Chiral catalysis on a chip

Chiral catalysis and analytical separation of the resulting enantiomers can now be performed on a single chip. The process could be scaled up to serve in high throughput screening for new enantioselective catalysts, claim the chemists who developed the chip. 

Detlev Belder and Manfret Reetz at the Max Planck Institute, M?lheim, Germany, created an integrated catalysis-analysis chip that combines a reaction channel with a separation channel. The reagents are loaded into separate microvials, from where they are sucked - using either a vacuum or an electrical field - into a long reaction channel designed to ensure mixing and incubation. A miniaturised version of capillary electrophoresis known as microchip electrophoresis (MCE) serves to separate and analyse the products of the reaction. Belder’s team had previously shown that this technique can perform the separation of enantiomers at record-breaking speed. 

As a prototype application for their new lab-on-a-chip system, the researchers analysed the enantioselectivity of mutant epoxide hydrolase enzymes, which relate to Reetz’s work on optimising enzymes by artificial evolution. In the case of the wild type enzyme from the fungus Aspergillus niger, the researchers could even use cell lysates and whole cells for the analysis. The device is well suited for high-throughput screening, they added.

Hans Niemantsverdriet from the Technical University Eindhoven agrees. ’The work elegantly illustrates the potential of miniaturised catalytic devices   for research purposes,’ Niemantsverdriet told Chemistry World. ’I am convinced that small to medium sized catalytic devices also have a future in the production of specialty products, in particular if we learn how to integrate smart catalysts with measuring and control techniques on the microscale.’ 

Michael Gross