title: Iron oxide/manganese oxide co-loaded hybrid nanogels as pH-responsive magnetic resonance contrast agents.
abstract: 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.
authors.affiliation: Department of Chemistry, and Advanced Research Institute, Tongji University, Shanghai 200092, China.
authors.forename: Xia
authors.initials: X
authors.lastname: Wang
authors.affiliation: Lab of Low-Dimensional Materials Chemistry, Key Laboratory for Ultrafine Materials of Ministry of Education, School of Materials Science and Engineering, East China University of Science and Technology, Shanghai 200237, China.
authors.forename: Dechao
authors.initials: D
authors.lastname: Niu
authors.affiliation: Department of Chemistry, and Advanced Research Institute, Tongji University, Shanghai 200092, China.
authors.forename: Qing
authors.initials: Q
authors.lastname: Wu
authors.affiliation: Department of Chemistry, and Advanced Research Institute, Tongji University, Shanghai 200092, China.
authors.forename: Song
authors.initials: S
authors.lastname: Bao
authors.affiliation: Department of Chemistry, and Advanced Research Institute, Tongji University, Shanghai 200092, China.
authors.forename: Teng
authors.initials: T
authors.lastname: Su
authors.affiliation: Department of Radiology, Shanghai Cancer Hospital, Fudan University, Shanghai 200032, China.
authors.forename: Xiaohang
authors.initials: X
authors.lastname: Liu
authors.affiliation: Department of Radiology, Shanghai Cancer Hospital, Fudan University, Shanghai 200032, China.
authors.forename: Shengjian
authors.initials: S
authors.lastname: Zhang
authors.affiliation: Department of Chemistry, and Advanced Research Institute, Tongji University, Shanghai 200092, China. Electronic address: wangqg66@tongji.edu.cn.
authors.forename: Qigang
authors.initials: Q
authors.lastname: Wang
mesh_terms: D000818:Animals; D003287:Contrast Media; D005260:Female; D005290:Ferric Compounds / Q000737:chemistry*; D005782:Gels; D056945:Hep G2 Cells; D006801:Humans; D006863:Hydrogen-Ion Concentration; D008279:Magnetic Resonance Imaging; D017895:Manganese Compounds / Q000737:chemistry*; D051379:Mice; D008819:Mice, Nude; D036103:Nanotechnology; D010087:Oxides / Q000737:chemistry*
chemical_list: D003287:Contrast Media; D005290:Ferric Compounds; D005782:Gels; D017895:Manganese Compounds; D010087:Oxides; C000499:ferric oxide; C027424:manganese oxide
keywords: Acid-responsive; Magnetic resonance imaging; Manganese species; Nanogel; Superparamagnetic iron oxide particles