Increased effectiveness of fibrin sealant with a higher fibrin concentration

We developed a new spray application method for fibrin sealant by which the fibrinogen solution is mixed with a smaller volume of thrombin to allow the final concentration of fibrin to be higher and to increase the performance of the sealant. In the present study, adhesive and sealing properties of fibrin sealant were examined by changing the mixing ratio of fibrinogen to thrombin solution, because the major uses of the sealant are in adhesive and sealing applications. Adhesion strength of the different components mixing ratios was evaluated by spraying sealant on a nylon sheet in a polystyrene dish and measuring the force necessary to cause failure in adhesion at the nylon sheet/polystyrene plate interface an hour after application. The results of the direct pull-off test showed that the adhesion strength greatly depends on the mixing ratio of fibrinogen to thrombin solution, indicating that the increase in adhesive force is apparently proportional to the final fibrin concentration. It was also demonstrated that when the fibrinogen solution was mixed with the thrombin solution in the ratio of 5 : I, the pressure needed to burst the seal on the pinholes in the lungs of rats was higher than that when the solution was mixed in the ratio of 1 :1. These results also indicate that once the homogeneity has been secured in the fibrin gel, the effectiveness of fibrin sealant depends on the final concentration of fibrin. (C) 2000 Elsevier Science Ltd. All rights reserved.