Biosurface and Biotribology最新文献

Tactile perception is essential for humans to recognise objects. This study systematically investigated the tribological behaviour of the finger and physiological response of the brain related to the width recognition of tactile perception using subjective evaluation, friction and electroencephalography methods. The results show that the texture feeling, recognition accuracy of the texture and proportion of deformation friction increased with the texture width. The average width recognition threshold of the fine texture was 45.4 μm. The load index, maximum amplitude of the vibration signal, entropy, longest vertical line and P300 amplitude were positively correlated with the texture width. P300 latency was negatively correlated with the texture width. When the texture width exceeded the width recognition thresholds of tactile perception, the main frequency of the vibration signals increased to the optimal perceptual range of the Pacinian corpuscle. The nonlinear features of the vibration signal increased, and the vibration system transitioned from a homogenous state to a disrupted state. Moreover, the activation intensity and area of the brain and the speed of tactile recognition increased. The study demonstrated that the mechanical stimuli of friction and vibration generated in the touching of fine textures having various widths affected the subjective evaluation and brain response.

Ti6Al4V alloy is widely used in artificial joints, artificial bones, and dental implants due to its elastic modulus similar to that of bone, good biocompatibility and non-cytotoxicity, low density, and excellent fatigue resistance. However, its utility is constrained by the low surface hardness and inadequate wear resistance. Micro-arc oxidation (MAO) technology emerges as a surface modification method characterised by a straightforward process and superior processing efficacy, making it particularly favoured in enhancing the wear resistance of Ti6Al4V. This paper commenced by elucidating the fundamental principles of micro-arc oxidation. Subsequently, it examined the impacts of crucial parameters such as electrolyte type, concentration, processing voltage, current, time, and electrolyte additives on the friction and wear properties of Ti6Al4V alloy MAO coatings, proposing three mechanisms for optimising wear resistance. The primary strategies for augmenting the microhardness and wear resistance of Ti6Al4V alloy MAO coatings involved pore reduction even sealing, lubrication enhancement, and hard compound generation. Following this, the article synthesised the friction and wear attributes of MAO coatings in conjunction with diverse modification techniques, alongside a review of fretting wear characteristics of Ti6Al4V alloy MAO coatings. Lastly, conclusions and prospects were presented to furnish a foundation for future exploration into the wear resistance of Ti6Al4V alloy MAO coatings in scholarly endeavours.

The development of metal implants as permanent replacements for hard tissue involves careful consideration of both interfacial bone integration for load-bearing support and interfacial energy dissipation to prevent bone resorption due to excess load. Currently, most implants are typically limited to excelling in only one of these functions. A promising approach to achieving a synergistic effect of interfacial bone integration and energy dissipation is the design of a nanofiber-chitosan (nanofiber-CS) composite flexible coating on titanium alloy surfaces. However, the tribological properties of this flexible coating remain uncertain. In this study, the authors evaluated the tribological properties of pure titanium substrates and the nanofiber-cs composite flexible coating in both dry and wet environments. The results demonstrated that while the nanofiber-cs composite flexible coating reduced surface wear in dry conditions, it increased surface wear in wet environments. This indicates that there is potential for improvement in the tribological characteristics of the nanofiber-cs composite flexible coating, particularly in wet conditions. This research offers theoretical and technical insights into the design of flexible coatings for implant surfaces from a tribological standpoint.

Advanced engineering coatings offer a promising solution to enhance the longevity and performance of medical biomaterials in orthopaedic implants. This study hypothesises that diamond-like carbon (DLC) coatings exhibit distinct frictional performance based on substrate and counterface material. Three different DLC coatings were tested using a pin-on-plate test in four material combinations. Virgin and DLC-coated CoCrMo and Ti6Al4V pins were tested under sliding against UHMWPE and glass plates with simulated body fluid lubrication. Results revealed that coating composition significantly impacts frictional performance, with silicon- and oxygen-doped coatings showing great potential to minimise friction. Surprisingly, reducing contact pressure had either a neutral or somewhat negative effect. Future investigations will focus on long-term testing and lubrication analyses of these material combinations.

Guidewire interventional radiotherapy is an important means for the diagnosis and treatment of cardiovascular disease, and the risk of intraoperative guidewire puncture jeopardises the life and health of patients. A bionic multilayer vascular model that conforms to the real vascular morphology and mechanical properties of arterial vessels can help surgeons familiarise themselves with the mechanical properties of blood vessels in preoperative simulations and thus avoid the risk of intraoperative vascular puncture. In this paper, porcine abdominal aortic vessels were used as a biological model to evaluate its mechanical properties by T-peel test, uniaxial tensile test and puncture force test. The results showed that the average delamination force between the intima and media of the vessels was 1.11 N. The radial tensile strength of the vessels was greater than the axial tensile strength and the elongation at the break of the media increased after peeling the intima. A multilayer vascular model manufacturing method was developed, and the structural integrity was improved using an intima–media nesting method. This research provides guidance for material selection and preparation processes for 3D printed bionic multilayer lower limb vascular models and contributes to the development of more accurate and functional 3D printed vascular models for biomedical applications.

Compromised hydration and biolubrication leads to untreatable disorders like osteoarthritis (OA), dry eye disease (DED) and dry mouth disease (xerostomia). Only symptomatic treatment is possible through bioactive molecules. This study aims to investigate the biolubrication properties of natural and modified phytoglycogen nanoparticles (PGNPs) which have shown superlubricious behaviour at mica-mica sliding interface. PGNPs were cationised (CPGNPs) by modifying hydroxyl groups into quaternary amine groups. Dynamic light scattering (DLS) was used to characterise the size and zeta-potential of both the PGNPs. The quartz crystal microbalance with dissipation (QCM-D) was used to investigate their adhesion to collagen type II and mucin. The tribological properties of the nanoparticles were studied using the polydimethylsiloxane (PDMS)-glass system, cartilage-glass (synovial) and eye-eyelid (ocular) systems. CPGNPs adhered better than PGNPs on synovial and ocular surfaces. Both particle types showed good lubrication for cartilage but no differences between PGNPs and CPGNPs in the eye-eyelid system were observed. Overall, the CPGNPs showed better lubrication properties than PGNPs. PGNPs and CPGNPs were observed to have good lubricating properties in the cartilage-glass system, indicating to great potential towards a possible implementation in the treatment of osteoarthritis.

In this study, the authors designed a paper-based electrochemical immunodevice modified with copper embedded in copper sulphide hollow nanocages wrapped with Au nanoparticles (Cu@CuS@Au NPs) for the specific detection of prostate-specific antigen (PSA), aiming to advance point-of-care testing. The large specific surface area of Cu@CuS nanocages enables efficient capture of biotin antibodies, leading to the direct amplification of the signal through the inhibition of electron transport in the redox process of Cu, eliminating the need for universal redox electron mediators. Additionally, Au NPs on the surface of Cu@CuS can accelerate charge transfer and conjugate with anti-PSA. The hierarchical morphology and structure of Cu@CuS nanocages were characterised using scanning electron microscopy and transmission electron microscopy. The fabrication process of the immunodevice was monitored using cyclic voltammetry and electrochemical impedance spectroscopy analyses. PSA was sensitively detected using differential pulse voltammetry on this proposed immunodevice within a linear range from 0 to 100 ng/ml (R² = 0.996), achieving a low detection limit of 0.077 ng/ml. In addition, the practicality of the developed immunosensor has been proven by successfully detecting PSA in human serum samples obtained from clinical settings. The integration of electrochemical sensors and microfluidic devices holds promise for developing cost-effective approaches in clinical immunoassays.

Additive manufacturing has enabled the creation of 3D porous metallic medical materials, crucial for enhancing cell ingrowth and tissue integration. However, despite extensive research on optimising pore size, inconsistencies persist in achieving optimal cells and tissues adhesion. In this study, the authors show that cell attachment and proliferation are hindered by the formation of bubbles within the pores, which may act as physical barriers. The authors fabricated porous titanium (Ti) and tantalum (Ta) scaffolds by selective laser melting and investigated the effects of bubble entrapment on cell adhesion and proliferation. The authors’ results demonstrate that bubble removal significantly enhanced cell integration. These results indicate the importance of both geometrical design and microenvironmental conditions to prevent bubble formation, ensuring cell adhesion and tissue integration in the development of next-generation porous metallic scaffolds.

Here, we present and synthesise some recent collaborative efforts in our laboratories to establish protocols for using dental microwear texture analysis, originally developed to reconstruct diets of fossil mammals and to aid in the clinical assessment of dental patients today. The idea is to propose a method where polyvinylsiloxane impressions, as used in many dental practices, can be combined with surface texture analysis for a rapid, non-invasive, and inexpensive approach to detect and monitor the progression of tooth wear at fine scales over short durations and help determine causal agents of dental tissue loss. We employed both in vitro experimentation and in vivo analysis for abrasion and erosion of enamel and dentin surfaces. Three-dimensional point clouds of impression surfaces were generated using a scanning confocal profiler and analysed using both standard ISO and scale-sensitive fractal analysis approaches. The authors’ results indicate that texture attributes distinguish sound, abraded, and eroded surfaces. Furthermore, microwear textures can parse erosive tooth wear by the causal pH level and duration of exposure. These and other related studies indicate that dental microwear texture analysis holds potential for determining the aetiology of pathological tooth wear and for the clinical assessment and monitoring of dental patients at risk for excessive dental tissue loss at fine scales over short intervals.

While the erosive potential of acidic beverages has been known for decades, many new and increasingly popular beverages and food fads have not been evaluated quantitatively for their dental associated risks. In this study, the authors utilise atomic force microscopy to monitor changes in the surface morphology of an enamel mimic, hydroxyapatite (HA), induced by hard seltzer and kombucha. The primary causes of enamel degradation were assessed through a combinatorial investigation probing the impact of carbonation, acid type, acid concentration, and saliva. The average surface roughness of HA discs was determined after successive demineralisation steps. The heterogeneity of the decay process was assessed using multiple spatial replicates per sample. To aid in the interpretation of the HA decay profiles, pH and titratable acidity of each beverage were also measured. The authors find that, in comparison to a reference sample of Coca-Cola®, kombucha is equally erosive after prolonged exposure while hard seltzer results in relatively minor surface damage. In addition, the presence of saliva was found to eliminate any measurable amounts of decay. Results from this study demonstrate the potential damage more recently popularised beverages can have on dental enamel and the significant dependence of oral health on the presence of saliva.