Given their durability and long‐term stability, self‐healable hydrogels have, in the past few years, emerged as promising replacements for the many brittle hydrogels currently being used in preclinical or clinical trials. To this end, the incompatibility between hydrogel toughness and rapid self‐healing remains unaddressed, and therefore most of the self‐healable hydrogels still face serious challenges within the dynamic and mechanically demanding environment of human organs/tissues. Furthermore, depending on the target tissue, the self‐healing hydrogels must comply with a wide range of properties including electrical, biological, and mechanical. Notably, the incorporation of nanomaterials into double‐network hydrogels is showing great promise as a feasible way to generate self‐healable hydrogels with the above‐mentioned attributes. Here, the recent progress in the development of multifunctional and self‐healable hydrogels for various tissue engineering applications is discussed in detail. Their potential applications within the rapidly expanding areas of bioelectronic hydrogels, cyborganics, and soft robotics are further highlighted.

Graphene The addition of a protective diluent (e.g., pyrene) to graphite during ball-milling results in a game-changer yield (>90%) of defect-free graphene, as described in article number 1603528 by Matat Buzaglo, Oren Regev, and co-workers. In the non-protected milling, there is a continuous fragmentation leading to amorphous carbon formation, whereas in a diluent-protected milling, the diluent adsorbs part of the impact forces, enabling exfo-liation into graphene, whose size is controlled by the milling energy and the diluent type. A Supercritical Lens Optical Label-Free Microscopy: Sub-Diffraction Resolution and Ultra-Long Working Distance Optical Imaging A planar metalens for achieving super-resolution imaging in far-field is proposed. This metalens, which has a non-sub-wavelength feature size, can be fabricated by conventional laser pattern generator. The imaging process is purely physical and captured in real time, without any pre-and post-processing. A new member of the layered pseudo-1D material family-monoclinic gal-lium telluride (GaTe)-is synthesized by physical vapor transport on a variety of substrates. The [010] atomic chains and the resulting anisotropic behavior are clearly revealed. The GaTe flakes display multiple sharp photoluminescence emissions in the forbidden gap, which are related to defects localized around selected edges and grain boundaries.

Ex vivo engineering of skeletal muscle represents an exciting new area of biotechnology. Although the ability of skeletal muscle cells to sense and respond to mechanical forces is well known, strategies based on the use of mechanical stimuli to optimize myogenesis in vitro remain limited. In this work, we describe a simple but powerful method based on uniaxial cyclic tensile strain (CTS) to induce assembly and differentiation of skeletal myocytes in vitro. Confluent mouse myoblastic precursors cultured on flexible-bottomed culture plates were subjected to either uniaxial or equibiaxial CTS. The uniaxial CTS protocol resulted in a highly aligned array of cross-striated fibers, with the major axis of most cells aligned perpendicularly to the axis of strain. In addition, a short period of myogenin activation and significant increase in the myotube/myoblast ratio and percentage of myosin-positive myotubes was found, indicating an enhanced cell differentiation. In contrast, cells under equibiaxial strain regimen had no clear orientation and displayed signs of membrane damage and impaired differentiation. These results, thus, demonstrate that the selection of a proper paradigm is a key element when discussing the relevance of mechanical stimulation for myogenesis in vitro. This study provides a rational framework to optimize engineering of functional skeletal muscle.

BackgroundAdipose-derived stem cells (ASCs) are being increasingly recognized for their potential to promote tissue regeneration and wound healing. These effects appear to be partly mediated by paracrine signaling pathways, and are enhanced during hypoxia. Mass spectrometry (MS) is a valuable tool for proteomic profiling of cultured ASCs, which may help to reveal the identity of the factors secreted by the cells under different conditions. However, serum starvation which is essentially required to obtain samples compatible with secretome analysis by MS can have a significant influence on ASCs. Here, we present a novel and optimized culturing approach based on the use of a clinically relevant serum-free formulation, which was used to assess the effects of hypoxia on the ASC proteomic profile.MethodsHuman ASCs from three human donors were expanded in StemPro® MSC SFM XenoFree medium. Cells were cultured for 24 h in serum- and albumin-free supplements in either normoxic (20 %) or hypoxic (1 %) atmospheres, after which the cells and conditioned medium were collected, subfractionated, and analyzed using MS. Prior to analysis, the secreted proteins were further subdivided into a secretome (>30 kDa) and a peptidome (3–30 kDa) fraction.ResultsMS analysis revealed the presence of 342, 98, and 3228 proteins in the normoxic ASC secretome, peptidome, and proteome, respectively. A relatively small fraction of the proteome (9.6 %) was significantly affected by hypoxia, and the most regulated proteins were those involved in extracellular matrix (ECM) synthesis and cell metabolism. No proteins were found to be significantly modulated by hypoxic treatment across all cultures for the secretome and peptidome samples.ConclusionsThis study highlights ECM remodeling as a significant mechanism contributing to the ASC regenerative effect after hypoxic preconditioning, and further underscores considerable inter-individual differences in ASC response to hypoxia. The novel culture paradigm provides a basis for future proteomic studies under conditions that do not induce a stress response, so that the best responders can be accurately identified for prospective therapeutic use.Data are available via ProteomeXchange with identifier PXD003550.Electronic supplementary materialThe online version of this article (doi:10.1186/s13287-016-0310-7) contains supplementary material, which is available to authorized users.

We have used the glancing angle deposition (GLAD) method as a simple and fast method to generate nano-rough surfaces for protein adsorption experiments and cell assays. The surface roughness and the detailed geometrical surface morphology of the thin films were characterized by atomic force microscopy (AFM) and scanning electron microscopy (SEM). As the GLAD deposition angle approaches grazing incidence, sharp and whisker-like columnar protrusions are formed. Smaller and less sharp surface features appear for the thin films synthesized at higher deposition angles. By changing the GLAD deposition angle together with the total amount of mass deposited per area on the respective surfaces, the size of the surface features can be varied on the nanoscale. Using the GLAD topographies as model surfaces, we have investigated the influence of the nano-roughness on fibrinogen adsorption and on the proliferation of primary human fibroblasts. It is found that fibrinogen, an important blood protein, preferentially adheres on the whisker-like nano-rough substrates in comparison to a flat surface. Furthermore, the proliferation of the human fibroblasts is significantly reduced on the nano-rough substrates. These results demonstrate that the GLAD technique can be used to fabricate nano-rough surface morphologies that significantly influence both protein and cellular adhesion to surfaces and are therefore well suited for biological assays.