Advanced alginate/58S bioactive glass inks with enhanced printability, mechanical strength, and cytocompatibility for soft tissue engineering.

Alginate-based hydrogels are promising biomaterials for extrusion-based bioprinting; however, their poor mechanical properties, printability, and shape integrity limit their utility in mimicking complex tissues and organs. In this study, a novel sodium alginate (Alg)/58S bioactive glass (BG)-based ink was developed for soft tissue engineering applications. The inks were characterised for shear-thinning, flowability, and shape integrity by printing various structures, including single filaments (0° and 90° nozzle movement), scaffolds, and rings. The ABG10 ink (10 wt% 58S BG in Alg) exhibited superior printability, achieving a printing accuracy of over 90 %, compared to a printing accuracy of 30-40 % for pure Alg. Fourier transform infrared spectroscopy revealed interactions between 58S BG and the Alg matrix, while scanning electron microscopy characterised the 58S BG morphology within the matrix. The storage modulus increased from 767 (pure Alg) to 13,604 Pa (ABG10), while compressive strength rose from 23 ± 3 to 43 ± 4 kPa (58 % enhancement). The cytocompatibility of the inks was assessed using an MTT assay (with SH-SY5Y cells), which confirmed that ABG10 ink supports cell viability. Overall, ABG10 hydrogel-based inks exhibited enhanced shear-thinning behaviour, printability, mechanical strength, and cytocompatibility, which could help to develop patient-specific soft tissues.