Optimal heparin surface concentration and antithrombin binding capacity as evaluated with human non‐anticoagulated blood in vitro

Abstract

Contact between blood and a biomaterial surface takes place in many applications and is known to activate the coagulation and complement systems. Heparin surface coatings have been shown to reduce blood activation upon contact with artificial surfaces. To establish the optimal heparin surface concentration, blood was incubated in a tubing loop model at 37 degrees C. The tubing was coated with different surface concentrations of heparin and rotated at three different velocities. We demonstrate that the blood compatibility of a surface with regard to coagulation, complement, and platelet activation can be improved by increasing the heparin surface concentration in the 6-12 pmol antithrombin/cm2 concentration interval. The binding of factor H is not influenced by the increased heparin surface concentration, suggesting that this factor is not the primary regulator of complement on heparin surfaces. In addition, the heparin coating has no effect on the complement activation that occurs on gas surfaces in extracorporeal circuits.

Improved ex vivo blood compatibility of central venous catheter with noble metal alloy coating

“…A modified Chandler loop model was used to assess the blood compatibility of BIP coating materials as previously described 14, 15, 16. Briefly, polyvinyl chloride (PVC) tubes (Medtronic, Minneapolis, USA), internally coated with Carmeda BioActive Surface (CBAS), with an internal diameter of 6.5 mm and 30 cm length, pre‐treated with saline for 5 min, were filled with 4.5 mL fresh whole blood.…”

Anchoring of Vascular Endothelial Growth Factor to Surface-Immobilized Heparin on Pancreatic Islets: Implications for Stimulating Islet Angiogenesis

“…38 This technique relies on the fact that a mass adsorbed onto the sensor surface of a shear-mode oscillating quartz crystal causes a proportional change in its resonance frequency, f. Changes in f reflect the amount of mass deposited onto the surface of the crystal. The corresponding dissipation change, DD, indicates frictional (viscous) losses induced by the deposited materials.…”

A Novel <em>In vitro</em> Model for Studying the Interactions Between Human Whole Blood and Endothelium

“…6 A protective heparin surface further eliminates activation of blood through surface contact by any surfaces other than the endothelial cells. 5 Indeed, incubation of whole blood supplemented with a small amount of unfractionated heparin in chamber without the protection of CHS resulted in clot formation.…”

“…A protective layer of immobilized heparin (hereafter referred to as Corline heparin surface (CHS)) that may be applied to most materials creating a surface where blood contact can occur without causing an activation of the coagulation cascade. 5 Thus, by furnishing the chambers with CHS, the blood endothelial cell chamber model enables use of very low concentrations of anticoagulant in the blood. Avoiding the addition of high concentrations of anticoagulant in the blood endothelial chamber model makes it possible to study sensitive interactions within a blood vessel that might otherwise be masked.…”