Studies for smart nanoprobe for magnetic resonance imaging

Abstract

At the end of the 20th century, our current science and technology has greatly advanced through the advent of fusion technology of bio- and nanotechnology in molecular imaging, molecular libraries, and nanomedicine. Here, the molecular imaging means the visualization of molecular or cellular phenomena in vivo environment in order to characterize and quantify the region of interest. In the field of nanomedicine, the medical application of nanotechnology, nanoparticles are used as key materials in molecular imaging for the analysis of protein and cellular behavior to the nano-scale research on cell biology and biochemistry. The current nanomedicine hold in one hand the simultaneous diagnosis and therapeutics, and on the other hand the personalized therapy of patient by using nanoparticles as a core platform.Ultrasensitive detection of cancer in its earliest stage would greatly help the ensuing treatment process, and therefore various imaging modalities and image enhancing methods are being developed.[1] In particular, metal oxide nanoparticles prove themselves as promising MRI contrast agents for ultrasensitive detection of cancer, and the principles for enhancing MRI contrast have been deciphered recently. For enhanced T1 contrast, nanoparticles should expose numerous high spin metal ions on the surface of nanoparticles, which leads to facilitated interactions between metal ions and surrounding water molecules.[5,6] This calls for the use of smaller size nanoparticles with a high surface-to-volume ratio, but the sheer high number of nanoparticles is not compatible with the frugal usage of targeting moieties. we have demonstrated a new MRI contrast concept by utilizing the different stabilities of metal oxides in low pH conditions. Specifically, the unstable MnO phase trapped by a stable ulchin-shaped Mn3O4 hollow container, synthesized via anisotropic etching, is delivered to tumor in a targeting moiety-efficient manner, and upon arrival to the tumor, the low pH unstable MnO is dismantled to release MnII ions in the low pH sites of tumor cells. The MnII ions randomly diffuse within the tumor mass and this leads to a complete mapping of the tumor morphology.Understanding the neovascularization of solid tumors and metastatic lesions has emerged as a key factor for the diagnosis and treatment of cancer. The well-defined magnetic resonance (MR) imaging technology using high quality MnFe2O4 nanoparticles (MNPs) as imaging contrast agents have been developed and applied for the detection of cancer in a tumor bearing mice model because MR imaging is non-invasive and provides three-dimensional high-resolution imaging data. Thus, the purpose of our study was to develop VEGF121/rGel-MnFe2O4 as a smart MR imaging contrast agent (Fig. 1) and prospectively evaluate in orthotopic bladder tumor mice whether the smart nanoprobes can be used to provide accurate anatomical details and angiogenic vessel due to tumor progression for effective cancer therapy.