INSERM U1201 1 article published in JoVE Biology Preparation and Observation of Thick Biological Samples by Scanning Transmission Electron Tomography Sylvain Trépout1, Philippe Bastin2, Sergio Marco1 1Institut Curie, INSERM U1196, Campus Universitaire d'Orsay, 2Institut Pasteur, Trypanosome Cell Biology Unit, Department of Parasites & Insect Vectors, INSERM U1201 This report describes a sample preparation protocol and specific imaging conditions for performing scanning transmission electron tomography of thick biological specimens.