Ratiometric near-infrared fluorescent pH probes with various pK_a values were innovatively designed and synthesized based on cyanine with a diamine moiety. The photochemical properties of these probes were thoroughly evaluated. Among the series, IR-PHA exhibited an optimal pK_a value of approximately 6.40, closely matching the pH of cancerous tissues. This feature is particularly valuable for real-time pH monitoring in both living cells and living mice. Moreover, when administered intravenously to tumor-bearing mice, IR-PHA demonstrated rapid and significant enhancement of near-infrared fluorescence and photoacoustic signals within the tumor region. This outcome underscores the probe's exceptional capability for dual-modal cancer imaging utilizing near-infrared fluorescence (NIRF) and photoacoustic (PA) modalities. Concurrently, the application of a continuous-wave near-infrared laser efficiently ablated cancer cells in vivo, attributed to the photothermal effect induced by IR-PHA. The results strongly indicate that IR-PHA is well-suited for NIRF/PA dual-modality imaging and photothermal therapy of tumors. This makes it a promising candidate for theranostic applications involving small molecules.

中文翻译：

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利用可修饰酸触发分子平台制备近红外光声成像和癌症光热治疗剂

基于含二胺基团的花青，创新设计并合成了具有不同pKa_值的比例近红外荧光pH探针。这些探针的光化学性质得到了彻底的评估。在该系列中，IR-PHA 的最佳 p K _a值约为 6.40，与癌组织的 pH 值非常匹配。此功能对于活细胞和活小鼠的实时 pH 监测特别有价值。此外，当对荷瘤小鼠进行静脉注射时，IR-PHA 表现出肿瘤区域内近红外荧光和光声信号的快速且显着的增强。这一结果强调了该探针利用近红外荧光 (NIRF) 和光声 (PA) 模式进行双模式癌症成像的卓越能力。同时，由于 IR-PHA 诱导的光热效应，连续波近红外激光的应用可以有效地消融体内癌细胞。结果强烈表明 IR-PHA 非常适合 NIRF/PA 双模态成像和肿瘤光热治疗。这使其成为涉及小分子的治疗诊断应用的有希望的候选者。