A new method for evalution of antithrombogenicity of materials

Abstract

SummaryA new method was developed for evaluating kinetically the antithrombogenicity of materials. The amount of thrombus formed was measured gravimetrically at an appropriate interval of time after calcium chloride was added to ACD blood in contact with a test material. Graphic curves for thrombus formation on glass, Silastic, Hydron, and treated natural timues were obtained and compared. There was good correlation between our in vivo tests and in vivo observations.To evaluate the thrombogenicity of materials in vitro, the modified Lee-White clotting time test is usually employed. The time required for a firm clot to appear is determined by adding calcium chloride to ACD blood that is placed in a tube made from or lined with the test, material. This clotting-time test is qualitative, and sometimes does not give reliable data because the end point of clot formation is not definite, especially with hydrophilic materials. Moreover, it is necessary to mold the material to be tested into a tube or a cup-like shape. Our efforts to overcome the disadvantages of the Lee-White method yielded a new quantitative method called the "kinetic method." The preliminary results of this method were reported previously.' The test is applicable to all materials of all types: flat film or sheet, rigid or elastic, hydrophilie or hydrophobic, transparent or opaque. This quantitative kinetic method, of which the principle is to measure the relative amount of thrombus formed at an appropriate interval of time, like the kinetic study of a chemical reaction, makes it possible to evaluate in detail the thrombogenicity of materials. The procedure for the method and the results obtained from the standard materials are presented in this report.

Synthesis and characterization of membranes obtained by graft copolymerization of 2-hydroxyethyl methacrylate and acrylic acid onto chitosan

“…5 shows the weights of the blood clots obtained on thrombogenicity test. It was observed that clot formation was lower in the membranes than in the control and for this reason, the polymers are classified as non-thrombogenic (Imai and Nose, 1972). This characteristic is directly related to the hydrophilicity of the materials.…”

“…The evaluation of thrombus formation on polymeric surfaces was carried out using a gravimetric method (Imai and Nose, 1972). Anticoagulated rabbit blood was used with this purpose.…”

Designing polyethylene glycol (PEG) – plasticized membranes of poly(vinyl alcohol-g-methyl methacrylate) and investigation of water sorption and blood compatibility behaviors

“…The antithrombogenic properties of hydrogels were evaluated with human ACD (Acid Citrate Dextrose) blood, using the method developed by Imai and Nose [19]. In brief, the gels were equilibrated with saline water (0.9% W/V NaCl) for 72 h. To these swollen gels was added 0.5 mL of acid citrate dextrose (ACD) blood followed by the addition of 0.03 mL of CaCl 2 solution (4 M) to start the thrombus formation.…”

Modification of the biopolymer castor oil with free isocyanate groups to be applied as bioadhesive

“…The gravimetric method of Imai and Nose [23] was followed to evaluate thrombus formation on three samples of polymeric surfaces. For that purpose, anticoagulated rabbit blood (ACD blood) was prepared by adding 1 mL of ACD solution to 9 mL of fresh rabbit blood.…”