ING-2 AM is a membrane-permeable fluorescent indicator specifically designed for sodium ions (Na+), exhibiting a binding affinity with a dissociation constant (Kd) of 20 mM. With excitation and emission maxima (λ) at 525 nm and 545 nm respectively, this compound achieves a 20-fold selectivity over potassium ions (K+). It is utilized both in vitro and in situ to monitor real-time sodium influx.