iGluSnFR3 is the current (2022) generation of Glutamate-Sensing Fluorescent Reporters developed at HHMI's Janelia Research Campus to image the most abundant neurotransmitter in the mammal brain with the greatest performance to date.
Building on the previous generation of the state-of-the-art SF-iGluSnFR scaffold (itself an improvement over earlier versions), Janelia Researchers, led by Abhi Aggarwal and Kaspar Podgorski, have further improved specificity for synaptic versus extrasynaptic glutamate. iGluSnFr3 variants are more sensitive, faster, and better localized for synaptic glutamate response than its predecessors. The report showing performance, experimental protocols and more is available on bioRxiv.
Two sensors with unique kinetics, affinity, and ∆F/F0 are available, v82 and v857, in three membrane-targeting backbones: PDGFR, GPI, and SGZ. These variants are available with Syn and CAG promoters, in plasmids and AAVs - listed below. These can be obtained directly from Addgene.