Self-contained on-chip fluid actuation for flow initiation in liquid cell transmission electron microscopy

Liquid cells for transmission electron microscopy enable the observation of liquid samples with nanometer resolution, but sample activity must often be triggered via external stimuli including liquid flow and mixing. Existing devices enable flow using specialized TEM holders and external pumping setups which limits technique accessibility. Here, a liquid cell with integrated MEMS valves and pumps is demonstrated with flow capabilities using an electrical-contact holder. On-chip electrochemical pumps and capillary burst valves allow for the injection of fluid from an integrated reservoir into an observation chamber using only electrical signals from a general microchip-sized TEM holder.