Theranostic nanoprobes can potentially integrate imaging and therapeutic capabilities into a single platform, offering a new personalized cancer diagnostic tool. However, there is a growing concern that their clinical application is not safe, particularly due to metal-containing elements, such as the gadolinium used in magnetic resonance imaging (MRI). We demonstrate for the first time that the photothermal melting of the DNA duplex helix was a reliable and versatile strategy that enables the on-demand degradation of the gadolinium-containing MRI reporter gene from polydopamine (PDA)-based theranostic nanoprobes. The combination of chemotherapy (doxorubicin) and photothermal therapy, which leads to the enhanced anti-tumor effect. In vivo MRI tracking reveals that renal filtration was able to rapidly clear the free gadolinium-containing MRI reporter from the mice body. This results in a decrease in the long-term toxic effect of theranostic MRI nanoprobes. Our findings may pave the way to address toxicity issues of the theranostic nanoprobes.

治疗诊断纳米探针有可能将成像和治疗能力整合到一个平台中，提供一种新的个性化癌症诊断工具。然而，人们越来越担心它们的临床应用不安全，特别是由于含有金属元素，例如磁共振成像 (MRI) 中使用的钆。我们首次证明 DNA 双链螺旋的光热熔化是一种可靠且通用的策略，可实现基于聚多巴胺 (PDA) 的治疗诊断纳米探针中含钆 MRI 报告基因的按需降解。化学疗法（多柔比星）和光热疗法的结合，导致增强的抗肿瘤作用。体内MRI 跟踪显示肾脏过滤能够快速清除小鼠体内游离的含钆 MRI 报告基因。这导致治疗诊断 MRI 纳米探针的长期毒性作用降低。我们的发现可能为解决治疗诊断纳米探针的毒性问题铺平道路。