 Direct Evidence of the Presence of Cross-Linked Aβ Dimers in the Brains of Alzheimer’s Disease Patients Aurelio Vázquez de la Torre, 1# Marina Gay, 2# Sílvia Vilaprinyó-Pascual, 1 Roberta Mazzucato, 1 Montserrat Serra-Batiste, 1 Marta Vilaseca, 2 Natàlia Carulla 1,3* 1 Institute for Research in Biomedicine (IRB Barcelona), The Barcelona Institute of Science and Technology (BIST), Baldiri Reixac 10, 08028 Barcelona, Spain 2 Mass Spectrometry and Proteomics Core Facility, Institute for Research in Biomedicine (IRB Barcelona), The Barcelona Institute of Science and Technology (BIST), Baldiri Reixac 10, Barcelona 08028, Spain 3 CBMN (UMR 5248), University of Bordeaux – CNRS – IPB, Institut Européen de Chimie et Biologie, 2 rue Escarpit, 33600, Pessac, France  Both authors have contributed equally to this work * Corresponding author: Natàlia Carulla, 2 rue Escarpit, 33600, Pessac, France, telephone: +33 (0) 5 4000 3008, e-mail: n.carulla@iecb.u-bordeaux.fr