Zeolitic imidazolate framework nanoparticles loaded with gadolinium chelate as efficient T1 MRI contrast agent

Gd-chelate magnetic resonance imaging (MRI) contrast agents used in conventional clinical medicine still have some shortcomings, such as their low relaxation rates and poor imaging sensitivity. In this work, a Gd-chelate (Gd-DTPA), with a comparison made to the commercial contrast agent Magnevist was loaded into a zeolitic imidazolate framework (ZIF-8) to construct the efficient T-1 MRI contrast agent Gd-DTPA@ZIF-8. At 0.5 T, the longitudinal relaxivity value (r(1)) of Gd-DTPA@ZIF-8 reaches 29.60 mM(-1) s(-1), which is about 6 times higher than that of Gd-DTPA. In terms of the retention of Gd-DTPA in ZIF-8, no obvious Gd3+ ions are released in water and complete culture solution over a long time period. Haemolysis and cytotoxicity experiments revealed that Gd-DTPA@ZIF-8 has good biocompatibility. In addition, the in vivo MRI results prove that Gd-DTPA@ZIF-8 can significantly enhance the T-1-weighted MRI contrast effect of the tumour site. These advantages make Gd-DTPA@ZIF-8 a potential candidate for biomedical applications.

Automated summary

This study successfully constructed the efficient T-1 MRI contrast agent Gd-DTPA@ZIF-8, which has good longitudinal relaxivity and biocompatibility, showing significantly enhanced imaging effects in in vivo MRI experiments.