| Platinum nanoparticles(Pt NPs)has aroused widespread interest in the field of biomedicine because of its unique physical and chemical properties.For example,Pt NPs has been used to treat oxidative stress-related diseases and biomarkers.Pt NPs has also been approved as an additive in consumer goods and cosmetics.The traditional physical method for the synthesis of Pt NPs is expensive,and the output and size adjustment are limited,while the traditional chemical method uses toxic end-capping agent and reducing agent.Pt NPs prepared by these two methods is not suitable for biomedical field.In order to reduce costs and the use of harmful reducing chemicals,the focus of this field has shifted to the use of biological synthesis of Pt NPs.In biosynthesis,the synthesis of Pt NPs by plant extracts is not only simple,fast and low cost,but also the size of Pt NPs can be controlled and the biocompatibility is high.Therefore,in this subject,we used chloroplatinic acid as raw materials,Nymphaea tetragona flower(N.tetragona)extract with antioxidant,anti-aging,antibacterial,anti-inflammatory and whitening effects was selected as reducing agent and stabilizer.Two sizes of Pt NPs were green synthesized according to different ratios,named L1-Pt NPs and L4-Pt NPs respectively.Pt NPs were characterized and their roles in skin protection were explored.Objective:To provide a simple and rapid method for green synthesis of Pt NPs,and to explore the role of green synthesis of Pt NPs in skin protection,so as to provide a theoretical basis for the potential use of Pt NPs in skin care products.Methods:Two sizes of Pt NPs were synthesized by heating reaction at 90℃,according to different ratios of chloroplatinic acid solution of 50 m M and N.tetragona extract solution of 50 mg/m L,UV-vis,TEM,EDX,XRD and FTIR were used to characterize.To evaluate the antioxidant capacity of Pt NPs,Trolox was used as positive control,the iron reduction ability of Pt NPs was determined by FRAP method and the free radical scavenging ability of Pt NPs was determined by ABTS method in vitro.In order to study the effect of Pt NPs on tyrosinase activity,its effect on mushroom tyrosinase activity was detected by UV-vis spectrophotometry in vitro.The effects of Pt NPs on tyrosinase activity and melanin synthesis in human malignant melanoma cell line A375 were determined.The effect of Pt NPs on tyrosinase gene expression in A375 cells was determined by q RT-PCR method.With kojic acid as the positive control,the melanin spots on the body surface of zebrafish treated with Pt NPs were observed and photographed by fluorescence microscope.The imaging results of zebrafish were imported by Image J software,and the effect of Pt NPs on melanin production in zebrafish was statistically analyzed.To study the effect of Pt NPs on collagen synthesis,the effects of Pt NPs on the expression of Collagen Ⅰ,TGF-β,Smad3 and p Smad3 in human skin fibroblast cell line HFF-1 were analyzed by Western Blot method.Results:1.TEM analysis indicated that the particle size of Pt NPs synthesized at ratios of 1:1-1:4 was small and well-dispersion,and its size was 4.04 ± 1.31 nm,3.76 ± 0.85 nm,3.53± 0.91 nm and 2.21 ± 0.80 nm,respectively.The size difference between the Pt NPs synthesized at 1:1-1:3 was small,so we choose the largest and smallest of L1-Pt NPs and L4-Pt NPs synthesized at the ratios of 1:1 and 1:4 for follow-up experiments.UV-vis analysis showed that the UV absorption peak and SPR peak of green synthetic Pt NPs was about 230 nm.EDX spectra displayed that there were more Pt signals in the spectra of Pt NPs,indicating that the synthesized Pt NPs was of high purity.XRD analysis displayed that Pt NPs were face-centered cube crystal structure.FTIR analysis demonstrated that the polyphenols and flavonoids from N.tetragona extract played the roles of reducing agents and stabilizing agents in the synthesis of Pt NPs.2.FRAP iron reduction ability and ABTS free radical scavenging experiments indicated that Pt NPs had strong antioxidant ability in vitro.Mushroom tyrosinase experiment in vitro showed that Pt NPs significantly inhibited mushroom tyrosinase activity in a concentration-dependent manner.Intracellular experiments showed that Pt NPs obviously decreased tyrosinase activity in A375 cells and alleviate the increase of melanin synthesis in A375 cells induced by UVB irradiation.q RT-PCR experiments indicated that Pt NPs obviously decreased the expression of tyrosinase m RNA gene in A375 cells.Zebrafish experiments in vivo showed that Pt NPs significantly inhibited the synthesis of melanin in zebrafish.Western Blot experiments showed that Pt NPs could significantly up-regulate the expression of Collagen Ⅰ protein in HFF-1 cells and alleviate the decrease of Collagen Ⅰ protein expression induced by UVB irradiation.Pt NPs can promote Collagen Ⅰ protein synthesis by activating TGF-β/Smad signaling pathway.Conclusion:Pt NPs were green synthesized by using N.tetragona extract as reducing agent and stabilizer,which was small and well-dispersion They can not only inhibit tyrosinase activity and reducing the production of melanin to achieve the effect of skin whitening,but also promote the synthesis of skin Collagen through TGF-β/Smad signaling pathway and play the role of anti-aging. |
