Heart valve

A method of manufacturing a heart valve, the method comprising:

• a step of injection moulding a first part of the heart valve from a material comprising a first block-copolymer, wherein the injection moulding is performed at a temperature below an order-disorder transition temperature of the first block copolymer, such that a phase structure is present in the molten block-copolymer;
• a step of injection moulding a second part of the heart valve from a material comprising a second block-copolymer that is different to the first block-copolymer, by over-moulding over the first part to form an over-moulded structure, wherein the injection moulding is performed at a temperature below order-disorder transition temperatures for the first and second block copolymers, such that a phase structure is present in the molten second block-copolymer and remains present in the first block-copolymer;
• and
• a step of cooling the over-moulded structure, without heating it above the order-disorder transition temperatures between the step of injection moulding the second part and the step of cooling, so as to preserve an arrangement of the phase structures created during the steps of injection moulding and produce anisotropic physical properties in the second part.