PDGF-B conjugating mesoporous IO/GdO nanocomposites for accurate diagnosis of orthotopic prostatic cancer through T1-T2 dual-modal MRI contrast enhancement

The development of highly efficient magnetic resonance imaging (MRI) contrast agent contributes to the early and accurate diagnosis of cancer. Herein, we developed a novel iron oxide and gadolinium oxide (IO/GdO) nanocomposite as T1-T2 dual modal MRI contrast agent through hydrothermal synthesis method. Subsequently, tumor-targeting ligand (PDGFB-PEG) was further conjugated to the surface of IO/GdO nanocomposite (PDGFB-pIO/GdO) to fabricate tumor-targeting MRI probe for accurate diagnosis of orthotopic prostatic cancer. IO/GdO nanocomposite exhibited obvious mesoporous structure, which would promote the contact between water molecules and Gd or Fe centers and enhance the T1 relaxation rate (r1) and T2 relaxation rate (r2) of IO/GdO composite. In addition, the r1 and r2 values of IO/GdO composite were up to be 11.6 mM−1s−1 and 102.7 mM−1s−1, respectively, and the r2/r1 ratio of IO/GdO nanocomposite was calculated to be 8.85, demonstrating a great potential as dual-mode MRI contrast agent. Further study indicated that PDGFB-pIO/GdO exhibited an excellent biocompatibility. Besides, PDGFB-pIO/GdO presented a higher accumulation in tumor than untargeted pIO/GdO, confirming its excellent in vivo tumor-targeting ability. Lastly, in orthotopic prostatic cancer model, the systemic delivery of PDGFB-pIO/GdO significantly enhanced T1- and T2-weighted signal of orthotopic prostatic cancer, achieving high quality of MR images and realizing accurate diagnosis of orthotopic prostatic cancer. Collectively, we proposed a rational designed nanoplatform, PDGF-B conjugating mesoporous IO/GdO nanocomposites, suggesting potential for diagnostic identification of prostate cancer via T1-T2 dual-modal MRI contrast enhancement.