This study demonstrates that chlorophosphonazo III (CPZ III) can be used as a contrast agent for photoacoustic calcium imaging. CPZ III can pass across the plasma membrane for labeling intracellular Ca²⁺ without cytotoxicity. In optical-resolution photoacoustic microscopy (OR-PAM), the photoacoustic (PA) signal intensity was strongly correlated with the presence of CPZ III and Ca²⁺ at various concentrations. The sensitivity of PA signal reception was enhanced by using an 8 MHz single-element focused ultrasound detector due to their matched frequency characteristics. Differences in the PA signal intensity were successfully found between the core and margin areas of tumorspheres in three-dimensional cell cultures. These findings indicate that CPZ III can serve as a novel PA contrast agent for functional Ca²⁺ imaging using OR-PAM.

中文翻译：

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在 3D 肿瘤细胞培养物中使用偶氮磷 III 进行功能性光声钙成像


本研究表明，偶氮氯膦 III (CPZ III) 可用作光声钙成像的造影剂。 CPZ III 可以穿过质膜标记细胞内Ca ²⁺而无细胞毒性。在光学分辨率光声显微镜 (OR-PAM) 中，光声 (PA) 信号强度与不同浓度的 CPZ III 和 Ca ²⁺的存在密切相关。由于频率特性匹配，使用 8 MHz 单元件聚焦超声检测器增强了 PA 信号接收的灵敏度。成功地发现了三维细胞培养物中肿瘤球核心区和边缘区之间 PA 信号强度的差异。这些发现表明 CPZ III 可以作为一种新型 PA 造影剂，用于使用 OR-PAM 进行功能性 Ca ²⁺成像。