Microliter Volumes Of Fluid Research Articles

Isolation and analysis of amyloid-β 1-42 monomer and oligomers in liquid droplets using an immunoaffinity membrane.

Monomeric molecules such as amyloid-β can aggregate and transform into oligomeric and fibrous forms, which are implicated in the development and progression of Alzheimer's disease. Novel analytical techniques for the formation of oligomers are required to examine the neurotoxic amyloid-β oligomers involving fibrils. After isolating amyloid-β monomer 1-42 using a biotinylated antibody bound to membrane-immobilized avidin (immunoaffinity membrane), their masses were determined by MALDI-TOF MS. Fluorometric determination of more than 0.5μM of aggregated amyloid-β in pipette droplets was performed after aggregation and dilution of 1mM amyloid-β. Thus, large (>105nm) amyloid-β oligomers in microliter volumes of fluids were isolated using the immunoaffinity membrane and quantitatively analyzed after removal of amyloid-β monomers and small oligomers by non-denaturing electrophoresis. In addition, amyloid-β oligomers were specifically isolated from a mixture of human plasma and aggregated amyloid-β and then fluorometrically analyzed. Our results show that the combination of immunoaffinity membrane-binding and fluorescence determinations together with one drop analysis could be used to isolate and detect huge neurotoxic amyloid-β oligomers such as fibrils in plasma samples.

Microchip-Based Assay Systems: Methods and Applications. Pierre N. Floriano, editor. Totowa, NJ: Humana Press, 2007, 229 pp; (hardcover). ISBN 978-1-59745-426-1

This is volume 385 in the long-established Methods in Molecular Biology series and is devoted to analytical microchips (lab-on-a-chip), one of the most actively developing areas in analytical chemistry and analytical biochemistry. The scope of analytical microchips spans microfluidic chips that allow control of microliter volumes of fluid, bioelectronic chips that incorporate both microfluidic and electronic control or detection components, and microarray chips formed from dense arrays of protein or nucleic acid reagents. Applications for each type of chip are presented among the 16 chapters in this book. This volume places heavy emphasis on analytical microchips fabricated from polymers, such …

Silicon-based ultrasonic microsensors and micropumps

Abstract With the addition of a thin piezoelectric zinc oxide film and transducing electrodes, a thin membrane of low-stress silicon nitride formed in a silicon die can be made into a versatile ultrasonic sensor and actuator. We will describe the fabrication and application of this device, which typically operates in the low megahertz frequency range and can perform many functions: measuring the viscosity of microliter volumes of liquids; measuring the densities of gases and liquids; serving, with the addition of a thin polymer film, as a sensor for measuring the concentrations of organic gases; determining, when immersed in a liquid, the mass per unit membrane area of adsorbed protein molecules, cells and bacteria; pumping air at velocitities of centimerters per second and pumping water at hundreds of microns per second; and stirring microliter volumes of fluids.

An inexpensive rotary infusion pump for delivering microliter volumes of fluids to animal subjects

The study of chemosensory responsiveness in developing animals often involves experimental designs in which fluid stimuli are infused into the mouth of the subject. In this report we describe an inexpensive alternative to commercially available syringe pumps for automatically delivering intraoral infusions on a programmed schedule.