Massachusetts Institute of Technology

Harvard College

Paul Warren Tillberg

Edward Stuart Boyden

Fei Chen

Adam H Marblestone

George M Church

Evan R Daugharthy

Shahar Alon

Mark Andrew Skylar-Scott

Ruixuan Gao

Chih-Chieh Yu

Samuel Gordon Rodriques

Daniel Oran

Jae-Byum Chang

Shoh Asano

The present invention leverages the techniques for expansion microscopy (ExM) to provide improved high-throughput super-resolution whole-organ imaging methodology to image protein architectures over whole organs with nanoscale resolution by using high-throughput microscopes in combination with samples that have been iteratively expanded more than once, in a method referred to herein as 'iterative expansion microscopy' (iExM). In the ExM method, biological samples of interest are permeated with a swellable material that results in the sample becoming embedded in the swellable material, and then the sample can be expanded isotropically in three dimensions The process of iteratively expanding the samples can be applied to samples that have been already expanded using ExM techniques one or more additional times to iteratively expand them such that, for example, a 5-fold expanded specimen can be expanded again 3- to 4-fold, resulting in as much as a 17- to 19-fold or more linear expansion.

Iterative expansion microscopy

The present invention enables three-dimensional nanofabrication by isotropic shrinking of patterned hydrogels. A hydrogel is first expanded, the rate of expansion being controlled by the concentration of the crosslinker. The hydrogel is then infused with a reactive group and patterned in three dimensions using a photon beam through a limited-diffraction microscope. Functional particles or materials are then deposited on the pattern. The hydrogel is then shrunk and cleaved from the pattern.

Three-dimensional nanofabrication by patterning of hydrogels

The invention provides in situ nucleic acid sequencing to be conducted in biological specimens that have been physically expanded. The invention leverages the techniques for expansion microscopy (ExM) to provide new methods for in situ sequencing of nucleic acids as well as new methods for fluorescent in situ sequencing (FISSEQ) in a new process referred to herein as 'expansion sequencing' (ExSEQ).

In situ nucleic acid sequencing of expanded biological samples

The invention provides a method termed protein retention ExM (proExM), in which proteins, rather than labels, are anchored to the swellable gel, using a cross-linking molecule. This proExM strategy can be used to perform nanoscale imaging of immunostained cells and tissues as well as samples expressing various FPs as fluorescent signals from genetically encoded fluorescent proteins and/or conventional fluorescently labeled secondary antibodies and streptavidin that are directly anchored to the gel are preserved even when subjected to the nonspecific proteolytic digestion.

Protein retention expansion microscopy

The present invention relates to an enlarged sample of interest for microscopy and methods for enlarging a sample of interest and the optical imaging of a sample of interest with resolution better than the classical microscopy diffraction limit, by synthesizing a swellable polymer network within a sample, it can be physically expanded, resulting in physical magnification.

Expansion microscopy

Growing community of inventors

Cambridge, MA, United States of America

Paul Warren Tillberg