In this project, a portable and inexpensive microfluidic paper-based analytical device (μPAD) is designed to achieve a quantitative and qualitative analysis of active antioxidants in cosmetics. This μPAD platform mainly consists of two responsive nanomaterials, WO₃ and MoO₃, which could react specifically and generate distinct colorimetric and detectable signals representing the chemical properties and concentration of active ingredients. After optimizing filter papers and nail polish and pretreatment of the pH of MoO₃ nanoparticles, we got decent relationships between the concentration of the six antioxidants and the corresponding blue color intensity of the two nanoparticle color indicators, which could convincingly identify and quantify an unknown cosmetic sample. Furthermore, this p...[ Read more ]

In this project, a portable and inexpensive microfluidic paper-based analytical device (μPAD) is designed to achieve a quantitative and qualitative analysis of active antioxidants in cosmetics. This μPAD platform mainly consists of two responsive nanomaterials, WO₃ and MoO₃, which could react specifically and generate distinct colorimetric and detectable signals representing the chemical properties and concentration of active ingredients. After optimizing filter papers and nail polish and pretreatment of the pH of MoO₃ nanoparticles, we got decent relationships between the concentration of the six antioxidants and the corresponding blue color intensity of the two nanoparticle color indicators, which could convincingly identify and quantify an unknown cosmetic sample. Furthermore, this platform is integrated with smartphones to enable remote wireless transmission and high throughout detection to analyze samples quickly and conveniently. Therefore, it can be used as smart labels to check the quality of antioxidant components in a large variety of cosmetic products without involving any sample pretreatment. Finally, real cosmetic samples were also analyzed with the μPAD. Integrated with the smartphone, this approach in this project shows satisfactory results with an inaccuracy of only 2.9% and 5.2% were obtained. These results would inspire at-home and on-site testing by consumers or manufacturing companies to check cosmetic products' identity and shelf life.