MEDICAL DEVICE FOR USE IN THE REGENERATION OF AN INJURED NERVE
A medical device having a tubular membrane with openings adapted to receive the ends of an injured nerve and a lumen to allow the regeneration of the nerve, such that the tubular membrane includes fibers of polyhydroxyalkanoate (PHA) containing 3-hydroxybutyrate monomer units. The fibers have an average diameter from 500 nm to 2000 nm. Preferably, the PHA is a poly-3-hydroxybutyrate homopolymer and the tubular membrane further includes silver nanowires (Ag). The medical device has the advantages of not causing inflammation of the surrounding tissues surrounding the injured nerve, thus demonstrating a high biocompatibility, and at the same time exhibiting high ability to induce the regeneration of the injured nerve, providing a valid support for the maturation of the newly formed nerve fibers.
1 . A medical device comprising: a tubular membrane having openings adapted to receive the ends of an injured nerve and a lumen to allow the regeneration of said nerve, wherein said tubular membrane comprises fibers of polyhydroxyalkanoate (PHA) containing 3-hydroxybutyrate monomer units, said fibers having an average diameter comprised from 500 nm to 2000 nm.
2 . The medical device according to claim 1 , wherein the PHA fibers are oriented in a direction substantially parallel to the longitudinal axis of the tubular membrane.
3 . The medical device according to claim 1 , wherein the PHA fibers are produced by electrospinning.
4 . The medical device according to claim 1 , wherein the tubular membrane further comprises silver (Ag) nanowires.
5 . The medical device according to claim 4 , wherein the tubular membrane comprises from 0.2% to 5% by weight, with respect to the overall weight of the membrane, of Ag nanowires.
6 . The medical device according to claim 4 , wherein the Ag nanowires are oriented in a direction substantially parallel to the longitudinal axis of the tubular membrane.
7 . The medical device according to claim 4 , wherein the Ag nanowires are coated by a binding agent.
8 . The medical device according to claim 7 , wherein the binding agent has a functionalized hydrocarbon chain with at least one group capable of binding with silver.
9 . The medical device according to claim 4 , wherein the Ag nanowires coated with the binding agent comprise from 60% to 90% by weight of Ag and from 10% to 40% by weight of the binding agent.
10 . The medical device according to claim 1 , wherein the PHA containing 3-hydroxybutyrate monomer units is a poly-3-hydroxybutyrate homopolymer (P3HB) or a copolymer containing at least 20% moles of 3-hydroxybutyrate monomer units, the remainder being hydroxyalkanoate monomer units other than 3-hydroxybutyrate.
11 . The medical device according to claim 10 , wherein the hydroxyalkanoate monomer units other than 3-hydroxybutyrate derive from: 4-hydroxybutyrate, 3-hydroxyvalerate, 3-hydroxyhexanoate, 3-hydroxyoctanoate, 3-hydroxyundec-10-enoate, and 4-hydroxyvalerate.
12 . A method for producing a medical device according to claim 1 , the method includes the following steps:
preparing a spinning solution by solubilization of polyhydroxyalkanoate (PHA) containing 3-hydroxybutyrate monomer units in an organic solvent, and
subjecting the spinning solution to an electrospinning process on a rotating support so as to obtain a tubular membrane.
13 . The method according to claim 12 , further including the step of:
dispersing Ag nanowires into the spinning solution, so as to achieve a co-deposition of PHA fibers and Ag nanowires on the rotating support.
14 . The method according to claim 12 , wherein the solvent is selected from the group consisting of 1,1,1,3,3,3-hexafluoro-2-propanol (HFIP), chloroform, N,N-dimethylformamide (DMF), and mixtures thereof.
15 . The method according to claim 12 , wherein in the spinning solution, the PHA containing 3-hydroxybutyrate monomer units has a concentration comprised from 1% to 20% w/v.
16 . The method according to claim 13 , wherein the Ag nanowires are present in the spinning solution in a concentration preferably comprised from 0.05% to 2.0% w/v.