Microfluidic inertia enhanced phase partitioning for enriching nucleated cell populations in blood.

Nucleated cells in blood like white blood cells (WBCs) and other rare cells including peripheral blood stem cells (PBSCs) and circulating tumor cells (CTCs) possess significant value for patient monitoring and clinical diagnosis. Enrichment of nucleated cells from contaminating red blood cells (RBCs) using label-free techniques without the use of antibodies or centrifugation is highly desirable to ensure minimal cell loss and activation. To accomplish this, we demonstrate proof-of-concept of a new microfluidic technique that combines aqueous phase partitioning with inertial focusing to accomplish enrichment of nucleated cells in blood.

Inertial lift enhanced phase partitioning for continuous microfluidic surface energy based sorting of particles.

A new microfluidics technique that exploits the selectivity of phase partitioning and high-speed focusing capabilities of the inertial effects in flow was developed for continuous label-free sorting of particles and cells. Separations were accomplished by introducing particles at the interface of polyethylene glycol (PEG) and dextran (DEX) phases in rectangular high aspect-ratio microfluidic channels and allowing them to partition to energetically favorable locations within the PEG phase, DEX phase or interface at the center of the microchannel. Separation of partitioned particles was further enhanced via inertial lift forces that develop in high aspect-ratio microchannels that move particles to equilibrium positions close to the outer wall.

Endothelial cell culture model for replication of physiological profiles of pressure, flow, stretch, and shear stress in vitro.

The phenotype and function of vascular cells in vivo are influenced by complex mechanical signals generated by pulsatile hemodynamic loading. Physiologically relevant in vitro studies of vascular cells therefore require realistic environments where in vivo mechanical loading conditions can be accurately reproduced. To accomplish a realistic in vivo-like loading environment, we designed and fabricated an Endothelial Cell Culture Model (ECCM) to generate physiological pressure, stretch, and shear stress profiles associated with normal and pathological cardiac flow states.

Exploiting osmosis for blood cell sorting.

Blood is a valuable tissue containing cellular populations rich in information regarding the immediate immune and inflammatory status of the body. Blood leukocytes or white blood cells (WBCs) provide an ideal sample to monitor systemic changes and understand molecular signaling mechanisms in disease processes. Blood samples need to be processed to deplete contaminating erythrocytes or red blood cells (RBCs) and sorted into different WBC sub-populations prior to analysis.

Microfluidic cardiac cell culture model (μCCCM).

Physiological heart development and cardiac function rely on the response of cardiac cells to mechanical stress during hemodynamic loading and unloading. These stresses, especially if sustained, can induce changes in cell structure, contractile function, and gene expression. Current cell culture techniques commonly fail to adequately replicate physical loading observed in the native heart.