# Effect of Nanoceria Suspension Addition on the Physicochemical and Mechanical Properties of Hybrid Organic–Inorganic Hydroxyapatite Composite Scaffolds

## TL;DR

This study explores how adding nanoceria to hydroxyapatite scaffolds affects their mechanical and physicochemical properties, finding that a 4% CeO2 addition improves strength and stability.

## Contribution

A novel bioinspired method for creating HAP-CeO2 scaffolds with optimized mechanical and antifungal properties is presented.

## Key findings

- The 2S series with 4% CeO2 showed the best mechanical response due to needle-like HAP crystal growth.
- The 2S series scaffolds had an average pore size of 100 μm and 89.5% open porosity.
- The 2S series exhibited the lowest dissolution rate in phosphate buffered saline.

## Abstract

In the current study, the synthesis of hydroxyapatite-ceria (HAP-CeO2) scaffolds is attempted through a bioinspired chemical approach. The utilized colloidal CeO2 suspension presents antifungal activity against the Aspergillus flavus and Aspergillus fumigatus species at concentrations higher than 86.1 ppm. Three different series of the composite HAP-CeO2 suspensions are produced, which are differentiated based on the precursor suspension to which the CeO2 suspension is added and by whether this addition takes place before or after the formation of the hydroxyapatite phase. Each of the series consists of three suspensions, in which the pure ceria weight reaches 4, 5, and 10% (by mass) of the produced hydroxyapatite, respectively. The characterization showed that the 2S series’s specimens present the greater alteration towards their viscoelastic properties. Furthermore, the 2S series’s sample with 4% CeO2 presents the best mechanical response. This is due to the growth of needle-like HAP crystals during lyophilization, which—when oriented perpendicular to the direction of stress application—enhance the resistance of the sample to deformation. The 2S series’s scaffolds had an average pore size equal to 100 μm and minimum open porosity 89.5% while simultaneously presented the lowest dissolution rate in phosphate buffered saline.