Patients with triple-negative breast cancer (TNBC) have
dismal
prognoses due to the lack of therapeutic targets and susceptibility
to lymph node (LN) metastasis. Therefore, it is essential to develop
more effective approaches to identify early TNBC tissues and LNs.
In this work, a magnetic resonance imaging (MRI) contrast agent (Mn-iCOF)
was constructed based on the Mn(II)-chelated ionic covalent organic
framework (iCOF). Because of the porous structure and hydrophilicity,
the Mn-iCOF has a high longitudinal relaxivity (r
1) of 8.02 mM–1 s–1 at 3.0 T. For the tumor-bearing mice, a lower dose (0.02 mmol [Mn]/kg)
of Mn-iCOF demonstrated a higher signal-to-noise ratio (SNR) value
(1.8) and longer retention time (2 h) compared to a 10-fold dose of
commercial Gd-DOTA (0.2 mmol [Gd]/kg). Moreover, the Mn-iCOF can provide
continuous and significant MR contrast for the popliteal LNs within
24 h, allowing for accurate evaluation and dissection of LNs. These
excellent MRI properties of the Mn-iCOF may open new avenues for designing
more biocompatible MRI contrast agents with higher resolutions, particularly
in the diagnosis of TNBC.