Biomedical subjects

Po Ki Yuen

Publications and source records attributed to Po Ki Yuen.

4 recordsLinked to original sources

PubMed2003

Microbarcode sorting device.

A novel and simple microfluidic device was developed for sorting 20 microm thick glass microbarcodes for imaging or scanning at the completion of a bead-based assay. Specifically, the microbarcodes are dried and kept from stacking on top of one another such that a monolayer of microbarcodes is created and the microbarcodes lay flat on a surface. The microbarcode sorting device consists of a reservoir, a sorting region, and a network of microchannels. With minimal microbarcodes loss, a monolayer of microbarcodes is created and trapped inside the sorting region for conveniently imaging or scanning. The device can also be used for any geometrical shaped beads with a range of thicknesses and can be adapted to a 96-well plate format for high throughput analysis.

Animals↗

PubMed2003

Rare earth-doped glass microbarcodes.

The development of ultraminiaturized identification tags has applications in fields ranging from advanced biotechnology to security. This paper describes micrometer-sized glass barcodes containing a pattern of different fluorescent materials that are easily identified by using a UV lamp and an optical microscope. A model DNA hybridization assay using these "microbarcodes" is described. Rare earth-doped glasses were chosen because of their narrow emission bands, high quantum efficiencies, noninterference with common fluorescent labels, and inertness to most organic and aqueous solvents. These properties and the large number (>1 million) of possible combinations of these microbarcodes make them attractive for use in multiplexed bioassays and general encoding.

Biotechnology↗

PubMed2002

Microfluidic devices for fluidic circulation and mixing improve hybridization signal intensity on DNA arrays.

Reactions of biomolecules with surface mounted materials on microscope slides are often limited by slow diffusion kinetics, especially in low volumes where diffusion is the only means of mixing. This is a particular problem for reactions where only small amounts of analyte are available and the required reaction volume limits the analyte concentration. A low volume microfluidic device consisting of two interconnected 9 mm x 37.5 mm reaction chambers was developed to allow mixing and closed loop fluidic circulation over most of the surface of a microscope slide. Fluid samples are moved from one reaction chamber to the other by the rotation of a magnetic stirring bar that is driven by a standard magnetic stirrer. We demonstrate that circulation and mixing of different reagents can be efficiently accomplished by this closed loop device with solutions varying in viscosity from 1 to 16.2 centipoise. We also show by example of a microarray hybridization that the reaction efficiency can be enhanced 2-5 fold through fluid mixing under conditions where diffusion is rate limiting. For comparison, similar results were achieved with a disposable commercial device that covers only half of the reaction area of the closed loop device.

DNA↗

PubMed1998

Controlling chaotic convection using neural nets-theory and experiments.

An exploratory study is conducted to assess the feasibility of using neural networks to control flow patterns and to evaluate the performance of these controllers. Neural networks were used to control (suppress) chaotic convection both in experiments and in a theoretical model of a thermal convection loop. It is demonstrated that the neural network controller can successfully cause the flow to behave in a desired way. The performance of the neural network controllers was compared with that of previously used conventional linear proportional controllers.

Journal Article↗