Safety Assessment of Starch Nanoparticles as an Emulsifier in Human Skin Cells, 3D Cultured Artificial Skin, and Human Skin.

Emulsion systems are widely used in various industries, including the cosmetic, pharmaceutical, and food industries, because they require emulsifiers to stabilize the inherently unstable contact between oil and water. Although emulsifiers are included in many products, excessive use of emulsifiers destroys skin barriers and causes contact dermatitis. Accordingly, the consumer demand for cosmetic products made from natural ingredients with biocompatibility and biodegradability has increased. Starch in the form of solid nanosized particles is considered an attractive emulsifier that forms and stabilizes Pickering emulsion. Chemical modification of nanosized starch via acid hydrolysis can effectively provide higher emulsion stability. However, typical acid hydrolysis limits the industrial application of starch due to its high time consumption and low recovery. In previous studies, the effects of starch nanoparticles (SNPs) prepared by treatment with acidic dry heat, which overcomes these limitations, on the formation and stability of Pickering emulsions were reported. In this study, we evaluated the safety of SNPs in skin cell lines, 3D cultured skin, and human skin. We found that the cytotoxicity of SNPs in both HaCaT cells and HDF cells could be controlled by neutralization. We also observed that SNPs did not induce structural abnormalities on 3D cultured skin and did not permeate across micropig skin tissue or human skin membranes. Furthermore, patches loaded with SNPs were found to belong in the "No irritation" category because they did not cause any irritation when placed on human skin. Overall, the study results suggest that SNPs can be used as a safe emulsifier in various industries, including in cosmetics.

Factors associated with adolescents' sexual experience based on the biopsychosocial model: a cross-sectional study using the Korea Youth Risk Behavior Web-based Survey (KYRBS).

OBJECTIVES: Sexual activity is an important integrative behaviour that interacts with biological, psychological and social factors among various changes in adolescence. However, starting sex at an early age is associated with adverse outcomes. Thus, this study aimed to investigate the factors associated with adolescents' sexual experience based on the biopsychosocial model. DESIGN: A cross-sectional study. SETTING: The participants were selceted through a complex sample design at high schools and middle schools nationwide in Korea. PARTICIPANTS: We employed 4-year data (2017-2020) of the cross-sectional Korea Youth Risk Behavior Web-based Survey. In total, 234567 participants attending middle school and high school were analysed. Sexual experience was defined as having had sexual intercourse (oral, anal or vaginal) in their lifetime. To identify variables associated with adolescents' sexual experiences, we used a biopsychosocial model. Logistic regression analysis was performed to identify the variables associated with sexual experience. RESULTS: 3.4% of boys and 1.6% of girls attending middle school had sexual experiences, showing a significant difference. A total of 10.4% of boys and 5.1% of girls attending high school had sexual experiences (p<0.001). Among the biological factors of the biopsychosocial model, age and gender were significantly associated with sexual experiences in adolescents. Regarding the psychological factors, suicidal thoughts were a significant risk factor associated with sexual experience. Furthermore, social factors including drinking, smoking and family structure were associated with sexual experience in adolescents. Particularly, a significantly higher sexual experience was found in the three groups living with a single parent, step-parents and no parents compared with the group living with both parents in family structure. CONCLUSIONS: This study demonstrated the factors associated with adolescents' sexual experience based on the biopsychosocial model. Further research and policy strategies that consider supporting family communication and mental health and preventing substance use are required to prevent adolescents' sexual health.