Poly(vinyl alcohol) nanoparticle stability in biological media and uptake in respiratory epithelial cell layers in vitro

The influence of the size and surface properties of nanoparticles (NP) upon respiratory epithelial cell uptake and translocation is difficult to study, because NP properties are often modified upon suspension in biological fluids. However, a recently developed novel fluorescently labelled poly(vinyl alcohol) (PVA) NP, which does not aggregate in simple biological fluids, is suitable for drug delivery and can be produced with a range of surface properties is a pertinent advance in this field. The aim of this study was to employ the PVA NP to investigate how surface properties influence particle uptake and translocation across Calu-3 epithelial cell layers. Several grades of PVA were synthesised, characterised and labelled covalently with carboxyfluorescein. The labelled PVA was used to fabricate trackable NP that displayed either neutral or positive charge when suspended in Hank’s Balanced Salt Solution. The NP were applied to the apical surface of Calu-3 cell layers which internalised up to 11% of the applied particle dose. The maximum fraction that translocated the Calu-3 barrier in 14 h was 1.3%.