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Copyright of Journal of Jilin University (Science Edition) / Jilin Daxue Xuebao (Lixue Ban) is the property of Zhongguo Xue shu qi Kan (Guang Pan Ban) Dian zi Za zhi She and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

Organic filters in conventional sunscreens generally have poor photo stability and can easily penetrate through stratum corneum and dermis into the blood vessel, thus causing potential health-threatening issues. Polydopamine (PDA) nanoparticles can be formed by self-polymerization of dopamine. Inspired by its excellent anti-ultraviolet, free radical scavenging and adhesion properties, the titanium dioxide (TiO2) precursor is prepared by the sol-gel method and blended with dopamine hydrochloride to prepare PDA-TiO2 hybrid nanoparticles. Infrared spectroscopy (FT-IR), X-ray photoelectron spectroscopy (XPS), scanning electron microscopy (SEM), transmission electron microscopy (TEM), ultraviolet-visible absorption spectroscopy (UV-Vis), thermogravimetric analysis (TGA) and skin penetration experiments were used to characterize the basic structures and properties of nanoparticles. Under the synergistic effect of PDA and TiO2, the particles have highly efficient UV protection. By simply adjusting the reaction material ratio, it was found that the more dopamine content, the better UV absorption effect was obtained, and it showed better UV absorption performance than small particle size PDA. Therefore, PDA-TiO2 (1/10) (m (DA)∶m(TiO2)=1∶10) had the best UV absorption effect. The PDA-TiO2 (1/10) was introduced as the sole active ingredient to formulating sunscreen, whose sun protection factor (SPF) values could reach 33.7, which can meet daily sun protection needs. Most importantly, PDA had good bioadhesion and can effectively prevent the penetration of PDA-TiO2 hybrid nanoparticles. The thickness of the stratum corneum of the human body was about 15—20 μm. Upon comparing the PDA-TiO2 with commercially available benzophenone small molecule sunscreens, it was found that the skin permeability of PDA-TiO2 was significantly reduced. The penetration depth was 9 —17 μm, mainly distributed in the upper and middle parts of the stratum corneum of the skin. It is not easy to enter the human body and will not pose a potential threat to skin health. The commercially available benzophenone sunscreen small molecules had a skin penetration of 18 —35 μm, indicating that they penetrate the stratum corneum to reach the living epidermis and enter the human body. Therefore, the prepared nanoparticles have excellent UV resistance and biocompatibility, ensuring their excellent performance and safe use in sunscreens. [ABSTRACT FROM AUTHOR]

Quaternized chitosan/nano-zinc oxide (QAC/ZnO) hybrid colloidal particles were prepared by the self-assembly of quaternized chitosan (QAC), L-cysteine (L-cys) and the precursor of nano-zinc oxide Zn(CH3COO)2·2H2O. The chemical composition of QAC/ZnO hybrid colloidal particles was determined by Fourier transform-infrared spectroscopy (FT-IR), X-ray diffraction (XRD), X-ray photoelectron spectroscopy (XPS) and thermogravimetic analysis(TG). The morphology and particle size of the hybrid colloidal particles were investigated in detail by means of Zeta potential analyzer, nanoparticle size analyzer and transmission electron microscopy (TEM). The ultraviolet transmittance, oxidation resistance, photocatalytic activity and cytotoxicity of the hybrid colloidal particles were studied by UV-Vis spectroscopy and the in vitro cell experiments. The results show that spherical QAC/ZnO hybrid colloidal particles can be successfully prepared by the selfassembly of QAC, L-cys and the precursor of nano-zinc oxide, and the size of the hybrid colloidal particles can be controlled by the concentration of nano-zinc oxide precursor. QAC/ZnO hybrid colloidal particles have good ultraviolet shielding property, excellent antioxidant property and low cytotoxicity. Moreover, the photocatalytic activity of the QAC/ZnO hybrid colloidal particles are significantly reduced in comparison with ZnO. It is expected to be used in cosmetics as an ultraviolet absorbent. [ABSTRACT FROM AUTHOR]

Herein, a comprehensive experiment was developed based on the fabrication and characterization of highmolecular- weight silk peptide functionalized graphene nanosheets (SP-Gr) and its application in electrochemical sensing of dopamine. In this experiment, transmission electron microscope, scanning electron microscope, X-ray photoelectron spectroscopy, X-ray diffraction and UV-Vis spectroscopy were used to characterize SP-Gr nanocomposites. SP-Gr nanocomposites were coated onto a glassy carbon electrode surface to fabricate an electrochemical sensor for determining dopamine. Experimental conditions for dopamine determination were optimized. An effective method was developed for determining dopamine. [ABSTRACT FROM AUTHOR]