Sigma-Aldrich POLY-L-LYSINE HYDROBROMIDE MOL WT

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. 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 hydrobromide has been used:

• as a component of polyplexes and in DNA condensation experiments[1]
• for coating circular mica disks for atomic force microscopy studies[2] and SuperFrost glass slides for immunofluorescence studies of in HL-60 cells[3]
• as a reference standard for generating calibration curve for the quantification of ε- Poly-L-lysine[4]

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

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. 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.