Biosurface and Biotribology最新文献

It is challenging to match the mutual interactions between implant and host because the biomaterials usually cannot actively adjust their performance to the changing microenvironment. Surface potential is one of the critical factors affecting the bioactivity of biomaterials, but it is difficult to be directly controlled in vivo. Magnetic stimulation has attracted much attention due to its deep penetrability, good reliability, and convenient operability. Here, titanium dioxide (TiO₂) nanotubes and Terfenol-D/P(VDF-TrFE) composite film are prepared by anodic oxidation and solution casting methods on opposite sides of a titanium sheet, respectively. Terfenol-D magnetostrictive microparticles deform under a magnetic field, generating surface potential on the P(VDF-TrFE) piezoelectric matrix through magneto-electric coupling. Correspondingly, equal opposite charges are induced on the surface of TiO₂ nanotubes. Stem cells cultured on TiO₂ nanotubes show that cell adhesion, proliferation, and differentiation abilities can be regulated by magnetic strength, which correlates with the absorption of charged proteins. Therefore, a cascade coupling of magnetic, mechanical, electric, biochemical, and cellular effects is established. This work demonstrates the feasibility of regulating the bioactivity of biomaterials in vivo through a magnetic field.

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.

Hydrogel is a polymer network system that can form a hydrophilic three-dimensional network structure through different cross-linking methods. In recent years, hydrogels have received considerable attention due to their good biocompatibility and biodegradability by introducing different cross-linking mechanisms and functional components. Compared with synthetic hydrogels, natural polymer-based hydrogels have low biotoxicity, high cell affinity, and great potential for biomedical fields; however, their mechanical properties and tissue adhesion capabilities have been unable to meet clinical requirements. In recent years, many efforts have been made to solve these issues. In this review, the recent progress in the field of natural polymer-based adhesive hydrogels is highlighted. The authors first introduce the general design principles for the natural polymer-based adhesive hydrogels being used as excellent tissue adhesives and the challenges associated with their design. Next, their usages in biomedical applications are summarised, such as wound healing, haemostasis, nerve repair, bone tissue repair, cartilage tissue repair, electronic devices, and other tissue repairs. Finally, the potential challenges of natural polymer-based adhesive hydrogels are presented.

In this study, a bioinspired hierarchical structure was formed with superomniphobicity on a 7075 aluminium alloy using laser ablation. The morphology and wetting characteristics of the biomimetic sample surface were characterised using scanning electron microscopy, laser confocal microscopy, and contact angle measurements. The effect of the liquid properties and surface structures on the rolling behaviour was investigated. The results suggest that the fabricated biomimetic sample surface was a hierarchical structure. The prepared sample had superomniphobicity and low adhesion properties, and the contact angles of six different liquid droplets on the sample surface reached or approached 150°. Specifically, the largest contact angle was 152°, and the average rolling angle was 7.7°. This multi-hydrophobic surface provides a valuable reference for the research study and use of a variety of solid–liquid contacts.

Excessive wear is a key issue affecting the performance of ultra-high molecular weight polyethylene (UHMWPE)-based artificial prosthesis. This work is focussed on the bio-tribology behaviours of UHMWPE when mating with different metal counterparts (iron-based 316L, Co-based Stellite-S21 and Stellite-S22). According to the ASTM F732 standard, two million cycles comparative wear tests were carried out under bovine serum lubrication. When coupled with S21, S22, and 316L metal counterparts, the obtained average wear factors of UHMWPE were 1.333 ± 0.192, 1.360 ± 0.160, and 1.190 ± 0.177 × 10⁻⁶ mm³/N · m, respectively. Initial surface roughness of the metal counterpart has shown an important role in controlling the volume of UHMWPE wear, especially the first one million cycles. Compared with 316L, CoCrMo-based counterparts possessed relative higher hardness and exhibited less rise in surface roughness caused by wear. For UHMWPE-on-metal bearings, random scratch, surface pit, and wear debris attachment were commonly seen, which suggested the coexistence of abrasion, third-body abrasion, and adhesion-based wear. In contrast, the metal counterpart was slightly scratched with no polymer transfer film formation. The work conducted in the present study gives useful knowledge regarding the UHMWPE-on-metal bearing design. With an intention to minimise wear, surface roughness of metal counterpart should be carefully controlled.

With one-third of patients having osteoarthritis predominantly in one compartment of the knee, unicompartmental knee spacers have been introduced as a less invasive alternative to total knee replacement. However, patients with the knee spacer implanted were seen to have persistent pain, resulting in high revision rates. A static finite element model of the knee and its interaction with a knee spacer implant at full extension and 90° flexion was used to investigate the tibio-femoral contact mechanics of the knee joint after a knee spacer surgery. Three different knee spacer designs (contoured, flat and C-shaped) were modelled and prescribed with cobalt-chrome, ultra-high molecular polyethylene and polyurethane material properties. The results suggested that a softer spacer is generally preferred as this helps in the conformity of knee spacer to the condyle, effectively distributing the load subjected to the implant. Flat spacers that result in high stresses resulting from lower contact areas should be avoided.

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 multifunctional 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, environmentally friendly and appropriate for large-area fabrication, which could be applied to various fields.

There are various walking pavements in daily life. Slip accidents will happen if required friction for safe walking is greater than available friction between the foot and ground surface. Existing researches mostly focus on horizontal or slope pavements, whereas the cross-slope walkways are less. A self-developed gait friction test platform was used to test friction, distribution of plantar pressure and spatiotemporal parameters of human walking under cross-slope condition. With the increase of cross-slope angles, the mediolateral friction increases (R ² = 0.972, P < 0.001), the anterior-posterior friction shows no significant change (R ² = 0.758, P = 0.017), the normal pressure decreases (R ² = 0.915, P = 0.007), and the high foot is more prone to slip and fall than low foot. Therefore, plantar pressure distribution of both feet was shifted to left. The gait cycle was prolonged (P < 0.001), swing period of both feet decreased (P = 0.029) and support period increased (P = 0.015) with the increase of cross-slope angle.

Hydrophilic polymers are very useful in biomedical applications. In this study, biocompatible polyethylene glycol (PEG) and polyvinylpyrrolidone (PVP) polymers end-capped with succinimidyl groups were either modified or synthesised and attached to polyvinylchloride surfaces. The modified surfaces were evaluated with cell adhesion and bacterial adhesion. 3T3 mouse fibroblast cells and three bacteria species were used to evaluate surface adhesion activity. Results showed that the modified surface exhibited significantly reduced 3T3 cell adhesion with a 50%–69% decrease for PEG and a 64%–81% for PVP, as compared to unmodified polyvinylchloride. The modified surface also showed significantly reduced bacterial attachment with 22%–78%, 18%–76% and 20%–75% decrease for PEG and 22%–76%, 18%–76% and 20%–73% for PVP to Staphylococcus aureus, Escherichia coli and Pseudomonas aeruginosa, respectively, as compared to unmodified polyvinylchloride. It seems that an appropriate chain length or molecular weight (neither the longest nor the shortest chain length) determines the lowest cell and bacterial adhesion in terms of PEG. On the other hand, a mixture of polymers with different chain lengths exhibited the lowest cell and bacterial adhesion in terms of PVP.

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 properties of CoCrMo, Ti6Al4V and Ti15Mo alloys in a simulated body fluid (SBF) solution. It was found that the tribo-corrosion behaviours of CoCrMo/Al₂O₃ and Ti15Mo/Al₂O₃ systems had significant wear-corrosion synergistic interaction, and wear-induced corrosion was dominant. For Ti6Al4V/Al₂O₃ systems, their wear mechanism under SBF lubrication was a combination of abrasive, adhesive and fatigue wear. While the wear mechanism of the Ti15Mo/Al₂O₃ 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).