Nano-sized MRI contrast agents for ultra-sensitive imaging of tumor microenvironment

2020 Fiscal Year Final Research Report

• Project/Area Number: 18K12079
• Research Category: Grant-in-Aid for Scientific Research (C)
• Allocation Type: Multi-year Fund
• Section: 一般
• Review Section: Basic Section 90120:Biomaterials-related
• Research Institution: Kyushu University
• Principal Investigator: Kawano Takahito 九州大学, 先端医療オープンイノベーションセンター, 特任講師 (90526831)
• Project Period (FY): 2018-04-01 – 2021-03-31
• Keywords: MRI / 造影剤 / タンパク質 / 癌 / ナノ材料 / 画像診断

Outline of Final Research Achievements

MRI (Magnetic Resonance Imaging) has the advantage of spatial resolution and non-invasiveness, but it has the disadvantage of sensitivity in detecting disease sites. In this study, we investigated to develop a new functional MRI nano-contrast agent that can improve the accuracy and sensitivity of MRI diagnosis, visualize the microenvironment of the tumor, and enable functional diagnosis of pathological conditions. Protein nanocapsules were used as the base of the MRI nanocontrast agent, and tumor-selective iRGD peptides were incorporated into the surface of the nanocapsules and gadolinium molecules were encapsulated inside. When the nanocapsules were administered to tumor-bearing mice , it was confirmed that the tumor could be detected using MRI. We also confirmed that the nanocapsules were almost free of cytotoxicity.

Free Research Field

生体機能材料

Academic Significance and Societal Importance of the Research Achievements

ナノカプセルは細胞毒性が低く、その体内動態は特に指向性もなく1時間程度で腎排出されることが分かっているが、今回、分子イメージング技術を用いてカプセル表面に腫瘍特異性iRGDペプチドを提示することで、MRIにより病変部位の検出が可能となった。このナノ造影剤を用いることによって、超早期画像診断の実現や、これまで組織レベルまで拡大進行した病変しか検出できなかった画像診断を、細胞から分子レベルの病変で見いだすMRIの機能診断への可能性を秘めていると考えられる。