A bioengineered trachea-like structure improves survival in a rabbit tracheal defect model.

A practical strategy for engineering a trachea-like structure that could be used to repair or replace a damaged or injured trachea is an unmet need. Here, we fabricated bioengineered cartilage (BC) rings from three-dimensionally printed fibers of poly(ɛ-caprolactone) (PCL) and rabbit chondrocytes. The extracellular matrix (ECM) secreted by the chondrocytes combined with the PCL fibers formed a "concrete-rebar structure," with ECM deposited along the PCL fibers, forming a grid similar to that of native cartilage.

Perfusable Vessel-on-a-Chip for Antiangiogenic Drug Screening with Coaxial Bioprinting.

Vessel-on-a-chips, which can be used to study microscale fluid dynamics, tissue-level biological molecules delivery and intercellular communication under favorable three-dimensional (3D) extracellular matrix microenvironment, are increasingly gaining traction. However, not many of them can allow for long-term perfusion and easy observation of angiogenesis process. Since angiogenesis is necessary for the expansion of tumor, antiangiogenic drugs play a significant role in cancer treatment.

3D printed high-resolution scaffold with hydrogel microfibers for providing excellent biocompatibility.

Melt electrowriting (MEW) can print high-resolution scaffolds with the ultrafine fibers from 800 nm to 20 µm. However, the cell seeding efficiency relatively low due to the large pore size of the MEW scaffold. Here, we reported a method to solve this dilemma by electrospinning a gelatin methacrylate (GelMA) hydrogel fibers membrane (HFM) on the MEW scaffold.

Directly coaxial 3D bioprinting of large-scale vascularized tissue constructs.

Three-dimensional (3D) bioprinting of soft large-scale tissues in vitro is still a big challenge due to two limitations, (i) the lack of an effective way to print fine nutrient delivery channels (NDCs) inside the cell-laden structures above the millimetre level; (ii) the need for a feasible strategy to vascularize NDCs. Here, a novel 3D bioprinting method is reported to directly print cell-laden structures with effectively vascularized NDCs. Bioinks with desired tissue cells and endothelial cells (ECs) are separately and simultaneously printed from the outside (mixed with GelMA) and inside (mixed with gelatin) of a coaxial nozzle.

Synchronous 3D Bioprinting of Large-Scale Cell-Laden Constructs with Nutrient Networks.

Maintaining an adequate supply of nutrients/oxygen is a major challenge in the biofabrication of large tissue constructs. However, building preformed nutrient networks may be an effective strategy for engineering thick tissues. Here, a novel way for bioprinting large-scale tissue constructs with intentional nutrient networks is presented.

3D printed multi-scale scaffolds with ultrafine fibers for providing excellent biocompatibility.

It is a dilemma that both strength and biocompatibility are requirements for an ideal scaffold in tissue engineering. The normal strategy is mixing or coating another material to improve the biocompatibility. Could we solve this dilemma by simply adjusting the scaffold structure? Here, a novel multi-scale scaffold was designed, in which thick fibers provide sufficient strength for mechanical support while the thin fibers provide a cell-favorable microenvironment to facilitate cell adhesion.

Micro/nanofabrication of brittle hydrogels using 3D printed soft ultrafine fiber molds for damage-free demolding.

Hydrogels are very popular in biomedical areas for their extraordinary biocompatibility. However, most bio-hydrogels are too brittle to perform micro/nanofabrication. An effective method is cast molding; yet during this process, many defects occur as the excessive demolding stress damages the brittle hydrogels.

Bioprinting of Cell-Laden Microfiber: Can It Become a Standard Product?

Hydrogel microfibers have many fascinating applications as microcarriers for drugs, factors, and cells, such as 3D cell culture, building micro-organoids, and transplantation therapy due to their simple structures. It is unknown whether cell-laden fiber can become a standard-use product like woundplast. Here, from the technical and practical view, the elements required for user-oriented microfibers are first discussed: i) the materials used should promote cell functionalization and be easily processed; ii) follow a manufacturing method for mass fabrication; iii) have the ability to be stored long-term and be available for immediate use.

Fiber-Based Mini Tissue with Morphology-Controllable GelMA Microfibers.

The use of microscale fibers could facilitate nutrient diffusion in fiber-based tissue engineering and improve cell survival. However, in order to build a functional mini tissue such as muscle fibers, nerve conduits, and blood vessels, hydrogel microfibers should not only mimic the structural features of native tissues but also offer a cell-favorable environment and sufficient strength for tissue functionalization. Therefore, an important goal is to fabricate morphology-controllable microfibers with appropriate hydrogel materials to mimic the structural and functional complexity of native tissues.

Three-Dimensional Printed Wearable Sensors with Liquid Metals for Detecting the Pose of Snakelike Soft Robots.

Liquid metal (LM)-based flexible sensors, which utilize advanced liquid conductive materials to serve as sensitive elements, are emerging as a promising solution to measure large deformations. Nowadays, one of the biggest challenges for precise control of soft robots is the detection of their real-time positions. Existing fabrication methods are unable to fabricate flexible sensors that match the shape of soft robots.