Figure 4.

Construction and characterization of IGD-Targeted. (A) Evaluation of pH-sensitive ability of DB67-active. DB67-active was incubated with IMR32 cells at pH 6.5 or 7.4. Fluorescence intensity of cells were assessed by flow cytometry. (B) Binding specificities evaluation. ssDNA strands with different length and sequences were all modified with fluorescent groups and quenching groups. Sequences were incubated with IMR32 in prepared buffers at different pH (6.5 and 7.4) at 37°C for 30 min. Cells were washed by PBS with equivalent pH and evaluated by flow cytometry. (C) Evaluation of IG-Targeted formation mechanism. IG-Targeted was modified with fluorescent groups and quenching groups, and treated in various pH environments (pH 6.5–10) and the fluorescence was monitored by fluorescence spectrometry (The difference compared with pH 10 was labeled with *, *p < 0.05, **p < 0.01). (D) Fluorescence histogram of doxorubicin solution (5 nM) with increasing molar ratios of the IG-Targeted. The fluorescence quenching indicates Dox loading into IG-Targeted (The difference compared with Free Dox was labeled with *, *p < 0.05, **p < 0.01, ***p < 0.001).