Distance-dependent magnetic resonance tuning (MRET) technology enables the sensing and quantitative imaging of biological targets in vivo, with the advantage of deep tissue penetration and fewer interactions with the surroundings as compared with those of fluorescence-based Förster resonance energy transfer. However, applications of MRET technology in vivo are currently limited by the moderate contrast enhancement and stability of T₁-based MRET probes. Here we report a new two-way magnetic resonance tuning (TMRET) nanoprobe with dually activatable T₁ and T₂ magnetic resonance signals that is coupled with dual-contrast enhanced subtraction imaging. This integrated platform achieves a substantially improved contrast enhancement with minimal background signal and can be used to quantitatively image molecular targets in tumours and to sensitively detect very small intracranial brain tumours in patient-derived xenograft models. The high tumour-to-normal tissue ratio offered by TMRET in combination with dual-contrast enhanced subtraction imaging provides new opportunities for molecular diagnostics and image-guided biomedical applications.

依赖于距离的磁共振调谐 (MRET) 技术能够实现体内生物目标的传感和定量成像，与基于荧光的 Förster 共振能量转移相比，具有深入组织穿透和与周围环境相互作用更少的优势。然而，MRET技术在体内的应用目前受到基于T ₁ MRET探针的适度对比度增强和稳定性的限制。在这里，我们报告了一种具有双重可激活T ₁和T ₂的新型双向磁共振调谐 (TMRET) 纳米探针与双对比增强减影成像耦合的磁共振信号。该集成平台以最小的背景信号实现了显着改善的对比度增强，可用于对肿瘤中的分子靶标进行定量成像，并在患者来源的异种移植模型中灵敏地检测非常小的颅内脑肿瘤。TMRET 提供的高肿瘤与正常组织比率与双对比增强减影成像相结合，为分子诊断和图像引导生物医学应用提供了新的机会。