Nanostructured Surfaces Research Articles

Advances in CuO Nanostructure-Based Glucose Biosensors: From Enzymes to Direct Oxidation

Copper oxide (CuO) nanostructures have gained popularity in glucose biosensor development due to their excellent electrochemical properties, affordability and ease of fabrication. This review examines the progress of glucose biosensors based on CuO nanostructures and shows differences between enzyme-based and enzyme-dependent systems. Enzyme-based glucose oxidase sensors offer high specificity but are hampered by difficulties associated with enzyme stability at different temperatures, pH and interfering inhibitors. Unlike nonenzyme-based sensors, those using glucose oxidation directly offer high sensitivity and long working life but are struggling with specificity. The main drivers of these sensors are nanostructure morphology, synthesis techniques, surface modifications and electrode materials. The switch from more conventional CuO to sophisticated nanostructures significantly improved the sensitivity and durability of the sensor. This research focuses on optimizing these variables to address existing limitations and to advance CuO nanostructures as leads for next-generation glucose biosensing technologies.

A supervised machine learning tool to predict the bactericidal efficiency of nanostructured surface

The emergence and rapid spread of multidrug-resistant bacterial strains is a growing concern of public health. Inspired by the natural bactericidal surfaces of lotus leaves and shark skin, increasing attention has been focused on the use of mechano-bactericidal methods to create surfaces with antibacterial and/or bactericidal effects. There have been several studies exploring the bactericidal effect of nanostructured surfaces under various combinations of parameters. However, the correlation and synergies between these factors still need to be clarified. Recently machine learning (ML), which enables prediction or decision-making based on data, has been used in the field of biomaterials with promising results. In this study, we explored ML in nanotechnology to investigate the antimicrobial potential of nanostructured surfaces. A dataset of nanostructured surfaces and their antimicrobial properties was built by extracting the published literature. Based on the literature review and the distribution of our dataset, 70% bactericidal efficiency was selected as a practical benchmark for our classification model that balances stringent bactericidal performance with achievable targets in diverse conditions. Subsequently, we developed an ML classification model, which demonstrated an 81% accuracy in its predictive capability. A regression model was further developed to predict the value of bactericidal efficiency for nanostructured surfaces. Feature importance analysis of the ML models suggested that nanotopographical features have a greater influence on bactericidal properties than material properties, thus providing insight into the principles of the mechano-bactericidal effect of nanostructured surfaces. Overall, this ML model tool could help researchers to effectively select and design the parameters of the surface structure prior to experimentation, thereby improving the timeliness and reducing the number of experiments and the associated costs.Graphical

Enhanced carbon fiber interface with thermoplastics via nanostructure surface modification: failure, morphology and wettability analysis

Improving the fiber-matrix adhesion in thermoplastic composites remains a significant challenge due to the lack of chemical bonding between thermoplastics and common reinforcing fibers. This study investigates the effectiveness of carbon fibers enhanced with nanostructure surface modification for strengthening the interfacial adhesion to thermoplastic matrices. The fiber surface was modified with graphene nanoplatelets (GNP) through the facile coating method, and the apparent interfacial shear strength (IFSS) was determined by the single-fiber pullout test. GNP-coated fiber improved IFSS by 74% with neat high-density polyethylene (HDPE-Neat) and 28% with maleic anhydride-grafted HDPE (HDPE-8MA), while reduced by 27% with polyamide 6 (PA6) due to different failure mechanisms. Morphology, chemical, and wettability analysis were conducted on the nano-enhanced carbon fibers to quantitatively elucidate these findings on micro/nanoscale, combining machine learning-based image segmentation, X-ray photoelectron spectroscopy (XPS), and contact-angle measurements of intermittent beading on fibers.

Molecular dynamics study on the impact of surface nanostructures and interfacial coupling strength on thermal transport at the Cu-water interface

Molecular dynamics study on the impact of surface nanostructures and interfacial coupling strength on thermal transport at the Cu-water interface

Bone Integration of Femtosecond Laser-Treated Dental Implants with Nanostructured Surfaces: A Controlled Animal Study

Background: The purpose of this study is to compare bone union and soft-tissue healing in titanium implants with sandblasted, large-grit, acid-etched surfaces (SLA group) and femtosecond laser-treated surfaces (FEMTO group) in a rabbit model. Methods: Implants were inserted into rabbit tibiae, and implant stability, soft-tissue healing, and microscopic analyses (micro-CT and biopsy) were conducted. All animals maintained normal weight and health post-surgery. Results: Hemostasis was achieved at the laser incision site on the surgery day, but healing was slower compared to conventional methods. Micro-CT showed no significant differences in new bone formation or inflammatory tissue infiltration between groups. Tissue biopsy revealed slightly higher bone-implant contact in the FEMTO group compared to the SLA group, though not statistically significant. Conclusion: These findings suggest that femtosecond laser surface treatment may provide bone union comparable to or better than SLA treatment, though laser-assisted soft-tissue incisions heal more slowly.

A new parameter unifying criterion for rectangular surface structure influences on vaporization nucleation: A molecular dynamics study

This study investigates the nucleation behavior on nanostructured surfaces and its impact on heat transfer efficiency. The significance of this research lies in the fact that accurate characterization of surface effects is crucial for optimizing heat transfer systems, which have profound implications for various industrial applications. Using molecular dynamics methods, we systematically analyze the influence of rectangular surface structures with varying heights, widths, and densities on nucleation behavior. Our findings reveal that traditional surface roughness metrics fail to capture critical surface details, limiting their ability to accurately describe the effects of different surfaces on nucleation. Furthermore, we observe that surface structures significantly influence nucleation by altering local liquid film thicknesses. To address these limitations, we propose a novel parameter that combines corrected effective liquid film thickness with surface roughness to provide a more comprehensive characterization of the nucleation process. Through computational modeling, we validate the effectiveness of this parameter in predicting heat flux density, heat transfer coefficient, and surface thermal resistance across different rectangular surface structures. The results of this study clarify the mechanisms through which surface structures affect nucleation, offering a more precise tool for characterizing these effects. This enhanced understanding not only advances the theoretical framework of nucleation science but also has practical implications for the design of more efficient heat transfer systems in various industrial settings. The novelty of this work lies in the introduction of a new parameter that surpasses previous efforts in the literature by providing a more accurate quantitative prediction of the impact of surface structures on nucleation and heat transfer efficiency.

Electrochemical self-construction to fabricate NiFeCoMnSn electrocatalysts: Enhanced lattice distortion effect induced by Sn incorporation for superior hydrogen evolution performance

High-entropy alloy electrocatalysts can better regulate the electronic structure and provide opportunities for catalytic reactions to a greater extent due to the synergistic effect between its multi-metal components. In this paper, Ni-Fe-Co-Mn-Sn high-entropy alloy (NFCMS-HEA) electrocatalysts were successfully prepared by one-step electrodeposition method on nickel foam substrate. The introduction of Sn atoms, which have significantly different atomic sizes compared to other elements, results in an increased degree of lattice distortion in the HEA and a highly open multi-level nanostructured surface, thereby endowing the catalyst with exceptionally high hydrogen evolution performance. The optimized NFCMS-HEA electrocatalyst exhibits a low overpotential of 4.3 mV at a current density of 10 mA cm−2 and a low Tafel slope of 59.7 mV dec−1 in 1 M KOH solution. In addition, it maintains a superior stability of electrolysis for more than 100 h in 1 M KOH solution. In conclusion, the present study offers prospects for the preparation of HER high-entropy catalysts by one-step electrodeposition.

Advances in Surface-Enhanced Raman Spectroscopy for Urinary Metabolite Analysis: Exploiting Noble Metal Nanohybrids

This review examines recent advances in surface-enhanced Raman spectroscopy (SERS) for urinary metabolite analysis, focusing on the development and application of noble metal nanohybrids. We explore the diverse range of hybrid materials, including carbon-based, metal–organic-framework (MOF), silicon-based, semiconductor, and polymer-based systems, which have significantly improved SERS performance for detecting key urinary biomarkers. The principles underlying SERS enhancement in these nanohybrids are discussed, elucidating both electromagnetic and chemical enhancement mechanisms. We analyze various fabrication methods that enable precise control over nanostructure morphology, composition, and surface chemistry. The review critically evaluates the analytical performance of different hybrid systems for detecting specific urinary metabolites, considering factors such as sensitivity, selectivity, and stability. We address the analytical challenges associated with SERS-based urinary metabolite analysis, including sample preparation, matrix effects, and data interpretation. Innovative solutions, such as the integration of SERS with microfluidic devices and the application of machine learning algorithms for spectral analysis, are highlighted. The potential of these advanced SERS platforms for point-of-care diagnostics and personalized medicine is discussed, along with future perspectives on wearable SERS sensors and multi-modal analysis techniques. This comprehensive overview provides insights into the current state and future directions of SERS technology for urinary metabolite detection, emphasizing its potential to revolutionize non-invasive health monitoring and disease diagnosis.

Novel surfactant-free electro-nanofabricating strategy for highly sensitive and selective colorectal cancer MicroRNA analysis

A label-free nanostructured electrochemical biosensor utilizing graphene quantum dot (GQD) decorated with gold nanoparticles (AuNPs), known as Au-GQD-NS, is presented to colorectal cancer (CRC) biomarker early detection, micro RNA-223 (miR-223). Thiolated DNA probes (Cap-223) are immobilized onto a fabricated and highly conductive nanostructure platform, which improves accessibility and miR-223 recognition. To analyze the nanostructured surface, various sophisticated techniques such as FESEM, EDAX, AFM, and electrochemical approaches are employed. Electrochemical approaches including DPV, EIS, and CV are applied to investigate the electroactivity of substrate, immobilization of Cap-223 on Au-GQD-NPs and subsequent hybridization with the miR-223. The electro-nanofabricated biosensor showcases a wide linear detection range (zepto M to nano M) with an impressively suitable LOD (0.024 atto M). The biosensor selectivity is demonstrated through discrimination studies between target and mismatched miRNA sequences (miR-9 and miR-21). This biosensor also exhibits significant potential for quantitative evaluation of miR-223 in real samples, enabling its applications in point-of-care (POC) detection of CRC. In addition, the Au-GQD-NS substrate is nano-fabricated in absent of surfactants and stabilizers, providing secure anchors for immobilization of cap-223. The well-established strategies for cap-223 immobilization and hybridization with miR, combined with superior electron exchange rate compared to uncovered FTO, upgrade the biosensor’s execution. Significantly, the biosensor demonstrates efficient miR-223 detection in human serum. Overall, this nano-fabricated biosensor shows great promise for miR-based early detection of CRC, and therefore, offering great sensitivity, selectivity, and favorable hydrophilicity for translational medicine investigation and clinical applications.

Surface Nanocrystallization and Improvement of the Mechanical and Tribological Properties of AISI 304 Steel Using Multi-Pass Nanostructuring Burnishing.

Owing to their high producibility and resistance to corrosion, austenitic chromium-nickel steels are widely used in the chemical, petroleum, and food industries. However, their significant disadvantage lies in their poor structural performance, which cannot be improved by heat treatment. This significantly limits the usability of these steels in parts of machines that operate under friction loads. Hardening can be achieved by decreasing the size of grains and applying deformation-induced martensitic transformation. Nanostructuring burnishing (NSB) may be one of the technologies suited for producing parts of tribological assemblies with enhanced operating characteristics. Nanostructuring burnishing using a sliding indenter is being developed as a method of industrial surface nanocrystallization through severe plastic deformation used in the mechanical machining of various types of parts. This article investigates the possibility of enhancing the mechanical and tribological properties of nanocrystallized surfaces of austenitic steels, which are formed through nanostructuring burnishing using a tool with a natural diamond spherical indenter and a change in sliding speed from 40 to 280 m/min with one, three, and five passes. Increasing the tool sliding speed makes surface nanostructuring machining of big parts highly effective. This paper aims to establish the influence exerted by the sliding speed and number of indenter passes on the formation of a nanocrystalline structure, as well as on the modification of microhardness and residual stresses, texture, and tribological properties of the surface layer in the nanostructuring burnishing of AISI 304 steel. Transmission microscopy and microdurometry, 3D-profilometry, and tribological tests of surfaces nanocrystallized with the "ball-on-disk" scheme with dry and lubricated friction established the optimal values of speed and number of passes for a spherical indenter in nanostructuring burnishing.

Transfunctional Optical Thin Films via Bioinspired Engineering.

Advanced multifunctional optical films or substrates have continued to develop as essential components in the diverse optical industry. Several functions, including high transparency, self-cleaning ability, structural color, flexibility, and durability, are required to obtain versatile and practical optical films. Herein, we introduce a cicada-wing-inspired transfunctional optical thin film (CITOTF) with nanostructures on both surface nanostructures inspired by the cicada-wings. CITOTFs made of perfluoropolyether (PFPE), which has a low refractive index, low surface energy, and high robustness as a substrate material, are obtained by a well-designed sandwich lithography method. We fabricated two types of CITOTFs depending on the size (300 and 1000 nm) of the surface nanostructure. 300-CITOTF and 1000-CITOTF exhibit high transparency and structural color effects, respectively. Both samples demonstrate self-cleaning ability, flexibility, and long-term stability. The bioinspired transfunctional optical films developed in this study can be used in various optical applications.

Surface Nanopatterning and Structural Coloration of Liquid Metal Gallium Through Hypergravity Nanoimprinting

AbstractNanoscale structuring of gallium‐based liquid metals has emerged as a promising approach for generating unique properties and functionalities in advanced materials and devices. However, their exceptionally high surface tension presents significant challenges for achieving surface nanostructuring using conventional fabrication techniques. Here, a hypergravity nanoimprinting method is introduced, which harnesses horizontal centrifugation to generate hypergravity fields that drive liquid gallium into nanoscale cavities on an elastic polymer stamp surface at subzero temperatures, where it solidifies and preserves imprinted features down to 100 nm lateral resolution. This surpasses previous limits of gallium patterning, enabling phenomena such as iridescent structural colors with a wide range of hues and high saturation. Numerical simulations reveal the intricate fluid dynamic behaviors and interfacial interactions during the imprinting process, providing valuable insights for process optimization and control. By synergistically combining advanced soft lithography techniques with the reversible solid‐liquid phase transition properties of liquid metals, hypergravity nanoimprinting offers a practical nanofabrication approach, facilitating the development of next‐generation nanoscale gallium devices with finely structured nanofeatures across diverse application domains, such as nanoelectronics and photonic metamaterials.

SERS impact of an electrodeposited nanostructured surface with Ag nanostructures

SERS impact of an electrodeposited nanostructured surface with Ag nanostructures

Electrothermal therapy for the in vivo elimination of circulating tumor cells by using a functionalized injection needle

The elimination of circulating tumor cells (CTCs) has recently emerged as a reliable route to inhibit metastasis of cancer. Despite some progress of photodynamic therapy and photothermal therapy (PTT), their unsatisfying efficacy or difficult operation has limited their clinical application. Herein, inspired by an immersion heater, an electrothermal therapy (ETT) strategy for the elimination of CTCs in the peripheral blood was proposed by using a functionalized injection needle. CTCs can be captured by the nanostructured surface of the injection needle and then killed in the energized state due to the temperature increase caused by electrothermal conversion. ETT not only avoids the irradiation through an external light source but also controls the temperature of the needle more easily and accurately than PTT. Thus, this study proposes a more applicable strategy for the elimination of CTCs.

Peptide‐Guided Self‐Assembly: Fabrication of Tailored Spiral‐Like Nanostructures for Precise Inorganic Templating

AbstractSelf‐assembling peptides (SAPs) are versatile building blocks in the creation of hierarchical nanostructures. Although SAPs promise precise control over assembled morphology and dimensions, experimental validation is still crucial. In this sense, recent efforts have focused on nanospiral structures, which mimic natural architectures and hold potential for biomedical and nanotechnological applications. Here, it is demonstrated that SARS‐CoV‐2 fusion peptides are able to form specific spiral‐like structures using interfacial assembly as a fabrication methodology, along with fine‐tuning of the spiral ensembles through an imposed interfacial flow due to the uniaxial compression in a Langmuir–Blodgett trough. Molecular characterization by atomic force microscopy, neutron reflectometry, interfacial shear rheology, and infrared spectroscopy, highlighted how variations in fusion peptide sequences influence assembly, highlighting the importance of molecular design. These spiral structures are subsequently modified to serve as templates for metallic replicas, expanding the potential of peptide‐guided self‐assembly in fabricating tailored nanostructured surfaces with sub‐10 nm dimensions over cm2 areas.

Graphene‐Induced Surface Softening and Nanostructure Evolution of Platinum Foils

While it has been previously accepted that graphene growth on metal films by chemical vapor deposition (CVD) protects the surfaces by stiffening and hardening, in this study, an unusual opposite effect is reported. Herein, we use nanoindentation to study the mechaniported. Herein, we use nanoindentation to study the mechanical behavior of graphene‐covered platinum foils. Two graphene growth recipes using undiluted and diluted methane flow are studied, aiming to achieve a bulk or a surface‐mediated graphene growth mechanism, respectively. Contrary to previous reports, a 17% decrease is observed in the elastic modulus of the Pt surfaces when covered by graphene compared to graphene‐free regions for both recipes, when using the real indentation contact area extracted via atomic force microscopy (AFM) for the estimation. By performing cross‐sectional transmission electron microscopy (TEM), subsurface multilayers responsible for the decrease in stiffness are revealed and these observations and the mechanism of layer formation are explained. Hence, in this study, it is highlighted that surface stiffening of metals by graphene CVD has exceptions, especially in the case of metals with high carbon solubility. Moreover, in this study, approaches for combining cross‐sectional TEM, topological scans from AFM, and raw load–displacement data from nanoindentation to provide a complete, multiscale elucidation of the mechanical behavior of a material surface are described.

Unveiling the fundamentals of flow boiling heat transfer enhancement on structured surfaces.

Micro- and nanostructured surfaces offer the potential to enhance two-phase heat transfer. However, the mechanisms behind these enhancements are not well-understood due to insufficient diagnostic methods, leading to reliance on trial-and-error surface development. We introduce in situ boroscopy to investigate microscale bubble dynamics during flow boiling nucleation and subsequent flow regime development. This method was applied in saturated flow boiling experiments within chemically etched aluminum and copper tubes. Although the surfaces have self-similar surface structures, our findings revealed varied heat transfer coefficient enhancements, with increases of up to 391% on aluminum and 41% on copper. Using boroscopy, we identified key mechanisms of heat transfer enhancement. We further used mercury porosimetry to determine the impact of pore size distribution on thermal performance. The boroscopy technique introduced here not only elucidates the underlying processes of flow boiling heat transfer enhancement but also has potential applications for the study of other two-phase phenomena.

Controllability of optical, electrical, and magnetic properties of synthesized Cd-doped MgFe2O4 nanostructure

This study explores the synthesis of cadmium-magnesium co-doped magnesium ferrite (Mg1+xCdxFe2–2xO4, 0.00 ≤ x ≤ 0.30, Δx = 0.05) via a citric acid-assisted sol-gel auto-combustion method. X-ray diffraction (XRD) analysis revealed crystal structure changes due to Cd and Mg co-doping, with the 0.25 Cd sample showing the smallest crystallite size and highest lattice strain. High-resolution transmission electron microscopy (HRTEM) confirmed the nanostructure and largest surface area for this sample. Diffuse reflectance spectra, analyzed using the Kubelka-Munk relation, indicated that the 0.25 Cd sample had the lowest energy gap (2.08 eV), supported by band position calculations. Electrical conductivity and charge transport mechanisms were examined at various temperatures. Magnetization studies showed reduced saturation magnetization at x = 0.25, ascribed to cation distribution changes and spin canting, with coercivity and anisotropy decreasing with higher Cd content. Overall, the 0.25 Cd sample exhibited optimized optical, electrical, and magnetic properties due to its distinct microstructure.

Dendritic copper nanostructures for ultrasensitive detection of rhodamine 6G and Congo red

Surface-Enhanced Raman Scattering (SERS) is a fast-responding and non-destructive ultra-sensitive detection technique that can replace traditional chromatographic and spectroscopic analysis techniques. In this experiment, dendritic copper nanostructures were prepared by the solid-state ionics method and the vacuum hot evaporation process with an applied current of I=9μA. Using them as a SERS substrate, Raman detection was performed on the dye molecules Rhodamine 6G (R6G) and Congo Red (CR) to determine SERS enhancement performance. It is found that the growth of the prepared copper nanostructures has a top-end dominant phenomenon. The fractal dimension of the copper nanostructure was calculated using fractal theory, and it was revealed to be 1.560. Scanning electron microscopy (SEM) results showed that a large number of 60-80 nm regularly arranged copper nanoparticles were attached to the surface of the dendritic copper nanostructure. This is beneficial to increase the surface roughness of the substrate and improve the detection level of dye molecules. Subsequently, copper nanostructures can sensitively detect R6G and CR solutions as low as 1×10-13 mol/L and 1×10-7 mol/L, reaching single-molecule levels. The Raman mapping experiment showed that the mean relative standard deviation (RSD) values of R6G and CR were 12.3% and 12.9%, indicating high uniformity and reproducibility of the structure. This structure effectively achieves the fusion of uniformity, repeatability, and sensitivity, and shows broad application prospects in food detection.

Electroactive covalent linkers for enhancing conducting polymer adhesion, charge transfer, and biological integration of PEDOT-coated carbon microfibers

Poly(3,4-ethylenedioxythiophene) (PEDOT)-coated carbon microfibers (PCMFs) are a key technology for developing advanced neuroprosthetic electrodes and electroactive tissue scaffolds. However, for their successful application in human therapeutics, PEDOT adhesion to the carbon substrate must be enhanced without compromising electric charge transfer. Here, electrically functional linkers are synthesized to modify the surface at the nanoscale, facilitating the covalent bonding of EDOT to carbon. The properties of the resulting microfibers are compared before and after PEDOT polymerization. PCMFs deterioration is studied by applying controlled mechanical stress in vitro or by implanting them in the rodent spinal cord in vivo. Amino phenyl-EDOT derivatives allow for efficient covalent carbon surface functionalization and PEDOT electropolymerization but substantially reduce charge transfer as assessed by chronopotentiometry, electrochemical impedance spectroscopy, and cyclic voltammetry. Nevertheless, the azido-EDOT (EDOT-Ph-N3) derivative is similarly effective for carbon surface modification, enabling PEDOT polymerization to develop a nanostructured CMF surface based on robust covalent bonds, and enhancing both electric charge transfer and PEDOT adhesion to the carbon substrate. This makes PCMFs more resistant to polymer delamination when assessed in vitro or when implanted into the neural tissue. Azido-EDOT modified PCMFs also show excellent biological integration within the spinal cord, causing negligible tissue damage and cell reactivity. Overall, azido-EDOT provides a superior electroconducting linker for anchoring PEDOT and optimizes the electrical, mechanical, and biological performance of PCMFs.