UniversitE J. Fourier 2 articles published in JoVE Bioengineering Traction Force Microscopy to Study B Lymphocyte Activation Anita Kumari1, Judith Pineau1, Ana-Maria Lennon-Duménil1, Martial Balland2, Paolo Pierobon1 1Institut Curie, PSL Research University, INSERM U932, 2Laboratoire Interdisciplinaire de Physique, Université Joseph Fourier (Grenoble 1) Here we present a protocol used to perform traction force microscopy experiments on B cells. We describe the preparation of soft polyacrylamide gels and their functionalization, as well as data acquisition at the microscope and a summary of data analysis. Chemistry Matrix-assisted Laser Desorption/Ionization Time of Flight (MALDI-TOF) Mass Spectrometric Analysis of Intact Proteins Larger than 100 kDa Luca Signor1, Elisabetta Boeri Erba1 1Institute of Structural Biology "J.P. Ebel", UMR5075, Commissariat à L'Energie Atomique et aux Energies Alternatives (CEA), Centre National de la Recherche Scientifique (CNRS), Université J. Fourier Accurate mass measurement represents an important step during the investigation of proteins. Matrix-assisted laser desorption/ionization (MALDI) mass spectrometry (MS) can be used for such determination and its key advantage is the tolerance to salts, detergents and contaminants. Here we illustrate an accessible approach for the analysis of proteins larger than 100 kDa by MALDI-MS.