Biomedical subjects

Abraham D Stroock

Publications and source records attributed to Abraham D Stroock.

6 recordsLinked to original sources

PubMed2003

A miniaturized, parallel, serially diluted immunoassay for analyzing multiple antigens.

This paper describes a microfluidic immunoassay that is applicable to the parallel determination of multiple analytes and that requires only a few microliters of sample. This assay relies on a microchannel network that achieves serial dilution of analytes; this network replaces manual dilutions employed in traditional immunoassays and enables the analysis of multiple analytes simultaneously. The immunoassay was demonstrated by an analysis of concentrations of antibodies against the HIV viral proteins gp120 and gp41 in human serum.

Antibodies↗

PubMed2002

Membraneless vanadium redox fuel cell using laminar flow.

This paper describes the design and characterization of a small, membraneless redox fuel cell. The smallest channel dimensions of the cell were 2 mm x 50 mum or x 200 mum; the cell was fabricated in poly(dimethylsiloxane) using soft lithography. This all-vanadium fuel cell took advantage of laminar flow to obviate the need for a membrane to separate the solutions of oxidizing and reducing components.

Carbon↗

PubMed2002

Patterning flows using grooved surfaces.

Through a simple analytical description we quantify how pressure-driven flows over grooved surfaces develop transverse components, which, for shallow grooves, can be modeled with simple anisotropic effective boundary conditions. Helical recirculation results in channels or capillaries with grooved walls. An experimental validation of our model is presented. Our analysis provides a workable guide for the design of 3D flows with simple patterns of grooved regions, e.g., to control the position of streams in the cross section of a channel or to promote mixing. Potential applications in microfluidics are outlined.

Algorithms↗

PubMed2002

Prototyping of microfluidic devices in poly(dimethylsiloxane) using solid-object printing.

A solid-object printer was used to produce masters for the fabrication of microfluidic devices in poly(dimethylsiloxane) (PDMS). The printer provides an alternative to photolithography for applications where features of > 250 microm are needed. Solid-object printing is capable of delivering objects that have dimensions as large as 250 x 190 x 200 mm (x, y, z) with feature sizes that can range from 10 cm to 250 microm. The user designs a device in 3-D in a CAD program, and the CAD file is used by the printer to fabricate a master directly without the need for a mask. The printer can produce complex structures, including multilevel features, in one unattended printing. The masters are robust and inexpensive and can be fabricated rapidly. Once a master was obtained, a PDMS replica was fabricated by molding against it and used to fabricate a microfluidic device. The capabilities of this method are demonstrated by fabricating devices that contain multilevel and tall features, devices that cover a large area (approximately 150 cm2), and devices that contain nonintersecting, crossing channels.

Animals↗

PubMed2002

Chaotic mixer for microchannels.

It is difficult to mix solutions in microchannels. Under typical operating conditions, flows in these channels are laminar-the spontaneous fluctuations of velocity that tend to homogenize fluids in turbulent flows are absent, and molecular diffusion across the channels is slow. We present a passive method for mixing streams of steady pressure-driven flows in microchannels at low Reynolds number. Using this method, the length of the channel required for mixing grows only logarithmically with the Péclet number, and hydrodynamic dispersion along the channel is reduced relative to that in a simple, smooth channel. This method uses bas-relief structures on the floor of the channel that are easily fabricated with commonly used methods of planar lithography.

Chemical Phenomena↗

PubMed2002

Components for integrated poly(dimethylsiloxane) microfluidic systems.

This review describes the design and fabrication of microfluidic systems in poly(dimethylsiloxane) (PDMS). PDMS is a soft polymer with attractive physical and chemical properties: elasticity, optical transparency, flexible surface chemistry, low permeability to water, and low electrical conductivity. Soft lithography makes fabrication of microfluidic systems in PDMS particularly easy. Integration of components, and interfacing of devices with the user, is also convenient and simpler in PDMS than in systems made in hard materials. Fabrication of both single and multilayer microfluidic systems is straightforward in PDMS. Several components are described in detail: a passive chaotic mixer, pneumatically actuated switches and valves, a magnetic filter, functional membranes, and optical components.

Dimethylpolysiloxanes↗