To test this approach, he and his colleagues fabricated a metal-coated dual-channel electrospray emitter, in which a single circular capillary, just 4.5 μm in diameter, is divided into two semi-circular channels. After first spraying different colour dye molecules from each channel and showing that the resultant Taylor cones merge together, the scientists sprayed the antibiotic vancyomycin from one channel and a version of the peptide it binds to from the other.
As expected, the two molecules bound to each other within the merged, femtolitre-size Taylor cone, with the whole reaction process taking just a few tens of microseconds. The resultant molecular complex formed by vancyomycin and the peptide could clearly be detected by the mass spectrometer.
"We showed that a device that works as hoped can be fabricated and that biochemical reactions do occur within the very small volume," says Derrick.
As well as offering a novel way to study biochemical reactions, this approach could provide a whole new way to conduct electrospray ionization. "This could become the standard method of doing electrospray," says Derrick, "because none of the myriad beneficial capabilities of present-day electrospray are lost through using just one channel for the sample. The other channel could then be used for compounds that can probe the chemical properties of the sample."
|Contact: Professor Peter Derrick|
IM Publications LLP