MDT: A simple tool to facilitate dropcasting on in situ TEM MEMS chips

<i>In situ</i> transmission electron microscopy with holders based on the use of micro-electromechanical systems provides valuable insights into material kinetics, yet sample preparation remains complex due to fragile silicon nitride (Si₃N₄) windows and the risk of leaks and contamination during dropcasting. This results in failed experiments and increases experimental costs. This paper introduces the MEMS Dropcasting Tool (MDT), a cost-effective, in-house 3D-printable solution that confines the droplet to a specific area, preventing particle migration under the O-ring and reducing contamination risks at the inlet and outlet ports of closed cell chip holders.