gold-coated microtiter plates

Matthias Pfeiffer pfeiffer at thermohybaid.de
Tue Aug 7 02:07:28 EST 2001

Try XNA on Gold by Thermo Hybaid.

XNA on Gold(tm) is the registered trade mark of the affinity array biochip
developed by ThermoHybaid. The biochip integrates scalar photolithographic
thick-film patterning and thin technologies with a robust, flexible, high
density Streptavidin-based immobilization scheme. This makes it possible to
use XNA on Gold(tm) with virtually any biological sensing element which can
be biotinylated. These biotinylated sensing elements may be purchased or
provided by the customer. The current format is designed to ask many
questions of a single sample.

A teflon-based hydrophobic thick film is used to pattern 50 µm deep
flat-wells. The sharp contrast between the hydrophobic thick film and the
hydrophilic streptavidin coated flat-wells reduces the risk of
cross-contamination during sensing element deposition. Quality control and
deposition of sensing elements are performed at our state-of-the-art biochip
facilities. The flat-well technology streamlines the assay procedure by
allowing the sample to be applied to the arrays in a single step.

Thin film immobilization technology is based on self-assembling monolayers
of long chain thiol alkanes adsorbed onto a layer of 24 carat gold only
10,000th of a millimeter thick. Biotin is coupled covalently to the surface
and saturated with Streptavidin. The robustness of the chemically bonded
self-assembling monolayers combined with the high affinity of the
streptavidin-biotin linker layer provide a flexible platform for assay
development. A newly developed adhesive frame simplifies sample addition and
eliminates evaporation effects. The chamber holds between 25 and 100 µl of

XNA on Gold(tm) is compatible with most imaging-based detection systems. At
present, radiometric and chemiluminescence provide the highest sensitivity
and largest linear range. A linear range of greater than 3 logs is achieved
typically with chemiluminescent detection for a single sensing element.
Simultaneous flourescent analysis of 96 sensing element arrays reduce the
linear range to 2 logs. Other detection systems, such as mass spectrometry,
imaging ellipsometry and reflectometry have been successfully applied. An
electrochemical detection is under investigation. 

XNA on Gold(tm) is designed to be compatible with a wide range of biological
assays and detection systems. Sensing elements ranging from nucleic acids,
such as DNA, RNA, and PNA to proteins such as antibodies and lectins can be
used. Use of the same assay format for ALL of your assays allows the
development of a unified protocol which simplifies laboratory automation,
streamlines the development of new assay routines and data analysis. The
integrated analysis of genomics, proteonomics and glyconomics provides a
powerful strategy for identifying subtle differences in complex biological

Currently, XNA on Gold(tm) is available in a 2 x 96 well format using a
microscope slide footprint (25 x 75 mm). The well size is 1.5 mm in diameter
and employs the standard 1536 well density (2.25mm spacing) making it
possible to use instruments and data analysis which conform to this
standard. The microscope slide footprint simplifies handling and allows the
use of a wide range of manual and automated slide handling equipment
available on the market. A 2 x 384 version using the microscope slide format
is under development. 



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