# Sunscreen Formula of FeO(OH)·H2O/TiO2 With Spectral Selectivity to Enhance Collagen Biosynthesis via Fibroblast Test

## TL;DR

A new sunscreen formula using TiO2 and FeO(OH)·H2O selectively blocks harmful light while allowing beneficial wavelengths to boost collagen production in skin cells.

## Contribution

The study introduces a novel sunscreen filter combination with spectral selectivity that enhances collagen biosynthesis.

## Key findings

- The TiO2 and FeO(OH)·H2O combination achieves optimal spectral selectivity at a 64:36 mixing ratio.
- This formula, when combined with traditional UV filters, significantly increases Collagen I levels in human dermal fibroblasts.

## Abstract

To develop a sunscreen formula with spectral selectivity that filters harmful light (280–550 nm) while allowing beneficial light (550–760 nm) to permeate and thus to boost collagen generation.

A variety of sunscreen filters and their combinations were tested for transmittance spectrum. The spectral selectivity was quantified by Selection Index (SI), and the optimal formula was identified. Then, human dermal fibroblasts (HDFs) were subjected to simulated sunlight exposure with the application of this formula. The cell viability and collagen levels were measured post‐exposure.

The combination of TiO2 and FeO(OH)·H2O displays spectral selectivity and reaches the optimal SI value at the mixing ratio of 64:36. This mixture, when formulated with traditional UV filters, significantly elevates the level of Collagen I.

This work uncovers the influence of spectral selectivity on the enhancement of sunscreen performance and proposes a filter combination with spectral selectivity. This formula, when integrated with conventional UV sunscreens, allows for the beneficial effects of sunlight to be more pronounced. This discovery may provide fresh insights for the design of future sunscreen products.