Femtosecond nanocrystallography is an emerging technique with the potential to obtain structural information of membrane proteins without the need to grow large crystals. Current crystallization methods for membrane proteins produce a broad crystal size distribution which hampers the effectiveness of nanocrystallography experiments. To isolate the desired nanocrystals from a bulk solution, we propose a microfluidic method to sort photosystem I crystals based on size using a combination of dielectrophoresis and electrokinesis within a microfluidic device.  A model system utilizing polystyrene beads of two sizes demonstrates the size selectivity of this approach by numerical modeling as well as experimentally based on particle counting and fluorescence intensity measurements.  When applied to sort photosystem I crystals, the device shows excellent selectivity for sizes below 1 �m as verified by dynamic light scattering. This sorting device thus represents a promising solution for protein nanocrystal sorting.

Nanocrystal sorting for femtosecond nanocrystallography of proteins

245th National Meeting (2013)

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