39、英文描述
Purpose of fixation is to preserve the original morphological structure of cells and tissues. Fixatives prevent autolysis of tissues and cells by endogenous lysosomal enzymes and inhibit the growth of bacteria and molds. Fixatives are categorized into aldehyde, mercury‑based, alcoholic, oxidizing agent, and picrate fixatives, among others. Formalin (aldehyde‑based) and ethanol (alcohol‑based) are the most commonly used ones.
The environmentally‑friendly tissue fixative (ready‑to‑use) is mainly formulated with plant polysaccharides and polyvinyl alcohol. It contains no harmful substances such as formaldehyde and is a non‑toxic eco‑friendly fixative. It yields well‑defined morphological structures and high background contrast for conventional paraffin‑embedded sections. It outperforms formaldehyde‑based fixatives in immunohistochemistry and molecular pathology. Most antibodies do not require antigen retrieval, which reduces fixation‑induced false‑positive results. The histomorphology of specimens fixed with this product is comparable to that of formaldehyde‑fixed samples, showing clear tissue‑cellular architecture without vacuolization or karyopyknosis. It features colorless appearance and non‑irritating, non‑toxic volatile components. Formaldehyde‑free, it can fully replace formaldehyde as a routine fixative in histopathology and cytopathology laboratories, minimizing health hazards for staff in pathology and surgery departments as well as environmental pollution. It is applicable to routine histopathological sectioning and staining, classical histochemistry and cytochemistry, immunohistochemistry and immunocytochemistry, in‑situ hybridization and other novel molecular pathological techniques. Suitable for fixation of most tissues and cells, it is one of the preferred fixatives for immunohistochemistry and cultured cells, and provides good preservation of cellular‑tissue morphology and nucleic acids. For research use only; not intended for clinical diagnosis or other clinical applications.
Procedures (for reference only):
1. Use directly without dilution according to experimental requirements.
2. Fixation time for general specimens: 1‑4 h per millimeter of tissue thickness; extend duration for large specimens.
3. Post‑fixed tissues can be stored long‑term in 10% formalin or 70% ethanol.
Precautions
1. Fixation performance may decline upon long‑term storage after opening.
2. Avoid excessive fixation duration, which may cause over‑crosslinking of biomacromolecules. Fixation time varies with tissue thickness.
3. Use sufficient volume of fixative; the volume ratio of fixative to tissue block shall be greater than 10:1.
4. Temperature markedly affects fixation. Elevated temperature accelerates fixation, yet excessive temperature should be avoided.
5. Fresh tissues should be fixed promptly. If immediate fixation is unavailable, store tissues in normal saline for timely delivery.
6. Use the reagent promptly after opening to avoid compromised experimental results.
