Tensegrity structures provide both structural integrity and flexibility through the combination of stiff struts and a network of flexible tendons. These structures exhibit useful properties: high stiffness-to-mass ratio, controllability, reliability, structural flexibility, and large deployment. The integration of smart materials into tensegrity structures would provide additional functionality and may improve existing properties. However, manufacturing approaches that generate multimaterial parts with intricate three-dimensional (3D) shapes suitable for such tensegrities are rare. Furthermore, the structural complexity of tensegrity systems fabricated through conventional means is generally limited because these systems often require manual assembly. Here, we report a simple approach to fabricate tensegrity structures made of smart materials using 3D printing combined with sacrificial molding. Tensegrity structures consisting of monolithic tendon networks based on smart materials supported by struts could be realized without an additional post-assembly process using our approach. By printing tensegrity with coordinated soft and stiff elements, we could use design parameters (such as geometry, topology, density, coordination number, and complexity) to program system-level mechanics in a soft structure. Last, we demonstrated a tensegrity robot capable of walking in any direction and several tensegrity actuators by leveraging smart tendons with magnetic functionality and the programmed mechanics of tensegrity structures. The physical realization of complex tensegrity metamaterials with programmable mechanical components can pave the way toward more algorithmic designs of 3D soft machines.

Ever since a new energy harvesting technology, known as a triboelectric nanogenerator (TENG), was reported in 2012, the rapid development of device fabrication techniques and mechanical system designs have considerably made the instantaneous output power increase up to several tens of mW/cm2. With this innovative technology, a lot of researchers experimentally demonstrated that various portable/wearable devices could be operated without any external power. This article provides a comprehensive review of polyvinylidene fluoride (PVDF)-based polymers as effective dielectrics in TENGs for further increase of the output power to speed up commercialization of the TENGs, as well as the fundamental issues regarding the materials. In the end, we will also review PVDF-based sensors based on the triboelectric and piezoelectric effects of the PVDF polymers.

Human subcutaneous fat-derived mesenchymal cells recently have been shown to have the potential to differentiate in vitro into a variety of cell types, including adipocytes, osteoblasts, chondrocytes, and myoblasts. This effect suggests that fat tissue may serve as an abundant and easily acquired source of multipotent cells for tissue engineering. The multipotential characteristics of fat-derived mesenchymal cells from the inguinial fat pad of rabbit have not been clearly defined. In this study we have isolated a population of mesenchymal cells from inguinal fat from adult New Zealand white rabbits. The cells that were maintained under various differentiation conditions were shown to differentiate in vitro into adipocytes, osteoblasts, or chondrocytes; this differentiation was demonstrated using gene expression for tissue-specific proteins. We also co-cultured the cells with intervertebral disk tissue from the nucleus pulpous or from the annulus fibrosus. The fat-derived cells co-cultured with nucleus pulposus showed an increase in expression of type II collagen and aggrecan genes, compared with cells in alginate alone and cells co-cultured with annulus fibrosus. The data suggest that the fat-derived mesenchymal cells responded to soluble mediators from the disk. Future studies on intervertebral disk reconstruction could be based on our findings with fat-derived multipotential cells from the inguinal region of the rabbit that were co-cultured with disk tissue and may prove useful in tissue engineering strategies.

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