Activatable NIRF/MRI dual imaging probe using bio-inspired coating of glycol chitosan on superparamagnetic iron oxide nanoparticles

MRI and NIRF multimodal imaging probe was fabricated and investigated. Glycol chitosan coated SPION was decorated by MMP-2 substrate conjugating BHQ-3 and Cy5.5 dye at each end (BCMG-SPION). NIRF signals were recovered in the presence of MMP-2 at a sub-nanomolar level. BCMG-SPION produced the maximum NIRF intensity at 48 h post injection in vivo. Evaluation of the BCMG-SPION in the tumor tissue by MRI showed that relative contrast enhancement was 34% higher than normal muscles. NIRF images of excised organs showed the highest NIRF signal in tumor and the intensity was at least 8 times higher than other organs.