Biosurface and Biotribology最新文献

Hydrogels exhibit a performance similar to that of the extracellular matrix and are compatible with human tissues and organs. Stimuli-responsive hydrogels that can respond smartly to a variety of stimuli have recently attracted extensive interest for biomedical applications. The response of these hydrogels to various single/multiple stimuli shows great potential for drug delivery, biosensors, wound dressing, cancer therapy, and tissue engineering. This review summarises the recent advances in the design of different stimuli-responsive hydrogels and their biomedical applications. We herein describe the mechanisms underlying the stimulus–response, and summarise the strategies for fabricating stimuli-responsive hydrogels that can respond to single or multiple stimuli from endogenous (i.e. pH, enzymes, glucose, and reactive oxygen species) or exogenous (i.e. magnetic and electric fields, temperature, and photo) sources. The current challenges faced by stimuli-responsive hydrogels are discussed and an outlook on future research directions is provided.

Wet adhesion has widespread applications in the fields of wearable electronics, medical devices and intelligent robots. In nature, many organisms have evolved with unique wet adhesion properties to adapt to complex habitats and climb in wet environments without falling. Tree frogs, as crawling masters in tropical rain forests, are representative of wet adhesion and give novel inspirations to design artificial wet adhesive materials by mimicking their specialised hexagonal structures and/or mucus composition. In this review, we first overview the research progress of tree frog toe pads from the perspective of toe pad structure and adhesion mechanism. Then, wet adhesive materials inspired by tree frog toe pads are systematically summarised from (i) the typical polymers, (ii) the preparation approaches, (iii) the adhesion test methods and (iv) the typical artificial adhesion surfaces. Third, various applications of bioinspired wet adhesive surfaces are highlighted. Finally, we present future challenges and opportunities to develop tree frog-inspired wet adhesive materials.

Hydrogels have been considered as potential candidates for cartilage replacement due to their high-water content, extreme network hydration, excellent biocompatibility and tunable mechanical properties. Currently, the development of high-performance cartilage-inspired hydrogel lubrication materials has become a hot topic in the field of biomedical materials. This review focusses on the recent development of cartilage-inspired high-strength hydrogels from the viewpoints of bionic surface/interface and biotribology. Specifically, the composition structure and extraordinary lubrication mechanism of the natural articular cartilage are overviewed first. Subsequently, some of the novel biomimetic design strategies for preparing high strength cartilage hydrogels with various network structures are summarised in detail, while systematic evaluation of lubrication properties and mechanisms are discussed. Furthermore, new surface modification means for improving the lubrication feature of high strength cartilage hydrogel materials are presented. In addition, in order to demonstrate the application potential of cartilage hydrogels in clinical, several bonding methods to decorate hydrogels onto surfaces of natural bone tissues or artificial joint materials are introduced. Finally, current challenges and future research directions are discussed for cartilage-inspired hydrogel lubrication materials.

The increasing development of biomedicine and bioelectronics has highlighted the requirement for smart materials that can respond to changes in physical and chemical properties under external environments, such as magnetic fields, electric fields, and temperature. Accordingly, hydrogels have been widely evaluated as promising candidates for smart materials owing to their intriguing structures comprising a cross-linked network of polymer chains with interstitial spaces filled with solvent water. This feature endows hydrogels with soft and wet characteristics, which not only induce high tissue affinity but also allow the introduction of environmentally responsive nanoparticles to release specific smart properties. Herein, we reviewed novel smart hydrogels that can be applied in biomedicine and bioelectronics, and highlighted and discussed existing challenges in current technologies and research.

A Zn-based coating with durable hydrophobicity and good corrosion resistance was formed on a mild steel substrate, which involves electroplating Zn from a non-aqueous electrolyte, followed by passivation in an oleic acid (OA) solution. The electrodeposited Zn coatings were porous, which facilitated the formation of a chemical conversion layer of Zn oleate (ZO) during OA passivation. The Zn coating after passivation had a two-layer structure, which included an outer layer of ZO with a thickness of ∼26 μm and an inner layer of Zn with a thickness of ∼6 μm. The outer layer ZO is a type of metal soap with a smooth surface and durable hydrophobicity, such that water droplets can easily slip off its surface. Corrosion testing and electrochemical measurements in 3.5 wt.% NaCl aqueous solution indicate that the Zn coating after OA passivation exhibits outstanding anti-corrosion properties compared with those exhibited by pure Zn coating. The corrosion products and mechanism of the two-layer coating were explored. This study shows that smooth metal oleate coatings can provide hydrophobicity and corrosion resistance simultaneously to mild steel substrates.

Marine biofouling will bring a series of environmental and social problems, which restrict the development and utilisation of marine resources. Therefore, how to prevent biofouling has become a global issue. With the exploration of antifouling methods, bionic antifouling technology with environmentally friendly, broad-spectrum, and long-term advantages has gradually attracted people's attention. Inspired by the antifouling strategy of soft coral (Sarcophyton trocheliophorum), the silicone rubber (RTV-2) with similar elasticity to coral skin was selected as the substrate. The composite structure of the upper transparent layer and the lower porous layer was prepared by simulating the structure of soft coral as the structural factors of the bionic antifouling coatings. Meanwhile, several organic antifouling components with high content contained in soft coral were added to the transparent layer and porous layer, respectively, as the component factors of biomimetic coatings. The bionic antifouling coatings, which are highly consistent with the coral structure, obtained the best antifouling performance under static and dynamic conditions. The above results provide new ideas for the synthesis of environmentally friendly bionic antifouling coatings.

Superhydrophobic surfaces (SHSs) exist in many biological organisms endowed by spectacular surface topographies, which provide important insights to drive a paradigm shift in design of engineering surfaces. Based on this, extensive progresses have been developed on bionic superhydrophobic strategies. Among them, SHSs based on topography of copper oxides exhibit considerable application prospects because of the steerability and diversity of topography, as well as additional performances, such as antibiosis, anticorrosion and catalysis. We first present a brief overview of the discovery of natural SHSs as well as fundamental understanding of surface wetting performance. Then, the structural effects in superhydrophobic systems based on the topographies of biological organisms and copper oxides are described. Finally, we highlight the perspectives on the novel design strategies of copper oxide-based SHSs that adapt to various practical applications.

The physiochemical properties of the implant interface significantly influence cell growth, differentiation, cellular matrix deposition, and mineralisation, and eventually, determine the bone regeneration efficiency. Cells directly sense and respond to the physical, chemical, and mechanical cues of the implant surface, and it is increasingly recognized that surface topography can evoke specific cellular responses, conferring biological functions on substrate materials and regulating tissue regeneration. Current progress towards the fundamental understanding of the interplay between the cell and topographical surface has been made by combined advance in fabrication technologies and cell biology. Particularly, the precise fabrication and control of nano/microscale topographies can provide the fundamental knowledge of the mechanotransduction process that governs the cellular response as well as the knowledge of how the specific features drive cells towards a defined differentiation outcome. In this review, we first introduce common techniques and substrate materials for designing and fabricating micro/nano-topographical surfaces for bone regeneration. We then illustrate the intrinsic relationship of topological cues, cellular signal transduction, and cell functions and fates in osteogenic differentiation. Finally, we discuss the challenges and the future of using topological cues as a cell therapy to direct bone tissue regeneration.

Through hundreds of millions of evolution, animals and plants have possessed their unique structures to adapt to natural variations. As a familiar process, liquid transportation plays an important part in both production and life, and researchers focus on how to achieve this process in a convenient and efficient way without energy input. Inspired by nature, various bioinspired structures are reported and have won multiple achievements. This review starts from basic theory about surface wettability, and then summarises the creatures with special liquid transport functions as well as crucial structures that cause this phenomenon. Next, the recent articles about transporting liquid by bioinspired materials are introduced. Finally, we proposed a brief conclusion and the prospect of bionic materials in the future.

To satisfy the requirements of social power development, it is urgently necessary to develop innovative and sustainable new energy storage devices. Supercapacitors have attracted considerable attention as a new type of energy storage device, owing to their high energy density, high power density, fast charging and discharging speeds, and long cycle life. The electrode material is an important factor in determining the electrochemical performance of supercapacitors. In recent years, researchers explored the application of metal-organic frameworks (MOFs) and their derivatives as electrode materials for supercapacitors. In this paper, the preparation of monometallic, bimetallic, and conductive MOFs, and their derivatives for application in supercapacitors are reviewed. In addition, challenges facing MOFs in the field of supercapacitors and their future development prospects are discussed.