Smart Slides for Optical Monitoring of Cellular Processes

The molecules released by cells are a fingerprint of their current state. Methods that measure them with high spatial and temporal resolution would provide valuable insights into cell physiology and diseases. Here, we develop a nanosensor coating that transforms standard cell culture materials/dishes into "Smart Slides" capable of optically monitoring biochemical efflux from cells. For this purpose, we use single wall carbon nanotubes (SWCNTs) that are fluorescent in the beneficial near-infrared (NIR, 850 - 1700 nm) window. They are chemically tailored to detect the neurotransmitter dopamine by a change in fluorescence intensity. These nanosensors are spin-coated on glass substrates and we show that such sensor layers can be sterilized by UV light and can be stored in dry condition or buffer for at least 6 weeks. We also identify the optimal sensor density to maximize sensitivity. Finally, we use these materials to image dopamine release from neuronal cells cultivated on top in the presence of various psychotropic substances, which represents a system to test pharmaceuticals for neurological or neurodegenerative diseases. Therefore, Smart Slides are a powerful tool to monitor cellular processes in cell culture systems.