Programming-Assisted Imaging of Cellular Nitric Oxide Efflux Gradients and Directionality via Carbon Nanotube Sensors.

Cell communication via chemical signaling depends on spatial and temporal concentration changes. Nitric oxide (NO), a gaseous signaling molecule, is critical in physiological and pathological processes. However, current NO sensing methods lack the spatiotemporal resolution necessary to study subcellular NO efflux. This study introduces an innovative sensory platform utilizing single-walled carbon nanotubes (SWNT) as an optical transducer for the spatial and temporal detection of extracellular NO. The platform quantifies NO diffusion gradients produced by human (THP-1) and murine (RAW 264.7) macrophage cells. The uniform fluorescence distribution of the nanoarray enables precise analysis of NO efflux directionality, both under and surrounding the cell. It is demonstrated that cellular adhesion to the surface of the sensory platform does not affect its fluorescence functionality or sensing response rate. By combining the platform's high spatiotemporal resolution with the advanced analysis methods, the SWNT sensor platform offers a robust tool for studying extracellular NO dynamics within the cellular microenvironment. This work lays the foundation for advanced diagnostic and therapeutic tools elucidating NO cellular communication analysis.