Although hydrogels based on biopolymers show many advantages, their low mechanical properties limit their applications in osteochondral tissue engineering. In this study, one part of our work aimed at preparing a high strength biohydrogel by using a double-network (DN) hydrogel system, which consisted of two interpenetrating polymer networks composed of γ-glutamic acid, lysine, and alginate, and meanwhile by incorporating bacterial cellulose into the DN structures. The results showed that compression modulus of the resultant hydrogel (0.322 MPa) was comparable with that of natural articular cartilage and swelling degree was greatly depressed by using these strategies. On this basis, a bilayer hydrogel scaffold based on the bionics principle for osteochondral regeneration was fabricated via chemical and physical cross-linking. Additionally, hydroxyapatite (HA) particles with two different sizes were introduced into the bilayer hydrogels, respectively: micro-HA in the top layer for promoting cartilage matrix deposition and HA nanocrystals in the bottom layer for enhancing compression modulus and osteogenesis. The osteochondral defect model of rabbits was used to evaluate the repair effect of the scaffolds with the bilayer structure, and the results showed such as-synthesized scaffolds had a good osteochondral repair effect.
Constructing biomimetic structure and immobilizing antithrombus factors are two effective methods to ensure rapid endothelialization and long-term anticoagulation for small-diameter vascular grafts. However, few literatures are available regarding simultaneous implementation of these two strategies. Herein, a nano-micro-fibrous biomimetic graft with a heparin coating was prepared via a step-by-step in situ biosynthesis method to improve potential endothelialization and anticoagulation. The 4-mm-diameter tubular graft consists of electrospun cellulose acetate (CA) microfibers and entangled bacterial nanocellulose (BNC) nanofibers with heparin coating on dual fibers. The hybridized and heparinized graft possesses suitable pore structure that facilitates endothelia cells adhesion and proliferation but prevents infiltration of fibrous tissue and blood leakage. In addition, it shows higher mechanical properties than those of bare CA and hybridized CA/BNC grafts, which match well with native blood vessels. Moreover, this dually modified graft exhibits improved blood compatibility and endothelialization over the counterparts without hybridization or heparinization according to the testing results of platelet adhesion, cell morphology, and protein expression of von Willebrand Factor. This novel graft with dual modifications shows promising as a new small-diameter vascular graft. This study provides a guidance for promoting endothelialization and blood compatibility by dual modifications of biomimetic structure and immobilized bioactive molecules.
Rechargeable aqueous zinc‐based batteries have gained considerable interest because of their advantages of high theoretical capacity, being eco‐friendly, and cost effectiveness. In particular, zinc‐based batteries with alkaline electrolyte show great promise due to their high working voltage. However, there remain great challenges for the commercialization of the rechargeable alkaline zinc‐based batteries, which are mainly impeded by the limited reversibility of the zinc electrode. The critical problems refer to the dendrites growth, electrode passivation, shape change, and side reactions, affecting discharge capacity, columbic efficiency, and cycling stability of the battery. All the issues are highly associated with the interfacial properties, including both electrons and ions transport behavior at the electrode interface. Herein, this work concentrates on the fundamental electrochemistry of the challenges in the zinc electrode and the design strategies for developing high‐performance zinc electrodes with regard to optimizing the interfaces between host and active materials as well as electrode and electrolyte. In addition, potential directions for the investigation of electrodes and electrolytes for high‐performance zinc‐based batteries are presented, aiming at promoting the development of rechargeable alkaline zinc‐based batteries.
SiOx anode with higher specific capacity than graphite and better capacity retention than pure Si has received great attention from both academia and the industry. However, the further application of SiOx suffers from its low initial Coulombic efficiency and inadequate capacity retention. The academia has reported numerous strategies to overcome these obstacles, such as nanosizing, pore designing, nanoarchitecture, etc., while seldom did they satisfy the requirement of the industry, which asks for anode material with excellent performance in all performance metrics (e.g., specific capacity, initial Coulombic efficiency, capacity retention, tap density). Besides, the reproducibility, production cost, and safety of the strategies are less concerned, leading to the “misalignment” between academia and the industry. In this review, the advancements in the modification strategies, which are already or likely to be accepted by the industry, are introduced in detail and critically evaluated. Moreover, the fundamental mechanisms of SiOx and the relationship between its structure and performance are systematically discussed. In the end, outlooks and suggestions for future research are given to provide meaningful guidance.
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