3D Printing of Bone Scaffolds Based on Alginate/Gelatin Hydrogel Ink Containing Bioactive Glass 45S5 and ZIF-8 Nanoparticles with Sustained Drug-Release Capability

Herein, 3D printing coupled with drug-release systems introduces many advantages to bone-regenerative medicine. In this research, hydrogel-based nanocomposite inks comprising alginate/gelatin (Alg/Gel) matrix supplemented with mesoporous bioactive glass (MBG) and zeolite-imidazole framework-8 (ZIF-8) nanoparticles are presented. A fixed wt% of mixed nanoparticles at MBG/ZIF weight ratios of 85:15 and 70:30 is added to Alg/Gel to prepare nanocomposite inks. All inks have shear-thinning behavior, facilitating scaffolds' 3D printing via extrusion. Scaffolds' 3D spatial and nanocomposite microstructures are confirmed using field-emission scanning electron microscope and energy-dispersive X-ray (FESEM/EDX) and Fourier transform infrared (FT-IR). Shear punch testing indicates an enhanced shear strength of 85:15 samples in both dry (9.49 +/- 0.23 MPa) and wet conditions (1.19 +/- 0.16 MPa). After 1 month, nanocomposite scaffolds have a higher degradation rate (65%) than Alg/Gel (50%) in phosphate-buffered saline. In vitro drug-release study using UV-visible spectrophotometry exhibits a similar prolonged release profile for 85:15 and 70:30 nanocomposites compared to Alg/Gel. Due to its better mechanical performance, 85:15 is used for bioactivity and cellular tests. MBG provides bioactivity in simulated body fluid by the rapid development of hydroxyapatite validated by FESEM/EDX, XRD, and FT-IR. Nanocomposite scaffolds exhibit significantly higher MG-63 cell viability (>90%) than Alg/Gel. Finally, these scaffolds provide a potential additive-manufacturing solution to bone tissue regeneration.