Fig. 5. (A) Fluorescence spectra of the aptasensor via different concentrations of theophylline (0, 10, 20, 40, 160 and 300 nM) in 50 mM TB (pH 7.4). (B) Relative fluorescence changes of the aptasensor via theophylline concentrations. Relative fluorescence changes are calculated by F0/F, where F0 and F are the fluorescence intensity without and with theophylline, respectively.
