A Compact and Novel Photoacoustic Sensing Technique for In Vitro Characterization of Blood Viscosity: A Phantom-Based Study

The feasibility of the continuous wave laser diode-based photoacoustic (CWPA)sensing technique in estimating blood viscosity and red blood cell concentration, as well as measuring the blood vessel diameter, is demonstrated here. The laser-enabled swept frequency acoustic interferometry (LE-SFAI) principle is applied here to obtain the high signal-to-noise ratio CWPA signal. The experiments are performed using the liquid dye–glycerol mixture and further with the tissue-mimicking phantoms. Certain distinct features from the time domain CWPA signal are used to estimate the aforementioned parameters. The results are verified by the results obtained from the standard instruments. The usage of a continuous wave laser diode enables a compact and economical photoacoustic (PA) sensing system for blood viscosity characterization and field deployment.