Optoacoustic tomography (OT) enables non‐invasive deep tissue imaging of optical contrast at high spatio‐temporal resolution. The applications of OT in cancer imaging often rely on the use of molecular imaging contrast agents based on near‐infrared (NIR) dyes to enhance contrast at the tumor site. While these agents afford excellent biocompatibility and minimal toxicity, they present limited optoacoustic signal generation capability and rapid renal clearance, which can impede their tumor imaging efficacy. In this work, a synthetic strategy to overcome these limitations utilizing biodegradable DNA‐based nanocarrier (DNA‐NC) platforms is introduced. DNA‐NCs enable the incorporation of NIR dyes (in this case, IRDye 800CW) at precise positions to enable fluorescence quenching and maximize optoacoustic signal generation. Furthermore, these DNA‐NCs show a prolonged blood circulation compared to the native fluorophores, facilitating tumor accumulation by the enhanced permeability and retention (EPR) effect. In vivo imaging of tumor xenografts in mice following intravenous administration of DNA‐NCs reveals enhanced OT signals at 24 h when compared to free fluorophores, indicating promise for this method to enhance the optoacoustic signal generation capability and tumor uptake of clinically relevant NIR dyes.

中文翻译：

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基于 DNA 的纳米载体可增强体内肿瘤的光声对比度

光声断层扫描 (OT) 能够以高时空分辨率对光学对比度进行非侵入性深层组织成像。OT 在癌症成像中的应用通常依赖于使用基于近红外 (NIR) 染料的分子成像造影剂来增强肿瘤部位的对比度。虽然这些药物具有出色的生物相容性和最小的毒性，但它们的光声信号产生能力和快速的肾脏清除能力有限，这可能会阻碍它们的肿瘤成像效果。在这项工作中，介绍了一种利用可生物降解的基于 DNA 的纳米载体 (DNA-NC) 平台克服这些限制的合成策略。DNA-NCs 能够在精确位置掺入 NIR 染料（在本例中为 IRDye 800CW），以实现荧光猝灭并最大限度地产生光声信号。此外，与天然荧光团相比，这些 DNA-NC 显示出延长的血液循环，通过增强的通透性和保留 (EPR) 效应促进肿瘤积累。与游离荧光团相比，静脉注射 DNA-NC 后小鼠肿瘤异种移植物的体内成像显示 24 小时 OT 信号增强，表明该方法有望增强临床相关 NIR 染料的光声信号产生能力和肿瘤吸收。