Co-Immobilization and Interaction of Heparin and Plasmin on Collageno-Elastic Tubes

Abstract

Heparin and plasmin were co-immobilized on collageno-elastic tubes (CETs) in order to develop a thromboresistant and fibrinolytic vascular prosthesis. The mutual interaction between heparin and plasmin both in the soluble and in the immobilized state was studied. The immobilization condition rendering maximum co-immobilized heparin and plasmin activity was identified to require heparin immobilization followed by plasmin immobilization. Soluble heparin exerts a positive synergistic effect on soluble plasmin. Immobilized heparin enhances plasmin loading on the CET as compared to the heparin-free graft. Heparin, in both the soluble or immobilized state, significantly decreases the Michaelis-Menten (M-M) parameter Km for immobilized plasmin over heparin-free immobilized plasmin. Furthermore, the M-M parameter Vmax for the immobilized plasmin in the presence of heparin decreases over heparin-free immobilized plasmin. These results suggest a decrease in the kinetic constant k3 for heparin-modified immobilized plasmin over the heparin-free form. Co-immobilized heparin-plasmin collagenous grafts represent a unique advance in the development of fibrinolytically active prostheses.

Current Techniques to Improve the Blood Compatibility of Biomaterial Surfaces

“…Shanker et al (68) co-immobilized heparin and plasmin onto collagenic tubes using EOC. The collagenic tubes were modified lamb carotid arteries which had been provided with primary amine groups by incubating them with a hydroxylamine sulfate solution.…”

Fluorocarbon Surfactant Polymers: Effect of Perfluorocarbon Branch Density on Surface Active Properties

“…The properties of poly(tetrafluoroethylene) (PTFE), including its mechanical strength, chemical inertness, nonadhesiveness, thermal stability, and low coefficient of friction, make it very useful for a variety of applications. − For many biomedical applications, however, it would be useful if the PTFE surface could be easily modified to facilitate surface modification with bioactive molecules like heparin , or cell adhesive peptide/proteins − to improve interfacial biocompatibility. However, the chemical inertness of PTFE makes it difficult to modify the surface in order to introduce chemically useful organic moieties.…”

Interactions of Proteins with Polyelectrolytes at Solid/Liquid Interfaces: Sequential Adsorption of Albumin and Heparin

“…Winterton et al (14) preadsorbed fihuman serum albumin and heparin at a solid/liquid interface bronectin which had a high affinity toward heparin and and on the formation of multiple alternating molecular layers bound it from its solutions. Shankar et al (15) co-immobiof albumin and heparin at acid pH. The rationale for studying lized heparin and plasmin to develop a thromboresistant and the system albumin-heparin follows from its ability to im-fibrinolytic vascular prosthesis.…”