Bio-interfaces--interaction of PLL/HA thick films with nanoparticles and microcapsules

The interaction of biocompatible, exponentially grown films composed of poly-L-lysine (PLL) and hyaluronic acid (HA) polymers with gold nanoparticles and microcapsules is studied. Both aggregated and non-aggregated nanoparticle states are achieved; desorption of PLL accounts for aggregation of nanoparticles. The presence of aggregates of gold nanoparticles on films enables remote activation by near-infrared irradiation due to local, nanometer confined heating. Thermally shrunk microcapsules, which are remarkably monodisperse upon preparation but gain polydispersity after months of storage, are also adsorbed onto films. PLL polymers desorbed from films interact with microcapsules introducing a charge imbalance which leads to an increase of the microcapsule size, thus films amplify this effect. Multifunctional, biocompatible, thick gel films with remote activation and release capabilities are targeted for cell cultures in biology and tissue engineering in medicine.