Green synthesis of platinum nanoparticles by Nymphaea tetragona flower extract and their skin lightening, antiaging effects

Platinum nanoparticles (PtNPs) were green synthesized by using chloroplatinic acid (H2PtCl6) as raw material and Nymphaea tetragona (N. tetragona) flower extract as the capping and reducing agents to improve skin health. Size-tunable PtNPs were obtained by volume ratios of the initial H2PtCl6/N. tetragona of 1:1 and 1:4, in which PtNPs prepared by the ratio of 1:1 and 1:4 was defined as L1-PtNPs and L4-PtNPs. Their characterizations were investigated by UV–visible spectroscopy, TEM, XRD and FTIR spectroscopy. TEM image analysis showed the particles were well dispersed with the average particle diameters of L1 and L4-PtNPs were 4.04 ± 1.31 nm and 2.01 ± 0.80 nm, respectively. The synthesized PtNPs showed effective antioxidant property and anti-tyrosinase activity in vitro. And further experiments exclaimed that PtNPs can significantly inhibit tyrosinase activity and UVB-induced melanin biosynthesis in A375 cells. This study also revealed PtNPs can promote collagen I biosynthesis in HFF-1 cells by activating the TGF-β/Smad pathway. This research showed the potential efficacy of PtNPs in the skin field and provided evidence for people to consider applying PtNPs to skin protection.