System and methods for sealing a channel in tissue

1. A system for sealing a channel in lung tissue created during a minimally invasive percutaneous procedure, comprising:

a medical device comprising a hydrogel delivery needle with a hydrogel outlet, and a coaxial cannula having an inner lumen configured for receipt of the hydrogel delivery needle, and

an injectable hydrogel provided in a syringe configured for fluidic connection to a proximal end of the hydrogel delivery needle,

wherein the injectable hydrogel is a viscoelastic shear-thinning hydrogel configured to exhibit sufficient stiffness after needle delivery to avoid lung tissue infiltration and push lung tissue away from the delivery needle,

in which the injectable viscoelastic shear-thinning hydrogel exhibits a storage modulus (G′) of at least 400 Pa in dynamic viscoelasticity measured by a rheometer at 1 Hz and 1% strain rate at 25° C.,

in which the injectable viscoelastic shear-thinning hydrogel comprises a crosslinked polymer.

2. A system according to claim 1 , in which the injectable viscoelastic shear-thinning hydrogel exhibits a tan δ (G″/G′) from 0.1 to 0.8 in dynamic viscoelasticity measured by a rheometer at 1 Hz and 1% strain rate at 25° C.

3. A system according to claim 1 , in which the injectable viscoelastic shear-thinning hydrogel exhibits a compressive modulus of greater than that of lung tissue.

4. A system according to claim 1 , in which the shear-thinning viscoelastic hydrogel is configured to exhibit an in-vivo residence time of at least 1 week.

5. A system according to claim 1 , in which the hydrogel outlet is disposed on a side of the hydrogel delivery needle proximal to the tip.

6. A system according to claim 1 , in which the viscoelastic hydrogel comprises a continuous phase comprising continuous phase polymer and a dispersed phase comprising micron-sized insoluble polymer particles.

7. A system according to claim 1 , in which the viscoelastic hydrogel comprises a continuous phase comprising continuous phase polymer and a dispersed phase comprising micron-sized insoluble polymer particles, and in which the micron-sized insoluble polymer particles have an average dimension of less than 100 microns.

8. A system according to claim 1 , in which the viscoelastic hydrogel comprises a continuous phase comprising continuous phase polymer and a dispersed phase comprising micron-sized insoluble polymer particles, in which the continuous phase polymer comprises hyaluronic acid (HA) or a salt thereof.

9. A system according to claim 1 , in which the viscoelastic hydrogel comprises a continuous phase comprising continuous phase polymer and a dispersed phase comprising micron-sized insoluble polymer particles, and in which the micron-sized insoluble polymer particles are formed of crosslinked gelatin.

10. A system according to claim 1 , in which the viscoelastic hydrogel comprises a continuous phase comprising continuous phase polymer and a dispersed phase comprising micron-sized insoluble polymer particles, and in which the viscoelastic hydrogel comprises 2-20% micron-sized insoluble polymer particles (w/v).

11. A system according to claim 1 , in which the hydrogel delivery needle comprises a piercing tip.

12. A system according to claim 1 , in which the viscoelastic hydrogel comprises a continuous phase comprising continuous phase polymer and a dispersed phase comprising micron-sized insoluble polymer particles, in which the continuous phase polymer comprises hyaluronic acid (HA) or a salt thereof, and in which the HA or salt thereof is not crosslinked and the micron-sized insoluble polymer particles are dehydrothermally crosslinked.

13. A system according to claim 1 , in which the viscoelastic hydrogel comprises a continuous phase comprising continuous phase polymer and a dispersed phase comprising micron-sized insoluble polymer particles, in which micron-sized insoluble polymer particles are crosslinked gelatin particles.

14. A system according to claim 1 , in which the system further comprises a syringe configured for fluidic connection to the hydrogel delivery needle, and in which the viscoelastic hydrogel is provided in the syringe.

15. A system according to claim 1 , which further comprises an adjustable positioning mechanism configured to limit the advancement depth of the hydrogel delivery needle through the coaxial cannula as indicated by a measurement scale forming part of the medical device, in which the adjustable positioning mechanism comprises a fixed housing attached to the hydrogel delivery needle, a movable hub mounted to the needle for axial movement along the hydrogel delivery needle relative to the fixed housing and having a distal-most face configured to abut a proximal face of the coaxial cannula luer lock.

16. A system according to claim 1 , which further comprises an adjustable positioning mechanism configured to limit the advancement depth of the hydrogel delivery needle through the coaxial cannula as indicated by a measurement scale forming part of the medical device, in which the measurement scale-is provided with the adjustable positioning mechanism and is configured to indicate an injection depth P of the hydrogel outlet and whereby the hydrogel outlet is positioned a distance P+X distal to the distal-most tip of the coaxial cannula when the distal-most face-of the adjustable positioning mechanism fully abuts the proximal face of the coaxial cannula.

17. A system according to claim 1 , in which the system further comprises a core needle with penetrating distal tip configured for insertion through the inner lumen of the coaxial cannula and attachment to the coaxial cannula luer lock.

18. A system according to claim 1 , in which the hydrogel delivery needle includes a radiopaque or radiolucent marker in which the radiopaque or radiolucent marker is optionally disposed distal to the hydrogel outlet.