FibrilJ: ImageJ plugin for fibrils' diameter and persistence length determination

Solution method: For this purpose we developed a FibrilJ plugin for ImageJ/FiJi program with an open source code. It automatically recognizes the fibrils on the surface of a mica, silicon, gold or formvar film and further analyzes them to calculate the distribution of fibrils on average diameters, lengths and persistence lengths. FibrilJ usage may unify the process of diameter and persistence length calculation and it may also contribute to comparison of results obtained by different research groups. Plugin FibrilJ which is presentedin this paper is free of DiameterJ or BoneJ weaknesses. It has been validated by artificially created images of rod-shape objects with predefined parameters and micrographs of Sup35NM protein fibrils.