Poly-L-lysine amplification of protamine immobilization and heparin adsorption.

We previously reported the development of a cellulose fiber based blood filter device containing immobilized protamine (termed protamine filter) that could be used to control both heparin- and protamine-induced complications during extracorporeal therapy. To achieve enhanced heparin adsorption on the fibers, we examined the possibility of utilizing the poly-L-lysine based amplification method to augment protamine loading on the fiber, as well as to create multiple layers of immobilized protamine for heparin interaction. Results show that such a method yielded about a threefold increase in protamine loading and, consequently, about a fourfold enhancement in heparin adsorption when compared with the control without poly-L-lysine amplification. This technological improvement may facilitate development of a new generation of protamine filters with capacity and efficacy suitable for various clinical applications in extracorporeal heparin removal.