Nanocomposite formulations of titanium dioxide and algal biomass: A rheological characterization for topical cosmetics and dermal applications

This study investigates rheological properties of novel, algae-based nanocomposites developed for potential use in dermal applications. The purpose of this investigation is to develop a highly tunable, biocompatible cosmetic base formulation and demonstrate how rheology relates to spreadability in its application. It was hypothesized that Spirulina biomass could be used in conjunction with titania (TiO 2 ) nanoparticles and crosslinking and binding agents of calcium and/or citric acid to form nanocomposite materials with highly tunable rheological characteristics in absence of chemical surfactants . In this study, Arthrospira platensis ( Spirulina ) biomass, titanium (IV) dioxide, calcium chloride , and citric acid are used to develop a formulation that is then tested for a wide range of rheological characteristics and sensory-related properties. The rheological tests include amplitude sweep, frequency sweep, viscosity flow curve, 3-interval strain oscillatory thixotropy , and creep – recovery. Additionally, yield stress, complex viscosity, zero-shear viscosity, and power law indices were determined. The sensory-related properties that are discussed include formulation pH, static load spreadability, and dynamic shearing spreadability. After completing the investigation, it was concluded that the surfactant-free formulations were highly tunable, in terms of viscosity, rigidity , and thixotropy . • Rheological and sensorial properties of algae-based nanocomposite materials were determined. • TiO 2 interacts with the biomass to create a unique and useful rheology. • These novel and sustainable formulations have potential dermal applications. • Spirulina biomass has a significant potential as a major constituent in cosmetic formulations. • These surfactant-free formulations should have minimal environmental impacts.