Bionic nerve graft and preparation method thereof

1 . A preparation method of a bionic nerve graft which comprises a helical stent, a nanofiber membrane, guide fibers and hBMSC-ECM (human-derived Bone Mesenchymal Stem Cell-Extracellular Matrix), wherein a surface of the helical stent is coated with the nanofiber membrane; the guide fibers and the hBMSC-ECM are placed in a tube cavity of the helical stent; and the helical stent, the nanofiber membrane and the guide fibers are formed of chitosan; wherein the preparation method comprises the following steps:

providing the chitosan and forming the helical stent by a mold pouring method;

providing the chitosan and coating the surface of the helical stent with one layer of nanofiber membrane in order to obtain a helical tube with a surface coated with the nanofiber membrane;

providing the chitosan and forming the guide fibers by a template method; and

filling the helical tube with the surface coated with the nanofiber membrane with the guide fibers and the hBMSC-ECM in order to obtain the bionic nerve graft;

wherein the step of forming the guide fibers comprises:

providing a chitosan solution with a concentration of 4 wt % to 7 wt %;

pouring the chitosan solution into a mold with a groove; and

putting the mold with the chitosan solution into a NaOH solution of 5 to 20% for curing and shaping, and washing with water, drying and demolding in order to obtain the guide fibers.

2 . The preparation method of the bionic nerve graft according to claim 1 , wherein the mold pouring method of forming the helical stent comprises:

providing a chitosan solution with a concentration of 4 wt % to 7 wt %;

pouring the chitosan solution on a threaded inner core mold;

placing the inner core mold with the chitosan solution into a NaOH solution of 5 to 20% for curing and shaping, and then washing with water, drying and demolding in order to obtain a helical stent semi-finished product; and

immersing the helical stent semi-finished product into an acetic anhydride solution containing methanol of 5 wt % to perform acetylation for 6 hours, performing fixation for 12 hours by using the NaOH solution of 5 to 20%, washing and drying in order to obtain the helical stent.

3 . The preparation method of the bionic nerve graft according to claim 1 , wherein the step of preparing the helical tube with the surface coated with the nanofiber membrane comprises:

preparing a blended solution of the chitosan and polyethylene oxide with the total concentration of 3 wt % to 5 wt %, wherein the mass ratio of the chitosan to the polyethylene oxide is 100:5 to 100:20;

placing the blended solution of the chitosan and the polyethylene oxide into an electrostatic spinning apparatus, placing the helical stent on a tubular receiving apparatus, performing electrostatic spinning, and coating the surface of the helical stent with one layer of nanofiber membrane; and

placing the helical stent coated with the nanofiber membrane into a NaOH solution of 5 to 20% for curing and shaping, followed by washing with water to remove the polyethylene oxide in order to obtain the helical tube with the surface coated with the nanofiber membrane.

4 . The preparation method of the bionic nerve graft according to claim 3 , wherein setting parameters of the electrostatic spinning comprise a voltage of 5 to 35 kV, a flow velocity of 0.1 to 2 mL/h, a receiving distance of 5 to 35 cm, and a rotating speed of the receiving apparatus of 5 to 150 rpm.

5 . The preparation method of the bionic nerve graft according to claim 1 , wherein the groove of the mold comprises an inner groove and an outer groove which communicate with each other, wherein a cross-sectional shape of the communicated inner groove and outer groove features the inner groove is located in the middle of the outer groove; wherein

a cross-sectional width of the outer groove is 100 to 500 μm,

a cross-sectional height of the outer groove is 20 to 50 μm,

a cross-sectional width of the inner groove is the same as the cross-sectional height of the outer groove,

a cross-sectional height of the inner groove is 25 to 240 μm,

the cross-sectional width of the outer groove is twice the sum of the cross-sectional height of the inner groove and the cross-sectional width of the inner groove, and

the inner groove and the outer groove have the same length of 1 to 3 cm.

6 . The preparation method of the bionic nerve graft according to claim 1 , wherein the hBMSC-ECM is obtained by a process comprising:

coating a culture dish with an Mesenchymal Stem Cell (MSC) adherent reagent diluted 100 times by Dulbecco's Phosphate-Buffered Saline (DPBS) solution;

planting resuscitated human-derived Bone Mesenchymal Stem Cell (hBMSC) into the coated culture dish, adding a complete culture medium, performing culture in a 5% CO 2 incubator at 37° C., and changing the culture medium once every two days; and

changing with a complete culture medium containing ascorbic acid when cell saturation reaches 80%, changing the solution once every two days in a dark place, discarding the culture solution after ten days, washing with DPBS three times, performing hypotonic operation with ultrapure water at 37° C. for 10 minutes, removing the ultrapure water, adding a cell lysis solution to perform reaction for 5 minutes, washing with DPBS, treating with DNA enzyme at 37° C. for 2 hours after washing, washing with DPBS, and storing at 4° C.