Biosurface and Biotribology最新文献

Cardiovascular disease (CVD) is regarded as the leading cause of morbidity and mortality worldwide within recent decades. Stent intervention is one of the main methods for treating CVD due to its advantages of minimal trauma, fast recovery and fewer complications. However, the main function of existing drug-eluting stents is anti-hyperplasia, and their re-endothelialisation function is still insufficient and needs to be strengthened. In this study, a novel coating containing traditional Chinese medicine ingredient, Ophiopogon Saponin D (OPH), is designed to enhance the re-endothelialisation function of stents: firstly, the dopamine (DA) and hexanediamine (HD) were co-polymerised to the bare metal stent, endowing rich-amino surface (PDA/HD) for conjugating functional molecules by chemical reaction; thereafter hyaluronic acid (HA) containing OPH were conjugated to the PDA/HD. Our data suggested that the OPH coating promoted surface re-endothelialisation not only by directly enhancing proliferation/migration and inhibiting apoptosis of endothelial cells, but also by regulating macrophages to M2 phenotype and smooth muscle cells to contractile phenotype. Our study may provide inspiration for designing more novel biomaterial coatings using traditional Chinese medicine ingredient.

The excessive and continuous contacting pressure tends to cause skin injury and pain when the lower limb contacting with prosthetic liners. To relate the subcutaneous pressure and the brain response induced by pain sensations, a mathematical model was established based on the finite element model, Hodgkin–Huxley model and GCT model. The results showed that stronger subcutaneous pressure stimulation can lead to higher frequency of the membrane potential and T-cell potential. The frontal, prefrontal cortex, primary somatosensory cortex and occipital lobe were involved in the processing of pressure pain. A significant increase was observed in γ oscillations in pain states compared with no pain, but no significant differences in different pain level, indicating mathematical model and EEG methods can distinguish the pain but cannot distinguish the pain intensities when the stimulation exceeded the pain threshold. Compared with silicone materials, a higher T-cell potential and a lower pressure pain threshold were observed as the skin contacted with foam materials, suggesting that the foam materials can induce more severe pain on the skin surface. This study is helpful to understand the mechanisms of pain from skin surface to brain response and to provide theoretical guidance for the optimal design of lower limb prostheses.

Loading modes and parameters on wear testing of unicompartmental knee prostheses are important. The difference in wear assessments of unicompartmental knee prosthesis under total knee loading mode and unicompartmental loading mode was investigated via computational simulation. The ISO standard testing protocol and the measured personalised load and kinematic data were further used to reveal the influence of the testing parameters on wear assessments. Compared with the total knee loading mode, the unicompartmental loading mode produced a larger peak contact pressure of the tibial insert throughout the wear cycle. Under ISO 14243-3 and Stan’s CAMS testing parameters, the predicted volumetric wear of tibial inserts of the unicompartmental loading mode increased by 28.21% and 15.18%, respectively, compared with the total loading mode. Compared with ISO 14243-3, volumetric wear increased by 42.64% for total knee loading mode and 28.14% for unicompartmental loading mode under Stan’s CAMS loading conditions. Both loading mode and parameters played an important role in the wear of unicompartmental knee arthroplasty simulation. Therefore, wear testing and computational simulation of wear predictions for unicompartmental knee prostheses should be performed in a unicompartmental loading mode, and it is more reasonable to use the patient’s in vivo measurement data.

Sensory properties of food, such as creaminess and smoothness, enhance the overall consumption experience. These properties are also linked to swallowing difficulties in elderly individuals. The direct characterisation of lubrication under soft oral conditions remains a challenge. In this study, relative optical interference intensity (ROII) technique was employed to measure the lubrication film thickness under compliant contact with improved image processing to correct the accuracy loss due to the interface's low reflectivity. Interferogram analysis revealed that oil exhibited a hydrodynamic lubrication state at a low entrainment speed. The minimum film thickness occurred near the edge of the contact zone. The whey protein isolate (WPI) reached to a soft-elastohydrodynamic state until the entrainment speed exceeded 7.5 mm/s. The variation in the Stribeck curve was influenced by the shape of the soft contacts. Both oil and WPI exhibited the state of soft-elastohydrodynamic lubrication when a compliant PDMS pin slid on a rigid steel disc, consistent with the film thickness measurements. When a rigid steel ball slid on a PDMS pad, the hydrodynamic state was delayed. These findings provide new insights into the in vitro development of oral soft friction and enhance our understanding of oral sensory perception.

Implants with high coefficients of friction reduce tightening torque requirements while mitigating fracture risks at bone–implant interfaces. This study engineered flexible nanowire textures on titanium surfaces to significantly increase the coefficient of friction without accelerating surface wear. Results demonstrate that these textures maintain a friction coefficient exceeding 0.8 during reciprocating sliding tests under both dry and water conditions. Our analysis reveals that this friction enhancement stems not from surface roughness but from increased tangential resistance during nanowire-textured deformation. Implementing such high-friction nanostructures on the implant surface is critical for enhancing preload and improving connection reliability.

Reducing surface friction resistance (SFR) is beneficial for the performance of high-speed marine equipment surfaces. To reduce SFR, a biomimetic surface was developed through a collaborative multi-process strategy involving a combination of laser ablation and spraying techniques. Initially, biomimetic fish scale (BFS) arrays with five different spacing (s) values were fabricated on an aluminium (Al) substrate using laser ablation, which was then replicated with polydimethylsiloxane (PDMS). Subsequently, a mixture of superhydrophobic nanoscale SiO₂ particles (SH-SiO₂), PDMS and n-hexane solution was uniformly sprayed onto the BFS surface to enhance its hydrophobic properties. The morphology of these biomimetic surfaces was characterised using a scanning electron microscope (SEM) and ultra-depth field microscope. The drag reduction (DR) performance of the biomimetic surfaces was evaluated within a Reynolds (Re) number range of 4.2 × 10⁴–2.2 × 10⁵ in a circulating water tunnel. The results indicated that a drag reduction rate of 11.82% was achieved with the modified BFS at s = 300 μm and Re = 1.7 × 10⁵. Additionally, the drag reduction mechanism of the modified BFS surface was analysed using the computational fluid dynamics (CFD) method. The excellent drag reduction performance was attributed to the combined effects of the ‘rolling bearing’ caused by streamwise vortices, high-low velocity streaks and the velocity slip effect caused by hydrophobic properties at the interface. These findings offer a novel approach for creating multi-effect coupled drag reduction surfaces.

Silver-based printed circuits have demonstrated significant potential in the field of flexible electronics, particularly for applications such as wearable devices, owing to their high conductivity, low cost, and ease of mass production. However, their structural and performance degradation under continuous mechanical and electrical loads during service poses a major challenge to achieving long-term stable functionality. Herein, this study investigates the performance and microstructural evolution of silver-based printed circuits under electromechanical coupling loads and unveils the underlying material degradation mechanisms. Resistance change curves reveal that, under identical bending loads, lower current density (208.3 A/cm²) accelerates circuit degradation more significantly than higher current density (1164.7 A/cm²). By analysing the thermal characteristics, conductive phase structure, and conductive network of printed circuits under mechanical loading, electric field stimulation, and electromechanical coupling, it is evident that heat plays a critical role in determining resistance changes in silver-based printed circuits. At lower temperatures, heat-induced oxidation of nanosilver to nonconductive silver oxide emerges as the primary driver of resistance increase. Conversely, at higher temperatures, heat-induced sintering of silver forms new conductive pathways that offset the resistance increase caused by the oxidation of silver nanoparticles. These findings not only elucidate the fatigue degradation mechanisms of silver-based printed circuits but also offer theoretical guidance for the development of high-performance silver-based printed circuits.

The development of multifunctional surfaces for titanium implants has become a hot research area due to their potential to elicit specific responses from various cells and infection agents. Solid-binding peptides are increasingly exhibiting their distinct advantages as a novel noncovalent surface modification method for titanium implants. In this study, titanium-binding peptide (TiBP2), a titanium-binding peptide with higher affinity for acid–alkali treatment titanium (AA) substrate, was screened using the phage display technique. The excellent affinity and stable binding of TiBP2 to the AA substrate was due to the interaction of its COO^– group with Ti⁴⁺ on the AA substrate. Linker-conjugated RGD–TiBP (TPR/TGR) was constructed, and its binding capacity and biofunctionality were analysed. RGD-TiBP exhibited high affinity and stable binding properties with AA substrate, as well as excellent biocompatibility (no toxic effect on L929 cells) and remarkable H₂O₂ scavenging ability. Notably, 40 μg/mL of TPR effectively promoted the polarisation shift of macrophages from a pro-inflammatory phenotype (M1) to an anti-inflammatory phenotype (M2). The present results indicated that TPR-based biofunctional modification of titanium implants can improve interfacial stability and immunomodulatory activity, making it a promising technique for application.

Patients undergoing posterior cruciate ligament (PCL) reconstruction may experience changes in the mechanical environment of cartilage and meniscus; however, limited information is available regarding the contact mechanism of the tibiofemoral joint following different PCL reconstruction techniques. In this study, finite element (FE) models of the PCL-reconstructed tibiofemoral joint—including the femur, tibia, fibula, menisci, cartilage and ligaments (ACL, PCL, MCL and LCL)—were developed with contact interactions among these tissues considered. Joint angles and axial forces based on the ISO 14243-3 were used as inputs. Using these FE models, the effect of different PCL reconstruction techniques on contact pressure, stresses of the cartilages and menisci and tibiofemoral kinematics was evaluated. Compared to the intact model, PCL-reconstructed models exhibited reduced anterior translation during swing phase and reduced external rotation during stance phase. The external rotation of the TA model was greater than that of the intact model, TI model and TL model during swing phase. The medial meniscus of the PCL-reconstructed models experienced lower contact pressure and stresses compared to that in the intact model. The altered kinematics and contact mechanics of the PCL-reconstructed models demonstrate that the typical PCL reconstruction techniques should be improved or adjusted to better restore the natural biomechanical function of the joint.

Periodontitis is a common and serious oral health problem. It not only damages the health of periodontal tissues but also has potential impacts on the whole body. Existing treatment methods, such as mechanical debridement and antibiotic treatment, have obvious limitations. Functional hydrogels can be used as drug carriers to deliver medications for treating periodontitis. Meanwhile, depending on different designs, hydrogels can achieve functions such as antioxidant, antibacterial, anti-inflammatory effects and osteoinduction, making them a promising material for periodontitis treatment. In this review, we first elaborate on the preparation methods of hydrogels for periodontitis, as well as the pathological characteristics and hazards of periodontitis. Then, we introduce the applications of hydrogels in antibacterial, anti-inflammatory, antioxidant and osteoinduction aspects related to periodontitis. Finally, we discuss the current challenges and future research directions in this field.