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 may provide valuable insights into cell physiology and diseases. Here, a nanosensor coating is developed that transforms standard cell culture materials/dishes into "Smart Slides" capable of optically monitoring biochemical efflux from cells. For this purpose, single wall carbon nanotubes (SWCNTs) that are fluorescent in the beneficial near-infrared (NIR, 850-1700 nm) window are used. They are chemically tailored to detect the neurotransmitter dopamine by a change in fluorescence intensity. These nanosensors are spin-coated on glass substrates and it is shown that such sensor layers can be sterilized by UV light and can be stored in dry condition or buffer for at least 6 weeks and have little influence on cell viability. The optimal sensor density to maximize sensitivity is also identified. Finally, these substrates are used 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.