An electrochemical-sensor system for real-time flow measurements in porous materials.

Flow monitoring in porous materials is critical for the engineering of paper-based microfluidic bioassays. Here, we present an electrochemical-sensor system that monitors the liquid flow in porous materials without affecting the real flow in paper-strip samples. The developed microfluidic sensor records an amperometric signal created by the solution movement mediated by paper wicking.

Flow-enhanced electrochemical immunosensors on centrifugal microfluidic platforms.

We present a novel fully integrated centrifugal microfluidic device with features for target antigen capture from biological samples, via a bead-based enzyme-linked immune-sorbent assay, and flow-enhanced electrochemical detection. The limit of detection (LOD) of our device for the C-reactive protein (CRP) was determined to be 4.9 pg mL(-1), a 17-fold improvement over quantification by optical density.

Pumps for microfluidic cell culture.

In comparison to traditional in vitro cell culture in Petri dishes or well plates, cell culture in microfluidic-based devices enables better control over chemical and physical environments, higher levels of experimental automation, and a reduction in experimental materials. Over the past decade, the advantages associated with cell culturing in microfluidic-based platforms have garnered significant interest and have led to a plethora of studies for high throughput cell assays, organs-on-a-chip applications, temporal signaling studies, and cell sorting. A clear concern for performing cell culture in microfluidic-based devices is deciding on a technique to deliver and pump media to cells that are encased in a microfluidic device.

Electrochemical velocimetry on centrifugal microfluidic platforms.

Expanding upon recent applications of interfacing electricity with centrifugal microfluidic platforms, we introduce electrochemical velocimetry to monitor flow in real-time on rotating fluidic devices. Monitoring flow by electrochemical techniques requires a simple, compact setup of miniaturized electrodes that are embedded within a microfluidic channel and are connected to a peripherally-located potentiostat. On-disc flow rates, determined by electrochemical velocimetry, agreed well with theoretically expected values and with optical measurements.

Infrared controlled waxes for liquid handling and storage on a CD-microfluidic platform.

A novel active valving technique, whereby paraffin wax plugs in microchannels on a centrifugal microfluidic platform are actuated using focused infrared (IR) radiation is demonstrated in this report. Microchannels were simultaneously or sequentially opened using a stationary IR source by forming wax plugs with similar or differing melting points. The presented wax plugs offer key advantages over current active valving techniques, including a less involved fabrication procedure, a simpler actuation process, and the ability to multiplex experiment with active valves.

The integration of 3D carbon-electrode dielectrophoresis on a CD-like centrifugal microfluidic platform.

We introduce the integration of a novel dielectrophoresis (DEP)-assisted filter with a compact disk (CD)-based centrifugal platform. Carbon-electrode dielectrophoresis (carbon-DEP) refers to the use of carbon electrodes to induce DEP. In this work, 3D carbon electrodes are fabricated using the C-MEMS technique and are used to implement a DEP-enabled active filter to trap particles of interest.