Fixation time is critical and varies depending on the type and size of the tissue. Over-fixation can cause excessive cross-linking, leading to hardening and difficulty in sectioning, while under-fixation can result in incomplete preservation. Here are some guidelines to optimize fixation time:
Small biopsies generally require 4-6 hours of fixation. Larger tissue samples may need 24-48 hours. For electron microscopy, shorter fixation times are often sufficient due to the small size of specimens.
