1 research outputs found
Bioinspired, Manganese-Chelated Alginate–Polydopamine Nanomaterials for Efficient in Vivo <i>T</i><sub>1</sub>‑Weighted Magnetic Resonance Imaging
Manganese-based
nanomaterials are an emerging new class of magnetic
resonance imaging (MRI) contrast agents (CAs) that provide impressive
contrast abilities. MRI CAs that can respond to pathophysiological
parameters such as pH or redox potential are also highly in demand
for MRI-guided tumor diagnosis. Until now, synthesizing nanomaterials
with good biocompatibility, physiochemical stability, and good contrast
effects remains a challenge. This study investigated two new systems
of calcium/manganese cations complexed with either alginate–polydopamine
or alginate–dopamine nanogels [AlgPDAÂ(Ca/Mn) NG or AlgDAÂ(Ca/Mn)
NG]. Under such systems, Ca cations form ionic interactions via carboxylic
acids of the Alg backbone to enhance the stability of the synthetic
nanogels (NGs). Likewise, complexation of Mn cations also increased
the colloidal stability of the synthetic NGs. The magnetic property
of the prepared CAs was confirmed with superconducting quantum interference
device measurements, proving the potential paramagnetic property.
Hence, the <i>T</i><sub>1</sub> relaxivity measurement showed
that PDA-complexed synthetic NGs reveal a strong positive contrast
enhancement with <i>r</i><sub>1</sub> = 12.54 mM<sup>–1</sup>·s<sup>–1</sup> in 7.0 T MRI images, whereas DA-complexed
synthetic NGs showed a relatively lower <i>T</i><sub>1</sub> relaxivity effect with <i>r</i><sub>1</sub> = 10.13 mM<sup>–1</sup>·s<sup>–1</sup>. In addition, both the
synthetic NGs exhibit negligible cytotoxicity with >92% cell viability
up to 0.25 mM concentration, when incubated with the mouse macrophage
(RAW 264.7) and HeLa cells, and high biocompatibility under in vivo
analysis. The in vivo MRI test indicates that the synthetic NG exhibits
a high signal-to-noise ratio for longer hours, which provides a longer
image acquisition time for tumor and anatomical imaging. Furthermore, <i>T</i><sub>1</sub>-weighted MRI results revealed that PEGylated
AlgPDAÂ(Ca/Mn) NGs significantly enhanced the signals from liver and
tumor tissues. Therefore, owing to the enhanced permeability and retention
effect, significantly enhanced in vitro and in vivo imagings, low
cost, and one-pot synthesis method, the Mn-based biomimetic approach
used in this study provides a promising and competitive alternative
for noninvasive tumor detection and comprehensive anatomical diagnosis