Hydrodynamic Confined Microfluidic Probes (K. Turner)

Overview of hydrodynamic confined microfluidic (HCM) probe technology. (a) Schematic side-view of HCM probe.  A confined flow is created between the device and bottom surface of the well by flowing fluid into one port and removing it through the second port.  The gap height, h, is typically 20-60 m. (b) A schematic and photograph of an HCM device.  The ports are deep reactive ion etched into silicon and a PDMS cap is bonded to the backside of the device to allow fluidic connections to the port.  (c) Comparison of measured flow envelopes beneath the device imaged by flowing a fluorescent solution through the device (top) to CFD predictions of the flow.  Results shown for two different port geometries; all results are for a gap of 40 m.

Purpose: Microfluidic approaches have numerous applications in cell biology.  Microfluidics can be used to apply controlled hydrodynamic loads to cells, selectively treat cells with particular chemistries or drugs, and pattern proteins on surfaces.  The traditional channel-based microfluidics have broad applications and have been widely used, but in some experiments having … Learn more

Track-etched magnetic micropore (TEMPO) filter for the rapid isolation of rare cells (D. Issadore)

Purpose: Rapid and accurate isolation of rare cells in fluid samples is a major challenge in medical diagnostics. There is a crucial need to isolate small numbers of cells from large populations, thus requiring high throughput techniques. The Issadore group at Penn has recently developed a new separation system to … Learn more

Microfabricated polymeric array detectors (mPADs) for measuring cell forces (D.A. Hammer, C. Chen)

Purpose: A variety of techniques are available to measure the forces that cells exert as they are adhering or crawling. These techniques are known as traction force microscopies, and they include bead based traction microscopy (where beads are embedded in hydrogels) and microfabricated polymeric array detectors (or mPADs). The Chen … Learn more

Dielectrophoretic (DEP) Positioning and Sorting of Macromolecules and Nanoparticles (H. Bau)

Purpose: Sorting and positioning of objects in microfluidic channels such as cells, macromolecules, and micro/nano-particles is useful in a broad range of studies.  For example, positioning and holding a specific cell sitting in suspension via a dielectrophoretic trap can facilitate detailed inspection via microscopy or other interrogation techniques.  Furthermore, dielectrophoretic … Learn more

Micro-stirrers (mixers), Micro-Pumps, Valves for Flow Control (H. Bau)

Purpose: As the complexity of microfluidic experiments increases, it is desirable to integrate flow manipulation and control functions onto the chip.  Moving from off-chip control devices (e.g., syringe pumps) to on-chip systems allows for the complexity of devices to be increased and creates the opportunity for devices that can perform … Learn more

Flexible, Multi-Scale Electrodes for Sensing and Stimulation of Tissue (C. Kagan and B. Litt)

Purpose: There is an urgent need for new implantable devices to help understand and treat “brain network disorders.”  For maximum research and clinical benefit, these implantable devices should allow signals to be recorded from clinically relevant volumes of brain, 100 cm2, at resolutions of 100 microns or less. Many of … Learn more

Lung-on-a-chip device (Huh, D)

Lung-on-a-chip microfluidics.  This device allows simultaneous control of fluid perfusion over an endothelium, exposure of air to the pulmonary epithelium at an air-liquid culture condition and independent control of the stretch of the epithelium and endothelium, thereby fully recreating the complex environment of alveolar inflation mechanics during lung inflation.  The device has broad use with respect to the understanding of acute lung injury, chronic obstructive pulmonary disease (COPD), respirator injury and respirator design, pulmonary embolism, lung inflammation and asthma.

Organ-like surrogates can be created using microfluidic devices to recreate air-liquid interfaces, cell-cell communication and complex tissue mechanics.  Such “organ-on-a-chip” devices are powerful tools to study a functional alveolar-capillary interface, relevant to infection, inflammation, and lung dysfunction and acute lung injury.

The upper and lower layers of the microfluidic device … Learn more

Microfluidic-gradient generator for studying amoeboid cell chemotaxis (Hammer, DA)

Microfluidic gradient chamber (Ricart BG, John B, Lee D, Hunter CA, Hammer DA. Dendritic Cells Distinguish Individual Chemokine Signals through CCR7 and CXCR4. Journal of Immunology Jan 2011; 186 (1): 53-61). A. Design of the chamber, verified by COMSOL modeling. The chamber was used to make counter gradients of two chemokines. B and C show measurements of green and red fluorescent dyes in the channel, and D. illustrates the comparison between modeled and measured profiles.

Purpose: Microfabricated chambers have been used for the study of cell motility, particularly the motility of ameoboid cells of the immune system.(Irimia, 2006, Jeon, 2002) These cells display directional motion, known as chemotaxis, in defined gradients of chemokines, which results from the differential occupancy of receptors. The purpose of the … Learn more