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Mesenchymal stem cells (MSCs) are primary candidates in tissue engineering and stem cell therapies due to their intriguing regenerative and immunomodulatory potential. Their ability to self-assemble into three-dimensional (3D) aggregates further improves some of their therapeutic properties, e.g., differentiation potential, secretion of cytokines, and homing capacity after administration. However, high hydrodynamic shear forces and the resulting mechanical stresses within commercially available dynamic cultivation systems can decrease their regenerative properties. Cells embedded within a polymer matrix, however, lack cell-to-cell interactions found in their physiological environment. Here, we present a “semi scaffold-free” approach to protect the cells from high shear forces by a physical barrier, but still allow formation of a 3D structure with in vivo-like cell-to-cell contacts. We highlight a relatively simple method to create core–shell capsules by inverse gelation. The capsules consist of an outer barrier made from sodium alginate, which allows for nutrient and waste diffusion and an inner compartment for direct cell-cell interactions. Next to capsule characterization, a harvesting procedure was established and viability and proliferation of human adipose-derived MSCs were investigated. In the future, this encapsulation and cultivation technique might be used for MSC-expansion in scalable dynamic bioreactor systems, facilitating downstream procedures, such as cell harvest and differentiation into mature tissue grafts.

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Fibrous scaffolds can be used to mimic the structure of cartilage extracellular matrix aiming at cartilage regeneration through optimal utilization of such scaffolds and chondrogenic cells. Herein, different types of fibrous structures are manufactured through electrospinning of blends of polyethylene oxide (PEO) and polycaprolactone (PCL), and the physical and chemical characteristics of the produced fiber mats are investigated. The amount of PEO influenced hydrophilicity, biodegradability, and mechanical properties of the blend fibers. To assess the cytotoxicity and biocompatibility of the scaffolds as well as the effect of fiber orientation, in vitro cell culture studies with a chondrogenic cell line (ATDC5) are conducted. The results show no cytotoxicity of the developed fibrous structures. A promising fibrous scaffold technology is presented with potential applications in cartilage tissue engineering.

To maximize the potential of 3D printing, several technological issues must be overcome, especially in the case of semisolid extrusion (SSE), where the 3D model is built up through the well‐defined extrusion of polymeric ink. Focusing on natural polymers, their physicochemical properties should be deeply investigated to evaluate 3D printability. This study aims to produce tablets easy to swallow, exploiting as 3D printing ink a crosslinked alginate hydrogel added of sorbitol, speculating that the plasticising action of sorbitol should allow to improve tablets’ swallowability. Three different amounts of 70% sorbitol solution (5%, 15%, 25% v/v) are evaluated to identify the best composition in terms of both printing and technological properties. The data obtained from the chemical, rheological, and mechanical evaluation of each ink are related to the printing performance, to reach the best manufacturing reproducibility. Linear regression fitting study (r 2 = 0.9982) confirms the predictable relationship between residual mass of final platforms and sorbitol amount loaded. To characterize the final products, all dried batches are subjected to technological evaluation highlighting differences in the matrix softability as well as in the swelling/erosion properties after the interaction with biological fluids.

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This article discusses alginate/gelatin-based bioinks in 3D bioprinting applications, providing a summary of the most relevant previous work in the field. It presents advanced compositions to enhance functionality and/or optimize hydrogels for 3D bioprinting. The article discusses advanced printing techniques for alginate/gelatin-based bioinks.