The human knee implant is computationally modelled in the mixed lubrication regime to investigate the tribological performance of the implant.This model includes the complex geometry of the implant components,unlike e...The human knee implant is computationally modelled in the mixed lubrication regime to investigate the tribological performance of the implant.This model includes the complex geometry of the implant components,unlike elliptical contact models that approximate this geometry.Film thickness and pressure results are presented for an ISO gait cycle to determine the lubrication regime present within the implant during its operation.It was found that it was possible for the lubrication regime to span between elastohydrodynamic,mixed and boundary lubrication depending on the operating conditions of the implant.It was observed that the tribological conditions present in one condyle were not necessarily representative of the other.Multiple points of contact were found within the same condyle,which cannot be computed by the elliptical contact solvers.This model can be used to balance forces in all directions,instead of only the normal loads,as often done in elliptical contact models.This work is an initial step towards understanding the role of the complex geometry in the tribological characteristics of the human knee implant when operating in physiological conditions.展开更多
Dental erosion results in excessive tooth wear.The contribution of low-concentration fluoride used daily in the prevention and treatment of erosion has not been fully understood.In this study,the effects of fluoride(2...Dental erosion results in excessive tooth wear.The contribution of low-concentration fluoride used daily in the prevention and treatment of erosion has not been fully understood.In this study,the effects of fluoride(225 ppm F−)on the surface morphology and nano-mechanical and anti-wear properties of human tooth enamel were investigated to explore whether low-concentration NaF solution could help protect tooth enamel from erosion.In total,40 enamel samples were divided into 5 groups,viz.group O:original surface with no treatment,group F:fluoride treatment(NaF,225 ppm F−,pH 6.3),group E:erosion treatment(0.001 M citric acid,pH 3.2,3 min),group EF:erosion treatment and then fluorination and group FE:fluoride treatment and then erosion.The mechanical and anti-wear properties of enamel samples were examined using a nano-indentation/scratch technique.Both surface morphology and scratch morphology of enamel samples were observed with scanning electron microscopy.The results showed that,from the perspectives of surface morphology and anti-wear properties,fluorination with low-concentration fluoride(225 ppm F−)before erosion has a certain potential for protection against dental erosion.Fluoride treatment after erosion has no obvious impact on the remineralisation of eroded enamel.展开更多
The clinical requirements for wound care are increasing daily, and the global wound dressing market is expanding;however, the research and development of new wound dressings are imminent. Natural biomolecules such as ...The clinical requirements for wound care are increasing daily, and the global wound dressing market is expanding;however, the research and development of new wound dressings are imminent. Natural biomolecules such as polyphenols, have been widely used in this field of vision. Owing to their unique anti-oxidative, adhesive, antibacterial and other bioactive functions, researchers have developed a series of wound dressings with excellent performance and applied them to a variety of biomaterials, such as hydrogels, nanofibers, films and scaffolds. They can effectively promote angiogenesis and fibroblast migration and proliferation, scavenge active oxygen free radicals, inhibit excessive in-flammatory reactions at wound sites and ultimately accelerate wound healing. The authors summarise the latest progress in polyphenol-derived biomaterials in skin wound repair to provide inspiration for future wound dressing research.展开更多
Laser surface texturing(LST)is a non-contact manufacturing process for fabricating functional surfaces in a manner that improves the corresponding wettability,and is widely used in biomedicine and industry.Laser surfa...Laser surface texturing(LST)is a non-contact manufacturing process for fabricating functional surfaces in a manner that improves the corresponding wettability,and is widely used in biomedicine and industry.Laser surface texturing is a facile approach that is compatible with various materials,can result in a hierarchical texture,and enables a high degree of surface wetting(i.e.,extreme wetting).In addition to surface structures,surface chemical modification is a primary factor in producing extreme wetting surfaces.This review discusses the effects of various surface textures and surface chemistries on wettability.Optimal laser parameters for the desired surface texture are based on the fundamental wettability and laser mechanism.In particular,bumps in the morphology are conducive to obtaining extreme wetting.Diverse surface chemical strategies result in extreme wetting by different mechanisms.This paper makes a rigorous evaluation of the laser parameters and optimal surface chemical modifications by elucidating the relationships between the surface structure,surface chemical modification,and wettability,and in so doing,determines the final wettability.The unresolved problems of LST are presented in the conclusion.This review provides guidance,development directions,and an integrated framework for LST,which will be useful for fabricating extreme wetting surfaces on various metals.展开更多
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 magn...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.展开更多
Because of their good performance,including biocompatibility and mechanical proper-ties,polyurethanes(PUs)are widely used in medical devices.However,undesired compatibility troubles,including thrombus,inflammation,and...Because of their good performance,including biocompatibility and mechanical proper-ties,polyurethanes(PUs)are widely used in medical devices.However,undesired compatibility troubles,including thrombus,inflammation,and hyperplasia,still limit the applications of PUs.In this study,copper-mediated polyurethane(PU-Cu)materials with enzyme-like catalysis were prepared.The PU-Cu materials effectively catalysed the nitric oxide(NO)released from endogenous NO donors because of the glutathione peroxidase(GPx)-like function of copper ion.The PU‐Cu materials were respectively evaluated via platelet adhesion and endothelial cell(EC),smooth muscle cell(SMC),and macrophage(MA)cultures.Scanning electron microscopy results showed that PU-Cu materials significantly inhibited platelet adhesion and activation.Meanwhile,PU-Cu materials not only promote the proliferation of EC but also inhibit SMC growth.Moreover,MA culture results intuitively stated the anti-inflammatory ability of PU-Cu.In addition,experimental samples were implanted into the subcutaneous tissue of Sprague Dawley rats.The anti-inflammatory function of PU-Cu was further confirmed by haematoxylin-eosin staining results.With regard to their excellent biological performance,PU-Cu materials are proposed for biocompatibility improvement of blood-contacting mate-rials,which should in turn provide new ideas for advanced medical devices.展开更多
Corrosion and wear play significant roles in the aseptic loosening of artificial hip joints for the long-term service.In this present study,tribo-corrosion tests were carried out through a reciprocating ball-on-plate ...Corrosion and wear play significant roles in the aseptic loosening of artificial hip joints for the long-term service.In this present study,tribo-corrosion tests were carried out through a reciprocating ball-on-plate system to evaluate the corrosion and wear prop-erties of CoCrMo,Ti6Al4V and Ti15Mo alloys in a simulated body fluid(SBF)solution.It was found that the tribo-corrosion behaviours of CoCrMo/Al_(2)O_(3)and Ti15Mo/Al_(2)O_(3)systems had significant wear-corrosion synergistic interaction,and wear-induced corro-sion was dominant.For Ti6Al4V/Al_(2)O_(3)systems,their wear mechanism under SBF lubrication was a combination of abrasive,adhesive and fatigue wear.While the wear mechanism of the Ti15Mo/Al_(2)O_(3)system under synergistic interaction was a combination of abrasive and adhesive wear.Finally,it was suggested that the Ti15Mo alloy would be the better alternative for metal implant applications compared with the CoCrMo alloy for the consideration of both wear and potential poisonous ions such as Co(III)and Cr(VI).展开更多
Material viscoelasticity is of particular importance for polymers,biotissues and many others,due to the significant influence not only on the elastic response of structures,but also on their failure mechanism in actua...Material viscoelasticity is of particular importance for polymers,biotissues and many others,due to the significant influence not only on the elastic response of structures,but also on their failure mechanism in actual applications.In this study,the experimental tests by nanoindentations are cate gorized according to the objective parameter combined with the indenter sha pe into four distinct cases,and the Fractional Derivative Zener model(FDZM)is employed to characterize this time-dependent property.The explicit data-fitting formulas are derived to determine the relaxation modulus and creep compliance te sted with the conical and spherical inde nters.Besides,a fitting scheme is provided to facilitate the identification of these viscoelastic parameters.In comparison with the general methods adopting the Prony series or empirical models,two silent merits present:(1)fewer model coefficients necessitate being determined based on the experimental data;(2)the relaxation modulus G(t)and the creep compliance J(t)can be obtained through one indentation test,and their exact interconversion is guaranteed as well.Several sets of experimental data are applied to examine the validity of the developed approach,and three more examples are adopted to demonstrate the exact interconversion between G(t)and J(t).A few concluding remarks are drawn eventually.展开更多
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 ...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 appli-cations.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.展开更多
Professor Duncan Dowson was a pioneer in the field of tribology and simulator design.His work sparked many branches of research across orthopaedics.The first knee simu-lator described by Dowson was intended to measure...Professor Duncan Dowson was a pioneer in the field of tribology and simulator design.His work sparked many branches of research across orthopaedics.The first knee simu-lator described by Dowson was intended to measure the wear performance of early total knee replacements(TKRs).The industry has since advanced to achieve simulator designs with significant improvements including multi-station,multi-axis,multi-control,and multi-environmental capabilities.These simulators are used to test and compare not only wear,but also the kinematic/kinetic behaviour of TKRs and many other TKR design interactions prior to implantation.This has led to changes to the design of TKRs ranging from improvements to the tibial insert to the femoral component;all,in some way,thanks to Professor Duncan Dowson's inquisitive nature.This article provides a selective review to show the interdependencies of research and development endeavours starting with the evolution of knee simulators,the many advances in TKRs and finally the interconnection with cadaveric motion simulators.展开更多
A fluorine-free and multifunctional superhydrophobic coating(r-MSC)was prepared by the one-step spraying method.The coating had superhydrophobic and low-adhesion properties with the water contact angle of 161.5°�...A fluorine-free and multifunctional superhydrophobic coating(r-MSC)was prepared by the one-step spraying method.The coating had superhydrophobic and low-adhesion properties with the water contact angle of 161.5°�1°and the sliding angle of 3.2°�0.5°.It could be prepared by spraying while maintaining superhydrophobic surface characteristics on any substrates.The coating owed outstanding mechanical durability and chemical stability.Moreover,the coating also possessed the ability of self-cleaning,anti-fouling,anti-icing,and flame retardant ability.Importantly,the presence of multifunc-tional coating endowed the substrate with both water-resistant and fireproof properties.Besides,it also showed excellent oil-water separation ability,which presented the oil-water separation efficiency of over 90%for different types of oils after 10 separation cycles.Furthermore,the coating could improve corrosion inhibition performance and the corrosion current density was reduced by two orders of magnitude from the polarization curve.The r-MSC had the advantages of simple preparation,fluorine-free,environ-mentally friendly and appropriate for large-area fabrication,which could be applied to various fields.展开更多
The lubricity and anti-wear ability of ionic liquids(ILs)were studied by a current-carrying friction test on IL-lubricated carbon brushes.The results indicated that the conductivity and wear resistance of different IL...The lubricity and anti-wear ability of ionic liquids(ILs)were studied by a current-carrying friction test on IL-lubricated carbon brushes.The results indicated that the conductivity and wear resistance of different ILs are different,and may vary for different carbon brushes.The E468e carbon brush was found to be more sensitive to IL lubrication than D172 carbon brush.Importantly,an analysis of the wear surfaces of the D172 and E468e carbon brushes revealed that,due to the different materials of the two carbon brushes and the composition of the IL,the lubrication effect on the carbon brushes was different.The viscosity of the IL will affect its wettability on the carbon brush surface.The better the wettability,the easier the movement of ions on the surface,which makes it easier to form a conductive physical adsorption film.Therefore,in practice,a better IL must be selected by considering the wettability of IL and carbon brushes.展开更多
Titanium and its alloys have been widely used as implant materials owing to several favourable properties.Bacterial infections are one of the most prominent reasons for implant failure.Antibacterial drugs are a possib...Titanium and its alloys have been widely used as implant materials owing to several favourable properties.Bacterial infections are one of the most prominent reasons for implant failure.Antibacterial drugs are a possible solution to bacterial infection but they kill the normal cells,and in many cases,some traces of the bacteria remain.The bacteria form a biofilm that can act as a conductive medium for regrowth of the bacteria.Customised implant surfaces that inhibit the formation of biofilms and retard the bacterial adherence have a significant potential in the design of futuristic implants.In this study,the antibacterial behaviour of textured titanium Grade-2 and Grade-5 surfaces is analysed and compared with a polished surface.The surface topography and its influence on the water wettability were investigated.A culture of Staphylococcus aureus was seeded on the prepared specimen and the bacterial adherence was compared.The results show that the bacterial adhesion and growth are reduced in textured specimens in comparison with a polished specimen.The fewer adherences of bacteria on the textured specimens are attributed to its surface topography and the presence of micro-dimples,which in turn influence the hydrophilicity of the surfaces.展开更多
Co-Cr-Mo ally(CCM)is commonly used for orthopaedic and dental implants due to its excellent mechanical properties and corrosion resistance.However,the influence of surface roughness on cell attachment and proliferatio...Co-Cr-Mo ally(CCM)is commonly used for orthopaedic and dental implants due to its excellent mechanical properties and corrosion resistance.However,the influence of surface roughness on cell attachment and proliferation remains unclear.This study aimed to elucidate the impact of surface roughness of CCM on the attachment and proliferation of osteoblasts.CCM samples with different values of surface rouges were prepared by polishing.MC3T3-E1 mouse osteoblasts were used for cell culture experiments.Cell attachment,morphology,and the expression of actin stress fibres,vinculin,and distri-bution of yes-associated protein were analysed.Our results suggest that surface rough-ness does not significantly affect cell attachment and proliferation on CCM,unlike on titanium.Thus implies that other properties of CCM,such as physicochemical properties,may play a more substantial role in modulating cell behaviour.This study provides important insights into the design of CCM implants,suggesting that approaches beyond tuning surface roughness may be necessary to improve biocompatibility and osseointegration.展开更多
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...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.展开更多
The purpose of this study is to achieve better understanding of associated mechanisms and to recommend and identify new strategies to develop new rock breaking technology for Tunnel Boring Machines(TBMs).Tunnel Boring...The purpose of this study is to achieve better understanding of associated mechanisms and to recommend and identify new strategies to develop new rock breaking technology for Tunnel Boring Machines(TBMs).Tunnel Boring Machine tunnelling mainly depends upon the rock breakage caused by cutters moving on a rock surface in a rolling and sliding motion while under the action of thrust force.The rock breaking behaviour is controlled by the mechanical interaction between the cutters and the rock.Due to the high hardness and high abrasiveness of rock,the cutters have to work under very high thrust force and suffer heavy-load-impact and abrasive wear,causing serious wear and low rock breaking efficiency.Rock-boring organisms exist in nature,which achieve drilling and/or tunnelling in rocks through a tribochemical interaction.This phenomenon is called bioerosion and the organisms are natural‘TBMs’to some degree.In this study,the interaction between TBM cutters and rock is presented,and current measures to improve cutter wear and rock breaking efficiency and their limitations are reported.Then,the connotation,mechanism and typical cases of bioerosion are presented.Finally,inspired by bioerosion,a new chemically assisted rock breaking technology is proposed for TBMs.展开更多
Exogenous grit adherent to the surface of food items and food fracture properties have each been considered important factors contributing to pattern and degree of tooth wear in mammals.However,the interactions betwee...Exogenous grit adherent to the surface of food items and food fracture properties have each been considered important factors contributing to pattern and degree of tooth wear in mammals.However,the interactions between these two factors in generating distinctive microwear textures have remained understudied.Here the authors revisit in-vitro results from simulated chewing to explore how adherent grit and physical properties of foods act together to create dental microwear textures on occlusal enamel surfaces.Results suggest that the effect of exogenous grit on microwear texture is dependent on the material properties foods to which they adhere.Grit in the absence of food causes more complex microwear surface textures than foods covered with similar levels and types of grit(for a given number of chews and angle of approach between opposing teeth).Different foods covered in grit also yield different complexity values.Grit-laden,pliant meat,for example,results in a less complex texture than does resistant,grit-laden raw carrot.This work implied that tooth wear assessment can benefit from considering grit load and food material properties together.展开更多
Wear occurring at the bearing surface and the consequent generation of wear debris has been identified as the primary cause of aseptic loosening in metal-on-polyethylene(MoP)hip joint replacements.The accurate estimat...Wear occurring at the bearing surface and the consequent generation of wear debris has been identified as the primary cause of aseptic loosening in metal-on-polyethylene(MoP)hip joint replacements.The accurate estimation of volume change in polyethylene cups due to creep and wear is,therefore,an important step for identifying the cause of failure and improving the longevity of MoP prosthesis.The purposes of this study were to present and apply a co-ordinate measuring machine(CMM)-based method for assessing the volume change of retrieved components due to wear and creep by using a combination of CMM data and a bespoke computer programme.The method was firstly validated against the standard gravimetric technique,and then applied to four retrieved polyethylene cups for wear assessment and analysis.The results show that the volume changes calculated using the present method match well with those assessed through the gravimetric technique.The CMM-based method presented in the study is capable of effectively and reliably determining the volume change and characterising the wear patch of retrieved components from MoP hip joint replacements.展开更多
The surfaces of biomaterials determine their efficacy and hence,have an important role in clinical applications.Through bio-inspired surface nanofunctionalisation,the surface properties of biomaterials such as physica...The surfaces of biomaterials determine their efficacy and hence,have an important role in clinical applications.Through bio-inspired surface nanofunctionalisation,the surface properties of biomaterials such as physical morphologyand chemical composition can be tailored using biomimicry.It is a powerful tool for improving the interactions betweenthe physiological environment and biomaterial surfaces.Therefore,research on bio-inspired nanofunctionalised surfaceshas attracted much attention in recent years.This review focus on the recent bio-inspired strategies based on the structureof the extracellular matrix(ECM)and composition of mussel-inspired polydopamine(PDA).The design,preparation,andproperties of ECM and PDA-inspired nanofunctionalised biomaterial surfaces are reviewed.l have also highlighted theeffects of these bio-inspired nanofunctionalised biomaterial surfaces on bone regeneration,cartilage repair,andantibacterial activities.展开更多
The micromechanical properties of soft tissue can be used as markers for the physiological state and function of the tissue.Deep understanding of the micromechanics of soft tissue,such as the oesophagus,is of great si...The micromechanical properties of soft tissue can be used as markers for the physiological state and function of the tissue.Deep understanding of the micromechanics of soft tissue,such as the oesophagus,is of great significance to the design of artificial oesophagi,endoscope materials and coatings for medical devices.Here,the micromechanical properties of oesophageal mucosa were studied under different loading rates,deflections,and dwell time by using atomic force microscopy.The micromechanical properties of soft tissue included elastic modulus,plasticity and adhesion force.Results showed that the micromechanical properties changed with increasing loading rate,deflection and dwell time.The micromechanical properties of oesophageal mucosa were related to time-dependent behaviours,such as contact stress,energy transformation,and strain gradient plasticity.Furthermore,the heterogeneity of oesophageal mucosa affected the micromechanical properties.The force mapping mode was a reliable and effective means to study the micromechanical properties of soft tissue.The results can provide a basis and technical support for the diagnosis of oesophageal diseases from a microscale as well as a material design perspective.展开更多
基金Imperial College Research FellowshipEngineering and Physical Sciences Research Council,Grant/Award Number:EP/N509486/1。
文摘The human knee implant is computationally modelled in the mixed lubrication regime to investigate the tribological performance of the implant.This model includes the complex geometry of the implant components,unlike elliptical contact models that approximate this geometry.Film thickness and pressure results are presented for an ISO gait cycle to determine the lubrication regime present within the implant during its operation.It was found that it was possible for the lubrication regime to span between elastohydrodynamic,mixed and boundary lubrication depending on the operating conditions of the implant.It was observed that the tribological conditions present in one condyle were not necessarily representative of the other.Multiple points of contact were found within the same condyle,which cannot be computed by the elliptical contact solvers.This model can be used to balance forces in all directions,instead of only the normal loads,as often done in elliptical contact models.This work is an initial step towards understanding the role of the complex geometry in the tribological characteristics of the human knee implant when operating in physiological conditions.
基金supported by the National Natural Science Foundation of China(No.51535010).
文摘Dental erosion results in excessive tooth wear.The contribution of low-concentration fluoride used daily in the prevention and treatment of erosion has not been fully understood.In this study,the effects of fluoride(225 ppm F−)on the surface morphology and nano-mechanical and anti-wear properties of human tooth enamel were investigated to explore whether low-concentration NaF solution could help protect tooth enamel from erosion.In total,40 enamel samples were divided into 5 groups,viz.group O:original surface with no treatment,group F:fluoride treatment(NaF,225 ppm F−,pH 6.3),group E:erosion treatment(0.001 M citric acid,pH 3.2,3 min),group EF:erosion treatment and then fluorination and group FE:fluoride treatment and then erosion.The mechanical and anti-wear properties of enamel samples were examined using a nano-indentation/scratch technique.Both surface morphology and scratch morphology of enamel samples were observed with scanning electron microscopy.The results showed that,from the perspectives of surface morphology and anti-wear properties,fluorination with low-concentration fluoride(225 ppm F−)before erosion has a certain potential for protection against dental erosion.Fluoride treatment after erosion has no obvious impact on the remineralisation of eroded enamel.
基金Shenzhen Funds of the Central Government to Guide Local Scientific and Technological Development,Grant/Award Number:2021SZVUP123Basic and Applied Basic Research Foundation of Guangdong Province,Grant/Award Number:2021B1515120019+2 种基金National Natural Science Foundation of China,Grant/Award Number:82072071Sichuan Science and Technology Program,Grant/Award Number:2022YFS0040Central University Basic Research Fund of China,Grant/Award Numbers:202241010,2682020ZT79。
文摘The clinical requirements for wound care are increasing daily, and the global wound dressing market is expanding;however, the research and development of new wound dressings are imminent. Natural biomolecules such as polyphenols, have been widely used in this field of vision. Owing to their unique anti-oxidative, adhesive, antibacterial and other bioactive functions, researchers have developed a series of wound dressings with excellent performance and applied them to a variety of biomaterials, such as hydrogels, nanofibers, films and scaffolds. They can effectively promote angiogenesis and fibroblast migration and proliferation, scavenge active oxygen free radicals, inhibit excessive in-flammatory reactions at wound sites and ultimately accelerate wound healing. The authors summarise the latest progress in polyphenol-derived biomaterials in skin wound repair to provide inspiration for future wound dressing research.
基金supported by Natural Science Foundation of Chongqing,China(Grant No.cstc2019jcyj-msxmX0114).
文摘Laser surface texturing(LST)is a non-contact manufacturing process for fabricating functional surfaces in a manner that improves the corresponding wettability,and is widely used in biomedicine and industry.Laser surface texturing is a facile approach that is compatible with various materials,can result in a hierarchical texture,and enables a high degree of surface wetting(i.e.,extreme wetting).In addition to surface structures,surface chemical modification is a primary factor in producing extreme wetting surfaces.This review discusses the effects of various surface textures and surface chemistries on wettability.Optimal laser parameters for the desired surface texture are based on the fundamental wettability and laser mechanism.In particular,bumps in the morphology are conducive to obtaining extreme wetting.Diverse surface chemical strategies result in extreme wetting by different mechanisms.This paper makes a rigorous evaluation of the laser parameters and optimal surface chemical modifications by elucidating the relationships between the surface structure,surface chemical modification,and wettability,and in so doing,determines the final wettability.The unresolved problems of LST are presented in the conclusion.This review provides guidance,development directions,and an integrated framework for LST,which will be useful for fabricating extreme wetting surfaces on various metals.
基金Key‐Area Research and Development Program of Guangdong Province,Grant/Award Number:2019B010941002National Natural Science Foundation of China,Grant/Award Numbers:82072071,51972276+2 种基金Sichuan Key Research and Development Program,Grant/Award Number:22ZDYF2034Shenzhen Funds of the Central Government,Grant/Award Number:2021SZVUP123Fundamental Research Funds for Central Universities,Grant/Award Number:2682020ZT79。
文摘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.
基金National Natural Science Foundation of China,Grant/Award Numbers:NSFC Project 32071328,NSFC Project 81801853Sichuan Science and Technology Programme,Grant/Award Number:2019YFH049+5 种基金International Cooperation Project by Science and Technology Department of Sichuan Province,Grant/Award Number:2020YFH0103Talent Promotion Project of Heze Branch of Shandong Academy of SciencesThis work was financially supported by Natural Science Foundation of China(NSFC Project 32071328&81801853)Sichuan Science and Technology Programme(2019YFH049)International Cooperation Project by Science and Technology Department of Sichuan Province(2020YFH0103)Talent Promotion Project of Heze Branch of Shandong Academy of Sciences.
文摘Because of their good performance,including biocompatibility and mechanical proper-ties,polyurethanes(PUs)are widely used in medical devices.However,undesired compatibility troubles,including thrombus,inflammation,and hyperplasia,still limit the applications of PUs.In this study,copper-mediated polyurethane(PU-Cu)materials with enzyme-like catalysis were prepared.The PU-Cu materials effectively catalysed the nitric oxide(NO)released from endogenous NO donors because of the glutathione peroxidase(GPx)-like function of copper ion.The PU‐Cu materials were respectively evaluated via platelet adhesion and endothelial cell(EC),smooth muscle cell(SMC),and macrophage(MA)cultures.Scanning electron microscopy results showed that PU-Cu materials significantly inhibited platelet adhesion and activation.Meanwhile,PU-Cu materials not only promote the proliferation of EC but also inhibit SMC growth.Moreover,MA culture results intuitively stated the anti-inflammatory ability of PU-Cu.In addition,experimental samples were implanted into the subcutaneous tissue of Sprague Dawley rats.The anti-inflammatory function of PU-Cu was further confirmed by haematoxylin-eosin staining results.With regard to their excellent biological performance,PU-Cu materials are proposed for biocompatibility improvement of blood-contacting mate-rials,which should in turn provide new ideas for advanced medical devices.
基金National Natural Science Foundation of China,Grant/Award Number:51875563The Tribology Science Found of State Key Laboratory of Tribology,Grant/Award Number:SKLTKF19A03。
文摘Corrosion and wear play significant roles in the aseptic loosening of artificial hip joints for the long-term service.In this present study,tribo-corrosion tests were carried out through a reciprocating ball-on-plate system to evaluate the corrosion and wear prop-erties of CoCrMo,Ti6Al4V and Ti15Mo alloys in a simulated body fluid(SBF)solution.It was found that the tribo-corrosion behaviours of CoCrMo/Al_(2)O_(3)and Ti15Mo/Al_(2)O_(3)systems had significant wear-corrosion synergistic interaction,and wear-induced corro-sion was dominant.For Ti6Al4V/Al_(2)O_(3)systems,their wear mechanism under SBF lubrication was a combination of abrasive,adhesive and fatigue wear.While the wear mechanism of the Ti15Mo/Al_(2)O_(3)system under synergistic interaction was a combination of abrasive and adhesive wear.Finally,it was suggested that the Ti15Mo alloy would be the better alternative for metal implant applications compared with the CoCrMo alloy for the consideration of both wear and potential poisonous ions such as Co(III)and Cr(VI).
基金National Natural Science Foundation of China(grant nos.51290291,51675447,51305362,11772274)the Young Scientific Innovation Team of Science and Technology of Sichuan(grant no.2017TD0017)the Fundamental Research Funds for the Central Universities(grant no.2682016CX024)。
文摘Material viscoelasticity is of particular importance for polymers,biotissues and many others,due to the significant influence not only on the elastic response of structures,but also on their failure mechanism in actual applications.In this study,the experimental tests by nanoindentations are cate gorized according to the objective parameter combined with the indenter sha pe into four distinct cases,and the Fractional Derivative Zener model(FDZM)is employed to characterize this time-dependent property.The explicit data-fitting formulas are derived to determine the relaxation modulus and creep compliance te sted with the conical and spherical inde nters.Besides,a fitting scheme is provided to facilitate the identification of these viscoelastic parameters.In comparison with the general methods adopting the Prony series or empirical models,two silent merits present:(1)fewer model coefficients necessitate being determined based on the experimental data;(2)the relaxation modulus G(t)and the creep compliance J(t)can be obtained through one indentation test,and their exact interconversion is guaranteed as well.Several sets of experimental data are applied to examine the validity of the developed approach,and three more examples are adopted to demonstrate the exact interconversion between G(t)and J(t).A few concluding remarks are drawn eventually.
基金This work was financially supported by the Key-Area Research and Development Programme of Guang Dong Province(2019B010941002)National Key Research and Development Program of China(2016YFB0700800)+2 种基金NSFC(82072071,82072073)Fundamental Research Funds for the Central Universities(2682020ZT79)the Sichuan Science and Technology Programme(2020YJ0009).
文摘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 appli-cations.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.
文摘Professor Duncan Dowson was a pioneer in the field of tribology and simulator design.His work sparked many branches of research across orthopaedics.The first knee simu-lator described by Dowson was intended to measure the wear performance of early total knee replacements(TKRs).The industry has since advanced to achieve simulator designs with significant improvements including multi-station,multi-axis,multi-control,and multi-environmental capabilities.These simulators are used to test and compare not only wear,but also the kinematic/kinetic behaviour of TKRs and many other TKR design interactions prior to implantation.This has led to changes to the design of TKRs ranging from improvements to the tibial insert to the femoral component;all,in some way,thanks to Professor Duncan Dowson's inquisitive nature.This article provides a selective review to show the interdependencies of research and development endeavours starting with the evolution of knee simulators,the many advances in TKRs and finally the interconnection with cadaveric motion simulators.
基金Defense Industrial Technology Development Program,Grant/Award Number:JCKY2019110D024JLU Science and Technology Innovative Research Team,Grant/Award Number:2020TD-03Scientific Research Project of Jilin Provincial Department of Education,Grant/Award Number:JJKH20211117KJ。
文摘A fluorine-free and multifunctional superhydrophobic coating(r-MSC)was prepared by the one-step spraying method.The coating had superhydrophobic and low-adhesion properties with the water contact angle of 161.5°�1°and the sliding angle of 3.2°�0.5°.It could be prepared by spraying while maintaining superhydrophobic surface characteristics on any substrates.The coating owed outstanding mechanical durability and chemical stability.Moreover,the coating also possessed the ability of self-cleaning,anti-fouling,anti-icing,and flame retardant ability.Importantly,the presence of multifunc-tional coating endowed the substrate with both water-resistant and fireproof properties.Besides,it also showed excellent oil-water separation ability,which presented the oil-water separation efficiency of over 90%for different types of oils after 10 separation cycles.Furthermore,the coating could improve corrosion inhibition performance and the corrosion current density was reduced by two orders of magnitude from the polarization curve.The r-MSC had the advantages of simple preparation,fluorine-free,environ-mentally friendly and appropriate for large-area fabrication,which could be applied to various fields.
文摘The lubricity and anti-wear ability of ionic liquids(ILs)were studied by a current-carrying friction test on IL-lubricated carbon brushes.The results indicated that the conductivity and wear resistance of different ILs are different,and may vary for different carbon brushes.The E468e carbon brush was found to be more sensitive to IL lubrication than D172 carbon brush.Importantly,an analysis of the wear surfaces of the D172 and E468e carbon brushes revealed that,due to the different materials of the two carbon brushes and the composition of the IL,the lubrication effect on the carbon brushes was different.The viscosity of the IL will affect its wettability on the carbon brush surface.The better the wettability,the easier the movement of ions on the surface,which makes it easier to form a conductive physical adsorption film.Therefore,in practice,a better IL must be selected by considering the wettability of IL and carbon brushes.
基金APJ Abdul Kalam Technological University Kerala,India under the Research Seed Money(RSM)scheme.
文摘Titanium and its alloys have been widely used as implant materials owing to several favourable properties.Bacterial infections are one of the most prominent reasons for implant failure.Antibacterial drugs are a possible solution to bacterial infection but they kill the normal cells,and in many cases,some traces of the bacteria remain.The bacteria form a biofilm that can act as a conductive medium for regrowth of the bacteria.Customised implant surfaces that inhibit the formation of biofilms and retard the bacterial adherence have a significant potential in the design of futuristic implants.In this study,the antibacterial behaviour of textured titanium Grade-2 and Grade-5 surfaces is analysed and compared with a polished surface.The surface topography and its influence on the water wettability were investigated.A culture of Staphylococcus aureus was seeded on the prepared specimen and the bacterial adherence was compared.The results show that the bacterial adhesion and growth are reduced in textured specimens in comparison with a polished specimen.The fewer adherences of bacteria on the textured specimens are attributed to its surface topography and the presence of micro-dimples,which in turn influence the hydrophilicity of the surfaces.
基金Japan Society for the Promotion of Science,Grant/Award Number:JP19K12798。
文摘Co-Cr-Mo ally(CCM)is commonly used for orthopaedic and dental implants due to its excellent mechanical properties and corrosion resistance.However,the influence of surface roughness on cell attachment and proliferation remains unclear.This study aimed to elucidate the impact of surface roughness of CCM on the attachment and proliferation of osteoblasts.CCM samples with different values of surface rouges were prepared by polishing.MC3T3-E1 mouse osteoblasts were used for cell culture experiments.Cell attachment,morphology,and the expression of actin stress fibres,vinculin,and distri-bution of yes-associated protein were analysed.Our results suggest that surface rough-ness does not significantly affect cell attachment and proliferation on CCM,unlike on titanium.Thus implies that other properties of CCM,such as physicochemical properties,may play a more substantial role in modulating cell behaviour.This study provides important insights into the design of CCM implants,suggesting that approaches beyond tuning surface roughness may be necessary to improve biocompatibility and osseointegration.
文摘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.
基金National Natural Science Foundation of China,Grant/Award Number:52075459China Railway Engineering Service Co.,Ltd,Grant/Award Number:LR01HX1102Y19044。
文摘The purpose of this study is to achieve better understanding of associated mechanisms and to recommend and identify new strategies to develop new rock breaking technology for Tunnel Boring Machines(TBMs).Tunnel Boring Machine tunnelling mainly depends upon the rock breakage caused by cutters moving on a rock surface in a rolling and sliding motion while under the action of thrust force.The rock breaking behaviour is controlled by the mechanical interaction between the cutters and the rock.Due to the high hardness and high abrasiveness of rock,the cutters have to work under very high thrust force and suffer heavy-load-impact and abrasive wear,causing serious wear and low rock breaking efficiency.Rock-boring organisms exist in nature,which achieve drilling and/or tunnelling in rocks through a tribochemical interaction.This phenomenon is called bioerosion and the organisms are natural‘TBMs’to some degree.In this study,the interaction between TBM cutters and rock is presented,and current measures to improve cutter wear and rock breaking efficiency and their limitations are reported.Then,the connotation,mechanism and typical cases of bioerosion are presented.Finally,inspired by bioerosion,a new chemically assisted rock breaking technology is proposed for TBMs.
基金support from the Natural Science Foundation of Zhejiang Province,China(no.LQ19E050006)Natural Science Foundation of Zhejiang Education Department(Y201839291)+1 种基金The Tribology Science Fund of State Key Laboratory of Tribology(SKLTKF18B08)startup funds from Ningbo University to LH and the K.C.Wong Magna Fund through Ningbo University.
文摘Exogenous grit adherent to the surface of food items and food fracture properties have each been considered important factors contributing to pattern and degree of tooth wear in mammals.However,the interactions between these two factors in generating distinctive microwear textures have remained understudied.Here the authors revisit in-vitro results from simulated chewing to explore how adherent grit and physical properties of foods act together to create dental microwear textures on occlusal enamel surfaces.Results suggest that the effect of exogenous grit on microwear texture is dependent on the material properties foods to which they adhere.Grit in the absence of food causes more complex microwear surface textures than foods covered with similar levels and types of grit(for a given number of chews and angle of approach between opposing teeth).Different foods covered in grit also yield different complexity values.Grit-laden,pliant meat,for example,results in a less complex texture than does resistant,grit-laden raw carrot.This work implied that tooth wear assessment can benefit from considering grit load and food material properties together.
文摘Wear occurring at the bearing surface and the consequent generation of wear debris has been identified as the primary cause of aseptic loosening in metal-on-polyethylene(MoP)hip joint replacements.The accurate estimation of volume change in polyethylene cups due to creep and wear is,therefore,an important step for identifying the cause of failure and improving the longevity of MoP prosthesis.The purposes of this study were to present and apply a co-ordinate measuring machine(CMM)-based method for assessing the volume change of retrieved components due to wear and creep by using a combination of CMM data and a bespoke computer programme.The method was firstly validated against the standard gravimetric technique,and then applied to four retrieved polyethylene cups for wear assessment and analysis.The results show that the volume changes calculated using the present method match well with those assessed through the gravimetric technique.The CMM-based method presented in the study is capable of effectively and reliably determining the volume change and characterising the wear patch of retrieved components from MoP hip joint replacements.
文摘The surfaces of biomaterials determine their efficacy and hence,have an important role in clinical applications.Through bio-inspired surface nanofunctionalisation,the surface properties of biomaterials such as physical morphologyand chemical composition can be tailored using biomimicry.It is a powerful tool for improving the interactions betweenthe physiological environment and biomaterial surfaces.Therefore,research on bio-inspired nanofunctionalised surfaceshas attracted much attention in recent years.This review focus on the recent bio-inspired strategies based on the structureof the extracellular matrix(ECM)and composition of mussel-inspired polydopamine(PDA).The design,preparation,andproperties of ECM and PDA-inspired nanofunctionalised biomaterial surfaces are reviewed.l have also highlighted theeffects of these bio-inspired nanofunctionalised biomaterial surfaces on bone regeneration,cartilage repair,andantibacterial activities.
基金supported by the National Natural Science Foundation of China(no.51675447).
文摘The micromechanical properties of soft tissue can be used as markers for the physiological state and function of the tissue.Deep understanding of the micromechanics of soft tissue,such as the oesophagus,is of great significance to the design of artificial oesophagi,endoscope materials and coatings for medical devices.Here,the micromechanical properties of oesophageal mucosa were studied under different loading rates,deflections,and dwell time by using atomic force microscopy.The micromechanical properties of soft tissue included elastic modulus,plasticity and adhesion force.Results showed that the micromechanical properties changed with increasing loading rate,deflection and dwell time.The micromechanical properties of oesophageal mucosa were related to time-dependent behaviours,such as contact stress,energy transformation,and strain gradient plasticity.Furthermore,the heterogeneity of oesophageal mucosa affected the micromechanical properties.The force mapping mode was a reliable and effective means to study the micromechanical properties of soft tissue.The results can provide a basis and technical support for the diagnosis of oesophageal diseases from a microscale as well as a material design perspective.
