Massachusetts Institute of Technology
Joha Park1,2,†, Sarim Khan1,3,†, Dae Hee Yun1,2,4,†, Taeyun Ku1,2,‡, Katherine L. Villa2,4,§, Jiachen E. Lee2,4, Qiangge Zhang4,5,6, Juhyuk Park1,2,7,8, Guoping Feng4,5,6, Elly Nedivi2,4,*, Kwanghun Chung1,2,4,7,8,9,*
1Institute for Medical Engineering and Science, Massachusetts Institute of Technology (MIT), Cambridge, MA 02139, USA. 2Picower Institute for Learning and Memory, MIT, Cambridge, MA 02139, USA. 3Department of Chemical Engineering, Indian Institute of Technology (IIT), Roorkee, Uttarakhand 247667, India. 4Department of Brain and Cognitive Sciences, MIT, Cambridge, MA 02139, USA. 5McGovern Institute for Brain Research, MIT, Cambridge, MA 02139, USA. 6Broad Institute of MIT and Harvard University, Cambridge, MA 02142, USA. 7Department of Chemical Engineering, MIT, Cambridge, MA 02142, USA. 8Center for Nanomedicine, Institute for Basic Science (IBS), Seoul 03722, Republic of Korea. 9Graduate Program of Nano Biomedical Engineer-ing (NanoBME), Advanced Science Institute, Yonsei University, Seoul 03722, Re-public of Korea.
†These authors contributed equally to this work.
‡Present address: KAIST Graduate School of Medical Science and Engineering, Daejeon 34141, Republic of Korea.
§Present address: Tevard Biosciences, Cambridge, MA 02139, USA
Synthetic tissue-hydrogel methods have enabled superresolution investigation of biological systems using diffraction-limited microscopy. However, chemical modification by fixatives can cause loss of antigenicity, limiting molecular interrogation of the tissue gel. Here, we present epitope-preserving magnified analysis of proteome (eMAP) that uses purely physical tissue-gel hybridization to minimize the loss of antigenicity while allowing permanent anchoring of biomolecules. We achieved success rates of 96% and 94% with synaptic antibodies for mouse and marmoset brains, respectively. Maximal preservation of antigenicity allows imaging of nanoscopic architectures in 1000-fold expanded tissues without additional signal amplification. eMAP-processed tissue gel can endure repeated staining and destaining without epitope loss or structural damage, enabling highly multiplexed proteomic analysis. We demonstrated the utility of eMAP as a nanoscopic proteomic interrogation tool by investigating molecular heterogeneity in inhibitory synapses in the mouse brain neocortex and characterizing the spatial distributions of synaptic proteins within synapses in mouse and marmoset brains.