Magnetic nanoparticles modified with DTPA-AMC-rare earth for fluorescent and magnetic resonance dual mode imaging

Abstract

In the present study, we report new water-soluble cell fluorescence imaging and contrast agents that are based on DTPA-AMC(7-amino-4-methyl coumarin)-Eu³⁺ and DTPA-AMC(7-amino-4-methyl coumarin)-Gd³⁺ compounds conjugated to Fe₃O₄ NPs via a PEG-NH₂ linker. The novel Fe₃O₄ NP-conjugates present two main advantages for cell fluorescence labelling: water solubility and targeting ability. The in vitro experiments demonstrate that water-soluble Fe₃O₄ NPs-DBI-PEG-NH-DTPA-AMC(7-amino-4-methyl coumarin)-Eu³⁺ has excellent cell permeating activity. Moreover, the relaxation rate test of Fe₃O₄ NPs-DBI-PEG-NH-DTPA-AMC(7-amino-4-methyl coumarin)-Gd³⁺ shows a higher T1 relaxation effect than traditional DTPA-Gd³⁺ MRI agents. According to in vivo liver MRI experiments, better contrast of the liver was achieved after addition of Fe₃O₄ NPs-DBI-PEG-NH-DTPA-AMC(7-amino-4-methyl coumarin)-Gd³⁺. The results will provide a significant guide for researchers exploring the biomedical applications of superparamagnetic Fe₃O₄ NPs.