Poly-L-lysine hydrobromide

Poly-L-lysine polymers can be used in promoting cell adhesion to solid substrates, conjugation to methotrexate for increased drug transport, microencapsulation of islets, cell microencapsulation technology, microarray glass slide coating, and chromosomal preparations. It has also been used as a transfection agent for efficient labeling and to facilitate endocytosis. Lower molecular weight poly-L-lysine (30,000-70,000) is less viscuous in solution, but higher molecular weight versions provide more attachment sites per molecule.

Poly-L-lysine 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. When it is absorbed to the cell culture surface, poly-L-lysine functions to increase the number of positively charged sites available for cell binding. With cells that can digest poly-L-lysine, poly-D-lysine should be used as the attachment factor.

Poly-L-lysine hydrobromide has a molecular weight >300,000. To remove the HBr, dissolve this product in a neutral buffer and dialyze to remove the salts. None of the poly-L-lysine products have been exposed to trifluoroacetic acid and are dialyzed to remove any monomers, dimmers, or trimers, confirmed by thin layer chromatography. 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.

Molecular weight based on viscosity and is also assayed by MALLS.

La poly-L-lysine est un polymère d′acide aminé à charge positive, comportant environ un HBr par résidu de lysine. Le bromhydrate permet de former une poudre cristalline de poly-L-lysine soluble dans l′eau. Une petite quantité de produit peut se trouver dans des structures bêta, car le HBr interfère avec la formation de liaisons d′hydrogène entre les groupes aminés et les groupes carboxyliques ou les parties contenant des atomes N ou O.

Les solutions stériles sont stables pendant environ 2 ans si conservées entre 2 et 8 °C. Conserver à une température de -20  C en présence d′un déshydratant.