Development of betaine-polymer probes conjugated with NIR dyes essential for photoacoustic imaging

2020 Fiscal Year Final Research Report

• Project/Area Number: 18K05353
• Research Category: Grant-in-Aid for Scientific Research (C)
• Allocation Type: Multi-year Fund
• Section: 一般
• Review Section: Basic Section 37030:Chemical biology-related
• Research Institution: Kyoto University
• Principal Investigator: Kondo Teruyuki 京都大学, 工学研究科, 教授 (20211914)
• Co-Investigator(Kenkyū-buntansha): 山田 久嗣 徳島大学, 大学院社会産業理工学研究部(生物資源産業学域), 講師 (80512764)
• Project Period (FY): 2018-04-01 – 2021-03-31
• Keywords: 光音響イメージング / 高分子プローブ / 近赤外蛍光色素 / ナノ粒子 / ベタイン

Outline of Final Research Achievements

Three-dimensional representation of a tumor with respect to its size, shape, location, and boundaries is still a challenge in photoacoustic (PA) imaging using artificial contrast agents as probes. We carried out PA imaging of tumors in mice using 800RS-PMPC, a highly selective tumor-targeting methacrylate polymer having phosphorylcholine side chains, as a probe. The conjugate 800RS-PMPC forms compact nanoparticles (dDLS = 14.3 nm), retains the biocompatibility of the parent polymer (PMPC) and exhibits unprecedented PA performance. When applied to mice bearing a 6 × 3 × 3 mm3 tumor buried 6 mm beneath the skin, the probe 800RS-PMPC selectively accumulates in the tumor and emits PA signals that are strong enough to be unambiguously distinguished from noise signals of endogenous blood/hemoglobin. The PA image thus obtained under high-threshold conditions allows 3D characterization of the tumor in terms of its size, shape, location, and boundaries.

Free Research Field

ナノ粒子造影剤の開発と生体イメージングへの応用

Academic Significance and Societal Importance of the Research Achievements

本研究で開発した NIR-PMPC プローブを用いる次世代の「光音響イメージング（PAI）」の実現は、腫瘍の高度画像診断や手術中の画像診断（術中ナビゲーション）への応用に加え、患者の負担軽減、薬物療法の最適化、さらには「がん（悪性腫瘍）」による死亡率の低減と医療費抑制に大きく貢献する。