A medical device includes a base material having an immobilized fibrinolytic enzyme and dextran sulfate. The dextran sulfate has a molecular weight that is less than 40 kilo dalton (kDa). The medical device is formed from at least a base material. A fibrinolytic enzyme is immobilized on the base material. The fibrinolytic enzyme is stabilized with a dextran sulfate having a molecular weight of less than 40 (kDa).