Manufacturing has historically followed a mass production approach due to economies of scale and the engineering challenges of large-scale customization, leading to a one-size-fits-all paradigm. This manufacturing-centric approach has forced consumers and patients to adapt to medical devices in terms of anatomical fit and biological performance, often significantly decreasing their quality of life. In order to improve the biological interface with the human body, the materials science and bioengineering communities are rapidly adopting three-dimensional (3D) printing, which promises high precision, automation, and a customized fit. However, numerous design and engineering constraints, many posed by the fragile nature of living cells and soft gels, suggest exciting opportunities for further research in materials synthesis, characterization, and integration. Specifically, materials innovations in bioinks and support materials, coupled with improved 3D bioprinting processes for multiple materials, have the potential to empower the next generation of biology by enabling precision engineered tissues, organoids, and eventually whole organs.

Nine possible native point defects in MgCaSi have been studied by employing density functional theory based ab initio calculations. The complex chemical potential limits are first determined using a two-dimension (∆μMg, ∆μCa) diagram, then the defect formation energies as a function of the atomic chemical potential are gained. The energetic results show that under Mg-rich conditions, the most favorable defect is MgCa rather than MgSi, while CaMg is predominant compared to CaSi under Ca-rich conditions. The bonding energy is first introduced to uncover the intrinsic feature of defect formation energy. The local geometric distortion around CaMg, MgSi, and CaSi antisite defects gradually increases due to the smaller atomic radii from Ca to Mg and Si, showing the important role of the geometrical mismatch. The density of states indicates that the higher stability of CaMg and MgCa originates from the smaller deviation of the Fermi level from the pseudo-gap.

Three-dimensional (3D) printing has expanded beyond the mere patterned deposition of melted solids, moving into areas requiring spatially structured soft matter—typically materials composed of polymers, colloids, surfactants, or living cells. The tunable and dynamically variable rheological properties of soft matter enable the high-resolution manufacture of soft structures. These rheological properties are leveraged in 3D printing techniques that employ sacrificial inks and sacrificial support materials, which go through reversible solid–fluid transitions under modest forces or other small perturbations. Thus, a sacrificial material can be used to shape a second material into a complex 3D structure, and then discarded. Here, we review the sacrificial materials and related methods used to print soft structures. We analyze data from the literature to establish manufacturing principles of soft matter printing, and we explore printing performance within the context of instabilities controlled by the rheology of soft matter materials.

The holy grail of regenerative technologies is to regrow a limb. This grand challenge requires us to develop truly innovative strategies and toolboxes across advanced materials science, stem cell science, physics, and developmental biology, and converge these advancements to address the limitations of wound healing and harness the regenerative capacity in humans. We discuss the convergence approach put forward by the field of regenerative engineering to develop translational strategies involving electrically conductive and novel polymers, stem cells, high-throughput technologies, and nanotechnology to regenerate the limb.

Bioprinting promises to create three-dimensional in vitro models to study pathological states and possible new therapies, and in the future, to produce complex tissue and organ replacements. This article will describe the recent advances in bioprinting technologies to engineer artificial tissues and organs by controlling spatial heterogeneity of chemical and physical properties of scaffolds and, at the same time, the cellular composition and spatial arrangement. Despite significant technological improvements in recent years, the positioning at the micrometric level and the switching of different cell types and biomaterials remain a challenge, which limits the development of resilient vascular, neural, and lymphatic networks for metabolites, signaling, and waste transport, and thus limits the development of thick and clinically relevant engineered vascularized tissues.

Three-dimensional (3D) bioprinting has become a fast-developing research field in the last few years. Many different technical solutions are available, with extrusion-based printing being the most promising and versatile method. In addition, a variety of biomaterials are already available for 3D printing of live cells. The real challenge, however, remains bioprinting of macroscopic, volumetric constructs of well-defined structures since hydrogels used for cell-embedding must consist of rather soft materials. This article describes recent developments to overcome these limitations that prevent clinical applications of bioprinted human tissues. New approaches include technical solutions such as in situ cross-linking or gelation processes that now can be performed during the bioprinting process, modified bioinks that combine suitable viscosity and cytocompatible gelation mechanisms, and utilization of additional materials to provide mechanical strength to the cell-laden constructs.