PROJECT SUMMARY The primary goal of this administrative supplement project is to characterize, optimize and disseminate the optical phantoms mimicking microvascular cerebral blood flow (CBF). In our parent R15 study (EB034986) entitled “Affordable Shortwave Infrared Spectroscopy for Stroke Risk Screening in Children with Sickle Cell Disease“, we have proposed to construct the advanced multilayered microfluidic phantoms to verify our prototyped optical flowmeter. Traditionally, the most common optical flow phantom is simply a bulk liquid wherein blood flow is manipulated by adjusting temperature, viscosity or particle size. The proposed phantoms here address the limitations of conventional laboratory-based optical phantoms by mimicking the multiple features of brain flow models: 1) two-layer features: extracerebral and cerebral layer with varying thickness of the extracerebral layer, 2) optical (scattering and absorption coefficients) properties and physiologically relevant flow rate of each layer 3) micro-sized multi-channel flow mimicking the dimension of arterioles, capillaries and venules. For this purpose, the overall objective of this administrative supplement is to characterize and optimize the multilayered microfluidic phantoms built using both non-cleanroom and cleanroom methods. We envision the proposed phantoms will be employed for 1) evaluation the basic performance of the developed optical flowmeter, 2) daily-basis quality check before any clinical measurements 3) benchmark reference for comparison of the different technologies. Successful completion of this proposed project will pave the way towards the first-ever standardized multilayered micro-sized flow phantoms to improve repeatability, reproducibility and quantification of the diffuse optics technologies that have the potential for clinical translation as a bedside tool for CBF monitoring.