Polymer microfluidic chip for online monitoring of microarray hybridizations.
A disposable single use polymer microfluidics chip has been developed and manufactured by micro injection molding. The chip has the same outer dimensions as a standard microscope slide (25 x 76 x 1.1 mm) and is designed to be compatible with existing microscope slide handling equipment like microarray scanners. The chip contains an inlet, a 10 microL hybridization chamber capable of holding a 1000 spot array, a waste chamber and a vent to allow air to escape when sample is injected. The hybridization chamber ensures highly homogeneous hybridization conditions across the microarray. We describe the use of this chip in a flexible setup with fluorescence based detection, temperature control and liquid handling by computer controlled syringe pumps. The chip and the setup presented in this article provide a powerful tool for highly parallel studies of kinetics and thermodynamics of duplex formation in DNA microarrays. The experimental setup presented in this article enables the on-chip microarray to be hybridized and monitored at several different stringency conditions during a single assay. The performance of the chip and the setup is demonstrated by on-line measurements of a hybridization of a DNA target solution to a microarray. A presented numerical model indicates that the hybridization process in microfluidic hybridization assays is diffusion limited, due to the low values of the diffusion coefficients D of the DNA and RNA molecules involved.
Noerholm
Mikkel
M
Exiqon A/S, Bygstubben 9, DK-2950 Vedbaek, Denmark. noerholm@exiqon.com
Bruus
Henrik
H
Jakobsen
Mogens H
MH
Telleman
Pieter
P
Ramsing
Niels B
NB
D001331:Automation; D004058:Diffusion; D004867:Equipment Design; D005453:Fluorescence; D044085:Microfluidics / Q000379:methods*; D009693:Nucleic Acid Hybridization; D020411:Oligonucleotide Array Sequence Analysis / Q000379:methods*; D011108:Polymers / Q000737:chemistry*; D012212:Rheology; D013696:Temperature
D011108:Polymers