Poly-D-lysine hydrobromide

Poly-D-lysine polymers can be used in preparing surfaces for cell attachment. The D-lysine polymers can also be used with cells that digest poly-L-lysine polymers and cause an excessive uptake of L-lysine.

This product is recommended as a cell culture substratum when using 0.5 - 1.0 mL of a 0.1 mg/mL solution to coat 25 cm². Lower molecular weight versions of the product are less viscous, but high more molecular weight versions provide more attachment sites per molecule.

Poly-D-lysine (PDL) hydrobromide is a nonspecific attachment factor for cells useful in promoting cell adhesion to solid substrates by enhancing electrostatic interaction between negatively charged ions of the cell membrane and the culture surface. After absorption to the culture surface, poly-D-lysine increases the number of positively charged cell binding sites.

Poly-D-lysine is a positively charged amino acid polymer with approximately one HBr per lysine residue. The hydrobromide allows the poly-D-lysine to be in a crystalline form soluble in water. A small amount of product may be found in the ß structure because the HBr interferes with hydrogen bonding between amino and either the carboxyl groups or N or O containing moieties.

Sterile solutions are stable for up to 2 years when stored at 2-8°C. It should be stored desiccated at -20°C.

This product has a molecular weight of 4,000-15,000. To remove the HBr, dissolve this product in a neutral buffer and dialyze to remove the salts. In general, to use this product as an attachment factor, add 50 mL of sterile tissue culture grade water to 5 mg of poly-lysine, and aseptically coat the surface with 1 mL per 25 cm² of solution. After 5 minutes, remove the solution through aspiration and thoroughly rinse the surface. Let dry for two hours before introducing cells and medium.