Evolving Emulsion Microcompartments via Enzyme-Mimicking Amyloid-Mediated Interfacial Catalysis.

Living organisms take in matter and energy from their surroundings, transforming these inputs into forms that cells can use to sustain metabolism and power various functions. A significant advancement in the development of protocells and life-like materials has been the creation of cell-like microcompartments capable of evolving into higher-order structures characterized by hierarchy and complexity. In this study, a smart emulsion system is designed to digests chemical substrates and generates organic or inorganic products, driving the self-organization and structuration of microcompartments.

Chemical and Structural Engineering of Gelatin-Based Delivery Systems for Therapeutic Applications: A Review.

As a biodegradable and biocompatible protein derived from collagen, gelatin has been extensively exploited as a fundamental component of biological scaffolds and drug delivery systems for precise medicine. The easily engineered gelatin holds great promise in formulating various delivery systems to protect and enhance the efficacy of drugs for improving the safety and effectiveness of numerous pharmaceuticals. The remarkable biocompatibility and adjustable mechanical properties of gelatin permit the construction of active 3D scaffolds to accelerate the regeneration of injured tissues and organs.

Harnessing 3D in vitro systems to model immune responses to solid tumours: a step towards improving and creating personalized immunotherapies.

In vitro 3D models are advanced biological tools that have been established to overcome the shortcomings of oversimplified 2D cultures and mouse models. Various in vitro 3D immuno-oncology models have been developed to mimic and recapitulate the cancer-immunity cycle, evaluate immunotherapy regimens, and explore options for optimizing current immunotherapies, including for individual patient tumours. Here, we review recent developments in this field.

Creating a semi-opened micro-cavity ovary through sacrificial microspheres as an model for discovering the potential effect of ovarian toxic agents.

The bio-engineered ovary is an essential technology for treating female infertility. Especially the development of relevant models could be a critical step in a drug study. Herein, we develop a semi-opened culturing system (SOCS) strategy that maintains a 3D structure of follicles during the culture.

Recombinant Human Collagen-Based Bioinks for the 3D Bioprinting of Full-thickness Human Skin Equivalent.

As a major extracellular matrix component within the skin, collagen has been widely used to engineer human skin tissues. However, most collagen is extracted from animals. Here, we introduced recombinant human type III collagen (rhCol3) as a bioactive component to formulate bioinks for the bioprinting of a full-thickness human skin equivalent.

Polysaccharide-Polyplex Nanofilm Coatings Enhance Nanoneedle-Based Gene Delivery and Transfection Efficiency.

Non-viral vectors represent versatile and immunologically safer alternatives for nucleic acid delivery. Nanoneedles and high-aspect ratio nanostructures are unconventional but interesting delivery systems, in which delivery is mediated by surface interactions. Herein, nanoneedles are synergistically combined with polysaccharide-polyplex nanofilms and enhanced transfection efficiency is observed, compared to polyplexes in suspension.

3D-printed Bioresorbable Stent Coated with Dipyridamole-Loaded Nanofiber for Restenosis Prevention and Endothelialization.

Intimal hyperplasia and restenosis caused by excessive proliferation of smooth muscle cells (SMC) are the main factors for the failure of stent implantation. Drug-eluting stents carried with antiproliferative drugs have emerged as a successful approach to alleviate early neointimal development. However, these agents have been reported to have an undesirable effect on re-endothelialization.

Advances in digital light processing of hydrogels.

Hydrogels, three-dimensional (3D) networks of hydrophilic polymers formed in water, are a significant type of soft matter used in fundamental and applied sciences. Hydrogels are of particular interest for biomedical applications, owing to their soft elasticity and good biocompatibility. However, the high water content and soft nature of hydrogels often make it difficult to process them into desirable solid forms.

3D Bioprinting of Multifunctional Dynamic Nanocomposite Bioinks Incorporating Cu-Doped Mesoporous Bioactive Glass Nanoparticles for Bone Tissue Engineering.

Bioprinting has seen significant progress in recent years for the fabrication of bionic tissues with high complexity. However, it remains challenging to develop cell-laden bioinks exhibiting superior physiochemical properties and bio-functionality. In this study, a multifunctional nanocomposite bioink is developed based on amine-functionalized copper (Cu)-doped mesoporous bioactive glass nanoparticles (ACuMBGNs) and a hydrogel formulation relying on dynamic covalent chemistry composed of alginate dialdehyde (oxidized alginate) and gelatin, with favorable rheological properties, improved shape fidelity, and structural stability for extrusion-based bioprinting.

Pushing the rheological and mechanical boundaries of extrusion-based 3D bioprinting.

3D bioprinting has long been subjected to trade-offs between physicochemical and biological outcomes. The resulting material properties of the initial bioinks and final printing products usually lie within a moderate range, which limits the application of bioprinting and its products. Recent progress in bioinks and bioprinting techniques has significantly expanded the window of material properties.

Tunable Microgel-Templated Porogel (MTP) Bioink for 3D Bioprinting Applications.

Micropores are essential for tissue engineering to ensure adequate mass transportation for embedded cells. Despite the considerable progress made by advanced 3D bioprinting technologies, it remains challenging to engineer micropores of 100 µm or smaller in cell-laden constructs. Here, a microgel-templated porogel (MTP) bioink platform is reported to introduce controlled microporosity in 3D bioprinted hydrogels in the presence of living cells.

Review of emerging nanotechnology in bone regeneration: progress, challenges, and perspectives.

The application of nanotechnology to regenerative medicine has increased over recent decades. The development of materials that can influence biology at the nanoscale has gained interest as our understanding of the interactions between cells and biomaterials at the nanoscale has grown. Materials that are either nanostructured or influence the nanostructure of the cellular microenvironment have been developed and shown to have advantages over their microscale counterparts.

Void-free 3D Bioprinting for In-situ Endothelialization and Microfluidic Perfusion.

Two major challenges of 3D bioprinting are the retention of structural fidelity and efficient endothelialization for tissue vascularization. We address both of these issues by introducing a versatile 3D bioprinting strategy, in which a templating bioink is deposited layer-by-layer alongside a matrix bioink to establish void-free multimaterial structures. After crosslinking the matrix phase, the templating phase is sacrificed to create a well-defined 3D network of interconnected tubular channels.

Expanding and optimizing 3D bioprinting capabilities using complementary network bioinks.

A major challenge in three-dimensional (3D) bioprinting is the limited number of bioinks that fulfill the physicochemical requirements of printing while also providing a desirable environment for encapsulated cells. Here, we address this limitation by temporarily stabilizing bioinks with a complementary thermo-reversible gelatin network. This strategy enables the effective printing of biomaterials that would typically not meet printing requirements, with instrument parameters and structural output largely independent of the base biomaterial.

Optimizing Bifurcated Channels within an Anisotropic Scaffold for Engineering Vascularized Oriented Tissues.

Despite progress in engineering both vascularized tissues and oriented tissues, the fabrication of 3D vascularized oriented tissues remains a challenge due to an inability to successfully integrate vascular and anisotropic structures that can support mass transfer and guide cell alignment, respectively. More importantly, there is a lack of an effective approach to guiding the scaffold design bearing both structural features. Here, an approach is presented to optimize the bifurcated channels within an anisotropic scaffold based on oxygen transport simulation and biological experiments.

Void-free 3D Bioprinting for In-situ Endothelialization and Microfluidic Perfusion.

Two major challenges of 3D bioprinting are the retention of structural fidelity and efficient endothelialization for tissue vascularization. We address both of these issues by introducing a versatile 3D bioprinting strategy, in which a templating bioink is deposited layer-by-layer alongside a matrix bioink to establish void-free multimaterial structures. After crosslinking the matrix phase, the templating phase is sacrificed to create a well-defined 3D network of interconnected tubular channels.

Buoyancy-Driven Gradients for Biomaterial Fabrication and Tissue Engineering.

The controlled fabrication of gradient materials is becoming increasingly important as the next generation of tissue engineering seeks to produce inhomogeneous constructs with physiological complexity. Current strategies for fabricating gradient materials can require highly specialized materials or equipment and cannot be generally applied to the wide range of systems used for tissue engineering. Here, the fundamental physical principle of buoyancy is exploited as a generalized approach for generating materials bearing well-defined compositional, mechanical, or biochemical gradients.

Facile Biofabrication of Heterogeneous Multilayer Tubular Hydrogels by Fast Diffusion-Induced Gelation.

Multilayer (ML) hydrogels are useful to achieve stepwise and heterogeneous control over the organization of biomedical materials and cells. There are numerous challenges in the development of fabrication approaches toward this, including the need for mild processing conditions that maintain the integrity of embedded compounds and the versatility in processing to introduce desired complexity. Here, we report a method to fabricate heterogeneous multilayered hydrogels based on diffusion-induced gelation.

A Generalizable Strategy for the 3D Bioprinting of Hydrogels from Nonviscous Photo-crosslinkable Inks.

An in situ crosslinking strategy is used for 3D bioprinting of nonviscous photo-crosslinkable hydrogels. This method can be generalized to various photo-crosslinkable formulations, maintaining high embedded cell viability and tunable cell behavior. Heterogeneous and hollow filaments can be printed using this strategy, allowing fabrication of complex engineered cell-laden constructs.

3D Printing of Shear-Thinning Hyaluronic Acid Hydrogels with Secondary Cross-Linking.

The development of printable biomaterial inks is critical to the application of 3D printing in biomedicine. To print high-resolution structures with fidelity to a computer-aided design, materials used in 3D printing must be capable of being deposited on a surface and maintaining a printed structure. A dual-cross-linking hyaluronic acid system was studied here as a printable hydrogel ink, which encompassed both shear-thinning and self-healing behaviors via guest-host bonding, as well as covalent cross-linking for stabilization using photopolymerization.

3D printing of photocurable poly(glycerol sebacate) elastomers.

Three-dimensional (3D) printed scaffolds have great potential in biomedicine; however, it is important that we are able to design such scaffolds with a range of diverse properties towards specific applications. Here, we report the extrusion-based 3D printing of biodegradable and photocurable acrylated polyglycerol sebacate (Acr-PGS) to fabricate scaffolds with elastic properties. Two Acr-PGS macromers were synthesized with varied molecular weights and viscosity, which were then blended to obtain photocurable macromer inks with a range of viscosities.

Effect of bioink properties on printability and cell viability for 3D bioplotting of embryonic stem cells.

3D cell printing is an emerging technology for fabricating complex cell-laden constructs with precise and pre-designed geometry, structure and composition to overcome the limitations of 2D cell culture and conventional tissue engineering scaffold technology. This technology enables spatial manipulation of cells and biomaterials, also referred to as 'bioink', and thus allows study of cellular interactions in a 3D microenvironment and/or in the formation of functional tissues and organs. Recently, many efforts have been made to develop new bioinks and to apply more cell sources for better biocompatibility and biofunctionality.

Three-dimensional bioprinting of embryonic stem cells directs highly uniform embryoid body formation.

With the ability to manipulate cells temporarily and spatially into three-dimensional (3D) tissue-like construct, 3D bioprinting technology was used in many studies to facilitate the recreation of complex cell niche and/or to better understand the regulation of stem cell proliferation and differentiation by cellular microenvironment factors. Embryonic stem cells (ESCs) have the capacity to differentiate into any specialized cell type of the animal body, generally via the formation of embryoid body (EB), which mimics the early stages of embryogenesis. In this study, extrusion-based 3D bioprinting technology was utilized for biofabricating ESCs into 3D cell-laden construct.