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To obtain a quantitative understanding of the transformation rules and mechanisms of wettability at the molecular level, an advanced sampling method of forward flux sampling is adopted to effectively solve the problem of time scale separation in direct molecular dynamics simulations for sampling rare events. The entire process of the wettability transition of droplets from Cassie state to Wenzel state on inverted triangular nanostructured surfaces with different solid-liquid interaction strengths is observed. The simulation results show that there are two mechanisms for the wettability mode transition with increasing solid-liquid interaction strength. One is that under weak solid-liquid interactions, the solid-liquid contact line is always pinned at the corner line of the rectangular nanoparticle protrusion structure, and the droplet deforms locally in the nanogroove under the curved surface. Another approach is that under slightly stronger solid-liquid interactions, the solid-liquid contact line moves downward along the inner wall of the nanogroove, and the curved surface inside the groove maintains its original smooth boundary. The wettability mechanisms obtained from research can help improve the stability of superhydrophobic surfaces and provide guidance for designing and manufacturing superhydrophobic nanostructured surfaces. [ABSTRACT FROM AUTHOR]

Explosive boiling is a fast-phase transition from an ultra-thin liquid film to vapor under an extremely high heat flux, which typically has been studied using the molecular dynamics simulation (MDS) method. The present MDS study investigated the explosive boiling of a liquid argon nanofilm over different solid copper surfaces with different nanowall patterns, including parallel and cross nanowalls. For each surface, atomic motion trajectories, the number of liquid and vapor argon atoms, heat flux, and, mainly, the onset time of explosive boiling were investigated. The simulation results indicated that explosive boiling occurs earlier on parallel and cross nanowall surfaces than on an ideally smooth surface, regardless of the topology and configuration of the nanowalls. Moreover, the results revealed that by using the cross nanowall surfaces, the onset time of explosive boiling decreased by 0.7–4% compared to the parallel nanowall surfaces. In addition, it was found that the onset time of explosive boiling strongly depends on the potential energy barrier and the movement space between nanowalls for both parallel and cross nanowall surfaces. Furthermore, the simulation findings showed that even though increasing the height of cross nanowalls increases the heat flux and temperature of the fluid argon domain, it does not necessarily result in a shorter onset time for explosive boiling. These findings demonstrate the capability of cross nanowall surfaces for explosive boiling, thereby being utilized in future surface design for thermal management applications. [ABSTRACT FROM AUTHOR]

The use of biocidal agents is a common practice for protection against biofouling in biomass-rich environments. In this paper, oligohexamethyleneguanidine (OHMG) polymer, known for its biocidal properties, was further modified with para-aminosalicylic acid (PAS) to enhance its properties against microorganisms coated with a lipid membrane. The structure of the product was confirmed by 1H NMR, 13C NMR, and FTIR spectroscopy. The values of the minimum inhibitory concentration (MIC) against Mycobacterium smegmatis ATCC 607 and Pseudomonas chlororaphis 449 were found to be 1.40 and 1.05 μg/mL, respectively. The synthesized substance was used as an additive to the polymer matrix of the composite optical oxygen sensor material. A series of samples with different contents of OHMG-PAS was prepared using a co-dissolution method implying the fabrication of a coating from a solution containing both polymers. It turned out that the mutual influence of the components significantly affects the distribution of the indicator in the matrix, surface morphology, and contact angle. The optimal polymer content turned out to be wt.3%, at which point the water contact angle reaches almost 122°, and the fouling rate decreases by almost five times, which is confirmed by both the respiratory MTT assay and confocal microscopy with staining. This opens up prospects for creating stable and biofouling-resistant sensor elements for use in air tanks or seawater. [ABSTRACT FROM AUTHOR]

Gold nanoparticles (AuNPs) can be described as nanozymes, species that are able to mimic the catalytic activities of several enzymes, such as oxidase/peroxidase, reductase, or catalase. Most studies in the literature focus on the colloidal suspension of AuNPs, and it is obvious that their immobilization could open the doors to new applications thanks to their increased stability in this state. This work aimed to investigate the behavior of surfaces covered by immobilized AuNPs (iAuNPs). Citrate-stabilized AuNPs (AuNPs-cit) were synthesized and immobilized on glass slides using a simple dip coating method. The resulting iAuNPs were characterized (surface plasmon resonance, microscopy, quantification of immobilized AuNPs), and their multi-enzymatic-like activities (oxidase-, peroxidase-, and catalase-like activity) were evaluated. The comparison of their activities versus AuNPs-cit highlighted their added value, especially the preservation of their activity in some reaction media, and their ease of reuse. The huge potential of iAuNPs for heterogeneous catalysis was then applied to the degradation of two model molecules of hospital pollutants: metronidazole and methylene blue. [ABSTRACT FROM AUTHOR]

In the current study, bulk tungsten material surfaces are exposed to hydrogen, deuterium, and helium plasmas in the radiofrequency domain (13.56 MHz) at an input power of 250 W using the hollow-cathode configuration. The ejected material is collected on titanium substrates at various distances (from 6 mm up to 40 mm). Therefore, the exposed tungsten materials are investigated for surface changes (blister occurrence, dust formation, or nano-structuration), along with the crystallinity, depending on the plasma's exposure times (from 30 min up to 120 min for each plasma type). Also, the collected materials are analyzed (morphological, structural, and statistical investigations) for dust and dust film-like appearance. Plasma discharges are analyzed using two methods: optical emission spectroscopy, and single Langmuir probes, to emphasize the nature of the used plasmas (cold discharges, ~2 eV), along with the presence of tungsten emission (e.g., WI 406.31 nm, WI 421.31 nm) during the plasma lifetime. By using a dedicated protocol, a method was established for obtaining fusion-relevant tungsten surfaces in the hydrogen and deuterium plasma discharges. By using the implemented method, the current paper introduces the possibility of obtaining a new tungsten morphology, i.e., the dandelion-like shape, by using helium plasma, in which the W18O49 compound can be found. [ABSTRACT FROM AUTHOR]

Abstract Nanostructures have a crucial impact on bubble nucleation. In this paper, different nano-grooved surfaces are constructed using complex trigonometric functions, and the nucleation process of liquid argon on the surfaces is investigated using molecular dynamics simulations. The nanostructures affect the bubble nucleation location, and the results show that the bubble nucleation always occurs in the groove region during the boiling process. In contrast, the bubbles on the flat surface appear randomly. In addition, bubble growth is also affected by the nanostructure. Increasing nanostructure size can reduce the bubble nucleation time and enhance the bubble growth rate. The nanostructure increases the solid-liquid interface area, which enhances the heat transfer between solid and liquid. Finally, the reasons for bubble nucleation on different nanostructured surfaces are analyzed. The heat transfer between solid and liquid is the leading factor for bubble nucleation when the difference in liquid atoms’ potential energy is slight. As the nanostructure size increases, the substrate attracts more argon atoms to form a non-evaporating liquid layer, improving heat transfer and promoting bubble nucleation. [ABSTRACT FROM AUTHOR]

Bacteria are difficult to be eliminated because of their multi‐drug resistance, which brings significant threats to public health. Among the antibacterial methods, mechanobactericidal surfaces provide a possible approach to solving this problem. In this study, a generally used mechanical sterilization is developed by fabricating a nanostructured coating. The functional coating is simply fabricated by growing zeolitic imidazolate frameworks (ZIFs, ZIF‐8 mixed with ZIF‐67) nanospikes on the surface of the fabric substrate in situ. The fabricated ZIF nanospikes are stable and effective, with the sterilization efficiency approaching 99.9999%. This technique provides a fast, safe, and low‐cost antibacterial method without drug resistance, which can be potentially used in hospitals, emergency treatments, and superbug protection in the future. [ABSTRACT FROM AUTHOR]

Abstract Bacteria are difficult to be eliminated because of their multi‐drug resistance, which brings significant threats to public health. Among the antibacterial methods, mechanobactericidal surfaces provide a possible approach to solving this problem. In this study, a generally used mechanical sterilization is developed by fabricating a nanostructured coating. The functional coating is simply fabricated by growing zeolitic imidazolate frameworks (ZIFs, ZIF‐8 mixed with ZIF‐67) nanospikes on the surface of the fabric substrate in situ. The fabricated ZIF nanospikes are stable and effective, with the sterilization efficiency approaching 99.9999%. This technique provides a fast, safe, and low‐cost antibacterial method without drug resistance, which can be potentially used in hospitals, emergency treatments, and superbug protection in the future.

A new comprehensive theory for the field emission from the nanostructured semiconducting SiC was built with allowance for specially worked out analytical model of the field enhancement coefficient for the case of comparatively “smooth” protrusions, described by the curve of Lorenzian type. For the purpose of this analytical model a verification of the direct numerical computation of the field enhancement coefficient for the mentioned protrusions was carried through solving of the Poisson-Boltzmann equation using the finite elements method. The obtained numerical estimations confirm the perspectives of these cathodes. For the “sharp” protrusions with the height greater than the half-width, the emission current of 1 mA order can be harvested from one square cm for the fields ~3×108 V/m. The advantage of the proposed nanostructured cathodes based on SiC is the simplicity of their fabrication.

A synthesis strategy for the manufacture of inexpensive highly efficient nanostructured catalysts has been developed. The developed unique nonplatinoid copper-based catalysts with different surface morphology were investigated as a functional layer with high activity in the ethanol oxidation in alkaline media. A modifying layer with controlled morphology, composition, and excellent electrocatalytic activity was synthesized by electrochemical deposition by varying such synthesis parameters as deposition temperature and time, concentration of structure-forming additives, and electrodeposition current. The dependence of the samples' electrocatalytic activity on the shaping factors was established. According to the electrochemical study results, the highest current density peak of up to 33.01 mA cm−2, and hence the highest catalytic activity in comparison to other samples, were possessed by a catalyst with a regular cubic particle shape. A catalyst consisting of plate-like nanoparticles with a certain percentage of disclinations had similar, but slightly less activity, with a current density peak of up to 31.59 mA cm−2. The samples' activity values are 8 times higher for cubic particles and 7.5 times higher for particles with a triangular plate shape than for an unmodified smooth copper film. The developed samples can be considered as quite competitive to platinoid catalysts, which significantly outperform copper analogues. [ABSTRACT FROM AUTHOR]

Nanostructuring surfaces is an emergent strategy to endow materials with abilities to combat pathogenic bacteria. Nevertheless, it remains challenging to create nanospike structures on the curved surfaces of polymer materials, including gauze and other microfibrous medical materials. Additionally, the effects of nanostructured surfaces on bacteria in the presence of proteins and in vivo remain largely unexplored. Herein, we demonstrated the decoration of gauze microfiber surfaces with nanospike structures via the self-assembly of cello-oligosaccharides and investigated the effects of the nanospiked gauze on bacteria in the presence of proteins. The nanospiked gauze had low bacterial adhesion properties in the absence of proteins, whereas in the presence of proteins, it promoted bacterial adhesion. Analyses suggested that the adsorbed protein layers on the nanospikes were involved in the promoted bacterial adhesion. Furthermore, the bacterial adhesion-promoting effects were exploited to remove pathogenic bacteria from burn wounds with exudate containing proteins using the nanospiked gauze.

Colloidal gold nanoparticles (AuNP) are well-known to present a catalytic activity. However, they are characterized by certain limitations, as a rather poor stability and lack of both handling and reusability. Their immobilization on surfaces could help to overcome these drawbacks. This work evaluated the impact of the immobilization of AuNP towards their catalytic activity on reduction and oxidation reactions. Colloidal AuNP stabilized with citrate ions were synthesized, characterized, and immobilized by the dip-coating method, the obtained immobilized AuNP (iAuNP) were characterized. The catalytic activity of AuNP and iAuNP was evaluated and compared to each other through the p-nitrophenol reduction reaction. The kinetic of the catalytic activity of iAuNP was slower than colloidal AuNP. The catalytic activity appeared to be impacted by the less available surface of iAuNP. The reduction efficiency of iAuNP was also evaluated with the DPPH•/DPPH2 reduction reaction. The capacity of iAuNP to catalyze the reduction of DPPH• in DPPH2 was shown even after 130 days and 20 reuses of the nanostructured surface on the contrary to non-reusable colloidal AuNP. The oxidation efficiency of iAuNP was measured by the ability to catalyze the auto-oxidation of curcumin (HPLC-UV/vis). For all these experiments, the addition of 4-mercapto-phenol on the surface of iAuNP passivated the surface, decreasing the catalytic activity of the materials. In conclusion, iAuNP are redox catalysts with both anti- and pro-oxidant effects and high reusability over a very long period.

Superhydrophobic coatings are widely studied for fluid regulation due to their water-repellent surface characteristics. However, there are not many reports on fluid behavior when it flows from a region of higher wettability to that of lower wettability. A fundamental understanding of such behavior would be very useful for regulating the fluid flow through a superhydrophobic channel. Therefore, this work focused on the fabrication of superhydrophobic nanostructured coatings inside fine cylindrical channels and the investigation of the fluid flow behavior through them. The superhydrophobic SiO2 coatings were obtained through an ultrasound-assisted one-step immersion technique. A self-stratified mechanically durable conformal superhydrophobic coating was obtained inside millimeter-sized fine 3D structures. A binder-free precursor solution has low viscosity and thereby enhances the penetration of the solvent into the polymer surface through ultrasonication. The self-stratification-based surface formation mechanism was explained using scanning electron microscopy images. The fluid behavior inside the superhydrophobic channels was experimentally investigated by analyzing the flow through the hollow cylindrical superhydrophobic channels. Experiments were conducted for different channel lengths (l) and radii (r), and mathematical formulations were developed to determine the maximum pressure (Pmax) that the superhydrophobic cylinders could hold when the fluid inside the channel was under static equilibrium. Finally, a self-regulated fluid delivery system was postulated based on the experimental and theoretical findings. [ABSTRACT FROM AUTHOR]

A controlled strategy for the electrochemical synthesis of mono- and bimetallic nanoparticles with a unique and complex morphology has been developed. The investigation of the effect of changing the surfactant concentration and current density regulating the medium pH has revealed the fundamental patterns of nanoparticle growth. The developed method has allowed to synthesis of nanoparticles with a controlled pentabranched structure for the monometallic palladium as well as for favorable combinations of metals—Pd-Ag and Pd-Pt. The obtained nanoparticles were investigated in alkaline methanol oxidation. The results demonstrated quite high catalytic activity up to 83.51 mA cm−2 and long-term stability, which are caused by the increase in electrochemically active surface area by increasing the active center's number. This was made possible due to the creation of unusual nanoparticle morphology, namely the presence of high-energy high-index facets. The developed nanoparticles were also studied as a modifying coating for hydrogen-permeable membranes in the processes of hydrogen transport. The membranes coated with the nanoparticles demonstrated sufficiently high hydrogen flux up to 11.33 mmol s−1 m−2 and high H2/N2 selectivity up to 2254. Such results can be explained by the obvious acceleration of surface processes through the application of the developed nanoparticles. The novel synthesis strategy can potentially be extended to other metal nanoparticle systems. Thus it can be an effective way to solve relevant problems of design of controlled synthetic methods allowing the nanoparticle morphology tuning according to the required functional properties. [ABSTRACT FROM AUTHOR]

In the last decade, there has been continuous competition between two methods for detecting the concentration of dissolved oxygen: amerometric (Clark electrode) and optical (quenching of the phosphorescence of the porphyrin metal complex). Each of them has obvious advantages and disadvantages. This competition is especially acute in the development of biosensors, however, an unbiased comparison is extremely difficult to achieve, since only a single detection method is used in each particular study. In this work, a microfluidic system with synchronous detection of the oxygen concentration by two methods was created for the purpose of direct comparison. The receptor element is represented by Saccharomyces cerevisiae yeast cells adsorbed on a composite material, previously developed by our scientific group. To our knowledge, this is the first work of this kind in which the comparison of the oxygen detection methods is carried out directly. [ABSTRACT FROM AUTHOR]

Introduction. In modern dentistry the oral rehabilitation of patients with the help of dental implants has a very high success rate. However, the problem is the situation of patients with serious chronic diseases in which the insertion of dental implants is problematic or dental procedures can complicate or aggravate the patients’ disease.

Thin Pd–40%Cu films were obtained via the classical melting and rolling method, magnetron sputtering, and modified with nanostructured functional coatings to intensify the process of hydrogen transportation. The films were modified by electrodeposition, according to the classical method of obtaining palladium black and “Pd–Au nanoflowers” with spherical and pentagonal particles, respectively. The experiment results demonstrated the highest catalytic activity (89.47 mA cm−2), good resistance to CO poisoning and long-term stability of Pd–40%Cu films with a pentagonal structured coating. The investigation of the developed membranes in the hydrogen transport processes in the temperature range of 25–300 °C also demonstrated high and stable fluxes of up to 475.28 mmol s−1 m−2 (deposited membranes) and 59.41 mmol s−1 m−2 (dense metal membranes), which were up to 1.5 higher, compared with membrane materials with classic niello. For all-metal modified membranes, the increase in flux was up to sevenfold, compared with a smooth membrane made of pure palladium, and for deposited films, this difference was manyfold. The membrane materials’ selectivity was also high, up to 4419. The developed strategy for modifying membrane materials with functional coatings of a fundamentally new complex geometry can shed new light on the development and fabrication of durable and highly selective palladium-based membranes for gas steam reformers.

• Systematically explore the geometric effects of nanostructured surfaces on bubble nucleation. • Not all nanostructured surfaces can provide preferential nucleation sites. • When the roughness factor of is below the critical value, bubble nucleation will be delayed, and the CHF will decrease. With the development of nanosurface preparation and nanoscale simulation techniques, the effect of nanostructured surfaces on bubble nucleation and boiling heat transfer capability has received much attention. Many studies have shown that nanostructured surfaces can provide preferential nucleation sites for bubble nucleation and effectively enhance heat transfer, attributing to the increased solid–liquid contact area. However, few studies have systematically compared and assessed the performance of different nanostructured surfaces. The geometric effects and negative impact on heat transfer under certain conditions are still not well understood. In this study, the bubble nucleation process on nanostructured surfaces with different geometries were simulated using molecular dynamics method. The geometric effects of nanostructured surfaces are studied for bubble nucleation and heat transfer enhancement, with mechanisms revealed through surface temperature and energy distribution. The critical roughness factor of nanostructured surfaces with different morphologies is obtained. The critical roughness factor for SCUP is 1.215 and SCOP has the lowest critical roughness factor of 1.062. It can be found that the nanostructured surface will inhibit bubble nucleation and weaken surface heat transfer when the surface roughness factor is less than the critical value. It can delay bubble nucleation time by up to 400 ps and reduce the surface critical heat flux by 6.9 %. We believe that the conclusions of this study can provide some quantitative basis for a more comprehensive understanding of nanostructured surface performance. [ABSTRACT FROM AUTHOR]

The elasticity mismatch between Ti and tissue limits the performance of Ti medical devices. How to create a coating with mimicking natural soft tissue stiffness and possessing strong mechanical bond is a challenge in implant manufacturing. Here, we developed a combined coating, that is, an anodized Ti surface (ATS) with nanostructures coated with a layer of PAAm hydrogel with tunable elasticity. Due to the nano-mechanical interlocking and hydrogen bonding synergy, the PAAm hydrogel layer was tightly anchored in nanostructures on the ATS. By regulating the oxidation voltage, nanostructures including nanopores, nanotubes, and punch-through nanotubes were fabricated on the ATS, and these three kinds of anodized nanostructures increase the porosity of the ATS sequentially. The lap shear test has shown that the shear strength increases linearly with increasing the porosity, and the shear strength of the punch-through nanotube structures with the PAAm hydrogel coating reaches 59.28 kPa. The adhesion mechanism between the anodized Ti nanostructures and the PAAm hydrogel coating is mainly due to the nano-mechanical interlocking and hydrogen bonding synergy, which was proven by morphology analysis, XRD, and ATR-FTIR characterization of the samples subjected to lap shear load. The hydrogel-nanostructures coating has demonstrated the potential to be applied in Ti medical devices. [Display omitted] • Anodized Ti surface (ATS) with different nanostructures ranging from nanopores to nanotubes were prepared. • Uniform hydrogel coating bonded on ATS with controllable elasticity modulus. • Interfacial bond strength between ATS and hydrogel coating is regulated by controllable nano-mechanical interlocking. [ABSTRACT FROM AUTHOR]

Structural coloring through plasmonic nanostructures involves the manipulation of light interaction with nanostructured metallic surfaces to selectively reflect specific spectral ranges within the visible spectrum. Unlike conventional pigments that absorb light based on their chemical properties, plasmonic nanostructures achieve color through their physical configuration. This study investigates the potential of generating plasmonic structural colors by utilizing self-assembled colloidal microsphere lattices that are coated with thin metal films. Finite-Difference Time-Domain (FDTD) simulations are employed on realistic models to analyze the optical reflectance of dielectric microsphere lattices ranging in sizes from 300 to 700 nm, coated with varying thicknesses (20–200 nm) of different metals (Al, Ag, Au). The reflectance spectra are then translated into specific colors using a software algorithm, with the color representations plotted on CIE1931 diagrams. Furthermore, to validate the theoretical findings, two-dimensional polystyrene microsphere arrays coated with Au and Ag films are prepared, and their reflectance spectra and color images are examined. The resulting plasmonic colors can be adjusted by altering the sphere size, the type of metal used, and the thickness of the coating, demonstrating their potential for diverse color-based applications. [Display omitted] • Metal films over nanospheres produce a broad palette of plasmonic colors. • Both vivid and pale colors are obtained with silver films over nanospheres. • Simple and promising approach to achieving tunable long-lasting, dye-free colors. [ABSTRACT FROM AUTHOR]

The possibility of the developing a biochemical oxygen demand (BOD) biosensor based on electroactive biofilms of activated sludge grown on the surface of a graphite-paste electrode modified with carbon nanotubes was studied. A complex of microscopic methods controlled biofilm formation: optical microscopy with phase contrast, scanning electron microscopy, and laser confocal microscopy. The features of charge transfer in the obtained electroactive biofilms were studied using the methods of cyclic voltammetry and electrochemical impedance spectroscopy. The rate constant of the interaction of microorganisms with the extracellular electron carrier (0.79 ± 0.03 dm3(g s)−1) and the heterogeneous rate constant of electron transfer (0.34 ± 0.02 cm s−1) were determined using the cyclic voltammetry method. These results revealed that the modification of the carbon nanotubes' (CNT) electrode surface makes it possible to create electroactive biofilms. An analysis of the metrological and analytical characteristics of the created biosensors showed that the lower limit of the biosensor based on an electroactive biofilm of activated sludge is 0.41 mgO2/dm3, which makes it possible to analyze almost any water sample. Analysis of 12 surface water samples showed a high correlation (R2 = 0.99) with the results of the standard method for determining biochemical oxygen demand. [ABSTRACT FROM AUTHOR]

Periprosthetic joint infection (PJI) is a devastating complication of orthopedic implant surgeries, such as total knee and hip arthroplasties. Treatment requires additional surgeries because antibiotics have limited efficacy due to biofilm formation and resistant bacterial strains such as methicillin‐resistant Staphylococcus aureus (MRSA). A non‐pharmaceutical approach is needed, and examples of this are found in nature; dragonfly and cicada wings are antibacterial because of their nanopillar surface structure rather than their chemistry. Carbon‐infiltrated carbon nanotube (CICNT) surfaces exhibit a similar nanopillar structure, and have been shown to facilitate osseointegration, and it is postulated that they might provide a structurally‐derived resistance to bacterial proliferation and biofilm formation. The objective of this study was to test the biofilm resistance of CICNT coatings. Two types of CICNT were produced: a vertically aligned CNT forest on a silicon substrate using a layer of iron as the catalyst (CICNT‐Si) and a random‐oriented CNT forest on stainless steel (SS) substrate using the substrate as the catalyst (CICNT‐SS). These were tested against SS and carbon controls. After 48 h in an MRSA biofilm reactor, samples demonstrated that both types of CICNT coatings significantly (p < 0.0001) reduced MRSA biofilm formation by 60%–80%. Morphologically, biofilm presence on both types of CICNT was also significantly reduced. Clinical Significance: Results suggest that a CICNT surface modification could be suitable and advantageous for medical devices susceptible to MRSA cell attachment and biofilm proliferation, particularly orthopedic implants. [ABSTRACT FROM AUTHOR]

The process of electrodeposition of nickel coatings from electrolytes based on a deep eutectic solvent (DES) mixture of choline chloride and lactic acid with a molar ratio of 1:3 was studied. The physicochemical properties and characteristics of DES, namely, con­ductivity, FT-IR and NMR analysis were determined. FT-IR results confirmed that H-bonds occurring between two components in DES were the main force leading to the eutectic formation. Electrochemical techniques were used to characterize the deposition process and scanning electron microscopy was used to study the deposit morphology. Based on polarization measurements, it has been found that at NiCl2·6H2O content of 1.14 M and a temperature of 75 °C, the limiting current density of nickel electrodeposition was near 2 A dm-2. The polarization of the cathodic nickel deposition varied within -0.63 to 1.1 V at current density of 0.25 A dm-2 It has been shown that an increase of water content in the electrolyte does not significantly affect the current efficiency of the nickel electrodeposition process, which was in a range 85-93 %. However, the increase in water content contributes to the increase of heterogeneity and crystal grains size distribution of galvanic deposits. The established values of the Wagner number indicate the predominance of the primary current density distribution in the process of electrodeposition of nickel coatings. Galvanic coatings possess a highly developed nanostructured surface, exhibit increased capillary properties, and can be used as electrode materials for the process of electrolysis of water.

Angiotensin I-converting enzyme (ACE) is a peptidase widely presented in human tissues and biological fluids. ACE is a glycoprotein containing 17 potential N-glycosylation sites which can be glycosylated in different ways due to post-translational modification of the protein in different cells. For the first time, surface-enhanced Raman scattering (SERS) spectra of human ACE from lungs, mainly produced by endothelial cells, ACE from heart, produced by endothelial heart cells and miofibroblasts, and ACE from seminal fluid, produced by epithelial cells, have been compared with full assignment. The ability to separate ACEs' SERS spectra was demonstrated using the linear discriminant analysis (LDA) method with high accuracy. The intervals in the spectra with maximum contributions of the spectral features were determined and their contribution to the spectrum of each separate ACE was evaluated. Near 25 spectral features forming three intervals were enough for successful separation of the spectra of different ACEs. However, more spectral information could be obtained from analysis of 50 spectral features. Band assignment showed that several features did not correlate with band assignments to amino acids or peptides, which indicated the carbohydrate contribution to the final spectra. Analysis of SERS spectra could be beneficial for the detection of tissue-specific ACEs. [ABSTRACT FROM AUTHOR]

The nanostructure-based surface texturing can be used to improve the materials wettability. Regarding oil–water separation, designing a surface with special wettability is as an important approach to improve the separation efficiency. Herein, a ZnO nanostructure was prepared by a two-step process for sol–gel process and crystal growth from the liquid phase to achieve both a superhydrophobicity in oil and a superoleophobic property in water. It is found that the filter material with nanostructures presented an excellent wettability. ZnO-coated stainless-steel metal fiber felt had a static underwater oil contact angle of 151.4° ± 0.8° and an underoil water contact angle of 152.7° ± 0.6°. Furthermore, to achieve water/oil separation, the emulsified impurities in both water-in-oil and oil-in-water emulsion were effectively intercepted. Our filter materials with a small pore (~5 μm diameter) could separate diverse water-in-oil and oil-in-water emulsions with a high efficiency (>98%). Finally, the efficacy of filtering quantity on separation performance was also investigated. Our preliminary results showed that the filtration flux decreased with the collection of emulsified impurities. However, the filtration flux could restore after cleaning and drying, suggesting the recyclable nature of our method. Our nanostructured filter material is a promising candidate for both water-in-oil and oil-in-water separation in industry. [ABSTRACT FROM AUTHOR]

The infection of surgically placed implants is a problem that is both large in magnitude and that broadly affects nearly all surgical specialties. Implant-associated infections deleteriously affect patient quality-of-life and can lead to greater morbidity, mortality, and cost to the health care system. The impact of this problem has prompted extensive pre-clinical and clinical investigation into decreasing implant infection rates. More recently, antimicrobial approaches that modify or treat the implant directly have been of great interest. These approaches include antibacterial implant coatings (antifouling materials, antibiotics, metal ions, and antimicrobial peptides), antibacterial nanostructured implant surfaces, and antibiotic-releasing implants. This review provides a compendium of these approaches and the clinical applications and outcomes. In general, implant-specific modalities for reducing infections have been effective; however, most applications remain in the preclinical or early clinical stages. [ABSTRACT FROM AUTHOR]

This study utilizes a hot water treatment (HWT) method for introducing antibacterial properties to aluminum (Al) surfaces, which has relevance in several industries ranging from food packaging and ventilation systems to biomedical materials. The HWT process can produce a nanostructured oxide layer on a wide range of metallic materials by simply immersing the metal in water at temperatures ranging from 75 °C to 95 °C. In this work, Al foil was treated in deionized (DI) water for 5 min at various temperatures, including 75 °C, 85 °C, and 95 °C. Concentrations of Gram-negative Escherichia coli (E. coli) and Gram-positive Staphylococcus epidermidis (S. epidermidis) were placed on Al foil for different times, ranging from 30 seconds to 60 min The survival time was measured, and the analysis of the results indicates a direct correlation between when the bacteria was exposed to HWT Al foil and the number of bacteria killed. As the temperature of the HWT increased, there was an increase in antibacterial activity. This finding is consistent with our expectations; at higher HWT temperatures, more prominent nanostructures are produced, causing increased inactivation of bacteria. Our results show the nanostructured HWT Al foil was superior at inactivating Gram-negative ( E. coli ) and Gram-positive ( S. epidermidis ) bacteria compared to the untreated control Al foil. HWT Al foil treated at 75 °C, 85 °C, and 95 °C was 58%, 64%, and 73% more effective in killing the Gram-negative bacteria, respectively, after only 30 seconds of contact time compared to untreated control Al foil, while the antibacterial efficacy was enhanced 88%, 92%, and 94% for the Gram-positive bacteria, respectively. The HWT nanostructures synthesized at 95 °C, after 60 min of contact time, were able to inactivate 97% of the gram-negative bacteria and 100% of the gram-positive bacteria, demonstrating the efficacy of its antibacterial properties. This research presents a novel, inexpensive, and environmentally friendly method of producing nanostructures that inhibit bacterial activity.

A method has been developed that has allowed a fivefold symmetry to be achieved for the first time in palladium nanocrystallites grown on the Pd–Cu film surface. Modification of the Pd–40% Cu membrane by pentatwinned (branched) palladium nanocrystallites with high-index facets ensured ultrahigh permeability for hydrogen reaching up to 10.1 mmol s–1 m–2 at 100°C. This level (comparable with the permeability of high-temperature analogs) is anomalous, since the expected values must be more than two times lower than obtained. This result is explained by the acceleration of dissociative adsorption and recombinative desorption due to the ultrahigh activity of pentatwinned particles in reactions involving hydrogen, which is confirmed by data on the selectivity of the modified membranes. [ABSTRACT FROM AUTHOR]

The paper presents results of several experiments to determine the cytotoxicity of porous silicon structures synthesized by different methods. Crystalline and amorphous, micro- and nanoporous silicon layers with and without annealing were studied. Cytotoxicity was studied by fluorescence micrographs and by standard colorimetric MTT testing. [ABSTRACT FROM AUTHOR]

Angiotensin I‐converting enzyme (ACE) is a glycoprotein, consisting of two homologous domains within a single polypeptide chain. ACE concentration in biological fluids is an important parameter of clinical observation; its increase or decrease may accompany various pathologies. Currently, the exact crystal structure of the two‐domain ACE form is still unknown because of microheterogeneity and intensity of the enzyme glycosylation. Raman spectroscopy provides the qualitative and quantitative analysis of many compounds, including proteins. For the first time, surface‐enhanced Raman scattering (SERS) spectra of native and thermo‐denatured human ACE have been demonstrated with full assignment. Denaturation leads to SERS intensity increase and bands shifting. Detailed band assignment and discussion are included to elucidate the potential site of ACE interaction with the silver surface. Based on SERS spectra, we characterized the region on the ACE molecule in contact with the substrate and demonstrated the model of the two‐domain ACE adsorbed on a silver matrix. [ABSTRACT FROM AUTHOR]

A new approach to the acceleration of the surface processes of hydrogen transport through Pd–40%Cu membranes by depositing a developed catalytic coating consisting of nanoparticles with a novel crystallographically atypical pentagonal structure is demonstrated. The number of localized potentially more active regions of the membrane surface increases significantly due to the presence of high-index facets with a large number of reactive undercoordinated atoms in such particles. This modification leads to a shift of the limiting stage, significantly accelerating the recombinative desorption on the surface, and to an increase in the influence of the diffusion stage. This improves the gas transport characteristics of the membrane, making it possible to achieve permeability of up to 8.9 mmol s−1 m−2 in the low-temperature mode (up to 100°C). The value obtained is up to sixfold higher than the corresponding value for smooth membranes and up to twofold higher for membranes modified with classical palladium black. [ABSTRACT FROM AUTHOR]

Nanostructured surfaces represent pertinent material technologies to improve the biocompatibility aspects of orthopedic implant surfaces. The present work reports the development of nanostructured titania surface on a low-modulus TNZT (Ti-35Nb-7Zr-5Ta) beta titanium alloy. The major focus is to gain more insights into the wettability, surface energy and corrosion resistance of the developed nanostructures. The developed nanomorphologies have been found to be nanopetal-like structures with nanotopographies and composed predominantly of anatase phase. Wettability studies revealed a highly hydrophilic surface with a concurrent enhancement in surface energy (68% increment in polar surface energy) advantageous for improved osseointegration. The developed layer has demonstrated comparable corrosion resistance with untreated surface. By incorporating the multiple aspects of low-modulus TNZT alloy, hydrophilic titania surface with elevated surface free energy and comparable corrosion resistance, the present work opens prospective avenues for effective biomaterial surface design paradigms. [ABSTRACT FROM AUTHOR]

Angiotensin I-converting enzyme (ACE) is a peptidase widely presented in human tissues and biological fluids. ACE is a glycoprotein containing 17 potential N-glycosylation sites which can be glycosylated in different ways due to post-translational modification of the protein in different cells. For the first time, surface-enhanced Raman scattering (SERS) spectra of human ACE from lungs, mainly produced by endothelial cells, ACE from heart, produced by endothelial heart cells and miofibroblasts, and ACE from seminal fluid, produced by epithelial cells, have been compared with full assignment. The ability to separate ACEs’ SERS spectra was demonstrated using the linear discriminant analysis (LDA) method with high accuracy. The intervals in the spectra with maximum contributions of the spectral features were determined and their contribution to the spectrum of each separate ACE was evaluated. Near 25 spectral features forming three intervals were enough for successful separation of the spectra of different ACEs. However, more spectral information could be obtained from analysis of 50 spectral features. Band assignment showed that several features did not correlate with band assignments to amino acids or peptides, which indicated the carbohydrate contribution to the final spectra. Analysis of SERS spectra could be beneficial for the detection of tissue-specific ACEs.

Our study aimed to produce SERS substrates using nanostructured copper (Cu) surfaces prepared by laser ablation in water. A laser ablation schema was designed for this purpose. The laser power and laser irradiation time for creating a nanostructured surface suitable for SERS were determined. To increase the enhancement factor (EF) of the SERS substrates, gold (Au) and silver (Ag) nanoparticles were deposited on the ablated Cu surfaces to produce AuNP/aCu and AgNP/aCu substrates. The Au (and Ag) nanoparticles were also prepared by laser ablation of a Au (and Ag) piece in ethanol. The EFs for SERS of the AuNP/aCu and AgNP/aCu substrates are 1.2 × 106 and 6 × 106, respectively. The SERS spectra of malachite green with low concentrations of 0.1 ppm can be detected with high quality by using these SERS substrates. [ABSTRACT FROM AUTHOR]

The paper proposes the manufacturing methods for modifying coatings for gas-diffusion membranes made of palladium-silver alloy comprising 23% Ag. Highly developed surface structures are synthesized to intensify chemisorption and dissociation and to accelerate the overall process of hydrogen transmission through the membrane. At a 0.6 MPa hydrogen overpressure and 100°C temperature, the density of the hydrogen flow through Pd/Ag23 wt.% membrane with the developed surface is 7 times higher than through the similar membrane without the modifying layer. The analysis of the proposed methods shows that the hydrogen density passing through the membranes with the modifying coating synthesized by a method with the included recrystallization stage, is 1.3 times higher than through the similar membranes synthesized in accordance with the standard procedures. The experiments show that the hydrogen transmission rate can be increased in the surface limited regime by creating a highly developed structure of the membrane surface. [ABSTRACT FROM AUTHOR]

The mechano-bactericidal activity of nanostructured surfaces has become the focus of intensive research toward the development of a new generation of antibacterial surfaces, particularly in the current era of emerging antibiotic resistance. This work demonstrates the effects of an incremental increase of nanopillar height on nanostructure-induced bacterial cell death. We propose that the mechanical lysis of bacterial cells can be influenced by the degree of elasticity and clustering of highly ordered silicon nanopillar arrays. Herein, silicon nanopillar arrays with diameter 35 nm, periodicity 90 nm and increasing heights of 220, 360, and 420 nm were fabricated using deep UV immersion lithography. Nanoarrays of 360-nm-height pillars exhibited the highest degree of bactericidal activity toward both Gram stain-negative Pseudomonas aeruginosa and Gram stain-positive Staphylococcus aureus bacteria, inducing 95 ± 5% and 83 ± 12% cell death, respectively. At heights of 360 nm, increased nanopillar elasticity contributes to the onset of pillar deformation in response to bacterial adhesion to the surface. Theoretical analyses of pillar elasticity confirm that deflection, deformation force, and mechanical energies are more significant for the substrata possessing more flexible pillars. Increased storage and release of mechanical energy may explain the enhanced bactericidal action of these nanopillar arrays toward bacterial cells contacting the surface; however, with further increase of nanopillar height (420 nm), the forces (and tensions) can be partially compensated by irreversible interpillar adhesion that reduces their bactericidal effect. These findings can be used to inform the design of next-generation mechano-responsive surfaces with tuneable bactericidal characteristics for antimicrobial surface technologies. [ABSTRACT FROM AUTHOR]

Objectives: It is well known that surface treatments of dental implants have a great impact on their rate of osseointegration. The aim of this study was to compare the biocompatibility and the bone–implant contact (BIC) of titanium dental implants with different surface treatments. Material and methods: Test implants (Biotech Dental) had a nanostructured surface and control implants (Anthogyr) were grit‐blasted with biphasic calcium phosphate and acid‐etched surface. Both titanium implants were inserted in mandible and maxillary bones of 6 Yucatan minipigs for 4 and 12 weeks (n = 10 implants/group). Biocompatibility and osseointegration were evaluated by non‐decalcified histology and back‐scattered electron microscopy images. Results: The reading of histology sections by an antomo‐pathologist indicated that the test implants were considered non‐irritating to the surrounding tissues and thus biocompatible compared with control implants. The BIC values were higher for test than for control dental implants at both 4 and 12 weeks. Conclusions: In summary, the new nanostructured titanium dental implant is considered biocompatible and showed a better osseointegration than the control implant at both 4 and 12 weeks. [ABSTRACT FROM AUTHOR]

Purpose: The use of nanotechnology to enhance endosseous implant surfaces may improve the clinical control of inter facial osteoblast biology. This study investigated the influence of a nanostructure-coated implant surface on osteoblast differentiation and its effects on bone-to-implant contact (BIC) and removal torque values. Materials and Methods: Titanium disks were machined (M) or machined and subsequently treated by acid etching (Ac) or by dipping in an aluminum oxide solution (Al2O3). Surfaces were characterized by scanning electron microscopy, atomic force microscopy, and x-ray microanalysis. For the in vitro experiment, rat mesenchymal stem cells (rMSCs) were grown in osteogenic supplements on the disk surfaces for 3 days. Real-time polymerase chain reaction (PCR) was used to measure mRNA levels of several gene products (bone sialoprotein, osteocalcin, osteopontin, and RUNX-2). For the in vivo experiment, titanium implants were placed in rat tibiae and harvested after 3 to 21 days for measurement of bone-specific mRNA levels by real-time PCR. Removal torque and BIC were measured 3 to 56 days after placement. Results: Average height deviation (Sa, in nm) values for M, Ac, and Al2O3 implants were 86.5, 388.4, and 61.2, respectively. Nanostructured Al2O3 topographic features applied to machined implants promoted MSC commitment to the osteoblast phenotype. Greater bone-specific gene expression was observed in tissues adjacent to Al2O3 implants, and associated increases in BIC and torque removal were noted. Conclusion: Nanostructured alumina may directly influence cell behavior to enhance osseointegration. [ABSTRACT FROM AUTHOR]

The investigation of carbon dioxide (CO 2) condensation on heat exchange surfaces is essential to the advancement of carbon capture, utilization, and storage (CCUS) technology. Molecular dynamics simulations are employed to explore the wetting and condensation behavior of CO 2 on nanostructured surfaces. The results indicate that the contact angle of CO 2 droplets on nanostructured surfaces is greater than that on smooth surfaces. Increasing the pillar height (h) or solid fraction (f) induces the transition of CO 2 droplets from the Wenzel to Cassie state, resulting in an increased contact angle. Nanostructured surfaces significantly enhance the nucleation rate, with molecules initially nucleating at the bottom of the pillars. A higher h or f accelerates the nucleation rate during the condensation. Droplets in the Wenzel state exhibit higher heat transfer efficiency than those in the Cassie state. Additionally, the formation of Cassie-state CO 2 droplets undergoes a dewetting transition, altering the heat conduction mode. The dewetting behavior of CO 2 droplets favors their detachment from the surface, potentially reducing the initial heat resistance. Therefore, appropriately increasing h and f can promote nucleation and droplet growth, enhancing dewetting transition and mass transfer performance. These simulation results hold great importance for inspiring the design of future CO 2 -phobic surfaces and guiding CO 2 condensation production. • Dropwise condensation of CO 2 on pillar-structured surfaces was first studied by MD. • Alterations in structural dimensions can regulate the wetting behavior of CO 2 droplets. • A thermal resistance model was developed to analyze heat transfer in various states. • Nanostructured surface improves the heterogeneous condensation and nucleation. • The CO 2 nucleation mechanism was explained by the potential energy distribution. [ABSTRACT FROM AUTHOR]

Hierarchical nanostructured surfaces demonstrate significant improvements in boiling heat transfer, making them particularly appealing in thermal energy applications. This study utilizes molecular dynamics simulations to investigate how the vertical spacing and shape of nanobumps impact boiling heat transfer processes over hierarchical nanostructured surfaces. The findings show a notable influence of nanobump shape and the liquid sectional-area beneath them on heat transfer performance. Increasing the vertical spacing of nanobumps is associated with a rise in argon temperature during vapor film formation. Then, the study reveals a reduction in interfacial thermal resistance with increasing vertical spacing of nanobumps and solid-liquid interfacial area of different nanobump shapes. Bubble inception is examined through the analysis of kinetic energy, potential energy, and total energy of atoms, revealing a two-stage phase-change process. The nanobump shape significantly affects liquid cluster detachment time. The surface featuring rectangular nanobumps exhibit larger solid-liquid interfacial area and demonstrate higher evaporation and heat transfer rates compared to surfaces with different nanobump shapes. These findings contribute to a comprehensive understanding of the complex boiling heat transfer at nanoscale on hierarchical nanostructured surfaces. [ABSTRACT FROM AUTHOR]

Abstract Microprobes are used to repair neuronal injury by recording electrical signals from neuronal cells around the surface of the device. Following implantation into the brain, the immune response results in formation of scar tissue around the microprobe. However, neurons must be in close proximity to the microprobe to enable signal recording. A common reason for failure of microprobes is impaired signal recording due to scar tissue, which is not related to the microprobe itself. Therefore, the device–cell interface must be improved to increase the number of neurons in contact with the surface. In this study, we developed nanostructured SU-8 microprobes to support neuronal growth. Nanostructures of 200 nm diameter and depth were applied to the surface of microprobes, and the attachment and neurite outgrowth of PC12 cells on the microprobes were evaluated. Neuronal attachment and neurite outgrowth on the nanostructured microprobes were significantly greater than those on non-nanostructured microprobes. The enhanced neuronal attachment and neurite outgrowth on the nanostructured microprobes occurred in the absence of an adhesive coating, such as poly-l-lysine, and so may be useful for implantable devices for long-term use. Therefore, nanostructured microprobes can be implanted without adhesive coating, which can cause problems in vivo over the long term.