Bipolar high-impulse electrophoretic process for cerium nanoparticle deposition on polylactic acid scaffolds

Abstract

Electrophoretic deposition is a well-known technique for depositing micro and nanoparticles on substrates of different geometries. The deposited coatings have applications in various areas, especially biomedical uses. Nevertheless, few studies focus on electrophoretic deposition on non-conductive substrates such as biopolymer scaffolds. The present paper uses a modified electrophoretic process to investigate the deposition of cerium oxide nanoparticles (CeO-NPs) on a polylactic acid (PLA) biocomposite scaffold substrate. The substrates were arranged in two ways: one with the scaffold samples freely moving in the liquid medium between the electrodes and the other with the scaffolds attached to the biased electrode. This paper's main goal is to use bipolar pulsed high voltages (if compared to traditional values used in electrophoretic deposition) with a time-off between pulses trains to control the power and prevent overheating. SEM and XPS analyses confirmed the nanoparticles' presence both on the surface – with Ce/C ratio up to 7.6 × 10⁻² for the freely moving scaffolds and 2.8 × 10⁻² for those attached to the biased electrode – and inside the scaffold's pores – presenting Ce/C ratio up to 2.2 × 10⁻² on one scaffold immersed in ethanolic medium – but also found agglomerates. Cell viability tests showed that the treated scaffolds enhance cell spreading and can be further studied for biomedical applications. The results also show that the agitation allied with altering voltage pulses may be beneficial for the deposition on the scaffold's surface and interior using water as solvent.