Table 1

Reagents

Table 2

Experimental instruments

Fig. 1

The synthesis route of Cy-F-cRGD

Table 3

Changes in the intermediate molecule's 19F{1H} NMR before and after the NTR reaction

Fig. 2

19F{1H} NMR changes of fluorine-containing intermediate molecules with different substitution sites and types before and after NTR activation: (a) ortho-difluoro, (b) meta-difluoro, (c) para-monofluoro, (d) ortho-hexafluoro. The solvent is 2% DMSO and 98% H2O. All 19F NMR data were acquired with 1H decoupling

Fig. 3

Time-dependent changes of fluorescence and 19F{1H} NMR dual-modal signals of Cy-F-cRGD before and after reaction with NTR. (a) UV-vis absorption spectra; (b) fluorescence spectra; (c) 19F{1H} NMR spectra, with the 19F signal at -128.82 ppm as the internal reference and the solvent is 2% DMSO + 98% H2O

Fig. 4

19F frequency-encoded imaging. (a) 19F{1H} NMR of pure intermediate molecule samples with ortho (δ1, δ2), meta (δ3, δ4), and para (δ5, δ6) substitution patterns. The concentration of intermediate molecules were 0.1 mmol/L, and the solvent were 2% DMSO + 98% H2O. (b) 19F MRI of samples δ1~δ6 acquired with the sampling center at δ1 and a bandwidth of 5 400 Hz. The sample concentration was 0.5 mmol/L. (c) 19F MRI acquired with a sampling bandwidth of 1 000 Hz and excitation frequencies set to the individual center frequencies of each sample. (d) Time-dependent 19F MRI of Cy-F-cRGD before and after reaction with NTR, with excitation centers set at δ1 (substrate Cy-F-cRGD) and δ2 (2,6-Difluoroaniline). In all solution imaging experiments, the concentration of probe was 0.5 mmol/L, with the solvent being 5% DMSO and 95% H2O

Fig. 5

In vivo fluorescence imaging and quantitative analysis. (a) In vivo fluorescence images of A549 tumor-bearing mice at 2, 4, 6, 8, 12, and 24 h after intravenous injection of Cy-F-cRGD (100 μmol/L, 100 μL) or Cy-F-PEG (100 μmol/L, 100 μL) (λex = 710 nm, λem = 760 nm). Red dashed circles indicate tumor regions; (b) Quantitative analysis of fluorescence intensity in the tumor regions