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Materials with engineered nano‐scale surface topographies, such as nanopillars, nanoneedles, and nanowires, mimic natural structures like viral spike proteins, enabling them to bypass biological barriers like the plasma membrane. These properties have led to applications in nanoelectronics for intracellular sensing and drug delivery platforms, some of which are already in clinical trials. Here, evidence is present that nanotopographic materials can induce transient openings in the nuclear membranes of various cell types without penetrating the cells, breaching the nucleo‐cytoplasmic barrier, and allowing uncontrolled molecular exchange across the nuclear membrane. These openings, induced by nanoscale curvature, are temporary and repaired through the Endosomal Sorting Complexes Required for Transport (ESCRT)‐mediated mechanisms. The findings suggest a potential for nano\topographic materials to temporarily breach the nuclear membrane with potential applications in direct nuclear sensing and delivery. [ABSTRACT FROM AUTHOR]

Summary: The photon‐trapping nanostructures greatly contributes in minimizing the light reflectance losses occurring due to air–semiconductor refractive mismatch in photodetector devices. Here we have proposed a vertically oriented CdSe/CdS/ZnSe tri material‐based multiple core–shell nanopillar array structure to act as a light‐trapping efficient antenna for broadband photodetection applications. The nanopillar structure consist of diamond shaped nanotexturization over its three layer pillar interfaces. The proposed nanotexturization over the triple‐layered nanopillar structure would feature multiple scattering mechanisms for the trapped photons enhancing their optical path length along with the defect‐free confinement of the exciton pairs. The lattice compatibility of the CdS and ZnS shell layers forms a bridge between the lattice‐mismatched CdSe core and ZnSe shell leading towards the attainment of a reduced strain as well as high photochemical stability and photo quantum efficiency. As compared to the single‐layered CdSe/ZnSe nanotextured core–shell nanopillar structure the double‐layered nanotextured CdSe/CdS/ZnSe exhibits a high photoresponsivity of 0.425 A/W and external quantum efficiency of 0.98 is attained. The obtained results exhibit that the double‐shell layered‐based nanotextured nanopillar array structure would be a well‐competent alternative as compared to the planar counterpart for next‐generation photodetector applications. [ABSTRACT FROM AUTHOR]

The antibacterial properties of cicada wings originate from hexagonally arranged pillar-like multi-functional nanostructures with species-dependent heights, which are super-hydrophobic and self-cleaning. In the present study, two cicada species with promising nanopillars were investigated in more detail. Selected methods were used to analyze the wing surfaces, including Atomic Force Microscopy, Scanning Electron Microscopy, and bacterial tests with live/dead staining. Verifying the antibacterial properties posed challenges, such as the bacteria concentration needed to confirm the antibacterial properties. These challenges will also impact the practical implementation of antibacterial nanostructures and support the findings of recent critical publications. [ABSTRACT FROM AUTHOR]

We present our findings on how orange peel coupling (OPC) between the ferromagnetic layers affects spin transfer torque-assisted magnetization reversal dynamics in CoPt, CoFeB, and EuO pentalayer nanopillar devices. We accomplish this by solving the Landau-Lifshitz-Gilbert-Slonczewski (LLGS) equation (dynamical equation) using the Runge-Kutta fourth-order numerical technique. To begin, we examine the influence of OPC on switching times by simulating the LLGS equation separately for each pentalayer device, both with and without OPC. The magnetization switching times for CoPt, CoFeB, and EuO devices in the absence of OPC are 58 ps, 82 ps, and 154 ps, respectively. When introducing OPC in the pentalayer alloys, we observe a reduction in switching times of 3.5%, 11%, and 40% for CoPt, CoFeB, and EuO devices, respectively. Furthermore, we calculate the current density required to reverse the magnetization of the free layer in CoPt, CoFeB, and EuO pentalayer devices, which is found to be 0.78 × 10 12 A / m 2 , 1.8 × 10 12 A / m 2 , and 4.4 × 10 12 A / m 2 , respectively. In addition, we investigate how the thicknesses of the free and spacer layers, as well as the wavelength and amplitude of interface roughness, affect the magnetization switching time. Understanding the effects of OPC paves the way for the practical implementation of spin transfer torque (STT)-based memory devices. [ABSTRACT FROM AUTHOR]

Abstract Sensitive and accurate capture, enrichment, and identification of drug-resistant bacteria on human skin are important for early-stage diagnosis and treatment of patients. Herein, we constructed a three-dimensional hierarchically structured polyaniline nanoweb (3D HPN) to capture, enrich, and detect drug-resistant bacteria on-site by rubbing infected skins. These unique hierarchical nanostructures enhance bacteria capture efficiency and help severely deform the surface of the bacteria entrapped on them. Therefore, 3D HPN significantly contributes to the effective and reliable recovery of drug-resistant bacteria from the infected skin and the prevention of potential secondary infection. The recovered bacteria were successfully identified by subsequent real-time polymerase chain reaction (PCR) analysis after the lysis process. The molecular analysis results based on a real-time PCR exhibit excellent sensitivity to detecting target bacteria of concentrations ranging from 102 to 107 CFU/mL without any fluorescent signal interruption. To confirm the field applicability of 3D HPN, it was tested with a drug-resistant model consisting of micropig skin similar to human skin and Klebsiella pneumoniae carbapenemase-producing carbapenem-resistant Enterobacteriaceae (KPC-CRE). The results show that the detection sensitivity of this assay is 102 CFU/mL. Therefore, 3D HPN can be extended to on-site pathogen detection systems, along with rapid molecular diagnostics through a simple method, to recover KPC-CRE from the skin. Graphical Abstract

Helium ion beam induced deposition using the gaseous precursor pentamethylcyclopentasiloxane is employed to fabricate high aspect ratio insulator nanostructures (nanopillars and nanocylinders) that exhibit charge induced branching. The branched nanostructures are analyzed by transmission electron microscopy. It is found that the side branches form above a certain threshold height and that by increasing the flow rate of the precursor, the vertical growth rate and branching phenomenon can be significantly enhanced, with fractalesque branching patterns observed. The direct-write ion beam nanofabrication technique described herein offers a fast single-step method for the growth of high aspect ratio branched nanostructures with site-selective placement on the nanometer scale.

A highly sensitive potentiometric pH sensor was developed based on nanopillar array electrodes of iridium oxide. The as‐prepared pH sensor exhibited a high pH sensitivity (69.43 mV/pH), fast response time (8.1 s), and good durability (0.76 mV/h). The sensing performance of the pH sensor was maintained under mechanical bending and even after 1000 repetitive bending/releasing cycles. As a proof‐of‐concept, a wearable headband sensor was fabricated by integrating the pH sensor with a wireless electronic module based on a printed circuit board. The on‐body test indicated that the wearable pH sensor provides reliable and stable data in the real‐time monitoring of pH changes in human sweat during stationary indoor cycling. The pH sensors based on nanopillar array electrodes of iridium oxide have great potential in many portable or wearable applications in healthcare systems, non‐invasive diagnostics, environmental analysis, and food sensors. [ABSTRACT FROM AUTHOR]

Sensitive and accurate capture, enrichment, and identification of drug-resistant bacteria on human skin are important for early-stage diagnosis and treatment of patients. Herein, we constructed a three-dimensional hierarchically structured polyaniline nanoweb (3D HPN) to capture, enrich, and detect drug-resistant bacteria on-site by rubbing infected skins. These unique hierarchical nanostructures enhance bacteria capture efficiency and help severely deform the surface of the bacteria entrapped on them. Therefore, 3D HPN significantly contributes to the effective and reliable recovery of drug-resistant bacteria from the infected skin and the prevention of potential secondary infection. The recovered bacteria were successfully identified by subsequent real-time polymerase chain reaction (PCR) analysis after the lysis process. The molecular analysis results based on a real-time PCR exhibit excellent sensitivity to detecting target bacteria of concentrations ranging from 102 to 107 CFU/mL without any fluorescent signal interruption. To confirm the field applicability of 3D HPN, it was tested with a drug-resistant model consisting of micropig skin similar to human skin and Klebsiella pneumoniae carbapenemase-producing carbapenem-resistant Enterobacteriaceae (KPC-CRE). The results show that the detection sensitivity of this assay is 102 CFU/mL. Therefore, 3D HPN can be extended to on-site pathogen detection systems, along with rapid molecular diagnostics through a simple method, to recover KPC-CRE from the skin. [ABSTRACT FROM AUTHOR]

With an objective of enhancing the device performance of a Nanopillar-based n-CdS/p-CdTe solar cell, an n-ZnO window and p-CdZnTe (CZT) electron reflecting layer has been proposed utilising a novel design for placing electrodes on the same and at the rear side of the device. The study has been carried out using the semiconductor device simulator TCAD Silvaco. For the effective utilization of the solar spectrum, the ZnO layer has been integrated at the cathode side and for the effective utilization of the photogenerated carriers, a Type II p-CdZnTe electron reflecting layer at the anode side of the device has been integrated. Comparison of the photovoltaic parameters such as open-circuit voltage (Voc), short circuit current density (Jsc), fill factor (FF) and solar cell conversion efficiency (η) for the proposed structure with the conventional nanopillar based solar cell have shown an improvement of 22, 11, 18 and 59%, respectively. Furthermore, the proposed device significantly improves internal quantum efficiency (IQE) without degrading FF. [ABSTRACT FROM AUTHOR]

• 1. The photoemission model of field-assisted NEA surface InGaN nanocones array photocathode is constructed in this work. • 2. The maximum collection efficiency of the nanocone photocathode is 42.61%, which is 120% higher than that of the nanowires with normal incidence and no electric field. • 3. This work proves that proper design of the nanocone structure can achieve higher photocurrent than the nanopillar photocathode. High-quality electron beam require high-quantum efficiency and high-lifetime photocathodes. A photoemission model of negative electron affinity (NEA) In 0.5 Ga 0.5 N nanocone array photocathode was established for performance evaluation. The finite element and finite difference methods jointly simulated the photocathode. The results show that the practical design of nanocones and the joint action of oblique light and additional electric field can effectively improve the photoelectric conversion efficiency of the In 0.5 Ga 0.5 N nanocone array photocathode. The collection efficiency of nanocones with H = 800 nm, T = 170 nm, β = 25°, and E out = 2 V/μm can be boosted by 144 % and 120 %, respectively, contrasted with the nanocones and nanopillars with normal incidence and without an additional electric field. [ABSTRACT FROM AUTHOR]

The oscillatory interlayer exchange coupling (OXC) between ferromagnetic layers sandwiched by non-magnetic spacer layers plays a significant role in spintronic device function. In this work, the effect of OXC on the current-induced magnetization switching process in four different pentalayer nanopillar alloys is numerically investigated by solving the dynamical equation governed by the Landau–Lifshitz–Gilbert–Slonczewski (LLGS) equation. The four nanopillars consist of four ferromagnetic alloys, CoPt, CoFeB, Fe 85 B 13 Ni 2 and EuO, which serve as pinned layers and free layers, with copper forming a spacer layer between all the layers. The critical current density required to switch the magnetization of the free layer is computed for all the devices and the values are 0.6 × 10 11 Am - 2 , 1.31 × 10 11 Am - 2 , 2.24 × 10 11 Am - 2 , 3.27 × 10 11 Am - 2 for CoPt, CoFeB, Fe 85 B 13 Ni 2 and EuO device, respectively. Then we studied how the thickness of the Cu layer influences the OXC field. Furthermore, we investigated the effect of Cu layer thickness on critical current density and magnetization switching time for all the four devices by numerically solving the LLGS equation and they exhibit oscillating behaviour. We can reduce the critical current density and switching time substantially by controlling the OXC field acting on the free layer and choosing the magnetic material having low saturation magnetization as the free layer. The OXC field is optimised by fixing the Cu spacer thickness from 1.7 to 1.9 nm in the pentalayer nanopillar device. [ABSTRACT FROM AUTHOR]

Mechano-bactericidal strategies represent a safe and sustainable method for preventing microbial contamination in the postantibiotic era. However, their effectiveness against Gram-positive bacteria (≤55%) is still limited due to the thick peptidoglycan layer in their cell walls. Herein, an intelligent biomimetic nanopillared biopatch is developed. It is assisted by low-voltage (8 V) electrical stimulation from TENG and significantly enhances antibacterial efficacy (>99%) against three types of stubborn Gram-positive bacteria. These collaborative antibacterial behaviors are solely based on purely physical actions, thus avoiding the risk of triggering bacterial resistance. Moreover, the slight mechanical energy generated by human physiological activities is converted into a power source, exhibiting energy-efficient, eco-friendly, and sustainable features. The conductive hydrogel in the biopatch can also act as an intelligent temperature sensor, monitoring, and real-time assessment of wound conditions. This intelligent biopatch holds immense potential for efficient healing and safe management of both acute and chronic wound infections.

Despite widespread interest in nanoscale pillar structures for various optical devices, including solar cells, photonic crystal lasers, and sensors, the critical challenges for mass production are the high equipment costs and limited scalability of traditional manufacturing methods. To overcome these hurdles, this study develops a simple and highly scalable etch-mask superposition technique based on thermally assisted nanotransfer printing (T-nTP) of Cr line patterns. The orthogonal superposition of linear Cr mask patterns creates double-height cross-point arrays that effectively and selectively protect the underlying SiO 2 during subsequent reactive ion etching. This process generates highly uniform nanoscale pillar arrays with an extremely high density of 0.1 tera-pillars per square inch, eliminating the need for high-cost patterning platforms. As an exemplary application, we demonstrate the use of these perfectly ordered nanopillar arrays as high-performance surface-enhanced Raman scattering (SERS) sensors through the deposition of noble metal films on the nanopillar surface. These nanopillars enable exceptionally uniform SERS intensity with spot variations of less than 7% in methylene blue (MB) measurements. Additionally, they exhibit sensitive detections and accurate quantification for thiabendazole (TBZ) at concentrations as low as 10 -8 M, along with multicycle reusability without noticeable degradation, owing to the outstanding robustness of the SiO 2 nanopillars.

Antiferroelectrics are fundamental mother compounds critical in developing innovative lead-free piezoelectrics and ferroelectrics and hold great promise for wide-ranging applications in energy conversion and electronic devices. However, harnessing their superior properties presents a significant challenge due to the delicate balance required between their various states. In this study, through the unique design of nanopillar structures to alleviate the local polar heterogeneity, we have achieved significantly improved piezo-/ferro-electricity in classic lead-free antiferroelectric Ag x NbO 3-δ ( x = 1, 0.9, and 0.8) epitaxial thin films. The effective piezoelectric coefficient reaches 440 pm V -1 , 1 order of magnitude larger than the stoichiometric AgNbO 3 , rivaling classic lead zirconate titanate piezoelectrics. Atomic-scale electron microscopy investigations unravel the underlying mechanisms. The nanopillars, characterized by antisite occupancy of both Ag and Nb atoms and forming out-of-phase boundaries with the matrix, reduce the local crystal symmetry via interphase strain. This leads to the creation of flexible multinanodomain structures that significantly facilitate polarization rotation, thus substantially enhancing the piezoelectric performance. This study demonstrates the feasibility of engineering local heterogeneity through nanopillar design, offering a generally applicable method for property improvement of a wide range of antiferroelectrics.

Gallium phosphide (GaP) is an important optical material due to its visible wavelength band gap and high refractive index. However, the bandgap of the thermodynamically stable zinc blende GaP is indirect, but wurtzite (WZ) structure GaP is direct bandgap. In this work, we demonstrate high-quality and dense GaP vertical nanopillar (NP) array directly on Si (111) substrates through selective area epitaxy (SAE) by MOCVD for the first time, through systemic studies of the effect of TMGa flow rate, growth temperature, and V/III ratio. Uniform GaP NPs are grown over a patterned $400\,\,\mu \text{m}\,\,\times 400\,\,\mu \text{m}$ area with 97.5% yield. Arrays of GaP vertical p-i-n NP diodes are demonstrated with a ideality factor and rectification ratio of 3.7 and 103, respectively. With the high yield of hexagonal structure and electrically proven device quality of GaP NPs through this growth method, this work represents a significant step in achieving GaP NP based optoelectronic devices, such as micro-LEDs emitting in the green wavelength range. [ABSTRACT FROM AUTHOR]

Light reflectance mitigation is the most crucial factor for achieving optimal photodetector performance. In this respect, light-trapping mechanisms based on nanostructures or microstructures such as nanopillars, nanocones and nanopyramids have emerged as the most promising candidate for reducing overall light reflectance. This is because of their large effective irradiation area, multiple scattering of incident light and increased path length of incident rays in these nanostructures. This paper proposes an optical model of a GaAs/GaSb material-based vertically oriented core–shell cone-topped octagonal nanopillar structure with periodical trapezoidal nanotexturization over it to be deployed on a circular planar detector surface with a radius of 50 μm. The geometric analytical investigation of the proposed model reveals 0.999 overall absorbance, 0.995A/W photoresponsivity, and 87% EQE at 1 μm operating wavelength. [ABSTRACT FROM AUTHOR]

• SERS substrates have potential applications in biomedical detection, food safety monitoring and quality control. In this letter, we introduce a method for producing designable and reproducible SERS substrates on a silica glass slide using femtosecond laser-induced two-photon polymerization and magnetron sputtering technology. • The novelty and impact of our work lay on the fact that (1)Compared to the lithography and FIB techniques, fs-TPP nanoprinting technology operates on the principle of layer-by-layer stacking, significantly enhancing flexibility and the ability to design micro-/nano-structures. • (2) Nanopillar arrays of the proposed SERS substrates are systematically optimized with geometrical parameters of diameter, height, spacing and arrangement. • (3) For Rhodamine 6G detection with the optimized substrates, a limit of detection of 10-7 M can be achieved and the enhancement factor is estimated to be up to 2 × 103. This work presents a femtosecond laser fabrication method for precision-engineered nanopillar arrays, applicable for surface-enhanced Raman scattering (SERS) substrates. The proposed method consists of two steps: (1) fabrication of nanopillar arrays using femtosecond laser-induced two-photon polymerization (TPP) technology; and (2) deposition of Ag nanoparticles on the fabricated nanopillar arrays. Nanopillar arrays of the proposed SERS substrates are optimized with geometrical parameters of diameter, height, spacing, and arrangement. A limit of detection (LOD) down to 10-7 mol/L for Rhodamine 6G solution is achieved and the enhancement factor is estimated to be up to 2 × 103. The experimental results indicate that the proposed SERS substrates have potential applications in biomedical detection, food safety monitoring, and quality control. [ABSTRACT FROM AUTHOR]

Physical features on the biomaterial surface are known to affect macrophage cell shape and phenotype, providing opportunities for the design of novel "immune-instructive" topographies to modulate foreign body response. The work presented here employed nanopatterned polydimethylsiloxane substrates with well-characterized nanopillars and nanopits to assess RAW264.7 macrophage response to feature size. Macrophages responded to the small nanopillars (SNPLs) substrates (450 nm in diameter with average 300 nm edge-edge spacing), resulting in larger and well-spread cell morphology. Increasing interpillar distance to 800 nm in the large nanopillars (LNPLs) led to macrophages exhibiting morphologies similar to being cultured on the flat control. Macrophages responded to the nanopits (NPTs with 150 nm deep and average 800 nm edge-edge spacing) by a significant increase in cell elongation. Elongation and well-spread cell shape led to expression of anti-inflammatory/pro-healing (M2) phenotypic markers and downregulated expression of inflammatory cytokines. SNPLs and NPTs with high availability of integrin binding region of fibronectin facilitated integrin β1 expression and thus stored focal adhesion formation. Increased integrin β1 expression in macrophages on the SNPLs and NTPs was required for activation of the PI3K/Akt pathway, which promoted macrophage cell spreading and negatively regulated NF-κB activation as evidenced by similar globular cell shape and higher level of NF-κB expression after PI3K blockade. These observations suggested that alterations in macrophage cell shape from surface nanotopographies may provide vital cues to orchestrate macrophage phenotype. [ABSTRACT FROM AUTHOR]

Fourier transform infrared (FTIR) spectroscopy is widely used for molecular analysis. However, for the materials situated in an aqueous environment, a precondition for live biological objects such as cells, transmission-based FTIR is prevented by strong water absorption of mid-infrared (MIR) light. Reflection-based cellular assays using internal reflection elements (IREs) such as high-index prisms or flat plasmonic metasurfaces mitigate these issues but suffer from a shallow probing volume localized near the plasma membrane. Inspired by the recent introduction of high-aspect-ratio nanostructures as a novel platform for manipulating cellular behavior, we demonstrate that the integration of plasmonic metasurfaces with tall dielectric nanostructures dramatically enhances the sensing capabilities of FTIR spectroscopy. We also demonstrate the ability of a metal-on-dielectric metasurface to transduce intracellular processes, such as protein translocation to high-curvature membrane regions during cell adhesion, into interpretable spectral signatures of the reflected light.

The development of biomaterials capable of regulating cellular processes and guiding cell fate decisions has broad implications in tissue engineering, regenerative medicine, and cell-based assays for drug development and disease modeling. Recent studies have shown that three-dimensional (3D) nanoscale physical cues such as nanotopography can modulate various cellular processes like adhesion and endocytosis by inducing nanoscale curvature on the plasma and nuclear membranes. Two-dimensional (2D) biochemical cues such as protein micropatterns can also regulate cell function and fate by controlling cellular geometries. Development of biomaterials with precise control over nanoscale physical and biochemical cues can significantly influence programming cell function and fate. In this study, we utilized a laser-assisted micropatterning technique to manipulate the 2D architectures of cells on 3D nanopillar platforms. We performed a comprehensive analysis of cellular and nuclear morphology and deformation on both nanopillar and flat substrates. Our findings demonstrate the precise engineering of single cell architectures through 2D micropatterning on nanopillar platforms. We show that the coupling between the nuclear and cell shape is disrupted on nanopillar surfaces compared to flat surfaces. Furthermore, our results suggest that cell elongation on nanopillars enhances nanopillar-induced endocytosis. We believe our platform serves as a versatile tool for further explorations into programming cell function and fate through combined physical cues that create nanoscale curvature on cell membranes and biochemical cues that control the geometry of the cell.

The ability to sensitively detect trace quantities of substances is important in many practical applications. Herein, the use of TiO2 nanopillar arrays, formed using oblique electron-beam deposition and thermal treatment at 800 °C, as substrates for laser desorption/ionization mass spectrometry (LDI-MS) is reported. The TiO2 nanopillar arrays effectively assist ionization of various analytes, including small amino acids, a sugar, pesticides, peptides, and proteins with molecular weights of up to 24,000. The fabricated surface nanostructures were analyzed by measuring contact angles and applying the Cassie–Baxter and Wenzel wetting models. The TiO2 nanopillar surface density was shown to significantly affect the thermal properties of the substrate and the wettability of analyte-containing droplets. A TiO2 nanopillared substrate with a lower surface density exhibited more intense signals for the detection of small (∼1.2 kDa) analytes. The use of the benzyl pyridinium ion ([BP]+), as a thermometer chemical, revealed that TiO2 substrates with the lower pillar density exhibited effective heat confinement due to the pillar morphology, which plays a significant role in increasing the signal intensities of small molecules. The wetting behavior of the droplet on the substrate revealed that analyte enrichment, facilitated by surface hydrophobization, is another factor that contributes to enhancing small-molecule LDI performance. In contrast, the homogeneous adsorption of target molecules onto the nanopillared surface is likely to be a dominant factor for the detection of proteins. In this work, it is demonstrated that the appearance and disappearance of "coffee rings" during the evaporation of droplets on the surface are closely related to analyte distribution and, consequently, the intensities of the detected LDI-MS signals. The heat confinement effect of the TiO2 nanopillars, along with suitable sample wettability, delivers significant LDI performance. [ABSTRACT FROM AUTHOR]

N-type ZnO top layer in view of improving the spectral response in the lower wavelength range (300–500 nm) has been integrated into the novel nanopillar-based n-CdS/p-CdTe solar cell. The device performance has been studied using physics-based device Simulator TCAD Silvaco. It has been found that integrated ZnO layer owing to its wide bandgap has not only improved the spectral response, and short circuit current density, but large valence band offset (VBO) energy ($\Delta {E}_{\text {v}} = 1$ eV) has also caused the increase in the open-circuit voltage (${V}_{\text {oc}}$) and efficiency ($\eta$) of the device. Besides, comparison of the device performance parameters such as short circuit current density (${J}_{\text {sc}}$), open-circuit voltage (${V}_{\text {oc}}$), and solar cell conversion efficiency ($\eta$) of the proposed device with its equivalent device structure without ZnO layer has shown the improvement by 13.96%, 3.09%, and 16.75%, respectively. Besides, added ZnO layer does not contribute to any series resistance leaving fill factor (FF) unaltered. [ABSTRACT FROM AUTHOR]

Since the first emergence of influenza viruses, they have caused the flu seasonally worldwide. Precise detection of influenza viruses is required to prevent the spreading of the disease. Herein, we developed an optical biosensor using peptide-immobilized nanopillar structures for the label-free detection of influenza viruses. The spin-on-glass nanopillar structures were fabricated by nanoimprint lithography. A sialic acid-mimic peptide, which can specifically bind to hemagglutinin on the surface of the influenza virus, was immobilized onto the nanopillars via polymerized dopamine. The constructed nanopillar sensor enabled us to detect influenza A viruses in the range of 103–105 plaque-forming units through simple measurements of reflectance. Our findings suggest that biomimetic modification of nanopillar structures can be an alternative method for the immunodiagnosis of influenza viruses. [ABSTRACT FROM AUTHOR]

The development in nanobiotechnology provides an in-depth understanding of cell-surface interactions at the nanoscale level. Particularly, several surface features have shown the ability to interrogate the bacterial behavior and fate. In the past decade, the mechanical and physical sterilization has attracted considerable attention, as paradigms of such do not rely on chemical substances to damage or kill bacteria, whereas it is associated with natural living organisms or synthetic materials. Of note, such antibacterial scenario does not cause bacterial resistance, as the morphology of nanometer can directly cause bacterial death through physical and mechanical interactions. In this review, we provide an overview of recently developed technologies of leveraging topographical nanofeatures for physical sterilization. We mainly discuss the development of various morphologic nanostructures, and colloidal nanostructures show casing the capacity of "mechanical sterilization." Mechanically sterilized nanostructures can penetrate or cut through bacterial membranes. In addition, surface morphology, such as mechanical bactericidal nanoparticles and nanoneedles, can cause damage to the membrane of microorganisms, leading to cell lysis and death. Although the research in the field of mechanical sterilization is still in infancy, the effect of these nanostructure morphologies on sterilization has shown remarkable antibacterial potential, which could provide a new toolkit for anti-infection and antifouling applications. The mechanical and physical sterilization has attracted considerable attention, as paradigms of such do not rely on chemical substances to damage or kill bacteria. Moreover, such antibacterial scenario does not cause bacterial resistance, as the morphology of nanometer can directly cause bacterial death through physical and mechanical interactions. In this review, we focus on the advanced development of various morphologic nanostructures and colloidal nanostructures that show the capacity of "mechanical sterilization." [ABSTRACT FROM AUTHOR]

Bacterial infection and contamination is a tough problem that generates numerous hazardous factors in areas ranging from human health, clinical to industrial manufacture. Here, an Ag/MoS 2 nanozyme-modified ZnO nanopillar surface was designed and assembled. This nanopillar surface can achieve remarkable antibacterial effects against Gram-positive Staphylococcus aureus and Gram-negative Escherichia coli. The obtained nanozyme-modified nanopillar surface demonstrated mechanical antibacterial property with a killing rate of 69.6% and 70.4% to Staphylococcus aureus and Escherichia coli , respectively. Moreover, the surface disables bacteria under H 2 O 2 efficiently, reaching a lethality rate of 89.7% and 98.4% in 30 min, respectively. The superiorities of fast and high lethality rate are owed to a synergistic antibacterial functions consisted of mechanical rupture, enormous ROS generation and silver ions release. Meanwhile, the nanozyme-modified nanopillar surface also shows the surface superhydrophobic property with an antibacterial adhesion rate of over 99.9%. Therefore, the scheme pdresented in this study can provide a potential perspective to solve bacterial infection and contamination in the fields of daily life, clinical and industrial manufacture. [Display omitted] [ABSTRACT FROM AUTHOR]

Abstract The biocompatible polyurethane acrylate (PUA) nanopillars were fabricated by soft lithography using three different sizes of nanobeads (350, 500, and 1000 nm), and the human adipose-derived stem cells (hASCs) were cultured on the nanopillars. The hASCs and their various behaviors, such as cytoplasmic projections, migration, and morphology, were observed by high resolution images using a scanning electron microscope (SEM). With the accurate analysis by SEM for the controlled sizes of nanopillars, the deflections are observed at pillars fabricated with 350- and 500-nm nanobeads. These high-resolution images could offer crucial information to elucidate the complicated correlations between nanopillars and the cells, such as morphology and cytoplasmic projections.

Efficient light absorption is the most crucial factor for high spectral responsive photodetection phenomenon. Nanopillars for photodetection constitute a great opportunity in enhancing the light absorption efficiency along with reducing the electrical cross-section of the device. Here an analytical investigation of a proposed periodic GaAs material based half octagonal cut based vertically oriented hexagonal nanopillar array deployed over a 5um x 5um front detector's surface has been done for attaining an optimum light absorbance by reducing the surface reflectivity of the incoming photons. The geometrical analysis of the proposed model exhibits a 0.999 absorbance and 0.97A/W photoresponsivity along with 86% EQE at 1um operating wavelength. [ABSTRACT FROM AUTHOR]

A novel nanopillar-based n-CdS/p-CdTe solar cell with p-CdZnTe electron-reflecting layer has been proposed. The proposed structure features a p-CdZnTe electron-reflecting layer at the anode electrode side of the device. Device simulation using TCAD device simulator SILVACO has shown that the open-circuit voltage (Voc) of the device can be improved without degrading the short circuit current density (Jsc) of the device. Furthermore, the effect of Zn composition in the p-CdZnTe layer has also been studied on the device performance parameters of interest such as open-circuit voltage (Voc), short circuit current density (Jsc), fill factor (FF), and solar cell conversion efficiency (η). A detailed analysis has shown that increasing the Zn composition beyond 40% limits the FF due to the increase in the valence band offset energy Δ Ev, on the other hand, lowering Zn composition below 40% decreases the much-desired conduction band offset energy (Δ Ec) value. The best tradeoff relationship between the Voc and FF has been achieved for the Zn composition of 40% in the p-CdZnTe layer. At this composition of Zn, the Voc, FF, and solar cell η of the device seem to be improved by 33%, 21%, and 61% respectively. [ABSTRACT FROM AUTHOR]

Although nanoscale textured surfaces are widely used in mechanical components to improve mechanical properties, how the texture-parameters such as the shape and density of the surface textures affect the contact deformation behaviors of AlN remains elusive. Therefore, the design of surface textures of AlN micro/nanoelectromechanical systems (MEMS/NEMS) is still challenging. To study the influence of surface textures on deformation behaviors of AlN at nanoscale, in this work we study the nanoindentation process of AlN textured surface using molecular dynamics simulations. The force and deformation behaviors in the nanoindentation process of AlN textured surface are thoroughly investigated. We find that the pop-in event in the indentation of AlN textured surface is mainly due to the phase transformation and amorphization of AlN, specifically caused by the nucleation of amorphous structure and the formation of the sixfold-coordinated B1-AlN. And the plastic deformation behaviors of textured AlN are associated with the phase transformation, amorphization and dislocation motion. It is also found that due to the existence of grooves in the textured surface, the vacant part can absorb some wear atoms. Therefore, the texture pattern has a beneficial effect on reducing the influence of surface deformation. The results demonstrate that the geometric parameters of the textures have great effect on the indentation load and deformation behaviors of AlN materials. The insights gained in this work can guide the design of AlN MEMS/NEMS with surface textures. [ABSTRACT FROM AUTHOR]

Device simulations of a novel nanopillar-based n-CdS/p-CdTe solar cell with back contacts are carried out using the SILVACO technology computer-aided design (TCAD) device simulator. The device consists of nanopillars of CdTe coated with a very thin layer of CdS. It is shown that, for nanopillars with increasing height but given width as well as increasing width and given height, device performance parameters such as the open-circuit voltage (Voc), short-circuit current density (Jsc), fill factor, and solar cell conversion efficiency (η) increase. However, there is an optimum number of nanopillars that can be integrated into a given device area, while integration of more or fewer than this optimum value will deteriorate the device performance. [ABSTRACT FROM AUTHOR]

Molecular dynamics simulations are performed to provide a detailed understanding of the functional degradation of nano-scaled NiTi shape memory alloys containing amorphous regions. The origin of the experimentally reported accumulation of plastic deformation and the anomalous sudden increase of the residual strain under cyclic mechanical loading are explained by detailed insights into the relevant atomistic processes. Our work reveals that the mechanical response of shape-memory-alloy pillars under cyclic compression is significantly influenced by the presence of an amorphous-like grain boundary or surface region. The main factor responsible for the observed degradation of superelasticity under cyclic loading is the accumulated plastic deformation and the resultant retained martensite originating from a synergetic contribution of the amorphous and crystalline shape-memory-alloy regions. We show that the reported sudden diminishment of the stress plateaus and of the hysteresis under cyclic loading is caused by the increased stability of the martensite phase due to the presence of the amorphous phase. Based on the identified mechanism responsible for the degradation, we validate reported methods of recovering the superelasticity and propose a new method to prohibit the synergetic contribution of the amorphous and crystalline regions, such as to achieve a sustainable operation of shape memory alloys at small scale. Image, graphical abstract [ABSTRACT FROM AUTHOR]

Atopic dermatitis (AD), a prevalent skin condition often complicated by microbial infection, poses a significant challenge in identifying the responsible pathogen for its effective management. However, a reliable, safe tool for pinpointing the source of these infections remains elusive. In this study, a novel on-site pathogen detection that combines chemically functionalized nanotopology with genetic analysis is proposed to capture and analyze pathogens closely associated with severe atopic dermatitis. The chemically functionalized nanotopology features a 3D hierarchical nanopillar array (HNA) with a functional polymer coating, tailored to isolate target pathogens from infected skin. This innovative nanotopology demonstrates superior pathogenic capture efficiency, favorable entrapment patterns, and non-cytotoxicity. An HNA-assembled stick is utilized to directly retrieve bacteria from infected skin samples, followed by extraction-free quantitative loop-mediated isothermal amplification (direct qLAMP) for validation. To mimic human skin conditions, porcine skin is employed to successfully capture Staphylococcus aureus, a common bacterium exacerbating AD cases. The on-site detection method exhibits an impressive detection limit of 10 3 cells mL -1 . The HNA-assembled stick represents a promising tool for on-site detection of bacteria associated with atopic dermatitis. This innovative approach enables to deepen the understanding of AD pathogenesis and open avenues for more effective management strategies for chronic skin conditions., (© 2024 Wiley‐VCH GmbH.)

We study the mechanical properties of nanoglass (NG) nanopillars with diameters ranging from 4.5 to 54 nm by means of molecular dynamic simulations and compare the results with those obtained for nanopillars prepared from homogeneous glasses. NG nanopillars of two different types of glasses, namely, Cu64Zr36 and Pd80Si20, were cut from samples prepared by nanoparticle consolidation. The influence of nanopillar diameter on the deformation behavior and strain localization is investigated. Moreover, cyclic loading is used to explore the origin of stress overshoots in the stress–strain curves of NGs. Finally, from the calculated properties, a deformation map for NG and homogeneous glass nanopillars is derived.

Physical features on the biomaterial surface are known to affect macrophage cell shape and phenotype, providing opportunities for the design of novel “immune-instructive” topographies to modulate foreign body response. The work presented here employed nanopatterned polydimethylsiloxane substrates with well-characterized nanopillars and nanopits to assess RAW264.7 macrophage response to feature size. Macrophages responded to the small nanopillars (SNPLs) substrates (450 nm in diameter with average 300 nm edge-edge spacing), resulting in larger and well-spread cell morphology. Increasing interpillar distance to 800 nm in the large nanopillars (LNPLs) led to macrophages exhibiting morphologies similar to being cultured on the flat control. Macrophages responded to the nanopits (NPTs with 150 nm deep and average 800 nm edge-edge spacing) by a significant increase in cell elongation. Elongation and well-spread cell shape led to expression of anti-inflammatory/pro-healing (M2) phenotypic markers and downregulated expression of inflammatory cytokines. SNPLs and NPTs with high availability of integrin binding region of fibronectin facilitated integrin β1 expression and thus stored focal adhesion formation. Increased integrin β1 expression in macrophages on the SNPLs and NTPs was required for activation of the PI3K/Akt pathway, which promoted macrophage cell spreading and negatively regulated NF-κB activation as evidenced by similar globular cell shape and higher level of NF-κB expression after PI3K blockade. These observations suggested that alterations in macrophage cell shape from surface nanotopographies may provide vital cues to orchestrate macrophage phenotype.

We have investigated the use of nanopillar structures on high indium content InGaN amber multiple quantum well (MQW) samples to enhance the emission efficiency. A significant emission enhancement was observed which can be attributed to the enhancement of internal quantum efficiency and light extraction efficiency. The size-dependent strain relaxation effect was characterized by photoluminescence, Raman spectroscopy and time-resolved photoluminescence measurements. In addition, the light extraction efficiency of different MQW samples was studied by finite-different time-domain simulations. Compared to the as-grown sample, the nanopillar amber MQW sample with a diameter of 300 nm has demonstrated an emission enhancement by a factor of 23.8.

Molecular dynamics simulations are performed to investigate the impact of a coherent Σ3 (111) twin boundary on the plastic deformation behavior of Cu nanopillars. Our work reveals that the mechanical response of pillars with and without the twin boundary is decisively driven by the characteristics of initial dislocation sources. In the condition of comparably large pillar size and abundant initial mobile dislocations, overall yield and flow stresses are controlled by the longest, available mobile dislocation. An inverse correlation of the yield and flow stresses with the length of the longest dislocation is established and compared to experimental data. The experimentally reported subtle differences in yield and flow stresses between pillars with and without the twin boundary are likely related to the maximum lengths of the mobile dislocations. In the condition of comparably small pillar size, for which a reduction of mobile dislocations during heat treatment and mechanical loading occurs, the mechanical response of pillars with and without the twin boundary can be clearly distinguished. Dislocation starvation during deformation is more pronounced in pillars without the twin boundary than in pillars with the twin boundary because the twin boundary acts as a pinning surface for the dislocation network. Image, graphical abstract [ABSTRACT FROM AUTHOR]

In this mini-review, we summarize fabrication methods, formation mechanisms, factors that control the characteristics, and applications of self-assembled nanopillars. Nanopillars prepared both in the gas phase and in solutions are discussed.

The addition of nanopillars to electrodes increases their electrochemical capabilities through an increase in electroactive surface area. The nanopillars can be applied on either cathodes or anodes to engage in reduction-oxidation reactions. This minireview summaries some work on cyclic voltammetry, chronoamperometry, impedance change on nanopillared surface and compared their electrochemistry behavior on planar surfaces.