Fig. 2

NTR response and ratiometric imaging of the Cy7-1/PG5-Cy5@LWHA nanoprobe. a Fluorescence spectra of the nanoprobe with (red) and without (black) the presence of NTR; emission peak at 666 nm corresponds to Cy5 fluorescence and emission peak at 785 nm corresponds to the activated Cy7-1 fluorescence. b Cy5 fluorescence emission at different nanoprobe concentrations. c Linear relationship between Cy5 fluorescence emission and the nanoprobe concentration. d Cy7-1 fluorescence emission (I₈₀₀) at different nanoprobe concentrations (left to right: 0, 0.073 mg/ml, 0.145 mg/ml, 0.290 mg/ml) and NTR levels (top to bottom: 0, 0.3 \({\mu g}/{\text{ml}}\), 0.6 \({\mu g}/{\text{ml}}\), 0.9 \({\mu g}/{\text{ml}}\), 1.2 \({\mu g}/{\text{ml}}\), 1.5 \({\mu g}/{\text{ml}}\)). e Cy5 fluorescence emission (I₆₈₀) at different nanoprobe concentrations (left to right: 0, 0.073 mg/ml, 0.145 mg/ml, 0.290 mg/ml) and NTR levels (top to bottom: 0, 0.3 \({\mu g}/{\text{ml}}\), 0.6 \({\mu g}/{\text{ml}}\), 0.9 \({\mu g}/{\text{ml}}\), 1.2 \({\mu g}/{\text{ml}}\), 1.5 \({\mu g}/{\text{ml}}\)). f I₈₀₀/I₆₈₀ ratiometric analysis eliminated the concentration effect and presented linear relationship with NTR concentration