Search Results (244)

Enhancing osseointegration is a common goal for many titanium implant coatings, since the naturally forming oxides are often bioinert and exhibit less than ideal bone-to-implant contact. Oxide coating surface topographies, chemistries, and crystallinities are known to play key roles in enhancing bone–implant interactions. In the present study, two novel anodization processes were developed in electrolytes based on juiced navel oranges to create bioactive oxide coatings on commercially pure titanium (CPTi) surfaces. Both oxide groups revealed multi-scaled micro and nano surface topographies, significant Ca and P-dopant incorporation exhibiting Ca/P ratios similar to human bone (1.7 and 1.8), and physiologically relevant Mg uptake levels of <0.1% and 1.4 at%. XRD and FTIR analyses of each oxide revealed a combination of tricalcium phosphate and hydroxyapatite phases that showed carbonate substitutions indicative of bone-like apatite formation. Finally, VDI indentation testing revealed good adhesion strengths, minimal cracking, and no visible delamination for both oxides. In summary, the anodization processes in the present study were shown to produce carbonated tricalcium phosphate and apatite containing oxides with contrasting levels of Mg uptake that show much promise to improve future implant clinical outcomes. Full article

In this paper, a series of polyaniline (PANI)/Ti₃C₂ MXene composites (PMCs) with a biomimetic structure were prepared and employed as an anticorrosion coating application. First, the PANI was synthesized by oxidative polymerization with ammonium persulfate as the oxidant. Then, 2D Ti₃C₂ MXene nanosheets were prepared by treating the Ti₃AlC₂ using the optimized minimally intensive layer delamination (MILD) method, followed by characterization via XRD and SEM. Subsequently, the PMC was prepared by the oxidative polymerization of aniline monomers in the presence of Ti₃C₂ MXene nanosheets, followed by characterization via FTIR, XRD, SEM, TEM, CV, and UV–Visible. Eventually, the PMC coatings with the artificial biomimetic surface structure of a macaw feather were prepared by the nano-casting technique. The corrosion resistance of the PMC coatings, evaluated via Tafel polarization and Nyquist impedance measurements, shows that increasing the MXene loading up to 5 wt % shifts the corrosion potential (E_corr) on steel from −588 mV to −356 mV vs. SCE, reduces the corrosion current density (I_corr) from 1.09 µA/cm² to 0.035 µA/cm², and raises the impedance modulus at 0.01 Hz from 67 kΩ to 3794 kΩ. When structured with the hierarchical feather topography, the PMC coating (Bio-PA-MX-5) further advances the E_corr to +103.6 mV, lowers the I_corr to 7.22 × 10⁻⁴ µA/cm², and boosts the impedance to 96,875 kΩ. Compared to neat coatings without biomimetic structuring, those with engineered biomimetic surfaces showed significantly improved corrosion protection performance. These enhancements arise from three synergistic mechanisms: (i) polyaniline’s redox catalysis accelerates the formation of a dense passive oxide layer; (ii) MXene nanosheets create a tortuous gas barrier that cuts the oxygen permeability from 11.3 Barrer to 0.9 Barrer; and (iii) the biomimetic surface traps air pockets, raising the water contact angle from 87° to 135°. This integrated approach delivers one of the highest combined corrosion potentials and impedance values reported for thin-film coatings, pointing to a general strategy for durable steel protection. Full article

To address the challenges of cotton cellulose materials being susceptible to environmental humidity and pollutant erosion, a strategy for constructing superhydrophobic functional coatings with biomimetic micro–nano composite structures was proposed. Through surface silanization modification, diatomite (DEM) and Fe₃O₄ nanoparticles were functionalized with octyltriethoxysilane (OTS) to prepare superhydrophobic diatomite flakes (ODEM) and OFe₃O₄ nanoparticles. Following the multi-scale composite principle, ODEM and OFe₃O₄ nanoparticles were blended and crosslinked via the hydroxyl-initiated ring-opening polymerization of epoxy resin (EP), resulting in an EP/ODEM@OFe₃O₄ composite coating with hierarchical roughness. Microstructural characterization revealed that the micrometer-scale porous structure of ODEM and the nanoscale protrusions of OFe₃O₄ form a hierarchical micro–nano topography. The special topography combined with the low surface energy property leads to a contact angle of 158°. Additionally, the narrow bandgap semiconductor characteristic of OFe₃O₄ induces the localized surface plasmon resonance effect. This enables the coating to attain 80% light absorption across the 350–2500 nm spectrum, and rapidly heat to 45.8 °C within 60 s under 0.5 sun, thereby demonstrating excellent deicing performance. This work provides a theoretical foundation for developing environmentally tolerant superhydrophobic photothermal coatings, which exhibit significant application potential in the field of anti-icing and anti-fouling. Full article

Laser-generated structures have a huge potential to induce an alignment of biological cells, which may be important for various fields in medicine and biotechnology. We describe the formation of fs-laser-induced micro- and nanostructures for achieving the directed growth of Schwann cells, a type of glial cell that can support the regeneration of nerve pathways by guiding the neuronal axons in the direction of their alignment. Polymer surfaces, i.e., polycarbonate (PC) or cellulose acetate butyrate (CAB), were exposed to the beam of a 1040 nm Yb-based amplified fs-laser system with a pulse length of about 350 fs. With appropriate parameters, the laser exposure resulted in a surface topography with oriented micro-grooves, which, for PC, were covered with nano-ripples. Schwann cell growth on these substrates was inspected after 3 to 5 days of cultivation by means of scanning electron microscopy (SEM). We show that Schwann cells can grow in a certain direction, predetermined by micro-groove or nano-ripple orientation. In contrast, cells cultivated on randomly oriented nanofibers or unstructured surfaces show an omnidirectional growth behavior. This method may be used in the future to produce nerve conduits for the treatment of injuries to the peripheral nervous system. Full article

Nanotopography refers to the intricate surface characteristics of materials at the sub-micron (<1000 nm) and nanometer (<100 nm) scales. These topographical surface features significantly influence the physical, chemical, and biological properties of biomaterials, affecting their interactions with cells and surrounding tissues. The development of nanostructured surfaces of polymeric nanocomposites has garnered increasing attention in the fields of tissue engineering and regenerative medicine due to their ability to modulate cellular responses and enhance tissue regeneration. Various top-down and bottom-up techniques, including nanolithography, etching, deposition, laser ablation, template-assisted synthesis, and nanografting techniques, are employed to create structured surfaces on biomaterials. Additionally, nanotopographies can be fabricated using polymeric nanocomposites, with or without the integration of organic and inorganic nanomaterials, through advanced methods such as using electrospinning, layer-by-layer (LbL) assembly, sol–gel processing, in situ polymerization, 3D printing, template-assisted methods, and spin coating. The surface topography of polymeric nanocomposite scaffolds can be tailored through the incorporation of organic nanomaterials (e.g., chitosan, dextran, alginate, collagen, polydopamine, cellulose, polypyrrole) and inorganic nanomaterials (e.g., silver, gold, titania, silica, zirconia, iron oxide). The choice of fabrication technique depends on the desired surface features, material properties, and specific biomedical applications. Nanotopographical modifications on biomaterials’ surface play a crucial role in regulating cell behavior, including adhesion, proliferation, differentiation, and migration, which are critical for tissue engineering and repair. For effective tissue regeneration, it is imperative that scaffolds closely mimic the native extracellular matrix (ECM), providing a mechanical framework and topographical cues that replicate matrix elasticity and nanoscale surface features. This ECM biomimicry is vital for responding to biochemical signaling cues, orchestrating cellular functions, metabolic processes, and subsequent tissue organization. The integration of nanotopography within scaffold matrices has emerged as a pivotal regulator in the development of next-generation biomaterials designed to regulate cellular responses for enhanced tissue repair and organization. Additionally, these scaffolds with specific surface topographies, such as grooves (linear channels that guide cell alignment), pillars (protrusions), holes/pits/dots (depressions), fibrous structures (mimicking ECM fibers), and tubular arrays (array of tubular structures), are crucial for regulating cell behavior and promoting tissue repair. This review presents recent advances in the fabrication methodologies used to engineer nanotopographical microenvironments in polymeric nanocomposite tissue scaffolds through the incorporation of nanomaterials and biomolecular functionalization. Furthermore, it discusses how these modifications influence cellular interactions and tissue regeneration. Finally, the review highlights the challenges and future perspectives in nanomaterial-mediated fabrication of nanotopographical polymeric scaffolds for tissue engineering and regenerative medicine. Full article

Constructing the surface structures of hydroxyapatite (HA) materials is a promising strategy for orchestrating the cell behaviors of bone marrow mesenchymal stem cells (BMSCs), beneficial for advancing BMSC-based tissue repair and regenerative therapies. The majority of previous strategies have focused on fabricating artificial micro-/nano-scale geometric topographies or patterns on HA surfaces. Yet, constructing surface crystal defects has received insufficient attention and application, despite their importance as highlighted by theoretical calculations. This is largely due to the instability of crystal defects, which tend to be eliminated during crystallization. Here, given the fact that stepped structures are rich in stable crystal defects along their edges and kinks, we crafted HA dishes featuring stepped surfaces and utilized them to establish cell culture models of BMSCs. The outcomes revealed that the stepped structures markedly altered the physicochemical properties of HA surfaces and affected the cytoskeleton structures, spreading area, cell morphology, and focal adhesions of BMSCs in the cell culture model, resulting in inhibited cell adhesion. Given that YAP is a key mechanical sensitive factor, and its nuclear translocation is closely tied to cytoskeletal reorganization, the nuclear translocation efficiency of YAP has been investigated. The results showed that a changed cell adhesion could affect the nuclear translocation efficiency of YAP, which would be an important reason for the change in proliferation and differentiation ability of BMSCs. This work not only enhances the understanding of the responses of BMSCs to HA surface structures but also facilitates the design and optimization of HA materials. Moreover, our manufacturing method is facile and efficient, positioning it to potentially integrate with other processing techniques for the more effective and precise regulation of BMSCs. Full article

This review summarizes the development of surface treatments applied to dental implants with the aim of improving their clinical performance. It covers the advancement of various techniques, from the conventional to the more advanced ones. Among the recent advancements, surface texturing has enabled atomic and structural modifications of implant surfaces at the micro- and nanoscales, improving tissue–material interactions. Acid etching and atomic layer deposition applied onto implant surfaces results in optimized osseointegration by stimulating the deposition and proliferation of osteoblasts and fibroblasts. The atomic layer deposition of TiO₂, ZnO, ZrO₂, and CaCO₃ has proven effective in improving osseointegration and tackling corrosion. Corrosion is still an important issue, whereby metals released from titanium implants and their associated degradation products cause local and systemic side effects, leaving a wide avenue for future research. The development of hybrid dental implants is envisaged through new materials and technologies, such as additive manufacturing, which may play a critical role in the fabrication of patient-specific implants with tailored nano-topography capable of enhancing such properties as antibacterial activity and osseointegration. Full article

This study evaluated the impact of a single variation in the etching time of H₂SO₄/H₂O₂-treated titanium (Ti) surfaces on the adsorption of growth and differentiation factor-5 (GDF-5) and their effects on the acquisition of the osteogenic phenotype in vitro. Rat primary calvarial osteogenic cells were grown for up to 14 days on the following Ti surfaces: (1) 30 min: nanotopography obtained with a 1:1 mixture of H₂SO₄/H₂O₂ for 30 min (control); (2) 30 min + GDF-5: a 30 min-etched Ti sample adsorbed with recombinant human (rh) GDF-5; (3) 4 h: nanotopography obtained with a 1:1 mixture of H₂SO₄/H₂O₂ for 4 h (control); (4) 4 h + GDF-5: a 4 h-etched Ti sample adsorbed with rhGDF-5. The GDF-5 adsorption procedure was carried out on the day before cell plating using 200 ng/mL rhGDF-5 overnight at 4 °C. The 30 min- and 4 h-etched Ti samples exhibited a high hydrophilic network of nanopits with a tendency towards larger nanopits for the 4 h group, which corresponded to an enhanced GDF-5 adsorption. For both etching times, coating with GDF-5 resulted in less hydrophilic surfaces that supported (1) a reduction in the proportion of spread cells and an enhanced extracellular osteopontin labeling at early time points of culture, and (2) increased alkaline phosphatase activity preceding an enhanced mineralized matrix formation compared with controls, with a tendency towards higher osteogenic activity for the 4 h + GDF-5 group. In conclusion, the osteogenic potential induced by the GDF-5 coating can be tailored by subtle changes in the nanotopographic characteristics of Ti surfaces. Full article

Atomic Force Microscopy (AFM) is an advanced imaging technique which features nanoscale resolution and the ability to work under physiological conditions on soft samples. Modern AFM systems offer easy access to Dynamic Mode imaging which reduces the tip–sample interaction and increases the effective resolution. However, the intrinsic nature of this driving strategy induces a trade-off between three different aspects: the scanning speed, an accurate topography reconstruction and weak interaction forces. The impact of this inherent trade-off is especially evident when imaging samples with steep and deep valleys, and artifacts are often created in the reconstructed topography. This phenomenon, known as parachuting, rapidly worsens at faster speeds. In this paper, a new strategy is proposed for limiting parachuting artifacts, based on an adaptive driving strategy, which can be easily implemented as an add-on to commercial AFM systems. The suggested method has been tested on grid samples, and it enhances the nano-imaging quality by effectively reducing artifacts in the topography. Full article

The increasing demand for higher resolution and faster machinery in silicon wafer inspection is driven by the rise in electronic device production and the decreasing size of microchips. This paper presents the design and implementation of a device capable of accurately measuring the surface of silicon wafers using the stitching technique. We propose an optical system design for measuring the surface profile, specifically targeting the roughness and nanotopography of a silicon wafer. The device achieves a lateral resolution of 7.56 μm and an axial resolution of 1 nm. It can measure a full 300-mm wafer in approximately 60 min, acquiring around 400 million data points. The technique utilized is a wavefront phase sensor, which reconstructs the surface shape using two images displaced a certain distance from the conjugate plane in the image space of a 4f system. The study details the calibration process and provides a method for converting local measurement coordinates to global coordinates. Quantitative phase imaging was obtained by using the wave front intensity image algorithm. The conclusive results validate the method different metrics over a wafer with bonded dies. In addition, the device demonstrates the ability to distinguish different dies that are thinned along with die-to-wafer bonding onto a carrier wafer to obtain the difference in coplanarity between the die and its surroundings as well as to detect defects during the die-to-wafer bonding. Lastly, the residual stress in the thin film deposited over the die is obtained using the Stoney model. Full article

Graphene is the wonder material of the 21st century, promising cutting-edge advancements in material science with significant applications across all industries. This study investigates the use of a graphene-based nanomaterials (GBNs) ans trade-registered Hastalex^®, as novel materials for surgical implants aimed at treating pelvic organ prolapse (POP). This study investigates the mechanical properties and physicochemical characteristics of the material, mainly focusing on its potential to address the limitations of existing polypropylene (PP) implants, which has been associated with numerous complications and banned across multiple countries. Attenuated total reflectance Fourier transform infrared (ATR-FTIR) confirmed the bonding between functionalised graphene oxide (FGO) and the base polymer chain. Hastalex exhibited excellent mechanical properties with 58 N/mm² maximum tensile strength at break and 701% elongation at break, whilst maintaining its shape with no plastic deformation. These results were comparable to that of sheep pelvic muscular tissue. Hastalex demonstrated its hydrophilic properties from contact angle measurements. Scanning electron microscopy (SEM) and atomic force microscopy (AFM) showed a uniform plane with surface nanotopography, promoting cell-to-material interaction. The results confirmed the suitability of Hastalex in the development of a new pelvic membrane to treat POP. Full article

A novel double-impurity doping process for silicon (Si) surfaces was developed, utilizing nanosecond-laser melting of an 11 nm thick gold (Au) top film and a Si wafer substrate in a laser plasma-activated liquid nitrogen (LN) environment. Scanning electron microscopy revealed a fluence- and exposure-independent surface micro-spike topography, while energy-dispersive X-ray spectroscopy identified minor Au (~0.05 at. %) and major N (~1–2 at. %) dopants localized within a 0.5 μm thick surface layer and the slight surface post-oxidation of the micro-relief (oxygen (O), ~1.5–2.5 at. %). X-ray photoelectron spectroscopy was used to identify the bound surface (SiN_x) and bulk doping chemical states of the introduced nitrogen (~10 at. %) and the metallic (<0.01 at. %) and cluster (<0.1 at. %) forms of the gold dopant, and it was used to evaluate their depth distributions, which were strongly affected by the competition between gold dopants due to their marginal local concentrations and the other more abundant dopants (N, O). In this study, 532 nm Raman microspectroscopy indicated a slight reduction in the crystalline order revealed in the second-order Si phonon band; the tensile stresses or nanoscale dimensions of the resolidified Si nano-crystallites envisioned by the main Si optical–phonon peak; a negligible a-Si abundance; and a low-wavenumber peak of the Si₃N₄ structure. In contrast, Fourier transform infrared (FT-IR) reflectance and transmittance studies exhibited only broad structureless absorption bands in the range of 600–5500 cm⁻¹ related to dopant absorption and light trapping in the surface micro-relief. The room-temperature electrical characteristics of the laser double-doped Si layer—a high carrier mobility of 1050 cm²/Vs and background carrier sheet concentration of ~2 × 10¹⁰ cm⁻² (bulk concentration ~10¹⁴–10¹⁵ cm⁻³)—are superior to previously reported parameters of similar nitrogen-implanted/annealed Si samples. This novel facile double-element laser-doping procedure paves the way to local maskless on-demand introductions of multiple intra-gap intermediate donor and acceptor bands in Si, providing related multi-wavelength IR photoconductivity for optoelectronic applications. Full article

Ti and its alloys, widely utilized in orthopedic and dental implants, inherently lack antibacterial properties, posing significant infection risks, especially in the context of growing antibiotic resistance. This review critically evaluates non-antibiotic antibacterial strategies, with a particular focus on surface modifications and micro/nano-structured surfaces. Micro/nano-structured surfaces, inspired by natural topographies, utilize physical mechanisms to eradicate bacteria. Despite their potential, the antibacterial efficacy of these surfaces remains insufficient for clinical application. Titanium dioxide (TiO₂), known for its excellent photocatalytic antibacterial activity and biocompatibility, is emerging as an ideal candidate for enhancing micro/nano-structured surfaces. By combining the photocatalytic antibacterial effects of TiO₂ with the mechanical bactericidal properties of micro/nano-structured surfaces, superior antibacterial performance can be achieved. The hydrothermal method is frequently employed to fabricate TiO₂ micro/nano-structured surfaces, and this area of research continues to thrive, particularly in the development of antibacterial strategies. With demonstrated efficacy, combined antibacterial strategies based on TiO₂ micro/nano-structured surfaces have become a prominent focus in current research. Consequently, the integration of physical stimulation and chemical release mechanisms may represent the future direction for TiO₂ micro/nano-structured surfaces. This review aims to advance the study of TiO₂ micro/nano-structured surfaces in antibacterial applications and to inspire more effective non-antibiotic antibacterial solutions. Full article

This study aimed to prepare a facile hierarchical aluminium surface using a two-step process consisting of chemical etching in selected concentrations of CuCl₂ solution and surface grafting through immersion in an ethanol solution containing 1H, 1H, 2H, 2H-perfluorodecyltriethoxysilane. The goal was to achieve superhydrophobic characteristics on the aluminium surface, including enhanced corrosion resistance, efficient self-cleaning ability, and improved anti-icing performance. The surface characterisation of the untreated aluminium and treated in CuCl₂ solutions of different concentrations was performed using contact profilometry, optical tensiometry, and scanning electron microscopy coupled with energy dispersive spectroscopy to determine the surface topography, wettability, morphology, and surface composition. The corrosion properties were evaluated using potentiodynamic measurements in simulated acid rain solution and salt-spray test according to ASTM B117-22. In addition, self-cleaning and anti-icing tests were performed on superhydrophobic surfaces prepared under optimal conditions. The results showed that the nano-/micro-structured etched aluminium surface with an optimal 0.5 M concentration of CuCl₂ grafted with a perfluoroalkyl silane film achieved superhydrophobic characteristics, with water droplets exhibiting efficient corrosion protection, self-cleaning ability, and improved anti-icing performance with decreased ice nucleation temperature and up to 545% increased freezing delay. Full article

The need for sustainable energy solutions is steering research towards green fuels. One promising approach involves electrocatalytic gas conversion, which requires efficient catalyst surfaces. This study focuses on developing and testing a hydrophobic octadiene (OD) coating for potential use in electrocatalytic gas conversion. The approach aims to combine a plasma-deposited hydrophobic coating with air-trapping micro- and nanotopographies to increase the yield of electrocatalytic reactions. Plasma polymerisation was used to deposit OD films, chosen for their fluorine-free non-polar properties, onto titanium substrates. We assessed the stability and charge permeability of these hydrophobic coatings under electrochemical conditions relevant to electrocatalysis. Our findings indicate that plasma-deposited OD films, combined with micro-texturing, could improve the availability of reactant gases at the catalyst surface while limiting water access. In the presence of nanotextures, however, the OD-coated catalyst did not retain its hydrophobicity. This approach holds promise to inform the future development of catalyst materials for the electrocatalytic conversion of dinitrogen (N₂) and carbon dioxide (CO₂) into green fuels. Full article