thermally insulating, infrared (IR), HTS format micro-titer plates were
designed for monitoring thermal (IR radiation) signatures of proteins-ligand
binding processes. These plates can be used for direct and immediate
monitoring of various exothermic (and endothermic) reactions.
Two types of
plates: Plates with semi-spherical wells and plates with reflecting
parabolic wells, have been developed and tested to serve as reaction
chambers and sensitive monitors of thermal activity (IR emission).
of plates are molded from thermally insulating plastic (which minimizes
external thermal noise) and coated with an IR reflecting layer of gold. (See
Semi-spherical well plates:
An array of
IR radiation integrating spheres is created when two semi-spherical well
plates are sandwiched together. The bottom plate usually serves as a
reaction chamber, while the top matching plate accommodates an array of
sensors. These sensors provide an integrated signal proportional to the
internally generated thermal IR emission. Various sensors can be embedded
into the top plate wells either directly, or linked via special IR
transmitting optic fibers. Utilization of fiber-optic links provide the
flexibility to position sensors in a remote environment for enhanced
performance. (i.e. liquid nitrogen - for reduced thermal noise and increased
sensitivity). (See photo)
well plates have the same IR monitoring characteristics of the
semi-spherical plates except for one major advantage in sensitivity.
Parabolic wells can direct and concentrate IR signals to a focal point of
collection. In this arrangement plates are sandwiched together, such that
the reaction and sensor of each set of opposing wells are located at their
focal points, providing signal amplification with minimal noise gain.
Utilization of parabolic wells also has the added advantage of using a
readily available flat IR sensitive CCD array for detection.
typical thermal signature screening assay, a collection of individual
compounds under investigation and reference blanks are dispensed into wells
using the appropriate dispensing device. The common "binding ligand" is then
dispensed by the area
"shower" dispenser to trigger the simultaneous initiation of the
binding process. This bottom (reaction) plate is covered immediately by the
top sensing plate, which will begin to monitor the thermal signatures of
each reaction and enable the comparative (ratiometric) analysis of activity
from all wells. The data can then be integrated into a profiling database.
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