Does paraformaldehyde fixation disrupt cell membranes?

Paraformaldehyde (PFA) is a commonly used tissue fixative that is commonly used to fix proteins and cellular structures in biological samples. Although PFA can help maintain cellular structure and protein morphology, PFA fixation may cause damage to cell membranes because PFA is permeable to immobilize proteins inside and outside the cell and the permeability is not uniform from cell to cell. The appropriate fixative should be selected according to which aspect of the cell membrane will be used for the study.