Daily Cosmetic Research Analysis
Methodological and safety advances dominate today’s cosmetic-related research. A new ISO-standardized in vitro SPF method shows high reproducibility and accuracy, reducing reliance on human testing. Parallel work reveals substantial dermal penetration and barrier disruption by PFAS, while a bioengineered humanized collagen (Y326) demonstrates preclinical anti-aging efficacy as a stable alternative to animal-derived collagens.
Summary
Methodological and safety advances dominate today’s cosmetic-related research. A new ISO-standardized in vitro SPF method shows high reproducibility and accuracy, reducing reliance on human testing. Parallel work reveals substantial dermal penetration and barrier disruption by PFAS, while a bioengineered humanized collagen (Y326) demonstrates preclinical anti-aging efficacy as a stable alternative to animal-derived collagens.
Research Themes
- Non-animal, standardized SPF testing (ISO 23675) for sunscreen evaluation
- Dermal safety and barrier effects of PFAS from consumer/cosmetic products
- Bioengineered collagen as an alternative to animal-derived materials for anti-aging
Selected Articles
1. Performance assessment of the Double Plate method (ISO23675) in ALT-SPF Consortium: A highly reproducible and accurate in vitro method to determine SPF.
Across five laboratories and 32 sunscreen products (with a 12-product follow-up), the ISO 23675 Double Plate method showed excellent intra- and inter-lab reproducibility and, after mathematical adjustment, close accuracy versus the ISO 24444:2019 in vivo reference. Its adoption as an ISO standard enables robust, ethical, and scalable in vitro SPF testing.
Impact: This work operationalizes a validated, standardized, non-animal SPF assay, directly impacting sunscreen development, labeling, and regulatory compliance.
Clinical Implications: Dermatologists can have greater confidence in SPF labeling backed by a robust in vitro standard, facilitating patient counseling on photoprotection while reducing human testing burdens.
Key Findings
- High intra- and inter-laboratory reproducibility met ISO/TC217/WG7 precision criteria.
- Post hoc mathematical adjustment yielded close alignment with the ISO 24444:2019 in vivo reference method.
- Standardized robotic application and spectrophotometry minimized variability across five laboratories.
- Evidence supported publication as ISO 23675 (December 2024), enabling an ethical in vitro SPF alternative.
Methodological Strengths
- Multi-laboratory ring testing with diverse global formulations
- Standardized robotic application and predefined ISO precision criteria
Limitations
- Accuracy required a mathematical adjustment to reduce initial bias versus the reference method
- Real-world factors (e.g., water resistance, user application variability) are not directly captured by in vitro plate testing
Future Directions: Expand validation to challenging formulations and integrate assessments of photostability and water resistance; promote global regulatory harmonization and data-sharing to enhance reproducibility.
OBJECTIVE: To perform a comprehensive statistical characterization of the Double Plate method (ISO 23675) as a potential in vitro alternative to the in vivo reference method (ISO 24444:2019) for determining the sun protection factor (SPF). METHODS: Five qualified laboratories were involved in testing the Double Plate method, as part of a large-scale ring test conducted by the International Consortium 'ALT-SPF'. About 32 sunscreen products, reflecting diverse global formulations, were tested using both the in vivo reference method and the Double Plate method. This method employs spectrophotometric measurements of sunscreen applied to UV-transparent plates with standardized robotic application to minimize the variability. A mathematical adjustment was introduced to address the initial bias compared to the reference method and further assessed in a follow-up ring test with 12 products, including ISO standards. RESULTS: The Double Plate method exhibited very high intra- and inter-laboratory reproducibility throughout the study, consistently meeting the precision criteria set by ISO/TC217/WG7. Following the mathematical adjustment, the accuracy significantly improved, demonstrating a close alignment with the reference method. CONCLUSION: The Double Plate method demonstrates excellent reproducibility and, following optimization, high accuracy for the SPF determination. These findings endorse the Double Plate method as a robust and ethical in vitro alternative to the in vivo reference method for SPF testing. This paved the way for its publication as a new ISO standard (ISO 23675), in December 2024, supporting consumer safety and informed product choices. OBJECTIF: Réaliser une caractérisation statistique complète de la méthode Double Plaque (ISO 23675) comme alternative in vitro potentielle à la méthode de référence in vivo (ISO 24444: 2019) pour déterminer le facteur de protection solaire (FPS). MÉTHODES: Cinq laboratoires qualifiés ont participé au test de la méthode Double Plaque, dans le cadre d'un essai circulaire à grande échelle mené par le Consortium international “ALT‐SPF”. Trente‐deux écrans solaires, reflétant diverses formulations mondiales, ont été testés à la fois par la méthode de référence in vivo et par la méthode Double Plaque. Cette méthode utilise des mesures spectrophotométriques de la crème solaire appliquée sur des plaques transparentes aux UV avec une application robotique standardisée pour limiter la variabilité. Un ajustement mathématique a été introduit pour tenir compte du biais initial par rapport à la méthode de référence et a ensuite été évalué dans un essai circulaire supplémentaire avec 12 produits, y compris des formulations solaires de référence ISO. RÉSULTATS: La méthode Double Plaque a montré une très grande reproductibilité intra‐ et inter‐laboratoire tout au long de l'étude, répondant systématiquement aux critères de précision définis par la norme ISO/TC217/WG7. Suite à l'ajustement mathématique, l'exactitude s'est nettement améliorée, démontrant un alignement net avec la méthode de référence. CONCLUSION: La méthode Double Plaque démontre une excellente reproductibilité et, après optimisation, une grande précision pour la détermination du FPS. Ces résultats confirment que la méthode Double Plaque est une alternative in vitro robuste et éthique à la méthode de référence in vivo pour les tests du FPS. Ils ouvrent la voie à sa publication en tant que nouvelle norme ISO (ISO 23675), en décembre 2024, pour améliorer la sécurité des consommateurs et faciliter les choix éclairés de produits.
2. Y326: A highly stable and bioactive substitute for animal-derived collagens in biomedical and cosmetic uses.
Rational engineering of humanized collagen III produced Y326, a stable, high-purity triple-helical protein that enhances adhesion, migration, proliferation, and ECM synthesis in vitro and improves wrinkles, hydration, dermal thickness, and collagen I expression in a photoaging model. Y326 directly addresses shortcomings of animal-derived collagens for anti-aging.
Impact: Introduces a bioengineered humanized collagen with preclinical efficacy, potentially transforming anti-aging materials by improving safety and consistency over animal sources.
Clinical Implications: If validated clinically, Y326 could replace animal-derived collagen in dermal fillers, wound repair matrices, and cosmeceuticals, reducing pathogen and immunogenic risks and improving batch consistency.
Key Findings
- Designed 19 humanized collagen III variants retaining RGD/GER motifs; selected variant 019 and developed repeating Y88, then optimized to Y326 by removing unstable residues.
- Y326 preserved triple-helical structure and promoted cell adhesion, migration, proliferation, and ECM synthesis in vitro.
- In a skin photoaging model, Y326 reduced wrinkles, improved hydration, increased dermal thickness, and upregulated endogenous collagen I.
Methodological Strengths
- Stepwise rational design with mass spectrometry-guided optimization
- Convergent validation across structural analysis, in vitro functional assays, and in vivo photoaging model
Limitations
- Preclinical stage without human clinical trials; long-term safety and immunogenicity remain unknown
- Manufacturing scalability, stability in finished formulations, and regulatory pathways require clarification
Future Directions: Conduct GLP toxicology and first-in-human studies, evaluate performance in dermal filler or scaffold applications, and benchmark against current animal-derived and recombinant collagens.
Collagen degradation is one of the marks of skin aging. Animal-derived collagens have been widely used to repair skin damage or anti-aging as medical devices in clinical application, but they still present a series of challenges, including resource shortage, pathogen contamination, immunogenicity, and batch inconsistency. To address this, 19 recombinant humanized collagen III variants were designed based on the sequence scanning of the triple-helical region (G168-C1196) of human collagen type III (UniProt ID: P02461), retaining critical adhesion sites (RGD and GER) and the GXY pattern. Variant 019 was selected for its highest adhesion activity and was further developed into a 6-repeated variant (Y88). Y88 was optimized subsequently by removing unstable residues identified by mass spectrometry analysis, yielding a stable, high-purity variant, Y326. Structural analysis confirmed Y326's triple-helical conformation; furthermore, functional assays demonstrated its ability to promote cell adhesion, migration, proliferation, and extracellular matrix synthesis in vitro. In a skin photoaging model, Y326 reduced wrinkles, improved hydration, increased dermis thickness and up-regulated endogenous collagen I expression. Thus, Y326 offers a promising substitute for animal-derived collagens in anti-aging applications.
3. In vitro assessment of dermal penetration and skin barrier impairment by per- and polyfluoroalkyl substances (PFASs) from consumer products.
Using porcine skin and human skin equivalents, several PFASs exhibited high dermal absorption (29.5–82.8%). PFAS exposure induced epidermal damage and metabolomic evidence of stratum corneum hydration and membrane pathway disruption, consistent with skin barrier breakdown; low-dose PFHxA effects may be reversible.
Impact: Provides mechanistic and quantitative evidence of PFAS dermal penetration and barrier impairment, informing risk assessment and regulation of cosmetics and personal care products.
Clinical Implications: Clinicians can counsel patients on minimizing PFAS skin exposure and recognize barrier-compromised presentations; findings support safer formulation and regulatory limits.
Key Findings
- In vitro porcine skin studies showed dermal absorption rates of several PFASs ranging from 29.5% to 82.8%.
- PFAS exposure caused scaly lesions, holes, and protrusions in human skin equivalents with concentration-dependent increases in surface roughness.
- Metabolomics indicated disrupted stratum corneum hydration and membrane-related metabolic pathways, consistent with skin barrier breakdown; low-dose PFHxA damage may be reversible.
Methodological Strengths
- Dual-model approach combining porcine skin absorption with human skin equivalent toxicity testing
- Use of SR-FTIR imaging and metabolomics to map biochemical and barrier changes
Limitations
- In vitro systems may not fully replicate human in vivo exposure dynamics and chronic low-dose scenarios
- Detailed exposure concentrations and full PFAS chemical space were limited to selected compounds (e.g., PFHxA, PFNA)
Future Directions: Extend to in vivo human-relevant exposure scenarios, evaluate chronic low-dose effects, and compare across broader PFAS chemistries to inform regulatory thresholds.
Per- and polyfluoroalkyl substances (PFASs) are a class of synthetic organic compounds that are extensively utilized in consumer products, including cosmetics, personal care products, and textiles. PFASs pose significant risks to both ecological systems and human health, leading to calls for their comprehensive restriction. Skin exposure constitutes one of the pathways through which PFASs enter the human body. To investigate the effects of PFASs exposure on the skin, this study employed two kinds of in vitro skin models to suit different study purposes. The excised porcine skin was used to predict the skin absorption rates of several PFASs, with the results ranging from 29.5 % to 82.8 %, and to observe the spatial distribution of nucleic acids, lipids and proteins in skin tissues by synchrotron radiation Fourier transform infrared (SR-FTIR). Then the histomorphology damage and metabolic toxicity of PFHxA and PFNA to human skin equivalents (HSE), which were grown from human skin cells in vitro, were evaluated. It was found that PFASs exposure led to scaly lesions, holes, and protrusions on the skin, and the roughness was proportional to the exposure concentration. The different epidermal layers exhibited morphological alterations consistent with cell damage. Metabolomics revealed that PFASs exposure disrupted the stratum corneum (SC) hydration and altered the membrane function-related metabolic pathways, signifying the skin barrier breakdown. Additionally, the damage caused by PFHxA at a lower concentration might be reversible. This study helps to understand the possible adverse effects of PFASs in products on the skin and further helps to regulate their production and use.