Genome Center 1 article published in JoVE Biology Internalization and Observation of Fluorescent Biomolecules in Living Microorganisms via Electroporation Louise Aigrain1,2, Marko Sustarsic1, Robert Crawford1, Anne Plochowietz1, Achillefs N. Kapanidis1 1Clarendon Laboratory, Department of Physics, University of Oxford, 2Wellcome Trust Sanger Institute, Genome Center Studies of biomolecules in vivo are crucial for understanding molecular function in a biological context. Here we describe a novel method allowing the internalization of fluorescent biomolecules, such as DNA or proteins, into living microorganisms. Analysis of in vivo data recorded by fluorescence microscopy is also presented and discussed.