Here, we constructs a whole vascular system, from arteries and capillaries to veins with a high resolution 3D printing. A bulk breast tumor tissue with a functional vascular network was built. The interaction between tumors and vessels is investigated.

3D printing of chitosan hydrogel has attracted wide interests because of its excellent biocompatibility, antibacterial activities, biodegradability, none-toxicity and low cost. However, chitosan inks are often involved in toxic and...

Peripheral nerve injuries are one of the most common types of traumatic damage to the nervous system. Treatment of peripheral nerve injuries aims to promote axon regrowth by imitating and improving the microenvironment for sciatic nerve regeneration. In this study, regeneration efficiency and behavior of peripheral nerves are compared under three treatment strategies: 1) transplantation of Schwann cell progenitors induced from purified neural crest stem cells; 2) implantation of a multiscale scaffold based on high‐resolution 3D printing; and 3) implantation of this bionic scaffold loading Schwann cell progenitors. The results of structural, electrophysiological, and behavioral tests demonstrate that the three treatment strategies result in different degrees of regeneration. The purified neural crest stem cells differentiate into functional Schwann cells and promote axon regeneration. The multifunctional 3D printed scaffold promotes oriented growth and myelination, and the myelinated nerve regrows with increased density and without visible scaffolds after six months. For the regeneration, scaffold treatment produces better performance than cell graft alone. Finally, it is shown that implantation of multiscale scaffolds preloaded with neural crest stem cell derived Schwann cell progenitors is the best strategy to promote peripheral nerve regeneration with improved anatomy and function among the three different strategies.

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. Here, we propose a brand-new damage-free demolding method and a soft ultrafine fiber mold (SUFM) to replace the traditional mold. Both mechanical and finite element analysis (FEA) reveal that SUFMs have obvious advantages especially when the contact area between hydrogel and mold gets larger. By means of a high-resolution 3D printing called electrohydrodynamic (EHD) printing, SUFMs with various topological structures can be achieved with the fiber diameter ranging from 500 nm to 100 μm, at a low cost. Microfluidics and cell patterns are implemented as the demonstration for potential applications. Owing to the tiny scale of microstructures and the hydrophilicity of hydrogels, significant capillary effect occurs which can be utilized to deliver liquid and cells autonomously and to seed cells into those ultrafine channels evenly. The results open up a new avenue for a wider use of hydrogels in biomedical devices, tissue engineering, hydrogel-based microfluidics and wearable electronics; the proposed fabrication method also has the potential to become a universal technique for micro/nanofabrication of brittle materials.

Liquid-metal (LM)-based flexible and stretchable electronics have attracted widespread interest in soft robotics, self-powered devices and electronic skins. Although nanometerization can facilitate deposition and patterning of LMs onto substrates, subsequent...

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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. In this study, we established an innovative and reliable antiangiogenic drug screening chip that was highly modularly integrated for long-term perfusion (up to 10 days depending on the hydrogel formula) and real-time monitoring. To maintain an unobstructed flow of cell-laden tubes for subsequent perfusion culture on the premise of excellent bioactivities, a polycaprolactone stent inspired by coronary artery stents was introduced to hold up the tubular lumen from the inside, while the perfusion chip was also elaborately designed to allow for convenient observation. After 3 days of perfusion screening, distinct differences in human umbilical vein endothelial cell sprouting were observed for a gradient of concentrations of bevacizumab, which pointed to the effectiveness and reliability of the drug screening perfusion system. Overall, a perfusion system for antiangiogenic drug screening was developed, which can not only conduct drug evaluation, but also be potentially useful in other vessel-mimicking scenarios in the area of tissue engineering, drug screening, pharmacokinetics, and regenerative medicine.