Poly-L-lysine hydrobromide

Poly-L-lysine serves as a versatile and indispensable component in cell culture and biochemical research. It plays a pivotal role in promoting cell adhesion to solid substrates by enhancing the electrostatic interactions between the negatively charged ions of cell membranes and the positively charged ions of attachment factors on culture surfaces. This facilitates a secure binding of cells to the substratum, making Poly-L-lysine highly recommended for cell culture applications.

Derived from the naturally occurring amino acid l-lysine, Poly-L-lysine is available in various forms, allowing for customization in terms of molecular weight and shape. As a synthetic positively charged polymer, it exists in two enantiomers, poly-D-lysine and poly-L-lysine, both of which have their unique applications.

In formulation research, Poly-L-lysine proves to be valuable in nucleic acid delivery. Its positive charge, attributed to the ε-amine on its side chain at physiological pH, enables it to condense plasmid DNA effectively based on salt concentration. While Poly-L-lysine appears suitable for gene delivery, unmodified versions have been associated with low transfection efficiency and cytotoxicity.

In conclusion, Poly-L-lysine offers a multifaceted solution in cell culture and formulation research, enhancing cell adhesion, enabling gene delivery, and contributing significantly to advancements in biochemical and cell biology research.

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 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 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.

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 30,000-70,000. 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 was also assayed by MALLS.