Acoustic Microstreaming for Blood Separation and Disease Diagnosis in Microfluidic Devices

Numerous applications in biology and medicine requires efficient and reliable separation of cellular or sub-cellular components from blood for disease diagnosis, genetic analysis, drug screening, and therapeutics. However, analyzing undiluted whole human blood is challenging due to its complex composition of hematopoietic cellular populations, plasma and sub-cellular components such as nucleic acids, metabolites, and proteins. In addition, current state-of-art for blood fractionation relies on multi-step density-based centrifugation or flow cytometry which are manual, time-consuming and unable to process whole blood. In this dissertation, we aim to demonstrate a multi-functional, low-cost microfluidic acoustic streaming platform to enrich and characterize cellular components from whole blood and utilize blood’s sub-cellular components for simultaneous detection of multiple infections. First, we present Lateral Cavity Acoustic Transducers (LCATs) that enables (1) the sorting of undiluted donor whole blood into its cellular subsets (platelets, RBCs, and WBCs), (2) the enrichment and retrieval of breast cancer cells (MCF-7) spiked in donor whole blood at rare cell relevant concentrations (10/ml), and (3) on-chip immunofluorescent labeling for the detection of specific target cellular populations by their known marker expression patterns. Our approach thus demonstrates a compact system that integrates upstream sample processing with downstream separation/enrichment, to carry out multi-parametric cell analysis for blood-based diagnosis and liquid biopsy blood sampling. Second, we integrated a passive (spiral inertial microfluidic device) and an active device (LCAT) for high-throughput separation, enrichment and release of specific target cellular population (such as larger side-population (SP) of DU-145 cells from tissue biopsy or larger monocytic cell population from blood sample). After optimization with particles spiked in blood, this platform removed >90% of the smaller cells, such as RBCs in a blood sample or smaller cancer cells in a heterogeneous cell line, and provided 44,000x enrichment from remaining sample within 5 minutes of device operation. Third, since whole blood comprises not only cellular subsets, but also sub-cellular components, we utilized the antibodies in both blood serum and saliva for the multiplexed screening of HIV, HPV and HSV within 17.5 minutes. We integrated this acoustic microstreaming platform with a protein microarray and verified reactivity of patient antibodies with HIV, HPV and HSV antigens. This integrated microfluidic protein array platform is the basis of a potent strategy to delay progression of primary infection, reduce the risk of co-infections and prevent onward transmission of infections by point-of-care detection of multiple pathogens