Researchers from Cambridge University and Syngenta have designed and fabricated a new microfluidic device optimised to allow the fluorescence lifetime imaging and used computational techniques to subtract molecular diffusion effects to enable reaction processes to be studied in greater detail than ever before.
For example, the device could be used to study the quenching of a protein's fluorescent signal on binding a drug molecule with a fluorescent tag.
Such a tool would be especially useful to the drug screening market, where the development of an inexpensive disposable kinetics chip would "suit the pharmaceutical companies who would want to incinerate the chip at the end of the day," said Dr Adrian Fisher, lead author of the article.
The latest research, to be published in an upcoming issue of Analytical Chemistry, uses computational techniques to separate the reaction kinetics and reactant diffusion that occur within a specially designed microfluidic reactor to allow accurate kinetic analysis.
Microfluidic approaches have been successful at studying physical processes such as protein folding, reaction kinetics, diffusion (mass transfer) and phase transfer.
Fluorescence lifetime imaging microscopy (FLIM) is a powerful tool for studying the variation in the fluorescence decay of a fluorescent sample and can be used to study a molecule's interaction with its surroundings.
The use of microfluidic channels speeds up the mixing of reactants due to their small size, and enables researchers to study rapid kinetic processes within liquid media that would otherwise be masked by mass transport effects.
"The biggest problem is that it's hard to induce turbulence into a micro-reactor - you have to rely on diffusion for mixing," said Dr Fisher.
Because "you can't ignore mass transfer effects" Dr Fisher's group has used computational methods to subtract these effects from the specially designed device that contains a simple "Y" shaped channel that can be interrogated with FLIM.
Finite difference (FD) computational techniques were used to calculate the concentration and fluorescence lifetime distributions to allow the quantification of mass transport and reaction processes.
While the current device can only study those processes where a change in the fluorescence lifetime occurs, Dr Fisher's group is looking to incorporate inexpensive electrode sensors into similar devices.
This would allow researchers in the pharmaceutical industry to study the reduction - oxidation (redox) chemistry that goes on in a wealth of biochemical processes.
