Establishing a simple perfusion cell culture system for light-activated liposomes.

The off-target effects of light-activated or targeted liposomes are difficult to distinguish in traditional well plate experiments. Additionally, the absence of fluid flow in traditional cell models can lead to overestimation of nanoparticle uptake. In this paper, we established a perfusion cell culture platform to study light-activated liposomes and determined the effect of flow on the liposomal cell uptake. The optimal cell culturing parameters for the A549 cells under flow conditions were determined by monitoring cell viability. To determine optimal liposome treatment times, particle uptake was measured with flow cytometry. The suitability of commercial QuasiVivo flow-chambers for near-infrared light activation was assessed with a calcein release study. The chamber material did not hinder the light activation and subsequent calcein release from the liposomes. Furthermore, our results show that the standard cell culturing techniques are not directly translatable to flow cultures. For non-coated liposomes, the uptake was hindered by flow. Interestingly, hyaluronic acid coating diminished the uptake differences between the flow and static conditions. The study demonstrates that flow affects the liposomal uptake by lung cancer cell line A549. The flow also complicates the cell attachment of A549 cells. Moreover, we show that the QuasiVivo platform is suitable for light-activation studies.