Electrospun filaments

1. A method for producing a continuous filament from electrospun fibres, comprising:

passing a conducting wire through free space to provide an elongate, three-dimensional collection surface accessible to electrospun fibres coming into contact with the conducting wire;

moving the conducting wire in a direction along its length;

forming an attractive electric field gradient between the conducting wire and a source of electrically charged fibres;

wherein the conducting wire is moved relative to the source of electrically charged fibres;

collecting the fibres on the elongate, three-dimensional collection surface of the conducting wire so as to form a continuous filament along the length of the underlying conducting wire;

wherein the elongate, three-dimensional collection surface of the conducting wire has a three-dimensional shape accessible in free space and the continuous filament thereby being formed with a corresponding three-dimensional shape that corresponds to the three-dimensional shape of the underlying conducting wire; and

separating the continuous filament from the elongate, three-dimensional collection surface of the underlying conducting wire whilst retaining the corresponding three-dimensional shape of the continuous filament.

2. The method of claim 1 , comprising using a blade to separate the continuous filament from the collection surface.

3. The method of claim 1 , comprising immersing the continuous filament in a liquid to separate it from the collection surface.

4. The method of claim 1 , comprising:

moving the collection surface with or relative to a non-conducting device spaced radially from the collection surface to interrupt trailing fibres.

5. The method of claim 1 , comprising:

twisting the continuous filament together with one or more other such filaments to produce a yarn.

6. The method of claim 1 , comprising:

providing multiple such collection surfaces in parallel to form multiple filaments; and

twisting the filaments together to produce a yarn.

7. The method of claim 5 , comprising twisting together M filaments in a first direction to form a thread and then twisting together N threads in a second direction opposite to the first direction.

8. The method of claim 1 , wherein the fibres have a diameter of at least 1 nm and up to 10 μm.

9. The method of claim 1 comprising braiding the continuous filament together with one or more other such filaments to produce a yarn.

10. The method of claim 5 , comprising knitting, weaving or plaiting the yarn with one or more other such yarns into a fabric structure for medical applications, including orthopaedic and soft tissue repair.