From Seaweeds to Cosmeceutics: A Multidisciplinar Approach

Macroalgae are widespread on the coasts of all the globe and lead to a negative ecological impact, requiring expensive remediations. Therefore, the valorization of invasive seaweed as a renewable source of bioactive products could represent a valid solution. In this context, three algal biomasses, belonging to brown, green, and red families (Sargassum muticum, Ulva lactuca, Solieria filiformis), collected in the venetian Laguna, were investigated as a source of active compounds for the formulation of cosmeceutics. Microwave (MW) and ultrasound (US) were applied to enhance the algae extraction by means of a hydroalcoholic solution. According to total phenolic content (TPC) evaluation, MW demonstrated the best performing outcomes, resulting in 19.77, 22.02, and 16.94 mgGAE/gExtr (30 min at 90 °C) for brown, green, and red algae, respectively. Antioxidant activity was tested as well, showing comparable trends (49.19, 26.24, and 3.02 mmolTrolox eq./gExtr for brown, green, and red algae, respectively). Due to natural algae predisposition to absorb contaminants, the metal content analysis helped to screen the applicability of these extracts, identifying Ulva lactuca as the most suitable source of antioxidants for cosmetic formulations. This MW extract was then adopted to formulate two different preparations, namely a gel and an emulsion. Thermal and mechanical tests confirmed the stability of each formulation, together with neutral organoleptic characteristics. Finally, the actives release was investigated by means of a tape stripping essay, showing an efficient controlled release for gel formulation, even after 7 h of test. The produced cosmeceutics merged non-conventional extraction technologies with formulation expertise, offering a valuable alternative to solve the macroalgae disposal issue.

A Dermal Biomarker Patch Displays Excellent Analytical Performance and Outperforms Tape Stripping in Psoriatic Skin

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Comparison of non-invasive Staphylococcus aureus sampling methods on lesional skin in patients with atopic dermatitis

There is evidence that Staphylococcus aureus colonisation is linked to severity of atopic dermatitis. As no gold standard for S. aureus sampling on atopic dermatitis skin lesions exists, this study compared three commonly used methods. In addition, effectiveness of standard skin disinfection to remove S. aureus colonisation from these inflamed skin lesions was investigated. In 30 atopic dermatitis patients, three different S. aureus sampling methods, i.e. detergent scrubbing, moist swabbing and tape stripping, were performed on naïve and disinfected skin lesions. Two different S. aureus selective media, mannitol salt agar and chromID agar, were used for bacterial growing. Quantifying the S. aureus load varied significantly between the different sampling methods on naïve skin lesions ranging from mean 51 to 1.5 × 104 CFU/cm2 (p < 0.001). The qualitative detection on naïve skin was highest with the two detergent-based techniques (86% each), while for tape stripping, this value was 67% (all on chromID agar). In comparison, mannitol salt agar was less sensitive (p < 0.001). The disinfection of the skin lesions led to a significant reduction of the S. aureus load (p < 0.05) but no complete eradication in the case of previously positive swab. The obtained data highlight the importance of the selected sampling method and consecutive S. aureus selection agar plates to implement further clinical studies for the effectiveness of topical anti-staphylococcal antibiotics. Other disinfection regimes should be considered in atopic dermatitis patients when complete de-colonisation of certain skin areas is required, e.g. for surgical procedures.

Acidic Skin Care Promotes Cutaneous Microbiome Recovery And Skin Physiology in An Acute Stratum Corneum Stress Model

Background: The skin microbiome and skin physiology are important indicators of the epidermal homeostasis status. Stress models are used to reveal pathological conditions and modulating effects. The recovery phase served to investigate the cutaneous microbiome in relation to skin physiology after mild tape stripping without treatment compared to two cosmetic leave-on lotions (pH 5.5 vs. pH 9.3). Material and MethodsThe prospective, randomized, controlled study was performed in 25 healthy volunteers: The microbiome was assessed via swabs and subsequent 16S-rRNA-gene amplicon sequencing. Skin physiology was analyzed in terms of barrier function, stratum corneum hydration, surface-pH, skin color non-invasively. All parameters were assessed before and immediately after 2hrs., 2 days and 7 days after tape stripping. Lotion A (pH 5.5) and the identical lotion B (pH 9.3) were applied 2-times per day for 7 days on the volar forearm.ResultsTape stripping reduced the alpha diversity with a recovery over 7 days without treatment. Both lotions significantly accelerated the recovery of the alphadiversity already after 2 days with a slightly higher rate for lotion A (pH 5.5). After tape stripping, the relative abundance of Proteobacteria was increased, whereas Actinobacteria were reduced. Further, mean relative abundances of typical skin-associated genera were reduced after tape stripping. Taxa compositions returned to normal levels after 7 days in all treatment groups, and an accelerated normalization could be observerd with treatment by both lotions already after tow days. A significant difference in skin-pH was observed at day2 and day7 with an increased pH in lotion B treatment. Both lotions induced an increase in stratum corneum hydration. Barrier function was only changed by tape stripping. DiscussionThe study proved the suitability of an experimental stress model in the assessment of skin surface microbiome in relation to skin physiology. Stratum corneum hydration increased significantly with both lotions already at day 2. Microbiome parameters (alpha-diversity, mean relative taxa, abundance of selected genera) normalized over 2-7 days. Three potential mechanisms could be responsible for the accelerated normalization: a) optimized hydration during the recovery phase b) the composition of the lotion, c) acidic pH of the lotion.

Assessment of dermal bioavailability: predicting the input function for topical glucocorticoids using stratum corneum sampling

Predicting the dermal bioavailability of topically delivered drugs is challenging. In this work, minimally invasive stratum corneum (SC) sampling was used to quantify the delivery of betamethasone valerate (BMV) into the viable skin. Betnovate® cream (0.1% w/w BMV) was applied at three doses (2, 5, and 10 mg cm−2) to the ventral forearms of 12 healthy volunteers. The mass of drug in the SC was measured using a validated tape-stripping method (a) after a 4-h “uptake” period, and (b) following a 6-h “clearance” period subsequent to cream removal. Concomitantly, the skin blanching responses to the same doses were assessed with a chromameter over 22 h post-application. BMV uptake into the SC was significantly higher for the 5 mg cm−2 dose compared to those of 2 and 10 mg cm−2. In all cases, ~30% of the drug in the SC at the end of the uptake period was cleared in the subsequent 6 h. From the SC sampling data, the average drug flux into the viable epidermis and its first-order elimination rate constant from the SC were estimated as 4 ng cm−2 h−1 and 0.07 h−1, respectively. In contrast, skin blanching results were highly variable and insensitive to the dose of cream applied. The SC sampling method was able to detect a 50% difference between two applied doses with 80% power; detection of a 20% difference would require a larger sample size. SC sampling enabled quantitative metrics describing corticosteroid delivery to the viable epidermis to be determined. Graphical abstract