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A Ti3C2 MXene/Ti composite powder was developed through surface modification and powder coating for producing a high-performance titanium matrix composites (TMCs) by laser power bed fusion. Introducing MXene rarely changed the original sphericity and flowability of Ti powder while it slightly enhanced the laser absorption capacity of Ti powder. The printing conditions in turn affected the morphology and distribution of MXene in as-printed composites. At optimised printing parameters, majority of MXene with high structural integrity and uniform distribution remained along the grain boundaries of as-printed composites, and a combination of high surface quality, geometrical accuracy and densification was obtained. The remaining MXene played the synergy of pulling-out effect and load transfer role, which increased the yield strength from 530 to 710 MPa, while retaining good ductility (elongation of 19.8%). Compared with ASTM standard cast Ti64 alloy, our MXene/Ti composites also exhibited superior comprehensive tensile properties and excellent strength-ductility synergy. [ABSTRACT FROM AUTHOR]

High entropy alloys (HEAs), consisting of five or more elements with nearly equal atomic composition with one another (5–35%), are new-generation alloys that have attracted signifi)cant interest since their advent in 2004 because of their unique structural and mechanical properties and thermodynamic and chemical stability. Some characteristics, including high mechanical strength at elevated temperatures, high ductility and fracture toughness at cryo)genic temperatures and high corrosion, erosion and wear resistance, have been demonstrated for HEAs that outperform traditional alloys and superalloys. Laser-cladding (LC) is an additive manufacturing technique that has good feasibility in designing and processing HEAs for advanced structural components and protective coatings. This overview provides a glimpse of recent advances in LC of HEAs in terms of design fundamentals, metallurgical phase and microstructure, specific properties for advanced coating applications and the effect of ceramic particles reinforcement in LC deposition of HEA coatings. [ABSTRACT FROM AUTHOR]

Polycrystalline nanoparticles of Al-doped and Ce-co-doped ZnO were processed through sol)gel co-precipitation. Crystallite sizes determined from XRD were in the range of 10.90 to 48.77 nm. FTIR spectra indicated a stretching mode of Zn-O bond. The insertion of Al and Ce at Zn-O site created Al-O and Ce-O bonds. UV-vis spectra favoured the formation of impurity levels by doping and co-doping. Their overlapping with the conduction band edge led to the reduction of band-gap. Blue-green emission which arises from radiative recombination of a photogenerated hole with an electron occupying oxygen vacancy was observed in photo)luminescence spectra. FESEM suggested granular growth in undoped ZnO which changed to diverse structures such as nano-bar and cluster of elongated grains. Significant improvement in room temperature ferromagnetism (RTFM) was noticed by co-doping of Ce in Al-doped ZnO. Formation of bound magnetic polarons (Ce3+-Vo-Ce3+) was the primary mechanism responsible for the improvement in RTFM. [ABSTRACT FROM AUTHOR]

Anodisation with electrochemical cathodic deposition method was employed to modify the surface of Ti implants with a bilayer coating made of Sr- doped titania (Sr-TiO2) and hydroxyapatite doped with magnesium (Mg-HAp). The Mg-HAp/Sr-TiO2 bilayer coating was compared with pure TiO2 and Sr-TiO2 single-layer coating. The Sr incorporation into TiO2 and Mg substitution into HAp strengthened their bioactive properties. The tensile test indicated increase in the mechanical strength of the bilayer coated substrate compared to pure TiO2 substrate. Moreover, the study indicated that the Sr and Mg ions were uniformly incorporated into the Mg-HAp/Sr-TiO2 bilayer coating with significantly higher roughness and hydrophilicity compared to the control. In vitro studies with osteoblasts cells had a superior response to the Mg-HAp/Sr-TiO2 bilayer surface. It was found that a bilayer Mg-HAp/Sr-TiO2 coating on Ti implants promotes bioactivity and has superior adhesion strength necessary for osseointegration and bone healing. [ABSTRACT FROM AUTHOR]

Ti-6Al-4 V and Ti-6Al-4 V ELI alloys were surface modified with nanotube layers by electrochemical anodisation technique. Osteoblast cell viability and their osteogenic behaviour were studied. It was found that the pore diameters of the nanotubes were in the range of 70–105 nm for Ti-6Al-4 V sample and 60–130 nm for Ti-6Al-4 V ELI sample. Porosity was calculated to be in the range of 75–85% of the total volume of formed nanotubes. Pores were arranged in a self-organised nanotube structure and the nanotubes emanated from the pores. MG63 cells cultured on the samples for 1, 7 and 14 days showed significant osteoblast cell growth on Ti-6Al-4 V ELI surface as compared to the grade 5 titanium alloy. CCK-8 assay results confirmed better cytocompatibility of the Ti-6Al-4 V ELI nanotube surface than the Ti-6Al-4 V surface which were ascribed to various inert or toxic ions released to the medium from Ti-6Al-4 V matrix. [ABSTRACT FROM AUTHOR]

Nanomaterials are attractive in biological analysis due to their advantages such as high surface-to-volume ratio, surface plasmonic effect, ease to be chemically modified, and have been applied for diagnosis and therapy of diseases like cancer, cardiovascular and infectious diseases. Meanwhile, microfluidic devices provide an ideal platform for disease diagnosis with a small sample, and for therapy evaluation by recapitulating in vivo like 3D models. The application of nanomaterials in microfluidic devices as capturing, signaling and energy transferring components has combined the advantages of both technologies. Here we focused on recent advances of nanomaterials incorporated microfluidic devices for analysis of proteins, nucleic acids, cells, and small molecules with various analytical methods such as optical, electrochemical, chemiluminescent approaches. Moreover, microfluidic based biological systems were used to evaluate nanoparticles based therapies including photodynamic therapy, photothermal therapy and controlled drug delivery. The combination of nanotechnology and microfluidic technology hold great potential toward medical and clinical applications in the future. [ABSTRACT FROM AUTHOR]

Electron transport layer (ETL) in perovskite-based solar cells (PSCs) is attractive from the perspective of photon-to-electron conversion efficiency. TiO2thin film is preferred in situations where microstructure, stability and charge transport characteristics are important. In this regard, we illustrate an approach that involves the synthesis of TiO2–pepsin thin film that can be used either as a mesoporous or compact layer depending on the device architecture of PSC devices. It was observed that pepsin acts as organic glue to TiO2nanoparticles and facilitates in controlling morphology of the thin film. The addition of pepsin did not have any adverse effect on TiO2anatase phase. Thickness and roughness of mesoporous and compact TiO2thin film suggested that controlled agglomeration can be achieved by tuning the concentration of pepsin in the precursor colloidal solution. The spin-coated thin films indicated high bulk mobility (205 cm2V−1 s−1) and good thermal stability over a wide range temperature (25–700°C). Furthermore, in the presence of pepsin group in TiO2thin film, the inherent optical properties were retained, as confirmed by UV–vis analysis. [ABSTRACT FROM PUBLISHER]

In recent years, magnesium alloys have attracted significant attention as a new class of biodegradable implant materials, because of their superior biocompatibility and low modulus. We describe here the inhibition of bacterial colonisation and biofilm formation on surfaces of Mg-2Zn-2Gd alloy with different grain structures (~44 µm to ~710 nm) obtained via multiaxial forging. Surface energy and contact angle measurements using goniometer and wettability were assessed with water, SBF, n-Hexane and DMEM. The higher surface energy of ultrafine-grained Mg-2Zn-2Gd alloy led to the release of more Mg+2 ions at an early stage, which consequently increased the pH of fluid in the vicinity of the implant, therefore producing unfavourable environment for the survival ofEscherichia coli(E. coli) bacteria. This led to damage of bacterial cell walls thereby reducing their adhesion. In summary, the study underscores that grain size had a significant impact on antimicrobial behaviour. [ABSTRACT FROM AUTHOR]

Magnesium alloys have recently attracted significant attention as a new class of biodegradable implant materials. The primary focus has been on mechanical properties, biological response and biodegradation. The alloys of current interest concern magnesium alloys with rare earth (RE) elements. We describe here the state-of-the-art knowledge on the corrosion behaviour of Mg-RE alloys in conjunction with the biological behaviour and mechanical properties. The addition of RE elements in magnesium alloys provide benefits of improved corrosion resistance via reduction in galvanic sites together with superior mechanical properties. [ABSTRACT FROM PUBLISHER]

There is currently a strong interest in nano- and ultrafine grained planar surface and coatings in the biomedical community, but there is a lack of understanding with regard to the interplay between grain size and cell differentiation. Motivated by our previous studies on the interplay between grain structure and biological response, we describe here the influence of grain size from nano- to coarse grain on osteoblast differentiation and mineralisation. This aspect constitutes the objective of the study. Experiments on the interplay between grain structure and osteoblast functions indicated that cell differentiation and mineralisation varied with grain size and were favourably modulated on the nanograin (NG) and ultrafine grain (UFG) surface, consistent with alkaline phosphatase activity. Furthermore, it is elucidated that the grain structure strongly influences the ability of the surface to form a well mineralised bone-like extracellular matrix by secreting bone markers, which in turn is governed by grain structure-hydrophilicity relationship. The study demonstrates potential for a new branch of nanostructured materials for biomedical applications. [ABSTRACT FROM AUTHOR]

Protein adsorption is the first of a complex series of events that regulate cell adhesion and cellular activity and define the hallmark of biological reactions at the biointerface. In this regard, materials with submicrometre to nanometre sized grains by virtue of their high grain boundary length to grain size ratio are excellent vehicles to fundamentally understand self-assembly of preadsorbed proteins and consequent cellular activity. The model protein (albumin) on a nanograined surface had the resemblance of 'leaf-like' in contrast to 'bare branch of a tree' on the coarse grained counterpart with consequent impact on biological functions, for instance, osteoblast response. This raises a fundamental question on the interplay between grain size and surface induced arrangement of plasma proteins into organised structures. It is envisaged that in a given polycrystalline material, the self-assembly of proteins at a biointerface is governed by grain structure because of differences in surface energy and microrheological behaviour that controls the kinetics and thermodynamics of protein adsorption. Furthermore, our capability to synthesise and process biomaterial surfaces with tailored surface morphology and consequently control assembly of proteins provides the possibility of eliciting specific, timely and desirable response from the surrounding cells and tissues necessary for implant efficiency. Studies on the early stages of protein adsorption are expected to impact interfacial processes including neurobiology, where the assembly of soluble proteins as organised structure is potentially considered to be characteristic of neurodegenerative diseases such as Parkinson's and Alzheimer's disease. This is particularly important when the most important relaxation mechanisms such as desorption and conformational changes alter adsorption and are impacted by grain structure and associated surface energy. [ABSTRACT FROM AUTHOR]