PROJECT SUMMARY Acquired or inherited diseases can alter the red blood cell (RBC), causing severe clinical complications affecting the vasculature and organ health. Inherited red cell disorders, renal failure, diabetes, and blood bank storage lesions can all produce stiff, non-deformable RBCs. Red cell stiffness is particularly problematic in sickle cell disease (SCD), a debilitating inherited blood disorder. An estimated 100,000 individuals in the US, and millions more world-wide, have SCD. The field has experienced an explosion of novel SCD therapeutics, designed to target specific individual abnormalities in the RBC in the last five years. Numerous gene-based therapies intending to cure SCD are in clinical trials. This marked shift in SCD therapeutics produced a need for diagnostics and analytical tools that assess RBC health and quality. We need biomarkers of red cell function to serve as endpoints in clinical trials, assist in optimal drug selection and personalized monitoring for the individual, and to determine if gene-based therapy has normalized the red cell. Many aspects of the red cell must be assessed, but a key feature is deformability. There is a lack of robust, inexpensive devices sensitive enough to capture small populations of poorly deformable red cells able to continue to hemolyze, damage the blood vessels, and cause organ damage and early mortality. It is essential that we vet therapies for their ability to normalize the entire population of red cells. Here we propose to develop and translate the Microfluidic Impedance Red Cell Assay (MIRCA) to functionally measure red cell deformability, reported as Occlusion Index (OI) of a biomimetic microcapillary network array on a chip. We propose an innovative approach and a novel collaboration between engineers and a hematology-trained physician scientist. We will do so with the following steps: 1. We will achieve instrumentation and analytical validation of MIRCA measurement of red cell OI. Analytic validation will be performed both in PI’s laboratory (Dr. Umut Gurkan, CWRU) and in Co-I’s hematology laboratory (Dr. Vivien Sheehan, Emory) to prove generalizability and permit stakeholder feedback and design modification. 2. We will clinically validate MIRCA by assessing the association between OI and clinical complications and traditional laboratory measures of disease severity in SCD. 3. We will expand the use of the optimized MIRCA to the clinical space by demonstrating its prognostic value in longitudinal assessments of patients with SCD experiencing clinical complications and transitions in therapy. Using our unique collaboration between biomedical engineers and a hematology trained physician-scientist, we will optimize, validate, and achieve clinical adoption of MIRCA technology in clinical trials and patient care for individuals living with SCD in the US and world-wide.