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Creating Sub-50 Nm Nanofluidic Junctions in PDMS Microfluidic Chip via Self-Assembly Process of Colloidal Particles

Polydimethylsiloxane (PDMS) is the prevailing building material to make microfluidic devices due to its ease of molding and bonding as well as its ...

New York University Abu Dhabi (NYUAD)

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.

Rare-cell enrichment by a rapid, label-free, ultrasonic isopycnic technique for medical diagnostics.

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.

Enrichment of reticulocytes from whole blood using aqueous multiphase systems of polymers.

Rapid screening of biomarkers, with high specificity and accuracy, is critical for many point-of-care diagnostics. Microfluidics, the use of microscale channels to manipulate small liquid samples and carry reactions in parallel, offers tremendous opportunities to address fundamental questions in biology and provide a fast growing set of clinical tools for medicine. Emerging multi-dimensional nanostructures, when coupled with microfluidics, enable effective and efficient screening with high specificity and sensitivity, both of which are important aspects of biological detection systems. In this review, we provide an overview of current research and technologies that utilize nanostructures to facilitate biological separation in microfluidic channels. Various important physical parameters and theoretical equations that characterize and govern flow in nanostructure-integrated microfluidic channels will be introduced and discussed. The application of multi-dimensional nanostructures, including nanoparticles, nanopillars, and nanoporous layers, integrated with microfluidic channels in molecular and cellular separation will also be reviewed. Finally, we will close with insights on the future of nanostructure-integrated microfluidic platforms and their role in biological and biomedical applications.

Abeer Syed

Division of Engineering

New York University Abu Dhabi (NYUAD)

Creating Sub-50 Nm Nanofluidic Junctions in PDMS Microfluidic Chip via Self-Assembly Process of Colloidal Particles

Abeer Syed

.css-o250i3{font-size:18px;font-family:Open Sans,sans-serif;line-height:21.6px;}Division of Engineering

New York University Abu Dhabi (NYUAD)

Creating Sub-50 Nm Nanofluidic Junctions in PDMS Microfluidic Chip via Self-Assembly Process of Colloidal Particles

Division of Engineering