Three-dimensional (3D) printing is well acknowledged to constitute an important technology in tissue engineering, largely due to the increasing global demand for organ replacement and tissue regeneration. In 3D bioprinting, which is a step ahead of 3D biomaterial printing, the ink employed is impregnated with cells, without compromising ink printability. This allows for immediate scaffold cellularization and generation of complex structures. The use of cell-laden inks or bio-inks provides the opportunity for enhanced cell differentiation for organ fabrication and regeneration. Recognizing the importance of such bio-inks, the current study comprehensively explores the state of the art of the utilization of bio-inks based on natural polymers (biopolymers), such as cellulose, agarose, alginate, decellularized matrix, in 3D bioprinting. Discussions regarding progress in bioprinting, techniques and approaches employed in the bioprinting of natural polymers, and limitations and prospects concerning future trends in human-scale tissue and organ fabrication are also presented.

Salivary gland (SG) dysfunction impairs the life quality of many patients, such as patients with radiation therapy for head and neck cancer and patients with Sjögren’s syndrome. Multiple SG engineering strategies have been considered for SG regeneration, repair, or whole organ replacement. An in-depth understanding of the development and differentiation of epithelial stem and progenitor cells niche during SG branching morphogenesis and signaling pathways involved in cell–cell communication constitute a prerequisite to the development of suitable bioengineering solutions. This review summarizes the essential bioengineering features to be considered to fabricate an engineered functional SG model using various cell types, biomaterials, active agents, and matrix fabrication methods. Furthermore, recent innovative and promising approaches to engineering SG models are described. Finally, this review discusses the different challenges and future perspectives in SG bioengineering.

There have been many efforts to valorise lignin to produce bio-based chemicals and advanced materials. In this study, alkaline delignification was initially employed to recover lignin from the rind, pulp, and whole bagasse fractions of Moroccan sugarcane. The lignin fractions were subsequently modified via silanization and acetylation reactions. The modified lignin and raw lignin were then characterised to assess changes in their physicochemical properties via Fourier transform infrared spectroscopy (FTIR), solubility and thermogravimetric assessment, with both salinization and acetylation modification shown to enhance the solubility properties of the raw lignin of both polar and non-polar solvents. Preliminary investigations into the suitability of employing the modified lignin in hydrogel preparation were also undertaken. The preliminary hydrogels were developed using heating and freeze-thawing methods, while polyvinyl alcohol (PVA) and epichlorohydrin (ECH) were used as the matrix and the crosslinking agents, respectively. Fourier transform infrared spectroscopy (FTIR), rheological analysis, scanning electron microscopy, and thermal analysis were then used to characterize the different lignin–PVA hydrogels. The study showed that the swelling behaviour of the hydrogels was mainly influenced by the nature of the lignin (i.e., modified or raw), and the morphology of the hydrogel surfaces varied depending on the preparation methods. The study showed that the hydrogel based on silanized lignin and PVA had superior mechanical performance and swelling capacity compared to the acetylated lignin–PVA and raw lignin–PVA hydrogels.

Vascularization is crucial for providing nutrients and oxygen to cells while removing waste. Despite advances in 3D-bioprinting, the fabrication of structures with void spaces and channels remains challenging. This study presents a novel approach to create robust yet flexible and permeable small (600–1300 μm) artificial vessels in a single processing step using 3D coaxial extrusion printing of a biomaterial ink, based on tyramine-modified polyethylene glycol (PEG-Tyr). We combined the gelatin biocompatibility/activity, robustness of PEG-Tyr and alginate with the shear-thinning properties of methylcellulose (MC) in a new biomaterial ink for the fabrication of bioinspired vessels. Chemical characterization using NMR and FTIR spectroscopy confirmed the successful modification of PEG with Tyr and rheological characterization indicated that the addition of PEG-Tyr decreased the viscosity of the ink. Enzyme-mediated crosslinking of PEG-Tyr allowed the formation of covalent crosslinks within the hydrogel chains, ensuring its stability. PEG-Tyr units improved the mechanical properties of the material, resulting in stretchable and elastic constructs without compromising cell viability and adhesion. The printed vessel structures displayed uniform wall thickness, shape retention, improved elasticity, permeability, and colonization by endothelial-derived - EA.hy926 cells. The chorioallantoic membrane (CAM) and in vivo assays demonstrated the hydrogel's ability to support neoangiogenesis. The hydrogel material with PEG-Tyr modification holds promise for vascular tissue engineering applications, providing a flexible, biocompatible, and functional platform for the fabrication of vascular structures.

Polycaprolactone (PCL) is widely utilized in biomedical applications such as tissue engineering and drug delivery; however, its limited bioactivity remains a key challenge. In this study, bioactive curcumin–polycaprolactone block copolymers (MCP) were synthesized via ring-opening polymerization of ε-caprolactone and maleic anhydride modified curcumin. The resulting MCP was characterized using FTIR, ¹H NMR, UV–Vis spectroscopy, and differential scanning calorimetry (DSC). It demonstrated enhanced antioxidant activity, UV-blocking capacity, and electro spinnability compared to PCL. Electrospun MCP films exhibited improved biocompatibility and promoted fibroblast migration. Furthermore, composite films incorporating MCP into a PVA matrix with and without copper or iron were evaluated for in vivo toxicity and antimicrobial activity. These formulations showed no systemic or contact toxicity in the Galleria mellonella model, confirming their biocompatibility. Films containing copper or iron exhibited selective anti-Pseudomonas aeruginosa activity and low but reproducible antioxidant capacity. This study highlights the multifunctionality and biomedical potential of MCP and its composites as tunable platforms for regenerative and antimicrobial applications.