Extraction of cells of interest directly from whole blood is in high demand, yet extraordinary challenging due to the complex hemodynamics and hemorheology of the sample. Herein, we describe a new microfluidic platform that exploits the intrinsic complex properties of blood for continuous size-selective focusing and separation of cells directly from unprocessed whole blood. The novel system only requires routinely accessible saline solution to form a sandwiched fluid configuration and to initiate a strong effect of shear-induced diffusion of cells, which is coupled with fluid inertia for effective separation. Separations of beads and cells from whole blood have been successfully demonstrated with high efficiency (89.8%) at throughput of 6.75 mL/hr (106–107 cells/s) of whole blood. Rapid isolation of circulating tumor cells (CTCs) from peripheral blood sample of hepatocarcinoma patients is also shown as a proof of principle.

Cell concentration adjustment is intensively implemented routinely both in research and clinical laboratories. Centrifuge is the most prevalent technique for tuning biosample concentration. But it suffers from a number of drawbacks, such as requirement of experienced operator, high cost, low resolution, variable reproducibility and induced damage to sample. Herein we report on a cost-efficient alternative using inertial microfluidics. While the majority of existing literatures concentrate on inertial focusing itself, we identify the substantial role of the outlet system played in the device performance that has long been underestimated. The resistances of the outlets virtually involve in defining the cutoff size of a given inertial filtration channel. Following the comprehensive exploration of the influence of outlet system, we designed an inertial device with selectable outlets. Using both commercial microparticles and cultured Hep G2 cells, we have successfully demonstrated the automated concentration modification and observed several key advantages of our device as compared with conventional centrifuge, such as significantly reduced cell loss (only 4.2% vs. ~40% of centrifuge), better preservation of cell viability and less processing time as well as the increased reproducibility due to absence of manual operation. Furthermore, our device shows high effectiveness for concentrated sample (e.g., 1.8 × 10 cells/ml) as well. We envision its promising applications in the circumstance where repetitive sample preparation is intensely employed.

An integrated microfluidic biochip was designed for the streamlined separation, capture, in situ culture and/or immunofluorescence characterization of tumor cells.

Cell patterning has been widely used in research on fundamental cell biology and in applications such as tissue engineering, neuron network formation, cell based biosensor and drug screening. Although various methods have been developed, cell patterning in an enclosed microfluidic device at single cell level remains challenging. This paper describes a microfluidic device with microwells and protein patterns paired together in a single microchannel for an easy cell patterning. Cells captured in the microwells were positioned directly onto the protein patterns within 5 min and the patterning performance was successfully demonstrated using HeLa cells and human gallbladder carcinoma cells (SGC-996). Cells survived for 6 days in the microchannel. Cell attachment, migration, proliferation and cell colony formation were observed. Our device is free of topographic constraint for the patterned cells and no complex chemical modification to the substrate is needed, offering a simple, fast, and easy-to-operate way of patterning cells at single cell level in an enclosed microfluidic channel.