Biosurface and Biotribology最新文献

The natural ligament–bone interface features gradient changes in matrix composition, architecture and cell phenotype, which play critical roles in reliable ligament fixation and smooth loading transfer. Mimicking such organisations in artificial composite tissue-engineering scaffolds is important for realising functional fixation between ligament implants and host bones. Here, the authors aim to provide a comprehensive review on the latest strategies to fabricate biomimetic composite scaffolds for the regeneration of ligament-to-bone interface. The biomimetic composite scaffolds are divided into stratified and gradient scaffolds, which are characterised as layer-specific and continuous changes, respectively, in scaffold materials and/or microstructures. Biofabrication strategies for different types of composite scaffolds are summarised. The effects of material/structural changes on cellular morphology, cell differentiation, in vivo osteointegration and multi-tissue interface regeneration are highlighted. Finally, the potential challenges and future perspectives in engineering biomimetic composite scaffolds for ligament–bone interface regeneration are discussed.

Low shape matching and high stress shielding rates between bone plate and human bone are not conducive to the primary healing of fracture. In this study, taking the fracture site of the lower one-third of human tibia as an application case, six types of personalised Ti6Al4V tibial plates with grooved surface were designed and evaluated by reverse engineering and finite element analysis. The results showed that the grooved design can reduce the stress shielding rate of bone plate and promote the facture healing. Among the six types of bone plates, the ‘OUT-MI’ bone plate has the lowest stress shielding rate and the most uniform stress distribution. Meanwhile, with the increasing tibial load during the convalescence, the average stress and maximum axial displacement of the tibial fracture surface increased, which can effectively improve the bone regeneration in the tibial fracture area. Moreover, there was no significant difference in four-point bending performance between the ‘OUT-MI’ bone plate and the ‘STR-BE’ bone plate, indicating that the mechanical properties of this bone plate were reliable. The results provide a theoretical basis for the design of fracture fixation plates on clinical treatment.

Anuran skin is a typical natural biomaterial with multifunctional features. A specific comparison of mechanical performance and morphology related to them was performed in the skin of Rana dybowskii and Bufo gargarizans using the tensile testing technique and morphological equipment. Rana dybowskii's skin has soft smooth surface covered by polygonal epidermal cells, while the Bufo gargarizans species has tough and uneven skin surface due to numerous verrucae structures. The collagen fibre bundles in lower dermis of Bufo gargarizans have wavelike organisation while the bundles of Rana dybowskii show a parallel arrangement. The mean elastic modulus of Rana dybowskii was nine times higher than that of Bufo gargarizans. This study clarified that the arrangement of collagen fibres play an important role in the strength and elasticity of skin material.

Tissue-adhesive materials are emerging biomaterials with potential applications in wound healing patches, tissue sealants, and haemostat materials. Tissue adhesives based on synthetic polymers generally have good adhesion but are not biodegradable. However, the long-term presence of non-biodegradable adhesives in the body can cause secondary harm to the patient. An ideal tissue adhesive should meet the following requirements: good adhesiveness, biodegradability, low cytotoxicity, and minimal inflammatory response. Natural polymers with inherent biodegradation and biocompatibility show great potentials in biomedical engineering, and the development of tissue adhesives based on natural polymers has become a hot topic in biomaterials science. This review systematically summarises the latest progresses in biodegradable tissue adhesives based on natural polymers, such as chitosan, hyaluronic acid, alginate, gelatin, dextran, and cellulose. Methods for preparing natural polymer tissue adhesives are summarised and their advantages and disadvantages are discussed. Finally, potential trends in the future direction of biodegradable tissue adhesives are discussed.

Calcite surface was modified with stearic acids, and the interaction between them was investigated both experimentally and theoretically. Stearic-acid-modified calcite powders were investigated with Fourier transform infrared spectroscopy, X-ray diffraction, zeta potential analyser and contact angle measurement. Then, the density functional theory calculations were performed to explore the interaction at the atomic scale. The experimental results and simulation indicated that stearic acids interact with calcite surface via chelation between the double-bond O atom of –COOH and the Ca atom on calcite surface. The terminal methyl group of the stearic acids decreases the hydrophilicity of the calcite surface, and the interaction between different crystal faces of calcite is different.

This review describes the principles of skin friction and wear for the benefit of sports scientists, engineers and clinicians. Skin exhibits complex behaviour, defying tribological laws for dry contact; hence, its friction and wear characteristics are affected by sliding speed, normal load, and contact area. Some sports seek to increase skin friction to enhance performance; however, this needs to be offset against injury risk given that skin abrades when slid across a rough and hard surface, delaminates when slid across a smooth and hard surface, and chafes or blisters when repeatedly rubbed against some fabrics. Whilst skin interactions can both define and hinder athlete performance, there exists a need to better understand skin biomechanics to optimise the balance of risk versus reward.

Ultrasound has been used for antifouling on the surface of medical devices or food utensils, but it is rarely applied in marine anti-biofouling on underwater instruments. To understand whether ultrasonic antifouling is suitable for underwater optical windows, the effect of ultrasonic conditions including frequency, power and duration on the removal of microbiofouling on the surface of polymethyl methacrylate (PMMA), a type of common optical material, was investigated in this study by three-factor and three-level orthogonal experiments. Before and after the ultrasonic treatment, both surface morphology and fouling degree of PMMA samples immersed in Escherichia coli suspension and seawater were characterized and quantified using laser scanning microscope. The results showed that ultrasonic treatment can effectively remove microfouling from the PMMA surface under suitable conditions. Ultrasonic technology has a great potential for the control of microfouling on the marine optical instruments. When compared with power and duration, ultrasonic frequency has a more significant effect on antifouling efficacy of ultrasound. It is useful for PMMA samples exposed to seawater within 2 days to conduct an antifouling treatment under the condition of an ultrasonic frequency of 20 kHz, ultrasonic power of 40 W, and ultrasonic duration of 7 min.

Professor Duncan Dowson had a major influence on my life, both personal and professional. He supervised my PhD, collaborated with me on setting up the Leeds–Waterloo Student Exchange Program and co-authored academic papers with me. During my PhD studies, he even, indirectly, found me a wife (Judith Dowling) who came from his research group. Duncan always took an interest in my career, my ideas and my life. He was my friend. I have tried, in this short rendition of stories and anecdotes, to convey the essence of my personal interactions with Duncan.

Personal stories and anecdotes on my visiting stay at University of Leeds and subsequent intercommunication on biotribology are briefly described. During this stay at the University of Leeds, some experiences are described including both a simulator testing and a retrieval study of knee prostheses. My subsequent interactions with Professor Dowson included mutual visits and discussions at Leeds–Lyon Symposiums.

Metal-organic frameworks (MOFs) refer to porous coordination materials that are formed from the assembly of metal ions and organic ligands. They have unique features, such as a large specific surface area, multiple active sites, easy functionalisation, and adjustable biocompatibility. MOFs have recently been widely used in the field of biomedical engineering owing to their unique structures and properties. This has enabled them to replace traditional materials and effectively address several problems. Through continuous development, MOF-based biomaterials have been remarkably improved by clarifying the relationship between MOF structures and properties. As a result, they are being extensively studied in the fields of chemical and material science. MOF-based biomaterials can meet the growing demands for efficient materials in biomedical applications. This review first discusses the basic structure of MOFs, followed by their preparation and functionalisation methods. The biomedical applications of MOF-based biomaterials in the fields of antibacterial activity, tumour therapy, skin repair, and bone repair are then summarised. Finally, challenges and future perspectives in the biomedical applications of MOF-based biomaterials are outlined.

Magnesium (Mg) and its alloys can be used as biomedical materials because of their excellent mechanical properties and biocompatibility. However, the rapid degradation rate of Mg-based materials limits their application in biodegradable intravascular stents. To overcome this issue, we constructed a hydrophobic coating on magnesium. After pre-treatments with alkali and a silane coupling agent of pure magnesium, 4,4’-diphenylmethane-diisocyanate (MDI) and amino-terminated polydimethylsiloxane (H₂N–PDMS–NH₂) were stepwise deposited on the surface, forming an amino-containing hydrophobic coating (–(M/P)₃) to enhance the corrosion resistance. Furthermore, polypeptide TK14 was immobilised on the hydrophobic coating to promote vascular endothelial cell adhesion and proliferation. The electrochemical results revealed that the self-corrosion current density (i_corr) of –(M/P)₃ decreased by approximately 4.5 orders of magnitude compared with that of pure Mg. After TK14 immobilisation, the number of endothelial cells adhering to the surface of –(M/P)₃–T increased significantly. Although the corrosion resistance of –(M/P)₃–T was slightly reduced, the subcutaneous implantation inflammatory response of the surrounding tissues was lower, showing suitable biocompatibility. Therefore, the polypeptide TK14 functionalised hydrophobic coating may be a promising candidate material for the interface of magnesium-based cardiovascular implants.