In vivo flow cytometry of circulating clots using negative photothermal and photoacoustic contrasts

• Published in: Cytometry. Part A 2011-10, Vol.79A (10), p.814-824
• Main Authors: Galanzha, Ekaterina I., Sarimollaoglu, Mustafa, Nedosekin, Dmitry A., Keyrouz, Salah G., Mehta, Jawahar L., Zharov, Vladimir P.
• Format: Article
• Language: English
• Subjects: Animal models; Animals; Blood; Blood Coagulation; Blood Platelets - cytology; Cardiovascular diseases; Carotid Arteries - metabolism; Carotid Arteries - pathology; circulating clots; Disease Models, Animal; Early Diagnosis; Flow cytometry; Flow Cytometry - instrumentation; Flow Cytometry - methods; Fluoresceins - analysis; Fluorescent Dyes - analysis; heart attack; Humans; imaging; in vivo flow cytometry; Ischemia; label‐free detection; Leukocytes; Mesentery - pathology; Mice; Mice, Nude; Molecular Imaging - instrumentation; Molecular Imaging - methods; Myocardial infarction; Myocardial Infarction - blood; Myocardial Infarction - diagnosis; Myocardial Infarction - pathology; photoacoustic method; Photoacoustic Techniques - instrumentation; Photoacoustic Techniques - methods; Photoacoustics; photothermal spectroscopy; Platelet Aggregation; Platelets; Probes; Prognosis; Rats; Rats, Sprague-Dawley; Risk factors; Spectroscopy; Splanchnic Circulation; Stroke; Stroke - blood; Stroke - diagnosis; Stroke - pathology; Succinimides - analysis; Thromboembolism; Thromboembolism - blood; Thromboembolism - diagnosis; Thromboembolism - pathology; Tumor cells
• ISSN: 1552-4922; 1552-4930; 1552-4930
• DOI: 10.1002/cyto.a.21106

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. © 2011 International Society for Advancement of Cytometry