Development and testing of vitamin coated titanium dioxide nanoparticles with improved biocompatibility

Abstract

Titanium dioxide (TiO2) is widely used in sunscreens because it protects against UV radiation. Current ones are micronized or nanoparticle formulations (TiO2@NP), which blend in with the skin tone and attain a better cosmetic effect. Nanosized titanium dioxide is approved by the Food and Drug Administration, but its biocompatibility is controversial. Concern about negative effects has lately been raised. In fact, cytotoxicity and oxidative stress produced by TiO2@NP when exposed to sunlight were demonstrated in some studies. The goal of this work was to coat this kind of nanoparticle to protect skin cells from the damage generated upon the interaction with light. Functionalization of TiO2@NP was done with antioxidant vitamin B2 (riboflavin) because it has the potential to bind to the nanoparticle through an amine group. Binding was achieved after a few minutes of sonication in aqueous media, followed by characterization. We used a model of prokaryotic cells (methicillin-sensitive Staphylococcus aureus biofilm) exposed to light to study the protective capacity of vitamins@TiO2NP. Viability was assessed using XTT salt. The absorbance values are proportional to the metabolic activity of the cells and indicate cell survival. The analysis of the supernatant by UV-Vis spectrometry showed that every gram of TiO2@NP is loaded with 0.8 grams of vitamin B2, after washing them. The IR spectrum of vitaminB2@TiO2NP showed signs of binding between compounds. The OH bending peak (1634 cm-1) corresponding to bare nanoparticle disappeared and the NH2 bending band characteristic of vitamin B2 appeared (1650 cm-1). Cell viability percent was higher for prokaryotic cells when they were treated with vitaminB2@TiO2NP (153 ± 9%) compared to the ones treated with bare TiO2@NP (82 ± 3%).Results proved the great potential of vitamin B2 to coat TiO2@NP and protect the cells, therefore we continue the study of this and other vitamins@TiO2NP on eukaryotic cells.