Intercellular signaling is central to understanding the molecular basis of biological processes ranging from nutrient uptake, response to stimulus in plants and animals, disease inception, neurobiology and cognition, immune responses, and cellular communication. Our MIRA R35 centers on developing nm-scale near-infrared biosensors that can report on extracellular chemical communication, through which we have already developed numerous near-infrared nanosensors to image extracellular chemical analytes in the first 3 years of our award. In late 2019, new commercial camera hardware became available that – for the first time – enables concurrent imaging of visible and near-infrared wavelengths with the same detector. We are requesting an equipment supplement to enable building a multiphoton microscope to enable concurrent near-infrared fluorescence imaging of cellular efflux with our nanosensors together with a new capability in imaging cellular transcriptional and morphological changes with visible fluorescence imaging that accompany cytokine signaling. In the first 3 years of our award, we have developed numerous near-infrared nanosensors for extracellular chemical analytes including dopamine, neuropeptide oxytocin, cytokine VEGF, glucose, and hydrogen peroxide. The purpose of our equipment supplement request is to take advantage of new fluorescence imaging technology, specifically a visible and near-infrared sensitive camera, that will enable us to image both intracellular and extracellular changes that underlie cell signaling in real-time. Direct cellular imaging of secreted cytokines (prior R35 goal) together with single-cell changes in transcription and morphology (new R35 goal with technology supplement) will provide a new paradigm on how cytokine secretion profiles from single or few individual cells are stimulated by chemokines and cytokines, which forms the basis of the cytokine secretion profiles currently used in biomarker-based diagnostics. Landry ABSTRACT AB-1