The invention provides a method comprising: forming an expandable tubular body comprising a plurality of braided filaments, wherein the expandable tubular body is configured to be implanted in a blood vessel, and wherein the plurality of braided filaments comprises a first filament comprising platinum or platinum alloy and a second filament comprising cobalt-chromium alloy； chemically bonding a first phosphorylcholine material directly on the platinum or platinum alloy of the first filament； applying a silane intermediate layer on the second filament comprising the cobalt-chromium alloy； and applying a second phosphorylcholine material on the silane intermediate layer on the second filament, wherein the first and second phosphorylcholine materials each define a respective thickness of less than 100 nanometers.
