Design of dichroic and emission filters for the simultaneous detection of sodium and calcium changes. a, Excitation and emission spectra of SBFI and OGB-1 in cuvettes (from the Chroma Technology website). The spectra have been arranged so the same wavelengths are aligned vertically. The excitation spectrum of SBFI shows the sodium bound form. The spectra of OGB-1 are much narrower. b, Design of custom dichroic and emission filters to detect responses from these indicators. The dichroic cuts on at 390 nm to allow excitation of SBFI at 380 nm. The notch at 460 allows excitation of OGB-1, which has a significant shoulder at that wavelength. The emission filter passes most of the emitted fluorescence from both indicators, missing only a part of the SBFI fluorescence around 460 nm. c, Spectra of bis-fura-2 and ANG-2 (from the Molecular Probes website and Roder and Hille, 2014). d, Design of custom dichroic and emission filters to detect responses from these indicators.