MIPAR and ImageJ FIJI as Tools for Electron Microscopy Quantification of Amyloid Fibrils

Measuring of tau filaments is an important method that can provide useful information in the study of tau <i>in vitro</i>. However, methods such as right-angle laser light scattering and Thioflavin T fluorescence assay only provide bulk information on the amount of tau aggregation that is occurring. Electron microscopy (EM) can be used to provide a semiquantitative method on the lengths of individual filaments and provide a length distribution of tau aggregates. The issue with quantifying tau aggregation through EM is that it can be time costly if done manually. Here we explore two different programs, MIPAR and ImageJ FIJI, as methods to automate the quantification of EM grids. Using both programs to measure filaments produced from inducing 2N4R tau with the fatty acid arachidonic acid (ARA), we are able to reliably measure filaments producing similar results from MIPAR and ImageJ, with these methods applicable to other filamentous biological structures.