In vivo flow cytometry of circulating clots using negative photothermal and photoacoustic contrasts.
ABSTRACT Conventional photothermal (PT) and photoacousic (PA) imaging, spectroscopy, and cytometry are preferentially based on positive PT/PA effects, when signals are above background. Here, we introduce PT/PA technique based on detection of negative signals below background. Among various new applications, we propose label-free in vivo flow cytometry of circulating clots. No method has been developed for the early detection of clots of different compositions as a source of thromboembolism including ischemia at strokes and myocardial infarction. When a low-absorbing, platelet-rich clot passes a laser-irradiated vessel volume, a transient decrease in local absorption results in an ultrasharp negative PA hole in blood background. Using this phenomenon alone or in combination with positive contrasts, we demonstrated identification of white, red, and mixed clots on a mouse model of myocardial infarction and human blood. The concentration and size of clots were measured with threshold down to few clots in the entire circulation with size as low as 20 μm. This multiparameter diagnostic platform using portable personal high-speed flow cytometer with negative dynamic contrast mode has potential to real-time defining risk factors for cardiovascular diseases, and for prognosis and prevention of stroke or use clot count as a marker of therapy efficacy. Possibility for label-free detection of platelets, leukocytes, tumor cells or targeting themby negative PA probes (e.g., nonabsorbing beads or bubbles) is also highlighted.
Full-textDOI: · Available from: Dmitry A Nedosekin, May 28, 2015
SourceAvailable from: Mazen A Juratli[Show abstract] [Hide abstract]
ABSTRACT: Background: Circulating tumor cells (CTC) form metastases in distant organs. The goal of this research was to determine if tumor manipulation could enhance cancer cells release from the primary tumor into the circulatory system. Methods: Nude mice were inoculated with melanoma or breast cancer cells. The implanted tumor underwent compression, biopsy, complete resection, or laser treatment. CTCs were monitored in bloodstream using in vivo photoacoustic and fluorescence flow cytometry. Results: We discovered that pressure, biopsy, and laser treatment can dramatically increase CTC counts (up to 60-fold), whereas proper tumor resection significantly decrease CTC counts. Conclusions: Standard medical procedures could trigger CTC release that may increase the risk of metastases. This finding suggests the guidance of cancer treatment and likely diagnosis by real-time monitoring of CTC dynamics followed by well-timed CTC treatment. In vivo detection of intervention-amplified CTCs could be used for early diagnosis of small tumor undetectable with conventional method. Head Neck, 2013.Head & Neck 08/2014; 36(8). DOI:10.1002/hed.23439 · 3.01 Impact Factor
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ABSTRACT: Flow cytometry offers great diagnostic opportunities in the vast majority of hematologic and oncologic diseases with multiple cellular and molecular information within an individual cell. We will discuss various applications of flow cytometry, particularly in hematology and oncology, in addition to general principles and limitations of flow cytometry. They include nucleic acid analyses in cancer cells, new methods for assessing rare circulating tumor cells and disease-specific applications in malignancy with emphasis on diagnosis and treatment of hematologic malignancy, including minimal residual disease. With improvement of monoclonal antibodies, fluorescence and laser technology, flow cytometry now offers new avenues of assessing cellular functionality through examination of intracellular compartments. High-throughput quantitative analysis, advancements of in vivo flow cytometry and assessment of minimal residual diseases, as exampled in patient stratification and prediction of leukemia therapeutic response, will further make flow cytometry indispensable in medicine.Expert Review of Molecular Diagnostics 12/2013; DOI:10.1586/14737159.2014.862153 · 4.27 Impact Factor
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ABSTRACT: A thin photothermal (PT) endoscope (similar to 80 mu m) for the noninvasive/minimally invasive hybrid-optical diagnosis of biological specimens is demonstrated. The technique has the unique advantage that the pump laser delivery fiber itself acts as the thermal wave sensor, which is a Bragg grating. It detects only the conductive component of the PT signal, thus enabling an emissivity independent measurement. The device is slidable through a syringe needle and PT analysis of exposed organs with limited accessibility for conventional PT techniques, and constricted regions can be examined noninvasively. For regions buried in thick tissues, a minimally invasive injection mode may be considered. Temperature measurement sensitivity is about 0.03 degrees C. The amplitude and phase channels are sensitive up to about 3 and 10 kHz, respectively. The endoscope has been used for the simultaneous estimation of flow velocity, absorption coefficient, and diffusivity for a phantom-blood flow. The endoscopically estimated values are in agreement with true flow velocities over a range of 1 to 1000 cm(-1). The endoscope has been used for the optical biopsy of goat bone marrow. (C) 2013 Society of Photo-Optical Instrumentation Engineers (SPIE)Journal of Biomedical Optics 09/2013; 18(9):7008-. DOI:10.1117/1.JBO.18.9.097008 · 2.75 Impact Factor