Measurement of TiO₂ Nanoscale Ingredients in Sunscreens by Multidetector AF4, TEM, and spICP-MS Supported by Computational Modeling

Abstract

There is a growing need to disclose the presence of nanostructures on the labeling of commercial products in South Africa. This work deals with complementary analytical techniques for the separation, quantification, and characterization of titanium dioxide nanoparticles (TiO 2 NPs) capped with poly(ethylene glycol) (PEG) for applications in cosmetic sunscreens. Asymmetrical flow field-flow fractionation (AF4) coupled online to multiangle light-scattering (MALS) and dynamic light-scattering (DLS) detectors has been implemented to optimize a method to evaluate the radius of gyration (r g -MALS), hydrodynamic radius (r h -DLS), and shape factor (r g /r h ) of the PEGylated TiO 2 NPs. The size distribution obtained using single-particle inductively coupled plasma mass spectrometry supported with imagery from transmission electron microscopy provided further information on the PEGcoated TiO 2 NPs in comparison to the uncapped TiO 2 NPs. Furthermore, computational adsorption studies coupled with Monte Carlo simulations provided structural insights into the spatial distribution of the curved TiO 2 NP interactions with PEG/water substrates at an atomistic and molecular level. Finally, the developed multidetector AF4 method was applied to two commercial SPF 50 sunscreens, exhibiting promising separation and detection efficiency. These findings may contribute to regulatory measures in line with the South African National Nanotechnology Strategy for the cosmetics industry.

Functionalized Electrochemical Aptasensor for Sensing of Ochratoxin A in Cereals Supported byin SilicoAdsorption Studies

“…Adsorption Locator (AL) functionality (MS software) was used for each generated configuration, thereby showing the best adsorption sites. Analogues of the electrochemical layer-by-layer strategy were modeled by carrying out Monte Carlo simulations of the substrate–adsorbate conformational space since the temperature slowly decreased in accordance with a simulated annealing strategy of the adsorption process. , …”

Aggregation Kinetics of TiO2 Nanoparticles in Human and Artificial Sweat Solutions: Effects of Particle Properties and Sweat Constituents

“…Titanium dioxide nanoparticles (TiO 2 NPs) are the most prevalent nanomaterials with an annual global production of 10,000 tons, which is expected to grow exponentially until at least 2025. , These nanomaterials are widely utilized in fields including construction, cosmetics, environmental treatment, food, paints, pharmaceuticals, and photocatalytic media . Among these applications, TiO 2 NPs are primarily (70–80%) used in personal care products such as sunscreen and cosmetics due to their efficient ultraviolet (UV)-light absorbency and adequate skin tolerance. , Therefore, human skin is likely exposed extensively to TiO 2 NPs via direct application of skin care products such as sunscreen containing 2.5–25 wt % TiO 2 NPs, , which have increasingly replaced microsized TiO 2 to overcome its cosmetic drawback . Meanwhile, unintentional dermal exposure to TiO 2 NPs released from textiles and pigments is also inevitable, , which could reach 11.6 μg/kg body weight mainly in the form of particulate TiO 2 …”