Expansion microscopy (ExM) is a sample preparation tool for biological samples that allows investigators to identify small structures by expanding them using a polymer system.[1] The premise is to introduce a polymer network into cellular or tissue samples, and then physically expand that polymer network using chemical reactions to increase the size of the biological structures. Among other benefits, ExM allows those small structures to be imaged with a wider range of microscopy techniques. It was first proposed in a 2015 article by Fei Chen, Paul W. Tillberg, and Edward Boyden.[2] Current research allows for the expansion of samples up to 16x larger than their initial size.[3] This technique has been found useful in various laboratory settings, such as analyzing biological molecules. ExM allows researchers to use standard equipment in identifying small structures, but requires following of procedures in order to ensure clear results.