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Skin assessment methodologies have focused mainly on intuitive aging characteristics, including facial wrinkles and pigmented spots, and usually adopt pattern recognition algorithms. Recently, distinct methods of interpreting skin aging, such as the detection of facial landmarks and age prediction using machine learning techniques, have been conducted.We defined two indices that represent the severity of facial aging. The first index was the ratio of the bizygomatic distance and bigonial distance. The second index was the ratio of the degrees of the near mandible. The indices extracted from two-dimensional frontal face images were intended to show the deformation of the facial skin downward with aging progress. To validate whether these proposed indicators can represent facial aging, we conducted correlation tests with age and facial skin characteristics and performed association tests between the indices and facial skin characteristics, adjusted for age.The indices showed strong correlations with age (r = 0.557 and 0.464, respectively) and facial skin characteristics. Although there were correlations between the indices and facial skin features, the associations between the indices and facial skin characteristics adjusted for age were weak or not significant. This suggests that the newly developed indices are appropriate for evaluating facial skin aging and distinct from typical measurements.We suggest two novel indices for evaluating facial aging based on frontal face images. The indices exhibited strong correlations with age and representative facial skin characteristics. The newly developed values can be differentiated indicators of facial aging compared with general skin features.

Human skin color is largely determined by genetic factors. Recent genome-wide association studies (GWAS) have reported several genetic variants associated with skin color, mostly in European and African populations. In this study, we performed GWAS in 17,019 Korean women to identify genetic variants associated with facial skin color, quantitatively measured as CIELAB color index. We identified variants in three, one, and six genomic loci associated with facial skin color index L*, a*, and b* values, respectively, and replicated the associations (combined analysis P-value

Background Recently, bacterial extracellular vesicles (EVs) have been considered to play crucial roles in various biological processes and have great potential for developing cancer therapeutics and biomedicine. However, studies on bacterial EVs have mainly focused on outer membrane vesicles released from gram-negative bacteria since the outermost peptidoglycan layer in gram-positive bacteria is thought to preclude the release of EVs as a physical barrier. Results Here, we examined the ultrastructural organization of the EV produced by gram-positive bacteria using super-resolution stochastic optical reconstruction microscopy (STORM) at the nanoscale, which has not been resolved using conventional microscopy. Based on the super-resolution images of EVs, we propose three major mechanisms of EV biogenesis, i.e., membrane blebbing (mechanisms 1 and 2) or explosive cell lysis (mechanism 3), which are different from the mechanisms in gram-negative bacteria, despite some similarities. Conclusions These findings highlight the significant role of cell wall degradation in regulating various mechanisms of EV biogenesis and call for a reassessment of previously unresolved EV biogenesis in gram-positive bacteria.

Purpose An increasing number of people are suffering from hair loss disorders. Niacinamide has long been used as an active ingredient for anti-hair loss preparations but the exact mechanism has not been clearly elucidated yet. The effects of niacinamide were investigated in cultured human dermal papilla cells (hDPCs). Methods To investigate the anti-hair loss effect of niacinamide and its molecular mechanisms, Western blot analysis, ELISA, quantitative RT-PCR and immunocytochemistry were performed. To study the protective effects of niacinamide against H2O2-induced oxidative stress, ROS generation and cytotoxicity were evaluated by DCF-DA assay and LDH release assay, respectively. Minoxidil was used as a positive control. Results Niacinamide decreased the protein expression level of DKK-1 which promotes regression of hair follicles by inducing catagen. The protein expression levels of cell senescence markers, p21 (CDKN1A) and p16 (CDKN2A) which are related to cell cycle arrest, were decreased. The expression of versican was increased by niacinamide treatment in cultured hDPCs. We have found that niacinamide decreased the H2O2-induced intracellular ROS production in cultured hDPCs. Moreover, niacinamide decreased the protein expression levels of H2O2-induced p21 and p16 and diminished the secretion of H2O2-induced DKK-1. Conclusion Our data demonstrate that niacinamide could enhance hair growth by preventing oxidative stress-induced cell senescence and premature catagen entry of hair follicles.

Microneedles have emerged as a novel transdermal delivery tool that enables the delivery of various products such as drugs, vaccines, or cosmetic ingredients. Although the demand for solid microneedles composed of biocompatible polymer is increasing, the manufacture of microneedles using poly-lactic acid (PLA) with rapid drug-releasing is yet to be established and the process is still in its infancy. Here, we propose a novel strategy for the fabrication of PLA solid microneedles which enable a drug to be burst-released based on a solvent-casting process. This approach offers extreme simplicity, broad geometric capability, cost-effectiveness, and scalability based on high fidelity-replicas. It was verified that microneedles of various heights (250–500 μm) could be fabricated with appropriate mechanical strength to penetrate the stratum corneum layer of skin. By adding sugar in the composition of PLA microneedle, it was observed that both hydrophilic and hydrophobic drugs can be rapidly released within 30 min. Our burst drug-releasing PLA microneedle having both characteristics of solid microneedle and soluble microneedle and its fabrication approach based on solvent-casting will contribute to getting microneedle technology close to commercialization and beyond existing technical limitations.

BACKGROUND Reduction in skin elasticity due to aging causes skin sagging and wrinkles. Although there are various objective and reliable techniques for measuring skin elasticity, it is difficult to obtain a visual representation of skin elasticity with them. Therefore, we developed a novel device, the Swing anglemeter, and analyzed its effectiveness for measuring skin elasticity of the cheek. MATERIALS AND METHODS Forty-five healthy Korean women (age, 23-60 years) participated. The Swing anglemeter works by dropping a rubber ball on a subject's cheek, which draws a curve as it collides with the cheek. After recording the movement of the ball using the slow-motion function on a mobile phone, we defined the maximum angle at which the ball bounces off the skin as the elastic angle, using frame-by-frame video analysis. Changes in the elastic angle were assessed according to age, and correlation with the Ballistometer® results (Dia-stron Ltd., Andover, UK) was analyzed for validation. RESULTS Elastic angles differed significantly (P

Surfactants are mainly used as mixtures to obtain the foam properties which are suitable for use and purpose. In this study, it was found that a mixture of glycinate- and glutamate-based surfactants produced a relatively rigid foam compared to that of single component only when the mixture was diluted with tap water and not deionized water. When the surfactant mixtures were diluted with deionized water, the foam hardness was linearly dependent on the weight fraction of the glycinate based surfactant. Meanwhile, the mixtures diluted with tap water produced foam which could withstand vertical loads. We observed the rheological behavior of the air-water interface to understand the ideal and nonideal mixing effect of amino acid-based surfactants. It was confirmed that the synergistic effect on the interfacial modulus and the foam texture was due to the divalent ions of tap water. However, the interaction by the divalent ions did not affect the foam stability. It is worth to noting that the existence of divalent ions is one of the important factors that should be considered to control the foam quality as well as interfacial rheology.

Variation in skin pigmentation can be affected by both environmental factors and intrinsic factors such as age, gender, and genetic variation. Recent GWASs revealed that genetic variants of genes functionally related to a pigmentation pathway were associated with skin pigmentary traits. However, these GWASs focused on populations with European ancestry, and only a few studies have been performed on Asian populations, limiting our understanding of the genetic basis of skin pigmentary traits in Asians. To evaluate the genetic variants associated with facial pigmented spots, we conducted a GWAS analysis of objectively measured facial pigmented spots in 17,019 Korean women. This large-scale GWAS identified several genomic loci that were significantly associated with facial pigmented spots (five previously reported loci and two previously unreported loci, to our knowledge), which were detected by UV light: BNC2 at 9p22 (rs16935073; P-value = 2.11 × 10−46), PPARGC1B at 5q32 (rs32579; P-value = 9.04 × 10−42), 10q26 (rs11198112; P-value = 9.66 × 10−38), MC1R at 16q24 (rs2228479; P-value = 6.62 × 10−21), lnc01877 at 2q33 (rs12693889; P-value = 1.59 × 10−11), CDKN2B-AS1 at 9p21 (rs643319; P-value = 7.76 × 10−9), and MFSD12 at 19p13 (rs2240751; P-value = 9.70 × 10−9). Further functional characterization of the candidate genes needs to be done to fully evaluate their contribution to facial pigmented spots.

Background Melanin is synthesized in melanocytes and transferred to keratinocytes through dendrites. Endogenous pyruvate is a key metabolite for ATP production in glycolysis, and the tricarboxylic acid (TCA) cycle and exogenous pyruvate provide protection against oxidative stress and acidosis in the intercellular space. The function of pyruvate in the regulation of dendrite outgrowth remains to be elucidated. Objective We examined the effect of pyruvate on dendritic elongation and skin pigmentation Methods Murine B16F10 melanoma cells and human primary melanocytes were used for in vitro analysis. Melanin quantitation and histochemical staining were performed in a 3D pigmented human skin model. Results We demonstrated the participation of monocarboxylate transporters (MCTs) responsible for the membrane transport of pyruvate in B16F10 melanoma cells. The accumulation of pyruvate occurred in a pH-dependent manner, which was highly sensitive to a specific MCT inhibitor (α-cyano-4-hydroxycinnamic acid). α-MSH-induced morphological changes, including dendrite elongation and growth-cone-like structure, were diminished in B16F10 cells upon treatment with pyruvate. In addition, the number of dendrite branches was reduced in normal human epidermal melanocytes. As the Rho-subfamily of monomeric GTP-binding proteins modulates dendrite formation, we subsequently examined the suppression of Rac1 activation by pyruvate, but not RhoA and Cdc42. Furthermore, pyruvate showed anti-melanogenic effects against UV-induced pigmentation in reconstructed pigmented epidermis, established by co-seeding autologous melanocytes and keratinocytes, which act similar to in vivo skin tissue. Conclusion These results suggest that pyruvate treatment may be an alternative or additive therapeutic strategy to prevent hyperpigmentation.

The endoplasmic reticulum (ER) apparatus is a part of the secretory pathway that transports proteins to the plasma membrane through vesicle trafficking, enabling post-translational modification of the newly synthesized proteins. Several diseases such as inflammation, neurodegenerative disorder, and bipolar disorder are closely associated with dysfunction of the ER stress response. Herein, we present an ER-targeting, intracellular delivery approach that utilized cell-penetrating peptide (CPP)-conjugated lipid/polymer hybrid nanovehicles (LPNVs). For this, we patched Penetratin, a type of CPP, onto the LPNVs with vesicular membranes formulated with poly(ethylene oxide)-b-poly(ε-caprolactone)-b-poly(ethylene oxide) (PEO-b-PCL-b-PEO) and 1,2-dipalmitoyl-sn-glycero-3-phosphocholine (DPPC). We found that the Penetratin-conjugated LPNV (LPNVPnt) was readily taken up by cells and showed specific ER-targeting ability, which was comparable to that of LPNVs conjugated with other types of CPPs. Moreover, we observed that remarkable lysosomal escape of the LPNVs occurred due to effective pH buffering with the aid of PEO-b-PCL-b-PEO. These results highlighted that our LPNVPnt system could pave the way for the development of an elaborate drug delivery technology for ER-targeting at the intracellular level.

Facial wrinkles are the predominant phenotypes of skin aging. To date, one of the most effective ways to improve wrinkles is botulinum toxin type A (BoNT/A) injection, which inhibits muscle contractions by reducing acetylcholine release from neurons. However, since BoNT/A is a hazardous neurotoxin, the injection can only be performed by medical doctors and the procedure is only possible through invasive injection, causing inconveniences such as pain. To overcome these inconveniences, we tried to find a way to reduce wrinkles non-invasively via mechanisms similar to BoNT/A. We first designed in vitro assays to test BoNT/A-like muscle contraction inhibition in two different model systems. By using the assays, we identified Zanthoxylum piperitum (Z. piperitum) fruit extract as a BoNT-like reagent (27.7% decrease of muscle contraction rates by 1000 ppm of Z. piperitum extract treatment). Next, we determined mechanisms of how Z. piperitum extract decreases muscle contraction rates and found that the extract treatment inhibits electrical signal transduction in neurons. We also showed that among known components of Z. piperitum extract, quercitrin is responsible for muscle contraction inhibition. We further identified that Z. piperitum extract has synergistic effects with acetyl hexapeptide-8 and BoNT/A light chain, which are well-known BoNT-like peptides. Finally, we showed that topical treatment of the Z. piperitum extract indeed decreases facial wrinkles and treatment of Z. piperitum extract with acetyl hexapeptide-8 has a tendency to improve wrinkles synergistically (14.5% improvement on average). The synergistic effect of the combination is expected to improve wrinkles effectively by implementing the BoNT/A mechanisms in a non-invasive way.

Background The Janus-III measurement system evaluates the overall skin characteristics such as skin pore, wrinkle, sebum, porphyrin, skin pigmentation, and skin color using high-resolution facial images. The values are measured from five different facial areas, namely, the forehead, nose, corner of/skin below the eyes, and cheeks. Owing to its convenience and diverse measuring characteristics, Janus-III has been widely used in skin research and the cosmetic industry in Korea. In our previous study, we revealed the consistency and reliability of the system with repeatedly measured values. Its measuring performance was investigated statistically, but to make it more reliable for academic skin research, additional verification by a professional dermatologist is needed. Materials and methods In this study, we conducted comparative analysis of three skin characteristics (pigmented spot, skin color, and eye wrinkle) by a dermatologist and the Janus-III measurement system. We utilized 330 image data that were cropped from the whole facial images of 330 different participants to avoid correlation among the three measuring items. Pearson's correlation coefficient exhibited similar patterns between the system and the dermatologist's findings. Results The main finding of our study was that the measured value of skin characteristics by the Janus-III system showed clear correlation with the values evaluated by a dermatologist, especially in a pigmented spot. Conclusion Therefore, it would be a plausible idea to consider the Janus-III system for specialized research of skin characteristics even with a small sample size.

Retinol, one of the most powerful cosmetic materials for anti-aging supported by a solid scientific background, exhibits a wide range of type and severity of irritation while showing limited user compliance. The lack of understanding of the mechanism of retinol-induced irritation has been the main hurdle in the development of anti-irritation strategies. Here, we identified 30 genetic markers related to the susceptibility to retinol-induced irritation in the Korean population. Based on the genetic analysis, a novel formula against retinol-induced irritation was developed, which mitigated the molecular pathogenesis—as indicated by the genetic markers—of the retinol-induced irritation. In human tests, this formula effectively decreased retinol-induced irritation. Furthermore, a polygenic risk score model for irritation was constructed and validated. Our comprehensive approach for the analysis of retinol-induced irritation will not only aid the development of anti-irritation strategies to ensure higher user compliance but also contribute to improving the current knowledge about the biological effects of retinoids.

Retinoids, one of the most robust bioactive materials, have been widely used to improve various dermatological and pathological conditions. The body has an endogenous mechanism that modulates the exogenous retinoid above physiological concentrations, which limits the bioavailability or pharmacological efficacy of retinoids. Considering that most retinoids trigger extensive irritation in users, it is necessary to enhance the pharmacological efficacy of retinoids, thereby achieving a higher efficacy at a lower dosage. Here, we present approaches for enhancing the efficacy of retinol by enhancing retinoid-induced RAR gamma (RAR-γ) activity and inhibiting the hydroxylation of retinoic acid. Using both in vitro and ex vivo experiments, retinoid boosters were demonstrated to enhance pharmacological efficacy. A small pilot study was conducted to investigate the efficacy for improvement of facial wrinkles, whose results revealed that these boosters could enhance the pharmacological efficacy of topical applications of both retinol and retinoic acid for cosmetic use. These results promote not only a higher compliance among retinoids users, but also provide significant insights into the mechanisms underlying the action of retinoids.

The androgen receptor is a hormone activated transcription factor that regulates the development and maintenance of male characteristics and represents one of the most well-established drug targets, being implicated not only in prostate cancer but also in many non-cancerous human diseases including androgenetic alopecia, acne vulgaris, and hirsutism. In this study, the antiandrogenic effects of FMN were investigated in 22Rv1 and LNCaP prostate cancer cells. FMN inhibited dihydrotestosterone (DHT)-induced protein expression of androgen receptor in 22Rv1cells. In another prostate cancer LNCaP cells, FMN decreased the protein level of DHT-induced prostate specific antigen (PSA). In addition, FMN downregulated DHT-induced mRNA expression of androgen regulated genes in both cell lines, showing less prominent inhibition in 22Rv1cells where androgen receptor had been significantly decreased by FMN. FMN was found to bind androgen receptor, demonstrating that it acted as a competitive androgen receptor antagonist. FMN increased the phosphorylation of Akt in 22Rv1 cells and this increment was abrogated by PI3K inhibitor wortmannin, resulting in a rescued androgen receptor protein level which was decreased by FMN. Additionally, FMN was found to increase the mRNA and protein level of E3 ligase mouse double minute 2. Our data suggest that the androgen receptor signaling is regulated through PI3K-Akt-MDM2 pathway in 22Rv1 cells. Together, our results indicate that FMN facilitated the degradation of androgen receptor in 22Rv1 cells and inhibited the expression of androgen regulated genes by competing the binding of DHT to androgen receptor in LNCaP cells, demonstrating its therapeutic potential as an antiandrogen.

Dexpanthenol (D-panthenol) is a precursor of vitamin B5 (pantothenic acid) and is widely used for dietary supplements and topical applications. D-panthenol has long been used in hair care products for the purpose of anti-hair loss, its effects and the underlying mechanisms, however, were barely reported. In this study, the effects of D-panthenol on human hair follicle cells, including dermal papilla cells (hDPCs) and outer root sheath cells (hORSCs), were investigated. D-panthenol enhanced the cell viability, increasing the cellular proliferation marker Ki67 in cultured hDPCs. The markers for apoptosis (Caspase3/9) and cell senescence (p21/p16), reported to be expressed in aged or resting phase follicles, were significantly reduced by D-panthenol. Anagen-inducing factors (ALP, β-catenin, versican), which trigger or elongate the anagen phase, were stimulated by D-panthenol. On the other hand, D-panthenol reduced TGF-β1 expressions in both mRNA and protein levels. The expression of VEGF, which is important for peripheral blood vessel activation, was up-regulated by D-panthenol treatment. In cultured hORSCs, cell proliferation and viability were enhanced, while the mRNA expression of cell senescence markers (p21/p16) was significantly down-regulated. The expressions of both VEGF and its receptor (VEGFR) were up-regulated by D-panthenol. In conclusion, our data suggest that the hair growth stimulating activity of D-panthenol was exerted by increasing the cell viability, suppressing the apoptotic markers, and elongating the anagen phase in hair follicles.

The oscillatory dilatational flow of interfacial rheology is a useful tool to unveil the motion of molecules and the interaction between adsorbed molecules at the interfacial layers. Despite its usefulness, it is difficult to analyze the dilatational moduli because they are functions of both the frequency and concentration. In this study, we adopted superposition behavior to investigate the diffusive transport of sodium alkyl sulfate surfactant based on the interfacial rheology under oscillatory dilatational flow. We found that the time-concentration superposition is valid for dynamic dilatational moduli. The shifting factors for superposition on time-axis exponentially decrease as concentration increases due to the molecular exchange between interface and bulk. It is found that the concentration dependence of the shift factors decreases as the size of the hydrophilic and hydrophobic groups increases. It is worth noting that the concentration dependence of the shift factors is related to the foaming speed of the surfactant solutions: As the concentration-dependence of shifting factors increases, the foaming speed increases. It is expected that the time-concentration superposition can be a new tool to study the dynamic dilatational rheology.

Interferon-γ (IFN-γ) regulates the human immune system. To study the interaction between macrophages and natural killer (NK) cells, we established a THP-1 macrophage-conditioned media. Among the 58 natural plant extracts tested, Curcuma longa exerted the strongest IFN-γ-enhancing effect in NK-92 cells through THP-1 macrophages. C. longa extract (CLE) enhanced IFN-γ secretion 2.3- and 4.2-fold at 50 and 100 µg/ml, respectively. Therefore, we evaluated its IFN-γ-enhancing effect in vitro. Although NK-92 cells did not produce IFN-γ following treatment with C. longa, enhanced IFN-γ secretion was observed after treatment with THP-1 macrophage-conditioned media. We hypothesized that the cytokines secreted by the CLE-treated THP-1 macrophages are responsible for stimulating NK-92 cells. Cytokine array results show upregulation of cytokines, including MIP-1α, CXCL-1, IL-1β, PAI-1, and TNF-α, in CLE-treated THP-1 macrophages. To determine the cytokines responsible for augmenting IFN-γ secretion, NK-92 cells were stimulated with MIP-1α, CXCL-1, IL-1β, or PAI-1. Enzyme-linked immunosorbent assay results show that all cytokines induced IFN-γ production, although the dose response was somewhat varied. High-performance liquid chromatography analysis of CLE revealed the concentrations of three active curcuminoids, curcumin, demethoxycurcumin, and bisdemethoxycurcumin, as 6.70%, 1.00%, and 0.95%, respectively. Their mixture (with concentrations comparable to their occurrence in CLE) exerted an effect similar to that of the whole CLE. Our findings reveal that CLE indirectly stimulated NK-92 cells to secrete IFN-γ, which is mediated by cytokines produced from THP-1 macrophages. Further, we identified three curcuminoids partly responsible for this IFN-γ-enhancing effect. Therefore, C. longa can be used as a functional food ingredient owing to its immune-boosting ability. PRACTICAL APPLICATION: This study demonstrates that CLE stimulates THP-1 macrophages to secrete cytokines, which can in turn stimulate IFN-γ production by NK-92 cells. A mixture of three curcuminoids present in the extract exerted effects similar to whole CLE, demonstrating that the curcuminoids are partly responsible for the IFN-γ-enhancing effect of C. longa. Since IFN-γ is a key regulator of human immune system, these results suggest the potential use of C. longa as an immune-boosting functional food ingredient.

Adenosine is a cellular metabolite with diverse derivatives that possesses a wide range of physiological roles. We investigated the molecular mechanisms of adenosine and cordycepin for their promoting effects in wound-healing process. The mitochondrial energy metabolism and cell proliferation markers, cAMP responsive element binding protein 1 (CREB1) and Ki67, were enhanced by adenosine and cordycepin in cultured dermal fibroblasts. Adenosine and cordycepin stimulated adenosine receptor signaling via elevated cAMP. The phosphorylation of mitogen-activated protein kinase kinase (MEK) 1/2, mammalian target of rapamycin (mTOR) and glycogen synthase kinase 3 beta (Gsk3b) and Wnt target genes such as bone morphogenetic protein (BMP) 2/4 and lymphoid enhancer binding factor (Lef) 1 were activated. The enhanced gene expression by adenosine and cordycepin was abrogated by adenosine A2A and A2B receptor inhibitors, ZM241385 and PSH603, and protein kinase A (PKA) inhibitor H89, indicating the involvement of adenosine receptor A2A, A2B and PKA. As a result of Wnt/β-catenin pathway activation, the secretion of growth factors such as insulin-like growth factor (IGF)-1 and transforming growth factor beta (TGFβ) 3 was increased, previously reported to facilitate the wound healing process. In addition, in vitro fibroblast migration was also increased, demonstrating their possible roles in facilitating the wound healing process. In conclusion, our data strongly demonstrate that adenosine and cordycepin stimulate the Wnt/β-catenin signaling through the activation of adenosine receptor, possibly promoting the tissue remodeling process and suggest their therapeutic potential for treating skin wounds.

OBJECTIVE Skin-brightening agents prevent melanogenesis and reduce melanin production. However, a lower melanin content leads to weaker protection against sunlight. In this study, we evaluated the effect of lysophosphatidylcholine (LPC) and its commercial-grade product, Lysofix Dry™ (LD), on heat shock protein 70 (HSP70) expression in epidermal cells and their anti-skin photoaging effect against ultraviolet B (UVB) and blue light. METHODS The HSP70 induction was detected using ELISA. To confirm the inhibition of melanin synthesis by LPC or LD, the melanin content assay and gene expression were analyzed. Cell viability was assessed to verify whether LPC or LD prevents photo-induced skin damage. The split-face test was performed to confirm skin-brightening effect of LD. Cream formulation with 2% of LD and placebo were used for 8 weeks, and skin brightness (L) was measured with chromameter (CR-400, Konica Minolta). RESULTS LPC- and LD-induced HSP70 expression in epidermal cells. LPC and LD effectively suppressed melanogenesis provoked by α-MSH in B16 cells. They also inhibited the mRNA transcription of MITF and tyrosinase under blue light irradiation. LD increased the viability of B16 and HaCaT cells after UVB and blue light irradiation in vitro. The cream containing 2% LD increased ΔL by 1.7 after 8 weeks of use, whereas the placebo led to an increase of 0.7. CONCLUSION LPC and LD were effective in suppressing melanogenesis and enhancing cell viability under UVB and blue light via HSP70 expression. Thus, they can be considered as potent skin-brightening agents with protective effects against skin photoaging.

Although dissolving microneedles have garnered considerable attention as transdermal delivery tools, insufficient drug loading remains a challenge owing to their small dimension. Herein, we report a one-step process of synthesizing semi-dissolving microneedle (SDMN) patches that enable effective transdermal drug delivery without loading drugs themselves by introducing TEMPO-oxidized bacterial cellulose nanofibers (TOBCNs), which are well dispersed, while retaining their unique properties in the aqueous phase. The SDMN patch fabricated by the micro-molding of a TOBCN/hydrophilic biopolymer mixture had a two-layer structure comprising a water-soluble needle layer and a TOBCN-containing insoluble backing layer. Moreover, the SDMN patch, which had a hole in the backing layer where TOBCNs are distributed uniformly, could offer novel advantages for the delivery of large quantities of active ingredients. In vitro permeation analysis confirmed that TOBCNs with high water absorption capacity could serve as drug reservoirs. Upon SDMN insertion and the application of drug aqueous solution through the drug inlet hole, the TOBCNs rapidly absorbed the solution and supplied it to the needle layer. Simultaneously, the needle layer dissolved in body fluids and the drug solution to form micro-channels, which enabled the delivery of larger quantities of drugs to the skin compared to that enabled by solution application alone.

Background For personalized skin care, noninvasive quantitative methods to evaluate facial skin characteristics are important. Janus-III is one of the most widely used imaging analysis devices in the skin care industry in Korea. Janus-III generates values for a range of skin characteristics. Due to the convenience of obtaining results for a variety of skin characteristics in a single measurement, the use of Janus-III in cosmetic stores and research institutes has been recently increasing. However, the consistency of skin measurements of Janus-III has not been elucidated yet. Materials and methods In this study, we repeated skin measurements three times for 70 different subjects and compared each numerical value in order to assess the consistency of the Janus-III. For this purpose, we compared between-sample distances and within-sample distances. Results We found important patterns for future analyses in terms of consistency. First, the average values of skin measurement categories were more reliable than individual part values of facial segments. Second, center part values such as forehead and nose were more reliable than side part values such as left and right part segments. Conclusion If researchers who use Janus-III for studies of facial characteristics analyze average and center part values first, they can obtain relatively reliable patterns of facial skin characteristics.

In the skincare field, water-dispersed bacterial cellulose nanofibers synthesized via an oxidation reaction using 2,2,6,6&ndash, tetramethyl&ndash, 1&ndash, piperidine&ndash, N&ndash, oxy radical (TEMPO) as a catalyst are promising bio-based polymers for engineered green materials because of their unique properties when applied to the surface of the skin, such as a high tensile strength, high water-holding capacity, and ability to block harmful substances. However, the conventional method of synthesizing TEMPO-oxidized bacterial cellulose nanofibers (TOCNs) is difficult to scale due to limitations in the centrifuge equipment when treating large amounts of reactant. To address this, we propose a one-pot TOCN synthesis method involving TEMPO immobilized on silica beads that employs simple filtration instead of centrifugation after the oxidation reaction. A comparison of the structural and physical properties of the TOCNs obtained via the proposed and conventional methods found similar properties in each. Therefore, it is anticipated that due to its simplicity, efficiency, and ease of use, the proposed one-pot synthesis method will be employed in production scenarios to prepare production quantities of bio-based polymer nanofibers in various potential industrial applications in the fields of skincare and biomedical research.

Surfactants during routine washing have a tremendous effect on lipid loss from hair. This study aims to understand the loss of lipids from hair upon contact with surfactants and develop a way to prevent the lipid loss. The change in lipid levels depends on the relative hydrophobicity of the lipid. We herein propose that the change in lipid levels can be protected by two modifications. In the case of fatty acids and cholesterol (group A), the concentration difference between virgin hair versus surface modified hair with highly charged polymer was 22 to 32% higher after washing with surfactants while the loss of squalene and wax esters (group B) in response to surfactants still occurred even after the surface modification. In the hair treated by internal modification with the carbodiimide reaction, 52.0 to 81.3% more lipids in group B were prevented than in the untreated hair. Finally, different types of lipids were successfully protected by surface and internal modifications from the surfactant treatment. This study will be the basis for understanding the mechanisms by which surfactants damage the lipid barrier of tissues including hair and for establishing strategies to defend the barrier.

Carnitine (CAR), an amino acid derivative, has great potential as a facial exfoliating agent owing to its calcium chelating property under weakly acidic or neutral conditions. However, its application is limited by its poor transdermal penetration. To optimise its exfoliation efficacy with minimal concentration, we propose the ion-pair method. The ionic interaction between CAR and a zwitterionic substance was successfully monitored by measuring conductivity. The alterations of penetration and exfoliation efficacy for CAR addition to different types of counter ions were investigated in vitro and in vivo. We found that hydrogenated soya phosphatidylcholine (HSC), an amphiphilic counter ion, significantly increases the stratum corneum penetration and exfoliation efficacy of CAR. The changes of the CAR-HSC ionic interaction in the presence of calcium ions were also investigated by 1H nuclear magnetic resonance (NMR) spectroscopy. The NMR spectra for amino groups of CAR first decreased with HSC and then gradually recovered and shifted as calcium ions were added. From the results, a noble exfoliating complex of CAR with high exfoliation efficacy could be proposed. Moreover, the results demonstrate that NMR spectroscopy is useful to obtain direct experimental evidence of the molecular dynamics simulations of the alteration of an exfoliating complex as it penetrates.

This study aims to understand the mechanism of lipid loss from the hair upon contact with surfactants. We herein proposes that the process of lipid loss can be categorized into two mechanisms. In the first mechanism, the lipids inside the hair diffuse through the cell membrane complex (CMC) to the outermost layer of hair and are removed by a roll-up mechanism. In the second mechanism, the surfactant that penetrates hair directly emulsifies the lipids. The mechanism of lipid loss depends on the relative hydrophobicity of the lipid. Highly hydrophobic lipids, such as squalene and wax esters, are primarily lost through the penetration pathway, while relatively less hydrophobic lipids, such as fatty acids and cholesterol, follow the roll-up mechanism. These mechanisms were validated by confirming that surface and internal modifications of hair protected different types of lipids from the surfactant treatment.

Background Due to internal or external factors, the desquamation (turnover) rate of the stratum corneum slows down, resulting in skin problems. Therefore, adjusting the exfoliation rate through cosmetics is an important issue. Objective This report aimed to develop exfoliating agents with lesser adverse effects and higher efficiency through an ex vivo screening method and in vivo turnover rate analysis of human skin. Methods Various molecules were evaluated by the ex vivo porcine skin exfoliation method and screened for their potential as effective agents. To confirm the effect and mechanism of each agent found, the exfoliation efficiency was evaluated. Each agent was also applied to the actual human skin to determine its efficacy and side effects. Results Despite the pH 6, carnitine and serine, which have similar or better efficiency compared to PHA, were selected. Based on the results, it was confirmed that calcium. And it is nonirritating to the human skin and increases the turnover rate (~130%). Conclusion Amino acid-based exfoliating agents, such as carnitine and serine, were identified and verified to enhance the rate of exfoliation of the stratum corneum. It is expected that the improvement of dullness, mild acne, fine wrinkles, and pores through skin exfoliation in the field of cosmetics can be achieved safely through these agents.

Organogels are semi-solid systems that consist of an apolar solvent as the liquid phase within a three-dimen-sional networked structure. In this study, we developed a stable and skin penetration-enhanced Lecithin Organogel (LO) containing genistein, which is one of the poorly soluble active ingredients in both polar and apolar phase. After screen-ing of various components (type of gelators, organic and aqueous phase), hydrogenated lecithin (HL), sunflower oil (SO), dipropylene glycol (DPG), and polyethylene glycol (PEG) were mainly used in this formulation. Phase ternary diagram was employed for optimization of the composition in the LO. The formulated LO were evaluated for its organoleptic characteristics, stability, pH, rheology, phase transition temperatures, microscopic analysis and skin penetration. The opti-mized stable LO system can be utilized as an effective and stable cosmetic formulation that can carry poorly soluble active ingredients at high concentration for topical dermal delivery.

Background The interaction between light and the skin determine how the skin looks to the human eye. Light can be absorbed, scattered, and reflected by different components of the skin in a variety of different ways. Here, we focus on the scattering properties of the outmost layer, the stratum corneum (SC). However, we currently have limited methods with which to distinguish the scattering of light by SC from the changes due to other components of the skin. Materials and methods Dark-field images of tape-striped corneocytes were used in vitro to study the differences in light scattered by the SC and other skin components. Several optical clearing agents (OCAs) were tested for their ability to reduce light scattering. Physical properties of the SC (water content, keratin configuration, and volume) after OCA treatment were investigated using FT-IR, confocal Raman microscopy, and 3D laser microscopy. Results Urea derivatives, several reducing sugars, and sugar alcohols, which were used as OCA in optics and also used as humectants in cosmetic area, could reduce scattering. However, unlike dehydration in optics, penetration of water into the keratin was increased at low OCA concentrations. In such conditions, the volume of corneocytes was increased but their stiffness was reduced. Conclusion By analyzing the tape-striped SC, we were able to measure the changes in the optical and physical properties of corneocytes in response to OCAs. Hydration of the SC layer by OCAs reduces light scattering from the corneocytes and would be helpful in moisturizing the skin and helping the skin look healthy.

Glyceryl monooleate (GMO) is a polar lipid that can exist in various liquid crystalline phases in the presence of different amounts of water. It is regarded as a permeation enhancer due to its amphiphilic property. Various phases of GMO/solvent system containing sodium fluorescein were prepared to compare permeability using confocal laser scanning microscopy (CLSM). GMO was melted in a vial in a water bath heated to 45 °C. Propylene glycol and hexanediol were homogeneously dissolved in the melted GMO. Sodium fluorescein in aqueous solution was diluted to various ratios and thoroughly mixed by an ultrasonic homogenizer. Each GMO/Solvent system with fluorescein was applied onto the epidermal side of excised pig skin and incubated overnight. CLSM was performed to observe how the GMO/solvent system in its different phases affect skin permeability. Cubic and lamellar phase formulations enhanced the fluorescein permeation through the stratum corneum. A solution system had the weakest permeability compared to the other two phases. Due to the amphiphilic nature of GMO, cubic and lamellar phases might reduce the barrier function of stratum corneum which was observed by CLSM as fluorescein accumulated in the dermis. Based on the results, the glyceryl monooleate lyotropic mixtures could be applied to enhance skin permeation in various topical and transdermal formulations.

The viscosity of highly concentrated protein solutions was evaluated using lysozyme as model protein. Viscosity profiles of lysozyme were examined with the effect of buffer and pH-value at various concentrations. The viscosity of lysozyme dissolved in water increased continuously with the concentration as the slope of shear stress against shear rate increased with the concentration. In addition, the viscosity of lysozyme was higher in histidine buffer than in acetate buffer at selected pH ranges. The effect of various excipient concentrations was also investigated in means of unfolding transition temperature (Tm), viscosity, hydrodynamic size and zeta potential by using differential scanning calorimetry (DSC), microviscometer and dynamic light scattering (DLS). The selected excipients except surfactants increased the viscosity of protein solution with their concentration. Carbohydrates increased the viscosity relatively higher than amino acids and also they increased the conformational stability (Tm) by enhancing the protein molecule more in compact form. Also amino acids increased the viscosity but decreased the conformational stability since they seemed to be only dispersed in the solution avoiding protein–protein interactions, resulting in a decrease of zeta potential. Consequently, the applied methods—DSC, DLS and microviscometer demonstrated the potential to develop a highly concentrated protein formulation to decrease the high viscosity effect with acceptable conformational stability.

The protein size, electrical interaction, and conformational stability of etanercept (marketed as Enbrel®) were examined by thermodynamic and light scattering methods with changing pH and buffer concentration. As pH of etanercept increased from pH 6.6 to 8.6, electrical repulsion in the solution increased, inducing a decrease in protein size. However, the size changed less in high buffer concentration and irreversible aggregation issues were not observed; in contrast, aggregates of about 1000 nm were observed in low buffer concentration at the pH range. Three significant unfolding transitions (Tm) were observed by differential scanning calorimetry (DSC). Unlikely to Tm1, Tm2 and Tm3 were increased as the pH increased. Higher Tm at high buffer concentration was observed, indicating increased conformational stability. The apparent activation energy of unfolding was further investigated since continuous increase of Tm2 and Tm3 was not sufficient to determine optimal conditions. A higher energy barrier was calculated at Tm2 than at Tm3. In addition, the energy barriers were the highest at pH from 7.4 to 7.8 where higher Tm1 was also observed. Therefore, the conformational stability of protein solution significantly changed with pH dependent steric repulsion of neighboring protein molecules. An optimized pH range was obtained that satisfied the stability of all three domains. Electrostatic circumstances and structural interactions resulted in irreversible aggregation at low buffer concentrations and were suppressed by increasing the concentration. Therefore, increased buffer concentration is recommended during protein formulation development, even in the earlier stages of investigation, to avoid protein instability issues.

Even though β-lapachone is a promising compound with antitumor, antiinflammatory, antineoplastic, and wound-healing effects, there are still issues concerning its chemical stability and degradation mechanisms. The objective of this study was to obtain degradation profiles of β-lapachone and evaluate its chemical stability under various stress conditions. Moreover, the correlation between stability and efficacy was evaluated. The degradation study of β-lapachone was performed using heat, acid, base, oxidation, and light conditions. Kinetics and degradation profiles were investigated with HPLC and LC-MS. The stability indicated in the LC method was validated according to the International Conference on Harmonization guidelines. Human dermal fibroblast (HDF) cells were cultured with the standard and its degraded samples in the cellular activity and cytotoxicity test. β-Lapachone was relatively unstable upon exposure to light, and its photodegradation was accelerated with high relative humidity. Three degradants were identified, and their degradation followed zero-order kinetics. It was shown to degrade to phthalic acid under oxidative conditions, and the degradation kinetics were dependent on the concentration of hydrogen peroxide. Two degradation products were identified upon exposure to basic conditions, which followed first-order kinetics. β-Lapachone was relatively stable under acidic and thermal conditions. It increased the synthesis of collagen compared with the control. However, as the contents decreased, the synthesis of collagen also decreased in the photodegraded samples. β-Lapachone did not exert cytotoxic effects at the effective concentration in the cytotoxicity test. Therefore, in order to ensure efficacy and safety, the chemical stability of β-lapachone needs to be controlled carefully while considering instability mechanisms.