Fig. 2

a Particle size of Cy7-SPIONs, b ANG/Cy7-SPIONs and c DANG/Cy7-SPIONs; d Selected area electron diffraction pattern of PEG-DSPE-SPIONs; e Magnetic hysteresis curve of NH2-PEG-DSPE-SPIONs; f Size distribution of Cy7-SPIONs, ANG/Cy7-SPIONs, and DANG/Cy7-SPIONs; g Zeta potential distribution of ANG/Cy7-SPIONs and DANG/Cy7-SPIONs; h UV–vis spectra of ANG and i DANG before and after conjugation