Techniques for delaying initiation of coagulation and suppressing fibrin formation may be provided. The disclosed techniques may include providing a percutaneous blood pump that may include a metal or ceramic surface (such as a surface of a shaft, bearing, rotor, stator, etc.) that has been modified with a bifunctional modifier. The modified surface may be within a motor section and/or pump section of the blood pump. The modified surface may be configured to interact with blood. When blood is allowed to interact with the modified surface, a desirable microenvironment may be formed. The bifunctional modifier may be a functionalized aminosilane, a functionalized aminosiloxane, and/or a functionalized silanetriol. The blood pump may be configured to have a purge fluid pass through at least a portion of the motor section and/or the pump section. The purge fluid may be free of anticoagulants.