One significant challenge in medical diagnostics lies in the development of label‐free methods to separate different cells within complex biological samples. Here we demonstrate a generic, low‐power ultrasonic separation technique, able to enrich different cell types based upon their physical properties. For malaria, we differentiate between infected and non‐infected red blood cells in a fingerprick‐sized drop of blood. We are able to achieve an enrichment of circulating cells infected by the ring stage of the parasite over nonparasitized red blood cells by between two and three orders of magnitude in less than 3 seconds (enabling detection at parasitemia levels as low as 0.0005 %). In a second example, we also show that our methods can be used to enrich different cell types, concentrating Trypanosoma in blood at very low levels of infection, on disposable, low‐cost chips.

We applied a simple evaporation-based self-assembly technique to create a sub-50 nm nanofluidic junction between two microchannels in PDMS.

This paper demonstrates the enrichment of reticulocytes by centrifuging whole blood through aqueous multiphase systems (AMPSs)—immiscible phases of solutions of polymers that form step‐gradients in density. The interfaces of an AMPS concentrate cells; this concentration facilitates the extraction of blood enriched for reticulocytes. AMPS enrich reticulocytes from blood from both healthy and hemochromatosis donors. Varying the osmolality and density of the phases of AMPS provides different levels of enrichment and yield of reticulocytes. A maximum enrichment of reticulocytemia of 64 ± 3% was obtained from donors with hemochromatosis. When used on peripheral blood from normal donors, AMPS can provide a higher yield of enriched reticulocytes and a higher proportion of reticulocytes expressing CD71 than differential centrifugation followed by centrifugation over Percoll. Blood enriched for reticulocytes by AMPS could be useful for research on malaria. Several species of malaria parasites show a preference to invade young erythrocytes and reticulocytes; this preference complicates in vitro cultivation of these species in human blood. Plasmodium knowlesi malaria parasites invade normal human blood enriched for reticulocytes by AMPSs at a rate 2.2 times greater (P < 0.01) than they invade unenriched blood. Parasite invasion in normal blood enriched by AMPS was 1.8 times greater (P < 0.05) than in blood enriched to a similar reticulocytemia by differential centrifugation followed by centrifugation over Percoll. The enrichment of reticulocytes that are invaded by malaria parasites demonstrates that AMPSs can provide a label‐free method to enrich cells for biological research. Am. J. Hematol. 90:31–36, 2015.

This review provides a framework for development of on-chip liquid biopsy platforms for capture, detection, and analysis of circulating tumor cells.

Wireless power transmission (WPT) is commonly used today in many important daily applications, such as electric vehicles, mobile phones, and implanted medical devices. The transmitter and receiver coils are essential elements in the WPT system, and the coupling coefficient between these coils plays an important role in increasing the power transfer efficiency. In this work, we introduce a new approach to optimizing the coupling coefficient between the transmitter and the receiver coils by changing the geometries and locations of the coil turns. In the optimization process, the geometry of the turns varies from a rhombus to a circular and then a rectangular shape according to a quasi-elliptical parameter value. The Neuman formula is used to calculate the self-inductance, mutual inductance, and coupling coefficient for each specific geometry and turn location. The configuration with the highest coupling coefficient is then selected at the end of the optimization process. The final WPT coils are tested and verified using Ansys software through electromagnetic and AC analysis simulations. The results show that the new approach could achieve smooth and easily manufacturable coils with higher coupling coefficients, thereby increasing the power transfer efficiency of WPT.