# Cerium Phosphate Nanoparticles: Synthesis, Characterization, Biocompatibility, Regenerative Potential, and Antioxidant Activity

## TL;DR

This paper describes the synthesis and biomedical evaluation of cerium phosphate nanoparticles, showing they are safe, promote cell growth, and have strong antioxidant properties.

## Contribution

A novel method for synthesizing cerium phosphate nanoparticles with regenerative and antioxidant properties is developed and validated.

## Key findings

- Cerium phosphate nanoparticles stimulate the proliferation of mesenchymal stem cells at concentrations of 10−2 to 10−3 M.
- The nanoparticles show strong antioxidant activity, outperforming ascorbic acid at concentrations of 10−2 to 10−5 M.
- The particles are non-cytotoxic and promote the metabolism of keratinocytes and fibroblasts over a wide concentration range.

## Abstract

The aim of this study was to synthesize, characterize, and investigate the biomedical effects of nanoscale cerium phosphate obtained via different synthesis techniques, as well as to evaluate the influence of various CePO4 concentrations on cells involved in skin structure regeneration (human mesenchymal stem cells, keratinocytes, and fibroblasts) and establish their antioxidant properties. Methods and Results: Cerium(III) orthophosphate was obtained by precipitation with ammonium dihydrogen phosphate from a nitrate solution. By changing the initial concentrations of the solutions and the drying and annealing temperatures, the best conditions for obtaining nanosized phosphate powders were established. The structure of rhabdophane was obtained by X-ray diffraction analysis, and the particle sizes were measured by transmission electron microscopy. The particle sizes ranged from 2 to 10 nm in the transverse direction and 20 to 50 nm in the longitudinal direction. Studies on cell lines have shown a high level of safety, as well as the regenerative potential of CePO4 nanoparticles, which have a stimulating effect on the proliferation of MSCs at concentrations of 10−2 to 10−3 M for 48 h after application and stimulate the metabolism of human keratinocytes and fibroblasts at a wide range of concentrations (10−3 to 10−5 M). A dose-dependent antioxidant effect of small CePO4 nanoparticles at a concentration of 10−2 to 10−5 has been established, which is stronger than ascorbic acid. Conclusions: A method for obtaining cerium phosphate nanoparticles with beneficial biomedical effects was developed. The non-cytotoxicity and regenerative potential of CePO4 were established at a wide range of concentrations on different cell lines that are involved in the healing of skin wounds, as were their antioxidant properties.