Expansion microscopy is a novel technique used to enlarge biological structures in a uniform manner so their structures can be imaged and analysed. This technique is used to overcome resolution limits which normally prevent the detailed imaging of very small structures using light microscopy. In the Richter labs, this process is useful in enlarging perineuronal nets (PNNs) to image and understand more about their physical and chemical properties.

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Process for perineuronal nets

1. Tissues containing PNNs are fixed, and immunocytochemistry is conducted to label structures of interest, in this case PNNs.

2. A polymer gel is then added which linking the PNN components together so that expansion can enlarge the structure in a uniform manner.

3. Cells are digested so that only the PNNs are expanded.

4. The structure embedded within the gel is physically expanded by inducing the hydrogel to swell. Fluorescence microscopy is used to image the PNN structures