3D printing stiff antibacterial hydrogels for meniscus replacement

Abstract 3D printing of high-strength and stiff hydrogel is of great significance in customizing individualized load-bearing soft tissues, but faces a significant challenge. Herein, inspired by fugitive ink generally adopted in supporting bath printing, gelatin is employed as a sacrificial rheological modifier material to thicken the multiple hydrogen bonding monomer N-acryloylsemicarbazide (NASC), affording direct printability. Post-UV light irradiation-initiated polymerization of NASC results in robust hydrogel in spite of disturbance of hydrogen bonding caused by gelatin. Notably, PNASC H-bonding interactions is well reconstructed after high temperature dialyzing of gelatin, which resumes the tensile strength, Young's modulus, compressive modulus, of the printed hydrogels to 2.3 MPa, 26.25 MPa, 4.22 MPa, respectively. The NASC/gelatin can be printed into different architectures including meniscus, and the printed hydrogel does not exhibit noticeable wear to cartilage in simulation test of femoral wear. In addition, polydopamine coated-ZIF-8 is modified onto the surface of PNASC/gelatin hydrogels through one-pot synthesis method, thereby affording an antibacterial property without varying mechanical performance and wear property. This printed PNASC/gelatin scaffold with high strength, stiffness, better biocompatibility, low wear property, and built-in antibacterial activity hold potential as a meniscus substitute with a potent ability to minimize infection-induced implantation failure.