compare SC thickness and tape weight between the two types of skin. Results The study found that frozen-thawed skin exhibited a non-linear rate(r = 0.65) of SC removal per tape strip in the first five strips compared to a linear removal for fresh skin (r = 0.96). By the fifth tape strip, frozen-thawed samples had lost 80.6% of their SC, while fresh samples had only lost 33.5% (P < 0.03). Tape weighing and histological measurements showed strong correlations (r = 0.93 for fresh skin and r = 0.95 for frozen-thawed skin), indicating that tape weighing is a reliable alternative to histology for assessing SC removal on both sample types. Conclusions Fresh and frozen-thawed porcine skin respond differently to tape stripping, with frozen-thawed skin showing accelerated SC removal in the first five strips. The strong correlation between tape weighing and histological analysis supports the use of tape weighing as a practical tool for evaluating SC removal. These findings have implications for specimen selection and methodological standardization in dermatological and pharmacological research. Future research should explore alternative preservation and SC thickness measurement methods and their impact on tape stripping outcomes.

The Effect of Polynucleotide‐Hyaluronic Acid Hydrogel in the Recovery After Mechanical Skin Barrier Disruption

ABSTRACTBackgroundThe epidermal barrier acts as a defense against external agents as well as helps to maintain body homeostasis. Polynucleotides (PN), exogenous DNA fragments, promote wound repair through their stimulatory and anti‐inflammatory effects. Recent findings indicate a synergistic effect of PN and hyaluronic acid (HA) combinations in regulating inflammation and promoting cell proliferation. This study aims to elucidate the effects of PN and HA on repairing the epidermal barrier following its disruption by tape stripping (TS) in a mouse model.Materials and MethodsAfter disrupting the epidermal barrier using TS, a formulation containing PN (14 mg/mL) and HA (6 mg/mL) was applied. Trans‐epidermal water loss (TEWL) was measured at 0, 3, 6, 24, 48, and 72 h. Mice were euthanized after the final application at 72 h, and tissue samples were analyzed for epidermal/dermal thickness, neutrophil infiltration, and filaggrin expression.ResultsWe observed a significant reduction in TEWL in the PN+HA group compared to that in the control group (20.8 ± 0.5 vs. 43.7 ± 0.5 g/m2h at 72 h, p &lt; 0.05), indicating an improvement in barrier function. Histological evaluation showed decreased epidermal and dermal thickening in the PN+HA group compared to that in the control group (epidermal: 29.4 ± 2.2 vs. 57.9 ± 3.5 μm; dermal: 464.8 ± 25.9 vs. 825.9 ± 44.8 μm, both p &lt; 0.05). Additionally, neutrophil infiltration in the dermis was significantly reduced, and filaggrin protein levels were significantly higher in the PN+HA group compared to those in the control group (4.8 ± 0.4 vs. 21.1 ± 3.3 for neutrophils; 0.84 ± 0.04 vs. 0.42 ± 0.03 for filaggrin, both p &lt; 0.05).ConclusionThese results suggest that PN+HA may be an effective therapeutic strategy for repairing skin barrier damage.

In vivo permeation of 2-phenoxyethanol in human skin

A number of baby wipe formulations contain 2-phenoxyethanol (PE) as a preservative and cetylpyridinium chloride (CPC) as a surfactant with antimicrobial activity. Previously, we reported the skin absorption of PE in porcine skin and human skin in vitro. In the present work, the permeation of PE from preparations with CPC and without CPC was investigated in human skin in vivo. The studies were conducted using Confocal Raman Spectroscopy (CRS) and tape stripping (TS) methods. The CRS studies showed that the area under the curve (AUC) of PE for the formulation with and without CPC were not significantly different (p > 0.05). The TS data indicated no significant difference in the amounts of PE recovered from tapes 1–6 for the preparation with and without CPC (p > 0.05). When comparing the in vitro and in vivo data, a correlation was observed between the cumulative amount of PE permeated through human skin in vitro at 24 h and the AUC as measured by CRS (r2 = 0.97). In addition, the cumulative amount of PE permeated through human skin in vitro at 24 h was found to correlate with the amount of PE recovered from tape 1 to 6 in vivo (r2 = 0.95). Both CRS and TS techniques demonstrated limitations in assessing the distribution of PE and CPC in the skin in vivo, primarily attributed to the Raman signal intensities of compounds under investigation and the variability in the amount of SC collected by TS. Despite the limitations of CRS and TS, the results from the present study add further insights to the in vitro permeation data. Additionally, the findings of the present study encourage the further development and application of CRS for non-invasive evaluation of topical skin formulations in vivo.

Characterising Skin Electrical Impedance Using Tape Stripping Methods: A Bioelectrical Study of a Porcine Model.

Background Recent advancements in ultra-low power electronics and wireless devices have facilitated the widespread adoption of wearable technology for fitness and health monitoring, paving the way for personalized medicine. Microneedle-based devices, comprising small epidermal patches that penetrate the skin's stratum corneum to potentially access biomarkers in the extracellular fluid of the viable epidermis, represent a promising innovation in this field. Objectives This project aimed to develop and validate a novel method to evaluate microneedle engagement in the skin in real-time. To our knowledge, there are no studies published to date that have characterized the electrical impedance of stratum corneum and epidermis using the tape stripping method to selectively remove cell layers. Additionally, no studies have been published comparing the electrical impedance of fresh to frozen-thawed porcine skin. The objective of this study was to develop and validate a novel method to evaluate microneedle engagement in skin, in real-time, that does not require processing of the tissue. Methods A tape stripping technique was employed to selectively remove the stratum corneum from fresh and frozen-thawed porcine skin samples which were then electrically characterized using an excitation frequency of 5 kHz with a peak Voltage of 1 V. Results This study demonstrated a mean impedance reduction of 97.08 ± 1.3 % for fresh porcine skin, and 98.04 ± 0.3 % for frozen-thawed porcine skin when transitioning from the surface stratum corneum to the viable epidermis. The correlation between the reduction of impedance and the number of tape strips across all 18 test sites was significant (r = 0.98, p < 0.00001). However, comparing the skin impedance of the fresh and frozen-thawed specimens showed poor equivalence, with the frozen-thawed sites approximately 5.5 times the impedance of the fresh sites before any tape stripping, and 4.19 times greater after 30 tape strips. Conclusions These findings suggest that monitoring for an interelectrode impedance decrease of greater than 95% between two projections of a microneedle device could provide a rapid and effective evaluation of skin engagement, crucial for advancing the development and clinical application of microneedle-based technologies in personalized medicine. The study also underscores the impact of the freeze-thaw process on the mechanical and electrical properties of skin, which is crucial for standardizing testing protocols.

Holistic investigation of the anti-wrinkle and repair efficacy of a facial cream enriched with C-xyloside.

To investigate the repairing and anti-wrinkle efficacy of the facial cream enriched with C-xyloside, aiming at comprehensively evaluating its skin anti- aging effect and clarify its potential mechanism of action. The repairing efficacy was studied on 3D epidermis skin model and the antiaging efficacy was studied on ex-vivo human skin. Two clinical studies were conducted with Chinese females. In the first study, 49 subjects aged between 30 and 50 with wrinkle concerns were recruited and instructed to apply the investigational cream containing C-xyloside for 8 weeks. Wrinkles attributes were assessed by dermatologist. Instrumental measurements on skin hydration, trans-epidermal water loss (TEWL), and skin elasticity were also conducted. In the second study, 30 subjects aged between 25 and 60 with self-declared sensitive skin and facial redness were recruited and instructed to apply the cream for 4 weeks. Biomarker analysis of the stratum corneum was conducted through facial tape strips. The cream improved the histomorphology of the 3D epidermis skin model after SLS stimulation, and significantly increase the expression of LOR and FLG. On human skin, the cream improved the histopathology induced by UV, and significantly increased the protein content of COL I and COL III, collagen density and the number of Ki-67 positive cell of skin compared with model group (n = 3, p < 0.01). The results from the first clinical study demonstrate a significant increased the skin hydration and elasticity by 21.90%, 13.08% (R2) and 12.30% (R5), respectively (n = 49, p < 0.05), and the TEWL values decreased by 33.94% (n = 49, p < 0.05), after 8 weeks application of the cream. In addition, the scores for nasolabial folds, glabellar wrinkle, underneath eye wrinkles, crow's feet wrinkle and forehead wrinkle in the volunteers exhibited a significant reduction of 34.02%, 43.34%, 50.03%, 33.64% and 55.81% respectively (n = 49, p < 0.05). The (rCE)/(fCE) ratio of volunteers based on tape stripping significant increased after using the sample cream (n = 30, p < 0.05). The cream containing C-xyloside showed improvement of skin wrinkles and enhancement of skin barrier function. These efficacies may be attributed to the fact that the sample cream can increase the expression of skin barrier related proteins LOR and FLG, promote the maturation of cornified envelope, enhance collagen I and III protein expression and stimulate skin cell proliferation, to provide sufficient evidence supporting its antiaging efficacy of skin.