Extraction and characterization of titanium dioxide nanoparticles from commercially available sunscreens

• Main Author: Tan, Yun Xuan
• Other Authors: Ng Kee Woei
• Format: Final Year Project
• Language: English
• Published: Nanyang Technological University 2021
• Subjects: Engineering::Materials
• Online Access: https://hdl.handle.net/10356/148141
• Institution: Nanyang Technological University

Over the past decades, the application of nanoparticles in cosmetics has been widely used, especially in sunscreen products. The enhanced properties of absorbing and scattering UV light more effectively lead to its usage popularity. It has not been fully addressed as studies use pristine nanoparticles rather than the complex nanoparticles found in commercial sunscreens to evaluate the bio-toxicity. In this project, we evaluated an extraction protocol for the TiO2 nanoparticles from sunscreen as a more representative method for subsequent studies. The proposed extraction protocol uses hexane organic solvent and DI water with sonication, centrifugation and decantation processes to extract the TiO2 corona particles. This procedure was tested on the Cetaphil UVA and UVB Defence sunscreen, pristine Natpure Screen TWG and pristine Degussa P25. After the extraction, scanning electron microscopy (SEM) with energy dispersive x-ray (EDX) and x-ray powder diffraction (XRD) characterisation techniques confirmed the presence of TiO2 nanoparticles in the samples. Matrix-assisted laser desorption/ionization with time of flight (MALDI-TOF) suggested the extracted TiO2 nanoparticles were coated. Dynamic light scattering (DLS) and transmission electron microscopy (TEM) showed differences in the primary and hydrodynamic diameter of the TiO2 nanoparticles. Hence, it can be successfully concluded that these TiO2 nanoparticles were not destroyed and retain its surface coating. This optimized extraction procedure can be further analysed on other commercial sunscreen brands.