Contrast-enhanced ultrasound (CEUS) is widely applied in cancer diagnosis clinically. However, the gas-filled contrast agents are unstable in the blood and exhibit shorter imaging time, which limit their clinical use. In this study, a diagnostic nanoparticle system was developed for dual-mode imaging (ultrasound and fluorescence), which after encapsulation with doxorubicin (DOX) demonstrated simultaneous therapeutic function towards cancer treatment. Thus, calcium carbonate (CaCO3) nanoparticles were encapsulated with doxorubicin (DOX) to obtain CaCO3-DOX. Under acidic conditions, it produced carbon dioxide (CO2) to enhance ultrasound imaging and increase the release of DOX. After intravenously injecting CaCO3-DOX to tumor-bearing mice, in the presence of an ultrasound field, CO2bubbles were sufficiently generated at the tumor tissues for echogenic reflectivity. Also, the indocyanine green (ICG) was encapsulated into CaCO3 nanoparticles, to further detect the tumor with fluorescence. The resultant theranostic nanoparticle system exhibited therapeutic efficacy towards tumour-bearing mice. Overall, this investigation provides an attractive strategy for dual-mode cancer diagnostics.

中文翻译：

---

用于双模型癌症成像和治疗的智能响应碳酸钙纳米粒子

对比增强超声（CEUS）在临床上广泛应用于癌症诊断。然而，充气造影剂在血液中不稳定，成像时间较短，限制了其临床应用。在这项研究中，开发了一种用于双模式成像（超声和荧光）的诊断纳米颗粒系统，在用阿霉素 (DOX) 封装后，它显示出对癌症治疗的同步治疗功能。因此，碳酸钙（CaCO3）纳米颗粒被阿霉素（DOX）包裹以获得CaCO3-DOX。在酸性条件下，它会产生二氧化碳 (CO2) 以增强超声成像并增加 DOX 的释放。在存在超声场的情况下，向荷瘤小鼠静脉注射 CaCO3-DOX 后，在肿瘤组织处产生了足够的二氧化碳气泡以实现回声反射。此外，吲哚菁绿 (ICG) 被封装在 CaCO3 纳米颗粒中，以进一步用荧光检测肿瘤。由此产生的治疗诊断纳米颗粒系统对荷瘤小鼠表现出治疗功效。总的来说，这项研究为双模式癌症诊断提供了一种有吸引力的策略。