Arkansas Nanomedicine Center, University of Arkansas for Medical Sciences, 4301 West Markham Street, Little Rock, AR 72205, USA.
Laboratory of Biomedical Photoacoustics, Saratov State University, 83 Astrakhanskaya Street, Saratov, 410012, Russia.
Sci Transl Med. 2019 Jun 12;11(496). doi: 10.1126/scitranslmed.aat5857.
Most cancer deaths arise from metastases as a result of circulating tumor cells (CTCs) spreading from the primary tumor to vital organs. Despite progress in cancer prognosis, the role of CTCs in early disease diagnosis is unclear because of the low sensitivity of CTC assays. We demonstrate the high sensitivity of the Cytophone technology using an in vivo photoacoustic flow cytometry platform with a high pulse rate laser and focused ultrasound transducers for label-free detection of melanin-bearing CTCs in patients with melanoma. The transcutaneous delivery of laser pulses via intact skin to a blood vessel results in the generation of acoustic waves from CTCs, which are amplified by vapor nanobubbles around intrinsic melanin nanoclusters. The time-resolved detection of acoustic waves using fast signal processing algorithms makes photoacoustic data tolerant to skin pigmentation and motion. No CTC-associated signals within established thresholds were identified in 19 healthy volunteers, but 27 of 28 patients with melanoma displayed signals consistent with single, clustered, and likely rolling CTCs. The detection limit ranged down to 1 CTC/liter of blood, which is ~1000 times better than in preexisting assays. The Cytophone could detect individual CTCs at a concentration of ≥1 CTC/ml in 20 s and could also identify clots and CTC-clot emboli. The in vivo results were verified with six ex vivo methods. These data suggest the potential of in vivo blood testing with the Cytophone for early melanoma screening, assessment of disease recurrence, and monitoring of the physical destruction of CTCs through real-time CTC counting.
大多数癌症死亡是由于循环肿瘤细胞 (CTCs) 从原发性肿瘤扩散到重要器官而导致的转移。尽管癌症预后取得了进展，但由于 CTC 检测的灵敏度低，CTC 在早期疾病诊断中的作用仍不清楚。我们使用具有高脉冲率激光和聚焦超声换能器的体内光声流动细胞术平台展示了 Cytophone 技术的高灵敏度，用于无标记检测黑色素瘤患者带有黑色素的 CTC。通过完整皮肤将激光脉冲经皮传输到血管中，会导致 CTC 产生声波，这些声波被内在黑色素纳米团簇周围的蒸汽纳米气泡放大。使用快速信号处理算法对声波进行时间分辨检测，使光声数据能够耐受皮肤色素沉着和运动。在 19 名健康志愿者中，在既定阈值内未识别到任何与 CTC 相关的信号，但 28 名黑色素瘤患者中有 27 名显示出与单个、聚集和可能滚动的 CTC 一致的信号。检测限低至 1 CTC/升血液，比现有检测方法好约 1000 倍。Cytophone 可以在 20 秒内以≥1 CTC/ml 的浓度检测到单个 CTC，还可以识别血栓和 CTC-血栓栓子。体内结果通过六种离体方法进行了验证。这些数据表明，使用 Cytophone 进行体内血液检测具有早期黑色素瘤筛查、评估疾病复发以及通过实时 CTC 计数监测 CTC 物理破坏的潜力。
