3D Bioprinted Constructs Enriched with Zinc‐Doped Bioactive Glass Promote Antibacterial Activity and Osteochondral Tissue Regeneration

Hydrogel-based bioprinting with living cells has opened new opportunities for regenerating bone and cartilage tissues. Nevertheless, the development of patient-specific, customized osteochondral implants with antimicrobial functionality employing biomimetic materials remains an unmet challenge. This study presents the development of extrusion-based 3D bioprinted osteochondral constructs utilizing functional biomaterial inks, exploiting the effect of ionic dissolution products from zinc-doped bioactive glass (Zn-BG) based on the ICIE16 BG composition, when combined with a flexible, biocompatible polymeric network comprising gellan gum and poly(vinyl alcohol). Adipose-derived stromal cells are incorporated within the bioinks, due to their enriched osteochondral differentiation capacity. The presence of Zn-BG improved printing accuracy up to 73 ± 2%, compared to that of the control at 62 ± 1%. Bioinks showed comparable rheological properties with viscosity recovery rates over 90%. Moreover, Zn-BG led to a significant reduction of biodegradation rate and statistically significant antibacterial activity against Staphylococcus aureus and Escherichia coli. The 3D bioprinted microcomposite structures displayed significantly increased osteogenic and chondrogenic differentiation capacity compared to their counterparts without Zn-BGs, as evidenced by the expression levels of characteristic osteogenic and chondrogenic genes, and by histochemical staining of extracellular markers. The in vivo subcutaneous implantation of the constructs in mice corroborated the absence of any adverse immunological reactions.