Para-formaldehyde-glutaraldehyde in PBS is widely used as a fixative in biological and medical research. It is particularly effective for preserving tissue samples for histological and electron microscopy studies. The combination ensures excellent structural preservation by cross-linking proteins, maintaining cellular architecture, and preventing degradation. It is commonly employed in immunocytochemistry and immunohistochemistry to stabilize antigens for antibody binding. Additionally, it is used in the preparation of cell and tissue samples for long-term storage, ensuring minimal alteration of morphology. Its use in PBS provides a stable and isotonic environment, enhancing its effectiveness in preserving biological specimens.