The influence of polycaprolactone coating on the internalization and cytotoxicity of gold nanoparticles

The interaction between mesoscopic colloids and cells is largely dependent on the particle size and surface properties. Under a mild reaction condition, gold particles with an average diameter of ∼100 nm were prepared by incubating poly(dimethylsiloxane) film in HAuCl4/acetic acid solution. The particles were then transferred into a polycaprolactone (PCL) film by thermal pressing. Bare and PCL-coated particles were obtained by control over the extent of rinsing. The bare and PCL-coated gold particles were co-cultured with ECV-304 cells to examine the particle internalization and their influence on the cell morphology and cytotoxicity. Transmission electron microcopy observed the subcellular distribution of the gold particles, which were found in the cell compartments (endosomes or lysosomes), cytoplasm, nucleic envelope, and even nucleus regardless of the existence of PCL coating. However, scanning electron microscopy and β-tubulin staining revealed a significant change in terms of the cell morphology and cytoskeleton caused by the bare gold particles. Higher cytotoxicity was also determined for the bare gold particles. By contrast, no significant difference of the cell morphology and cytoskeleton change was caused by the PCL-coated gold particles, which have also shown lower cytotoxicity.