Paraformaldehyde Fixative is commonly used in immunohistochemicstry and immunocytochemistry. It is relatively mild and can well preserve antigenicity and ultrastructure, suitable for long-term storage of tissue speicimen and cell sections in tissue and cell immunohistochemistry research. 4% PFA, RNase/DNase free is mainly composed of PFA, phosphate salts, enzyme-free sterile water, pH7.2-7.4, suitable for fixation of most tissue and cells, especially for experiments on RNA and DNA as it can well protect structure and RNA/DNA in tissue and cells. This product is for scientific research only, not supposed for clinical diagnosis. This product (3ml and 15ml) is in PBS-prefilled tube, sterile and enzyme-free, can directly fix cleaned tissue.