3D printing stiff antibacterial hydrogels for meniscus replacement

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.