The SDS-FRL technique together with HPF from neuroanatomy seems to be a sophisticated but once established in a lab a more reliable source for IHC than pre- and postembedding labeling for TEM. So I try to digest heart muscle tissue with buffered 2,5% SDS @ 80 C o/n after fractioning and replication but I obtained a jelly clumb of tissue. I wonder if this is due to the high collagen amount in the tissue and used a collagenase prior digestion with SDS, with minor more success. Does somebody have an idea how to digest heart muscle tissue entirely?