Poly-D-Lysine Hydrobromide

Poly-lysine is a polycation which binds to DNA, red cell membrane and any negatively charged protein. When adsorbed to the culture surface, poly-lysine increases the number of positively charged sites available for cell binding. A compromise between the easier to use lower molecular weight products and the extremely viscous higher molecular weights would be the products in the range of 70,000-150,000.

It is typically used as a coating substrate for culture dishes, slides, etc. It enhances electrostatic interaction between negatively charged ions of the cell membrane and the culture surface. Both the D- and L- form of the poly-lysine can be used as a coating substrate since poly-lysine is a nonspecific attachment factor for cells; however, certain cells can digest poly-lysine. In this case, poly-D-lysine should be used as the attachment factor so that the cells are not disrupted by excessive uptake of L-lysine.

Other uses for poly-lysine have been reported as well:

• Conjugation to methotrexate for increased drug transport.
• Microencapsulation of islets.
• Use in simple reproducible procedure for chromosomal preparations from a variety of tissues.
• Immobilation of living cells in biocompatible semipermeable microcapsules.
• In the preparation of polycationic beads.
• Conjugation to albumin and horseradish peroxidase to enhance cellular uptake.

Poly-D-lysine hydrobromide is a synthetic amino acid that enhances cell adhesion to solid substrates. It has additionally been shown to eliminate prion proteins from infected cells.