Miniaturized and highly parallel protein crystallization on a microfluidic disc

For the first time we present a new microfluidic system for miniaturized and highly parallel protein crystallization experiments by the free interface diffusion (FID) method. The novel system is based on a microfluidic disc fabricated by hot embossing which features 100 protein crystallization chambers enabling up to 100 different crystallization experiments in parallel. The mi- crostructures exhibit minimal feature sizes of 30mum and a maximum aspect ratio of 1. The fluidic design of the disc enables lamination of nanoliter volumes of protein and crystallization solution (precipitant) in a crystallization chamber of minimum volume of 5 nL. The protein sample is loaded to the disc by a non-contact nL-dispenser with a minimal dosage volume of 1 nL and dead volume of only 500 nL. All liquid processing steps on the disc are accomplished by centrifugal forces caused by rotation of the disc. Up to 80mum large crystals of catalase, lysozyme, proteinase K and insulin, have been produced on the disc to demonstrate the proper performance. Subsequently the crystals have been analyzed in situ in an X-ray experiment without removing them from the disc.