4% Paraformaldehyde (PFA) Solution in PBS (with DEPC)

General Description

Paraformaldehyde (PFA) is the polymerization product of formaldehyde with a typical degree of polymerization of 8–100 units. Paraformaldehyde is not a fixative itself; it must be depolymerized to formaldehyde in solution. In cell culture, typical formaldehyde fixing procedure would involve using a 4% formaldehyde solution in phosphate buffered saline (PBS) on ice for 10 minutes. Fixing ensures that sample cell structures stay intact and that antigens are immobilized, while ideally still permitting unfettered access of antibodies to target antigens.

Our 4% Paraformaldehyde is the most preferred fixative agent as it builds covalent cross-links between molecules. This glues them together hence effectively preserving cells and tissue components. Use of this 4% paraformaldehyde can guarantee consistency in the physical and chemical properties of the cell, hence no change in chemical and morphology characteristics of the cells and tissues.

Since the 4% paraformaldehyde is not fixative itself, it is required that formaldehyde is freshly prepared from the PFA stock.

Overview

Properties

Safety and Handling

•Causes serious eye damage .

• Suspected of causing cancer.

• May cause an allergic skin reaction.

• Causes skin irritation.

• Avoid breathing dust/fume/gas/mist/vapors/spray.

• Wear protective gloves/protective clothing/eye protection/face protection.

•IF IN EYES: Rinse cautiously with water for several minutes. Remove contact lenses, if present and easy to do. Continue rinsing.

• Store locked up.

•Dispose of contents/container in accordance with local/regional/national/international regulations.

General Notes

• Adjust pH to 7.2-7.6 with NaH2PO4 if pH <7 after long storage.

• Deposition is normal for this product.

4% Paraformaldehyde Recipe

To prepare a solution of 4% paraformaldehyde you need to use this protocol. The following ingredients are required:

•1M Sodium Hydroxide

•10X phosphate-buffered saline (PBS)

•1M Hydrochloric acid

Note: This should be done in a fume chamber with gloves, safety glasses, and a face mask.

1. To prepare a 4% of paraformaldehyde (PFA) solution in PBS, add 4 grams of granular or prill paraformaldehyde to water (H2O)

2. Use stirring hot plate to heat the solution to 60-degree celsius. Add 1mL of 1M NaOH until the paraformaldehyde is fully dissolved.

3. Add 10 mL of 10x phosphate-buffered saline (PBS) and allow the mixture to cool.

4. Adjust the solution pH with 1M HCL then top up the volume to 100 mL with H2O.

5. Filter the solution to remove any deposit.

Validation Images & Assay Conditions

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