In vivo full-field functional optical hemocytometer.

We present an in vivo lab-free full-field functional optical hemocytometer (FFOH) for application to the capillaries of a live biological specimen, based on the absorption intensity fluctuation modulation (AIFM) effect. Because of the absorption difference between the red blood cells (RBCs) and background tissue under low-coherence light illumination, an endogenous instantaneous intensity fluctuation is generated by the AIFM effect when RBCs discontinuously traverse the capillary. The AIFM effect is used to highlight the RBC signal relative to the background tissue by computing the real-time modulation depth. FFOH can simultaneously provide a flow video, the flow velocity and the RBC count. Ourexperimental results can potentially be applied to study the physiological mechanisms of the blood circulation systems of near-transparent live biological samples.