Biosurface and Biotribology最新文献

Titanium (Ti) dental scaffolds are widely used in dental prosthetics due to their excellent mechanical properties and biocompatibility. However, conventional Ti scaffolds manufactured through machining often do not fit perfectly with the bone defect site. Laser powder bed fusion (LPBF) technology enables the personalised manufacturing of custom-made Ti scaffolds. A custom-made Ti scaffold was prepared using LPBF and its surface roughness was improved through chemical polishing. To enhance the surface roughness, a nitric acid mixed solution with a specific composition of HF: HNO₃:C₃H₆O₃ = 2:2:3 was used. The polishing mechanism was investigated by adjusting the F/Ti ratio to control the formation and dissolution of the oxide film. As a result, the surface of the Ti scaffold after polishing exhibited a smooth and flat appearance compared to the LPBF part, with a reduced surface roughness (Ra) of 1.23 ± 0.19 μm. The custom-made Ti scaffold also demonstrated favourable mechanical properties, with a bending strength of 335.18 ± 33.62 MPa and stiffness of 2.13 ± 0.21 GPa. Furthermore, in vitro cell tests confirmed the excellent biocompatibility of the custom-made Ti scaffold. The authors present a feasible strategy for the further clinical application of custom-made Ti scaffolds, offering enhanced surface properties and addressing the limitations of conventional machining methods.

It is a developed photosynthetic co-culture system to alleviate the hypoxia and hypoxia/reoxygenation (H/R)-injured human umbilical vein endothelial cells (HUVECs). The algae, Chlorella vulgaris, were encapsulated to slow their growth while not affecting the photosynthetic oxygen-producing capacity by Layer-by-layer (LbL) using gelatin and sodium alginate as the positive and negative charges materials, respectively. Then, the photosynthetic co-culture system of HUVECs and self-oxygenating alginate hydrogel (Algae-gel) was constructed in which the optimal ratios between algae and HUVECs were 5:1 and 20:1 for a 2D or 3D co-cultured manner, respectively. It indicated that the 3D co-cultured manner of HUVECs needed more O₂ by the production of algae than it did in a 2D co-cultured manner. The co-cultured Algae-gel could alleviate hypoxia and the oxidative stress injury of hypoxia and hypoxia/reoxygenation (H/R)-treated HUVECs in the proliferation, intracellular ROS and cellular migratory ability. In addition, the Algae-gel could downregulate the expression of hypoxia-inducible factors 1α (HIF-1α) and vascular endothelial growth factor (VEGF) of hypoxia and H/R-injured HUVECs due to the improvement of hypoxia and H/R injury. This photosynthetic co-culture system could offer a promising approach for repairing hypoxia and H/R-injured cells or tissue by providing safe and stable O₂.

Bone implantation surgery is often accompanied by bacterial infection, resulting in infectious bone non-union, pathological fracture and other serious consequences, which will aggravate the pain of patients. A non-antibiotic coating consisting of sodium dodecyl sulphate (SDS) and levulinic acid (LA) with different concentrations was prepared by the authors on the zinc–aluminium alloy (ZA6-1) using a wet chemistry treatment for orthopaedic application. The influence of SDS/LA concentrations on the surface morphology, composition and performance of the developed coating was investigated. The results showed that as-prepared coating on a zinc alloy surface could improve the substrate's corrosion resistance and increase the degradation rate from 0.82 to 19.70 μm/year upon raising the SDS/LA concentration. Furthermore, higher hydrophilicity (<14°), better cell proliferation (>100%) and morphology, as well as good cell adhesion and differentiation (ALP >95% for 7 days) were observed on coated zinc alloys. The increased SDS/LA concentration slightly weakens the biocompatibility and enhances the antibacterial performance of coated zinc alloys due to the synergistic effect of SDS/LA. Overall, the coating comprising 6 wt.% SDS and 9 wt.% LA showed excellent antibacterial action with a high level of biocompatibility, confirming its potential application for orthopaedic implants.

For high-speed moving objects, drag reduction has been a prolonged major challenge. To address this problem, passive and negative strategies have been proposed in the preceding decades. The integration of creatures and nature has been continuously perfected during biological evolution. Unique structure characteristics, material properties, and special functions of marine organisms can provide inexhaustible inspirations to solve this intractable problem of drag reduction. Therefore, a simple and low-cost laser ablation method was proposed. A multi-scale and multi-level riblet (MSLR) surface inspired by the denticles of the sharkskin was fabricated by controlling the density of the laser path and ablation times. The morphology and topographic features were characterised using an electron microscope and a scanning white-light interfering profilometer. Then, the drag reduction capacity of the bionic riblet surface was measured in a circulating water tunnel. Finally, the mechanism of drag reduction was analysed by the computational fluid dynamics (CFD) method. The results show that the MSLR surface has a stable drag reduction capacity with an increase in Reynold (Re) number which was contributed by high-low velocity stripes formed on the MSLR surface. This study can provide a reference for fabricating spatial riblets with efficient drag reduction at different values of Re and improving marine antifouling.

Harmful components in cigarette smoke, such as nicotine, tar, and organic particulate matter, are the primary culprits behind lung diseases. While conventional filter materials based on cellulose, carbon, and molecular sieves exhibit commendable filtration capabilities, their high cost restricts their widespread applications. Based on this, the authors aim to prepare PET-based filter materials with good adsorption properties through a simple surface functionalisation strategy. The adsorption performance of the PET-based non-woven fabric was enhanced by the introduction of sodium alginate (SA). The gas adsorption experiments results reveal that SA-modified PET (SA-PET) exhibits significantly improved filtration efficiency for nicotine, tar, and total particulate matter—increasing by 27.1%, 26.2%, and 21.3%, respectively. Moreover, SA-PET exhibits more odour control ability than traditional activated carbon-based filter materials. These results prove that surface-functionalised SA-PET has better filtration performance for harmful substances in smoke and provides a new strategy for the design of high-performance filtration materials.

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 inflammatory 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.

1D magnetic nanomaterials with iron, with the special physical properties and biological behaviour, have been found to possess the great promising applications in many fields. In this review, the components, structure, physicochemical properties, biocompatibility and in vitro and in vivo biomedical functions of magnetic nanowires (MNWs), nanorods (MNRs) with iron are summarised, especially their anisotropy shape and magnetism result in their many applications in biodetections and medical treatment fields. The potential future functions of these 1D magnetic nanomaterials compared to magnetic nanoparticles also is discussed by highlighting the possibility of integration with other metal-compositions or bio-compositions and with existing biotechnology as well as by pointing out their specific properties. Current limitations in the property improvement and issues related with the outcome of the MNRs in the body are also summarised in order to address the remaining challenge for the extended biomedical functions of MNRs in the clinical application field.

In this work, a novel coating with a non-antibiotic agent for inhibiting Gram-positive bacteria and promoting osteogenesis was prepared on zinc-aluminium alloy (ZA6-1) via mussel mimetic polydopamine (PDA) containing lysozyme (LYS) and parathyroid hormone (PTH). The results indicate that as-deposited coatings can efficiently decrease the degradation rate of ZA6-1 from 0.52 to 0.16 mm/year, and the addition of LYS weakens the coating resistance, while the addition of PTH enhances the coating resistance. In spite that no obvious inhibition of Escherichia coli is observed, the coated zinc alloys show good in vitro antibacterial performance against Staphylococcus aureus. Compared with ZA6-1 zinc alloys, the increase of antibacterial efficacy reaches 86.9%–90.1%. Furthermore, the lower hydrophilicity (26.4°), higher osteoblast cell viability (>100%), good osteoblast cell morphology and better osteoblast cell differentiation (ALP = 107.7%) for PDA-LYS/PTH coated samples support that as-prepared coating is promising for modifying biodegradable zinc implants.

In order to explore the potential application of Ramie fibre (RF) in medical dressing, the absorbency ratio of ramie fibre cloth, medical gauze and natural cotton fibre cloth was tested, and the factors affecting the absorbency ratio of materials were analysed. Meanwhile, the hemocompatibility of the three fibre materials were also studied. The results showed that the RF cloth had good moisture absorption and hemocompatibility. Therefore, RF is a potential material for medical dressing.

The objective of this study was to coat negatively charged polymer brushes by a covalent bond onto the surface of polyvinylchloride using a simple conventional surface free radical polymerisation technique. The coated surfaces were assessed with contact angle, protein adsorption, cell adhesion, and bacterial adhesion. Bovine serum albumin and bovine fibrinogen were used for protein adsorption evaluation. Mouse fibroblast (NIH-3T3) cells and Pseudomonas aeruginosa were used to assess surface adhesion. Results show that the surface modified with all the attached polymers exhibited significantly reduced contact angle, protein adsorption, and cell as well as bacterial adhesion among which the negatively charged polymers showed extremely low values in all the tests. The negatively charged polymer shows its contact angle at 5° as compared to 70° for original polyvinylchloride. Its bovine serum albumin, bovine fibrinogen, 3T3 adhesion, and P. aeruginosa adhesion were 93%, 84%, 92%, and 92% lower than the original PVC, respectively. Furthermore, the polyvinylchloride surface coated with negatively charged polymer brushes exhibited a hydrogel-like property. The results indicate that coating a polyvinylchloride surface with acrylic acids using a simple surface-initiated free radical polymerisation and then converting those to negatively charged salts can be an effective and efficient route for fouling-resistant applications.