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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 s

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 s

In this thesis, acoustofluidics has been used to process blood samples as a sample preparation step prior to biomarker detection. This is often required as the large amount of blood cells otherwise can interfere with the detection method. Acoustofluidics means moving particles or cells with acoustic forces within microfluidic channels. Ultrasound is used to create a standing wave between the channel walls. By matching of the frequency to the channel with, a half wavelength standing wave can be created between the side walls. Blood cells introduced into this channel will then be focused to the centre pressure node while the plasma can be extracted from the sides. This approach has here been used for three different applications. First it was integrated with a prostate-specific antigen (PSA) immunoassay which not only enabled detection of PSA from whole blood but also resulted in a faster detection because of the continuous flow of produced plasma, constantly bringing new analyte close to the capturing antibodies. Secondly a similar blood plasma separation was integrated with an acoustic trap for enrichment and microchip PCR to enable fast identification of bacteria from sepsis blood samples. In a small clinical study this acoustofluidic based detection system could identify Escherichia coli (E. coli) in half of the samples compared to blood culture, probably the ones with the highest bacteria load. In an attempt to improve the bacteria recovery of the blood bacteria separation, another setup where buffer flow in the centre of the channel laminated the blood sample along the sides was tested. By carefully control the dilution of blood sample and the acoustic impedance (density times speed of sound) bacteria recovery was significantly improved. Third, simple and fast haematocrit (HCT) measurements were also achieved in an acoustofluidic device combined with image analysis. The area of the focused blood cells compared to the whole channel area gave a measure with linear

Evaluation and diagnosis of blood alterations is a common request for clinical laboratories, requiring a complex technological approach and dedication of health resources. In this paper, we present a microfluidic device that owing to a novel combination of hydrodynamic and dielectrophoretic techniques can separate plasma from fresh blood in a microfluidic channel and for the first time allows optical real-time monitoring of the components of plasma without pre- or post-processing. The microchannel is based on a set of dead-end branches at each side and is initially filled using capillary forces with a 2-mu L droplet of fresh blood. During this process, stagnation zones are generated at the dead-end branches and some red blood cells (RBCs) are trapped there. An electric field is then applied and dielectrophoretic trapping of RBCs is used to prevent more RBCs entering into the channel, which works like a sieve. Besides, an electroosmotic flow is generated to sweep the rest of the RBCs from the central part of the channel. Consequently, an RBC-free zone of plasma is formed in the middle of the channel, allowing real-time monitoring of the platelet behavior. To study the generation of stagnation zones and to ensure RBC trapping in the initial constrictions, two numerical models were solved. The proposed experimental design separates up to 0.1 mu L blood plasma from a 2-mu L fresh human blood droplet. In this study, a plasma purity of 99 % was achieved after 7 min, according to the measurements taken by image analysis., Postprint (published version)

Over the last decades the ongoing work in the fields of Lab-on-a-Chip and Micro-Total-Analysis-Systems has led to the discovery of new or improved ways to handle and analyse small volumes of biofluids and complex biosuspensions. The benefits of working on the microscale include: miniaturization of the analysis systems with less need for large sample volumes; temporal and spatial control of suspended particle/cell positions; low volume sheath flow lamination or mixing; novel separation techniques by using forces inherent to the microscale domain; precise regulation of sample temperatures and rapid analysis with less volumes needed to be processed. Researchers now seek to implement these techniques in integrated systems to benefit the biomedical research field as well as clinics. Acoustophoresis, a method that utilizes acoustic forces to move particles and cells in microfluidic channels has been gaining increased attention over the last decade. The acoustophoretic method has been shown to handle a number of biosuspensions e.g., blood, cell cultures and raw milk as well as other biofluids, and comes with a variety of available unit operations e.g., free flow separation, binary density separation, particle positioning, contactless trapping, buffer changes, washing, and surface chemistry based sorting that allows integration into a wide range of application. The theoretical and experimental understanding of the acoustic radiation force which is the principal force used to manipulate particles in these systems (often generated with standing waves) has also evolved during this time. Chip-based acoustic systems have been presented in e.g., silicon, glass and PDMS, further illustrating the versatility of the method. This dissertation presents some of the recent developments in the acoustophoretic field to illustrate how acoustic forces can be used in cytometry and biomedical applications, specifically by utilizing multiple acoustic wavelength geometries or two-dimensional pa