Characterization of blood coagulation dynamics and oxygenation in ex-vivo retinal vessels by fluorescence hyperspectral imaging

Abstract

Blood coagulation mechanisms forming a blood clot and preventing hemorrhage have been extensively studied in the last decades. Knowing the mechanisms behind becomes very important particularly in the case of blood vessel diseases. Real-time and accurate diagnostics accompanied by the therapy are particularly needed, for example, in diseases related to retinal vasculature. In our study, we employ for the first time fluorescence hyperspectral imaging (fHSI) combined with the spectral analysis algorithm concept to assess physical as well as functional information of blood coagulation in real-time. By laser-induced local disruption of retinal vessels to mimic blood leaking and subsequent coagulation and a proper fitting algorithm, we were able to reveal and quantify the extent of local blood coagulation through direct identification of the change of oxyhemoglobin concentration within few minutes. We confirmed and illuminated the spatio-temporal evolution of the essential role of erythrocytes in the coagulation cascade as the suppliers of oxygenated hemoglobin. By additional optical tweezers force manipulation, we showed immediate aggregation of erythrocytes at the coagulation site. The presented fluorescence-based imaging concept could become a valuable tool in various blood coagulation diagnostics as well as theranostic systems if coupled with the laser therapy.

Keywords: biomedical optics and biophotonics; blood coagulation; comparative animal models; diagnostics; fluorescence hyperspectral imaging; hemoglobin oxygenation; optical tweezers.