Figure 2. Fluorescence spectrum changes of RN-NA in buffer under SIN-1 titration.

A, B: Fluorescence spectra changes of 10 µmol/L RN-NA stimulated by SIN-1 at different concentrations in PBS solution (pH=7.4, with 5% DMSO). A: λex=420 nm; B: λex=580 nm; C: Linear fit analysis of fluorescence at ratiometric channel I₅₄₀/I₇₁₀; D: Selectivity of RN-NA toward various species, number 1-14 represent Glu, Cys, S₂O₃²⁻, ClO⁻, S²⁻, SO₃²⁻, HSO₃⁻, NO₂⁻, H₂O₂, •OH, Vc⁻, Zn²⁺, Fe³⁺, and ONOO⁻, respectively. Error bar, n=3. SIN-1: 3-morpholinosyndnomine; PBS: Phosphate buffered saline; DMSO: Dimethyl sulfoxide.