A novel method to physically expand small biopsy tissue samples could help pathologists predict and diagnose disease more accurately using light microscopy. Researchers at the Massachusetts Institute of Technology, Harvard Medical School, and the Broad Institute developed the method, called expansion pathology (ExPath).
In ExPath, clinical samples are attached to a polymer that swells when wet. An enzyme called proteinase K digests parts of the samples that are not of interest before water is added, swelling the remaining tissues. Expanded to 100 times their original volume, the larger specimens enable 70-nm-resolution imaging on conventional diffraction-limited microscopes. This level of resolution is currently limited to costly electron microscopes, which are rarely used in the clinic.
Jennifer Abbasi. Expanded Tissue Samples Poised to Assist Pathologists. JAMA. 2017;318(10):898. doi:10.1001/jama.2017.13167