Microchip isoelectric focusing using a miniature scanning detection system.

A miniature scanning fluorescent detector has been developed for plastic microchannel isoelectric focusing (mIEF) analysis. The detector, comprised of a lamp and photomultiplier tube (PMT) on a moving stage, measured the real-time distribution of fluorescently labeled peptides subjected to gel-free mIEF. During the run, the effective length of the 6-cm channel was scanned every 9 s.

Lysing bacterial spores by sonication through a flexible interface in a microfluidic system.

Cell disruptions using ultrasonic energy transmitted through a flexible interface into a liquid region has limitations because the motion of the vibrating tip is not completely transferred into the liquid. To ensure that some degree of contact will be maintained between the ultrasonic horn tip and the flexible interface, the liquid must be pressurized. The pressure conditions that yield consistent coupling between the ultrasonic horn tip and the liquid region were explored in this study by using an analytical model of the system and test fixture experiments.

A battery-powered notebook thermal cycler for rapid multiplex real-time PCR analysis.

A compact, real-time PCR instrument was developed for rapid, multiplex analysis of nucleic acids in an inexpensive, portable format. The instrument consists of a notebook computer, two reaction modules with integrated optics for four-color fluorescence detection, batteries, and a battery-charging system. The instrument weighs 3.

A microfluidic cartridge to prepare spores for PCR analysis.

A prototype cartridge system is described that rapidly disrupts Bacillus spores by sonication, adds PCR reagent to the disrupted spores, and dispenses the mixture into a PCR tube. The total time to automatically process the spores in the cartridge and then detect the spore DNA by real-time PCR was 20 min.

A minisonicator to rapidly disrupt bacterial spores for DNA analysis.

Concerns about the use of anthrax spores as a weapon of mass destruction have motivated the development of portable instruments capable of detecting and monitoring a suspected release of the agent. Optimal detection of bacterial spores by PCR requires that the spores be disrupted to make the endogenous DNA available for amplification. The entire process of spore lysis, PCR, and detection can take several hours using conventional methods and instruments.

Rapid, automated nucleic acid probe assays using silicon microstructures for nucleic acid concentration.

A system for rapid point-of-use nucleic acid (NA) analysis based on PCR techniques is described. The extraction and concentration of DNA from test samples has been accomplished utilizing silicon fluidic microchips with high surface-area-to-volume ratios. Short (500 bp) and medium size (48,000 bp) DNA have been captured, washed, and eluted using the silicon dioxide surfaces of these chips.

Real-time microchip PCR for detecting single-base differences in viral and human DNA.

This report describes real-time 5' nuclease PCR assays to rapidly distinguish single-base polymorphism using a battery-powered miniature analytical thermal cycling instrument (MATCI). Orthopoxviruses and the human complement component C6 gene served as targets to demonstrate the feasibility of using the MATCI for diagnosis of infectious diseases and genetic disorders. In the Orthopoxvirus assay, consensus Orthopoxvirus PCR primers were designed to amplify 266-281 base-pair (bp) segments of the hemagglutinin (HA) gene in camelpox, cowpox, monkeypox, and vaccinia viruses.

Rapid PCR for identity testing using a battery-powered miniature thermal cycler.

A microfabricated, battery-powered thermal cycler was implemented in PCR-based DNA typing for human identification. HLA DQ alpha and an STR triplex were PCR amplified using a device known as the Miniature Analytical Thermal Cycling Instrument (MATCI). The extremely efficient heating properties of the MATCI enabled thermal cycling to be completed in as little as 21 min.

A miniature analytical instrument for nucleic acids based on micromachined silicon reaction chambers.

In this paper, we describe a miniature analytical thermal cycling instrument (MATCI) to amplify and detect DNA via the polymerase chain reaction in real-time. The MATCI is an integrated, miniaturized analytical system that uses silicon-based, high-efficiency reaction chambers with integrated heaters and simple, inexpensive electronics to precisely control the reaction temperatures. Optical windows in the silicon and solid-state, diode-based detection components are employed to perform real-time fluorescence monitoring of product DNA production.

Functional integration of PCR amplification and capillary electrophoresis in a microfabricated DNA analysis device.

Microfabricated silicon PCR reactors and glass capillary electrophoresis (CE) chips have been successfully coupled to form an integrated DNA analysis system. This construct combines the rapid thermal cycling capabilities of microfabricated PCR devices (10 degrees C/s heating, 2.5 degrees C/s cooling) with the high-speed (< 120 s) DNA separations provided by microfabricated CE chips.

Fluorescent particle image velocimetry: application to flow measurement in refractive index-matched porous media.

This paper presents results in which particle image velocimetry (PIV) is used in conjunction with refractive index matching to measure fluid flow velocities within complex, multiphase systems. This application required the adaptation of PIV for use with fluorescent, rather than scattering, seed particles; we refer to the technique as fluorescent PIV (FPIV). We applied index-matched FPIV to the measurement of low flow velocities (tens of microns per second) at high spatial resolution (tens of microns) in a porous medium.