Description:
The growth of the microarray market has been limited by detection methods
requiring complicated and unreliable external labeling. A new sampling and analysis
technique that quickly determines the elemental composition of a microscopic
sample was invented at ORNL. This sensitive, molecule-specific detection method
offers a rapid and reliable solution that can sample virtually any surface.
The automated sampling system moves over a microscopic surface, where proteins
and chemicals are arranged in self-assembling arrays, and directs a probe that takes
continuous samples. Samples are then transferred for analysis by mass spectroscopy.
When this approach is applied to sampling protein microarrays, it is possible for the
first time to rapidly identify complex protein interactions, protein substrates, and any
other components, such as candidates in the drug discovery process.
The invention uses a probe with flowing fluid to form a “liquid bridge” to the sample
surface. The probe applies a solvent to the sample that removes molecules adsorbed
to the surface and directs them up the probe. The analyte materials can be intact
proteins, protein fragments, pharmaceutical agents, or antibodies. An electrospray
ion source then ionizes the sample and breaks it into fragments. These fragments are
analyzed by mass spectroscopy, while the probe continues moving over the surface,
repeating the sampling process. A scanning probe electrochemical microscope
moves the probe over the surface, providing positional control with a minimum one
nanometer resolution.
