Browsing by Author "Niu, Dechao"

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    Dual-Enzyme-Loaded Multifunctional Hybrid Nanogel System for Pathological Responsive Ultrasound Imaging and T2-Weighted Magnetic Resonance Imaging.
    (ACS nano, 2015-06) Wang, Xia; Niu, Dechao; Li, Pei; Wu, Qing; Bo, Xiaowan; Liu, Boji; Bao, Song; Su, Teng; Xu, Huixiong; Wang, Qigang
    A dual-enzyme-loaded multifunctional hybrid nanogel probe (SPIO@GCS/acryl/biotin-CAT/SOD-gel, or SGC) has been developed for dual-modality pathological responsive ultrasound (US) imaging and enhanced T2-weighted magnetic resonance (MR) imaging. This probe is composed of functionalized superparamagnetic iron oxide particles, a dual enzyme species (catalase and superoxide dismutase), and a polysaccharide cationic polymer glycol chitosan gel. The dual-modality US/MR imaging capabilities of the hybrid nanogel for responsive US imaging and enhanced T2-weighted MR imaging have been evaluated both in vitro and in vivo. These results show that the hybrid nanogel SGC can exhibit efficient dual-enzyme biocatalysis with pathological species for responsive US imaging. SGC also demonstrates increased accumulation in acidic environments for enhanced T2-weighted MR imaging. Further research on these nanogel systems may lead to the development of more efficient US/MR contrast agents.
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    Iron oxide/manganese oxide co-loaded hybrid nanogels as pH-responsive magnetic resonance contrast agents.
    (Biomaterials, 2015-01) Wang, Xia; Niu, Dechao; Wu, Qing; Bao, Song; Su, Teng; Liu, Xiaohang; Zhang, Shengjian; Wang, Qigang
    This work described a proof of concept study of hybrid nanogel-based magnetic resonance contrast agents, SPIO@GCS/acryl/biotin@Mn-gel, abb. as SGM, for highly efficient, pH-responsive T1 and T2 dual-mode magnetic resonance imaging (MRI). SGM have been synthesized by assembling superparamagnetic iron oxide particles into polysaccharide nanoclusters, followed by in-situ reduction of the manganese species on the clusters and a final mild polymerization. The dual-mode SGM showed an interesting pH-responsiveness in in vitro MRI, with both T1 and T2 relaxivities turned "ON" in the acidic environment, along with an increase in the r1 and r2 relaxivity values by 1.7-fold (from 8.9 to 15.3 mM(-1) S(-1)) and 4.9-fold (from 45.7 to 226 mM(-1) S(-1)), due to desirable silencing and de-silencing effects. This interesting acidic-responsiveness was further verified in vivo with both significantly brightened signal of tumor tissue in T1-weighted MR images and a darkened signal in T2-weighted MR images 50 min post-injection of SGM. This smart hybrid nanogel may serve as a promising candidate for further studies of dual-mode (T1 and T2) contrast agents in MRI, due to its high stability, interesting pH-response mechanism and indicative imaging of tumors.