Method for making a knitted mesh
A biocompatible surgical silk mesh prosthetic device employs a knit pattern that substantially prevents unraveling and preserves the stability of the mesh device, especially when the mesh device is cut. An example prosthetic device employs a knitted mesh including at least two yarns laid in a knit direction and engaging each other to define a plurality of nodes. The at least two yarns include a first yarn and a second yarn extending between and forming loops about two nodes. The second yarn has a higher tension at the two nodes than the first yarn. the second yarn substantially prevents the first yarn from moving at the two nodes and substantially prevents the knitted mesh from unraveling at the nodes.
1. A method for making a biocompatible, bioresorbable, implantable knitted silk mesh comprising:
(a) applying a first set of silk yarns in a first wale direction on a single needle bed machine, the first set of silk yarns forming a first series of loops at each of a plurality of courses for the knitted silk mesh;
(b) applying a second set of silk yarns in a second wale direction on the single needle bed machine, the second wale direction being opposite from the first wale direction, the second set of silk yarns forming a second series of loops at every other of the plurality of courses for the knitted silk mesh;
(c) applying a third set of silk yarns in every predetermined number of courses for the knitted silk mesh, the application of the third set of silk yarns defining openings in the knitted silk mesh; and
(d) depleting sericin from the first, second and third sets of silk yarns or from the knitted silk mesh before the knitted silk mesh is implanted,
wherein the first set of the silk yarns interlaces with the second set of the silk yarns at the every other course to define nodes for the knitted silk mesh, and the second set of the silk yarns has a greater tension than the first set of the silk yarns, the difference in tension substantially preventing the knitted silk mesh from unraveling at the nodes,
thereby making the biocompatible, bioresorbable, implantable, knitted silk mesh.
2. The method of claim 1 , wherein the first, second, and third sets of yarn are approximately 20 to 1000 μm in diameter.
3. The method of claim 1 , wherein the first, second, and third sets of yarns have a substantially constant diameter.
4. A method for making a biocompatible, bioresorbable, implantable, knitted silk mesh, comprising:
(a) applying a first set of silk yarns to a first needle bed of a double needle bed machine in a wale direction;
(b) applying a second set of silk yarns to a second needle bed of the double needle bed machine in a wale direction;
(c) applying a third set of silk yarns in every predetermined number of courses for the knitted silk mesh, the application of the third set of the yarns defining openings in the knitted silk mesh; and
(d) depleting sericin from the silk yarns or from the knitted silk mesh before the knitted silk mesh is implanted,
wherein the first set of the silk yarns and the second set of the silk yarns are alternately applied to form staggered loops at the first needle bed and the second needle bed, respectively, and the first set of the silk yarns interlaces with the second set of the silk yarns to define nodes for the knitted silk mesh, the alternating application of the first set of the silk yarns and the second set of the silk yarns causing the first set of the silk yarns to have a different tension relative to the second set of the silk yarns at the nodes, the difference in tension substantially preventing the knitted silk mesh from unraveling at the nodes,
thereby making the biocompatible, bioresorbable, implantable, knitted silk mesh.
5. The method of claim 4 , wherein the first, second, and third sets of yarn are approximately 20 to 1000 μm in diameter.
6. The method of claim 4 , wherein the first, second, and third sets of yarns have a substantially constant diameter.