Abstract
Expansion microscopy (ExM) is a powerful imaging strategy that offers a low-cost solution for nanoimaging with conventional microscopes by physically and isotropically magnifying preserved biological specimens embedded in a cross-linked water-swellable hydrogel. Current ExM protocols require prior treatment with specialized reactive anchoring chemicals to link specific labels and biomolecule classes to the gel. In addition, most techniques reportedly use strong Proteinase K to digest endogenous epitopes to enable expansion and are limited by using mechanically fragile gel formulas to expand specimens by at most 4.5× linearly. Here we describe a new ExM framework, Molecule Anchorable Gel-enabled Nanoscale In-situ Fluorescence MicroscopY (MAGNIFY), that uses a mechanically sturdy gel that enables broad retention of nucleic acids, proteins, and lipids without the need for a separate anchoring step. MAGNIFY expands biological specimens up to 11× and facilitates imaging of cells and tissues with effectively ~25-nm-resolution using an ∼280-nm diffraction-limited objective lens on conventional optical microscopes or with ~13 nm-resolution if combined with Super-resolution Optical Fluctuation Imaging (SOFI). Further, MAGNIFY generalizes well across a broad range of biological specimens, providing insight into nanoscopic subcellular structures including synaptic proteins from mouse brain, podocyte foot processes in human kidney, and defects in cilia and basal bodies in drug-treated human lung organoids. MAGNIFY provides a novel advance that expands the precision, utility, accessibility, and generality of subcellular nanoscopy.
Low-Cost Implementation of Bilinear and Bicubic Image Interpolation for Real-Time Image Super-Resolution