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Mallomonas thrive primarily in freshwaters and dominate plankton communities, especially in oligotrophic waters. The cells have a siliceous cell covering of regularly arranged scales. Despite their ecological importance, the intricate structure and evolutionary significance of their silica scales are still unexplored. We investigated the nanopatterns on the scales and hypothesized that they may play a role in UV shielding. UVA and UVB exposure experiments were performed with 20 Mallomonas species, categorized into four groups based on the nanopattern of the scales (plain‐scaled, meshed, striated, and papilliferous group); a fifth group consisted of the species that have extremely thick, robust scales regardless of the nanopattern. We revealed that thick scales were associated with enhanced UVB resistance, suggesting a protective role. No significant differences in UVA response were observed among the groups, except for the meshed group, which showed lower resistance, likely due to the less regular pattern on the shield. In conclusion, the scale case, composed of sufficiently silicified scales, provides effective UV protection in freshwater environments, regardless of the particular nanopattern. In increased UVB radiation, the thickness of the scales plays role. Contrary to expectations, cell size and phylogeny do not strongly predict UV resistance. The study highlights the diverse UV responses of Mallomonas, but further studies are needed to understand the role of scales/nanopatterns in the ecological adaptations of the species. [ABSTRACT FROM AUTHOR]

Nanofabrication of two-dimensional materials through mechanical machining is normally influenced by not only process parameters such as load and velocity but also intrinsic properties such as strength and thickness. Herein, we examined the effects of graphene oxide (GO) film thickness on nanofabrication on the plane surfaces and at the step edges using scanning probe microscope lithography. The material removal of GO initiates at the load above a critical value, which strongly depends on film thickness and locations. With the increase in film thickness, the critical load decreases monotonically on the plane surfaces but increases gradually at the step edges. Further, the critical load for the GO monolayer at the step edges is at least 25 times lower than that on the plane surfaces, and the gap decreases to around 3 times when GO thickness increases to four layers. Then, mechanical nanofabrication initiating from the GO step edge allows producing various nanopatterns under extremely low loads around 1 nN. Finally, the GO nanostructures are deoxidized by annealing at 800 °C in high-purity argon to restore their highly functionalized conjugated structures, which are supported by X-ray diffraction and Raman characterizations. This work provides a novel approach to fabricating graphene-like nanostructures by deoxidizing GO after nanofabrication, which holds significant potential for applications in graphene-based devices. Highlights: The minimum load for GO removal initiation presents negative layer dependence on the plane surface but positive at the step edge. The minimum load for GO monolayer nanofabrication at the step edge is at least 25 times lower than that at the plane surface. GO nanopatterns can be fabricated under a low load and further deoxidized by high-temperature annealing. [ABSTRACT FROM AUTHOR]

Area‐selective deposition (ASD) is a bottom‐up technique that provides numerous opportunities for nanoelectronic device fabrication. For example, advanced nano‐interconnect structures with barrierless metals like Ru in the contact holes can be created by Ru ASD with the bottom metals as growth surfaces and dielectrics as non‐growth surfaces. This work investigates Ru ASD by chemical vapor deposition (CVD) on industrially relevant substrates and nanopatterns and reveals how selectivity and growth rate are modulated by the CVD conditions and type of nanopattern. For low‐k dielectric/Cu substrate combinations, the selectivity reverses from metal‐on‐metal to metal‐on‐dielectric upon only changing the CVD co‐reagent from H2 to NH3. In contrast, NH3 is the preferred co‐reagent for SiO2‐TiN line patterns with critical dimension (CD) of 40 nm due to the more favorable adsorption and diffusion kinetics that cause growth rate and selectivity enhancement. Consistent with a diffusion‐mediated mechanism, the growth rate enhances even more for Ru CVD on nanoscale contact holes with CD of 10.5 nm, becoming 2.4 times higher as compared to unpatterned substrates. Thus, the ASD process changes drastically when pattern dimensions reach the nanoscale. The reported insights facilitate rational design of metal ASD processes for multiple applications in nanofabrication. [ABSTRACT FROM AUTHOR]

The development of nanoelectronics and nanotechnologies has been boosted significantly by the emergence of 2D materials because of their atomic thickness and peculiar properties, and developing a universal, precise patterning technology for single-layer 2D materials is critical for assembling nanodevices. Demonstrated here is a nanomachining technique using electrical breakdown by an AFM tip to fabricate nanopores, nanostrips, and other nanostructures on demand. This can be achieved by voltage scanning or applying a constant voltage while moving the tip. By measuring the electrical current, the formation process on single-layer materials was shown quantitatively. The present results provide evidence of successful pattern fabrication on single-layer MoS2, boron nitride, and graphene, although further confirmation is still needed. The proposed method holds promise as a general nanomachining technology for the future. ARTICLE HIGHLIGHTS: HIGHLIGHTS • Successful patterning of 2D materials by electrical breakdown. • A maskless, pollution-free method for patterning various 2D materials. • Nanopattern size is characterized by number of voltage scanning cycles. [ABSTRACT FROM AUTHOR]

Very recently, the synthesis of 2D MoS2 and WS2 through pulsed laser-directed thermolysis can achieve wafer-scale and large-area structures, in ambient conditions. In this paper, we report the synthesis of MoS2 and MoS2 oxides from (NH4)2MoS4 film using a visible continuous-wave (CW) laser at 532 nm, instead of the infrared pulsed laser for the laser-directed thermolysis. The (NH4)2MoS4 film is prepared by dissolving its crystal powder in DI water, sonicating the solution, and dip-coating onto a glass slide. We observed a laser intensity threshold for the laser synthesis of MoS2, however, it occurred in a narrow laser intensity range. Above that range, a mixture of MoS2 and MoO2 is formed, which can be used for a memristor device, as demonstrated by other research groups. We did not observe a mixture of MoS2 and MoO3 in the laser thermolysis of (NH4)2MoS4. The laser synthesis of MoS2 in a line pattern is also achieved through laser scanning. Due to of the ease of CW beam steering and the fine control of laser intensities, this study can lead toward the CW laser-directed thermolysis of (NH4)2MoS4 film for the fast, non-vacuum, patternable, and wafer-scale synthesis of 2D MoS2. [ABSTRACT FROM AUTHOR]

The design of functional micro or nanostructured surfaces is undergoing extensive research for their intriguing multifunctional properties and for large variety of potential applications in biomedical field (tissue engineering or cell adhesion), electronics, optics or microfluidics. Such nanosized topographies can be easily fabricated by various lithography techniques and can be also further reinforced by synergic effect by combining aforementioned structures along materials with already outstanding antibacterial properties. In this work we fabricated novel micro/nanostructured substrates using soft lithography replication method and subsequent thermal nanoimprint lithography method, creating nanostructured films based on poly (l-lactic acid) (PLLA) fortified by thin silver films deposited by PVD. Main nanoscale patterns were fabricated by replicating surface patterns of optical discs (CDs and DVDs), which proved to be easy, fast and inexpensive method for creating relatively large area patterned surfaces. Their antimicrobial activity was examined in vitro against the bacteria Escherichia coli and Staphylococcus epidermidis strains. The results demonstrated that nanopatterned films actually improved the conditions for bacterial growth compared to pristine PLLA films, the novelty is based on formation of Ag nanoparticles on the surface/and in bulk, while silver nanoparticle enhanced and nanopatterned films exhibited excellent antibacterial activity against both bacterial strains, with circa 80 % efficacy in 4 h and complete bactericidal effect in span of 24 h.

Liquid crystal (LC) orientation films are one of the key technologies in display devices. Currently, the commonly used polyimide rubbing method exposes problems such as micro‐defects and static electricity. In this paper, a thin film was prepared from a mixture of UV‐curable polymer and NiO solution using the UV‐NIL method. At room temperature, all three temperatures showed good liquid crystal alignment properties. However, in terms of thermal stability, it was more thermally stable in the 1‐min sample. This means that the formation of patterns has a significant impact on orientation properties, and the change in van der Waals force due to chemical changes also affects the orientation properties to some extent. In addition, excellent electro‐optical properties were also confirmed. [ABSTRACT FROM AUTHOR]

Cell cultures of dispersed cells within hydrogels depict the interaction of the cell–extracellular matrix (ECM) in 3D, while the coculture of different cells within spheroids combines both the effects of cell–cell and cell–ECM interactions. In this study, the cell co-spheroids of human bone mesenchymal stem cells/human umbilical vein endothelial cells (HBMSCs/HUVECs) are prepared with the assistance of a nanopattern, named colloidal self-assembled patterns (cSAPs), which is superior to low-adhesion surfaces. A phenol-modified gelatin/hyaluronan (Gel-Ph/HA-Ph) hydrogel is used to encapsulate the multicellular spheroids and the constructs are photo-crosslinked using blue light. The results show that Gel-Ph/HA-Ph hydrogels with a 5%-to-0.3% ratio have the best properties. Cells in HBMSC/HUVEC co-spheroids are more favorable for osteogenic differentiation (Runx2, ALP, Col1a1 and OPN) and vascular network formation (CD31+ cells) compared to HBMSC spheroids. In a subcutaneous nude mouse model, the HBMSC/HUVEC co-spheroids showed better performance than HBMSC spheroids in angiogenesis and the development of blood vessels. Overall, this study paves a new way for using nanopatterns, cell coculturing and hydrogel technology for the generation and application of multicellular spheroids. [ABSTRACT FROM AUTHOR]

Ultraviolet (UV) nanoimprint lithography (NIL) was performed using a hybrid solution of ZnO and UV-curable polymer. The concentration of the UV-curable polymer was varied as 5, 10, and 15 wt.%, and the surface was analyzed for each film. Physical modification of the surface morphology was analyzed by atomic force microscopy, and the clearest pattern was confirmed at 15 wt.%. Through X-ray photoelectron spectroscopy analysis, it was confirmed that the difference in the concentration of the UV-curable polymer caused a difference in the atomic and bonding composition on the film surface. Through optical transmittance measurements, it was observed that all of the patterned ZnO hybrid films exhibited sufficient transmittance. To investigate liquid crystal (LC) alignment, each of these films was assembled into an antiparallel structure to fabricate LC cells. Using polarized optical microscopy and thermal stability tests, it was confirmed that the LC cells fabricated with the 15 wt.% solution showed the most stable LC alignment. Moreover, pretilt angle measurements showed that the most stable transmittance curve was obtained with the 15 wt.% LC cell. The relationship between the height of the groove pattern and alignment of the LC molecules was analyzed using Berreman's model. Highlights: Nanoimprint lithography was performed by coating a hybrid solution of zinc oxide and UV-curable-polymer. Surface modification was analyzed through AFM, TEM, XRD, and XPS. It showed good LC alignment performance when cured for 15wt%. [ABSTRACT FROM AUTHOR]

Nanoimprinting lithography (NIL) technique is widely utilized for nanostructure engineering of soft materials. Owing to the soft organic/inorganic hybrid nature, the optical and crystallographic properties of halide perovskites (HPs) are improved by the NIL process. However, the wide application of NIL into various HPs has lagged. Herein, a defect‐free nanopatterned‐(FAPbI3)0.85(MAPbBr3)0.15 (NP‐FAMA) film is successfully developed via optimized NIL. As surface energy is a key parameter to be controlled for accomplishing NIL process, trichloro(1H,1H,2H,2H‐perfluorooctyl)silane (CF3(CF2)5CH2CH2SiCl3) treatment on polymeric mold, which prevents the peeling‐off problem. Along with surface morphology modification, NP‐FAMA exhibits enhanced crystallographic and photophysical properties. The photoresponsivity of NP‐FAMA‐based photodetectors outperforms bare (b‐) FAMA‐based devices. Surprisingly, the external quantum efficiency (EQE) of the NP‐FAMA‐based devices dramatically increases to 225%, photomultiplication (PM), under 1 nW illumination without any charge‐injecting materials. To clarify these PM phenomena, the trap‐assisted PM mechanism is suggested as a model system for promoting photocurrent generation of HPs that is supported by PL analysis. [ABSTRACT FROM AUTHOR]

Cell cultures of dispersed cells within hydrogels depict the interaction of the cell–extracellular matrix (ECM) in 3D, while the coculture of different cells within spheroids combines both the effects of cell–cell and cell–ECM interactions. In this study, the cell co-spheroids of human bone mesenchymal stem cells/human umbilical vein endothelial cells (HBMSC/HUVECs) are prepared with the assistance of a nanopattern, named colloidal self-assembled patterns (cSAPs), which is superior to low-adhesion surfaces. A phenol-modified gelatin/hyaluronan (Gel-Ph/HA-Ph) hydrogel is used to encapsulate the multicellular spheroids and the constructs are photo-crosslinked using blue light. The results show that Gel-Ph/HA-Ph hydrogels with a 5%-to-0.3% ratio have the best properties. Cells in HBMSC/HUVEC co-spheroids are more favorable for osteogenic differentiation (Runx2, ALP, Col1a1 and OPN) and vascular network formation (CD31+ cells) compared to HBMSC spheroids. In a subcutaneous nude mouse model, the HBMSC/HUVEC co-spheroids showed better performance than HBMSC spheroids in angiogenesis and the development of blood vessels. Overall, this study paves a new way for using nanopatterns, cell coculturing and hydrogel technology for the generation and application of multicellular spheroids.

[Display omitted] We describe the antithrombotic properties of nanopatterned coatings created by self-assembly of poly(styrene- block -2-vinylpyridine) (PS- b -P2VP) with different molecular weights. By changing the assembly conditions, we obtained nanopatterns that differ by their morphology (size and shape of the nanopattern) and chemistry. The surface exposition of P2VP block allowed quaternization, i.e. introduction of positive surface charge and following electrostatic deposition of heparin. Proteins (albumin and fibrinogen) adsorption, platelet adhesion and activation, cytocompatibility, and reendothelization capacity of the coatings were assessed and discussed in a function of the nanopattern morphology and chemistry. We found that quaternization results in excellent antithrombotic and hemocompatible properties comparable to heparinization by hampering the fibrinogen adhesion and platelet activation. In the case of quaternization, this effect depends on the size of the polymer blocks, while all heparinized patterns had similar performance showing that heparin surface coverage of 40 % is enough to improve substantially the hemocompatibility. [ABSTRACT FROM AUTHOR]

A liquid crystal (LC) alignment layer was created using the nanoimprint lithography method and ultraviolet (UV) curing. A hybrid film of a solution of gallium oxide (GaO) and a UV-curing polymer was coated on a substrate and cured by UV irradiation. After that, an LC cell was manufactured by assembling two films by an antiparallel method. The LC orientation characteristics and the surface were analyzed by varying the curing time. The molecular composition of the coated film surface was confirmed via X-ray photoelectron spectroscopy, and nanopattern formation was observed through atomic force microscopy. The LC alignment characteristics were analyzed by polarized optical microscopy and pretilt angle measurements, and thermal stability tests were performed. It was confirmed that the refractive index anisotropy and van der Waals forces based on the nanopattern formation enabled a homogeneous and uniform alignment of the LC molecules; further, it was found that the GaO hybrid film was suitable for use as an LC alignment layer. [ABSTRACT FROM AUTHOR]

Severe bone injuries can result in disabilities and thus affect a person's quality of life. Mesenchymal stem cells (MSCs) can be an alternative for bone healing by growing them on nanopatterned substrates that provide mechanical signals for differentiation. This review aims to highlight the role of nanopatterns in directing or inducing MSC osteogenic differentiation, especially in bone tissue engineering. Nanopatterns can upregulate the expression of osteogenic markers, which indicates a faster differentiation process. Combined with growth factors, nanopatterns can further upregulate osteogenic markers, but with fewer growth factors needed, thereby reducing the risks and costs involved. Nanopatterns can be applied in scaffolds for tissue engineering for their lasting effects, even in vivo, thus having great potential for future bone treatment.

The stiffness and the topography of the substrate at the cell–substrate interface are two key properties influencing cell behavior. In this paper, atomic force acoustic microscopy (AFAM) is used to investigate the influence of substrate stiffness and substrate topography on the responses of L929 fibroblasts. This combined nondestructive technique is able to characterize materials at high lateral resolution. To produce substrates of tunable stiffness and topography, we imprint nanostripe patterns on undeveloped and developed SU-8 photoresist films using electron-beam lithography (EBL). Elastic deformations of the substrate surfaces and the cells are revealed by AFAM. Our results show that AFAM is capable of imaging surface elastic deformations. By immunofluorescence experiments, we find that the L929 cells significantly elongate on the patterned stiffness substrate, whereas the elasticity of the pattern has only little effect on the spreading of the L929 cells. The influence of the topography pattern on the cell alignment and morphology is even more pronounced leading to an arrangement of the cells along the nanostripe pattern. Our method is useful for the quantitative characterization of cell–substrate interactions and provides guidance for the tissue regeneration therapy in biomedicine.

2D nanoscale patterns have been extensively investigated for various applications including information storage devices, non‐volatile memory devices, chemical or biological sensors. Recently, such nanostructured patterns have been gaining lots of attention because of their potential uses as meta‐materials or meta‐surfaces with unnatural optical properties. In particular, self‐assembled colloidal monolayers of gold nanoparticles (NPs) have been demonstrated as optical meta‐materials for unnaturally high refractive index (neff > 4) at optical frequency. Raspberry‐like particles or spherical assembly of NPs are also investigated for negative or near‐zero index of refraction. Thanks to the recent advance in colloidal chemistry for shaping NPs with controlling the interaction, non‐close‐packed, or even non‐periodic colloidal nanostructures can be achieved, which may be potentially useful for optical meta‐surfaces. In this article, a brief introduction of optical meta‐materials is provided and recent progress for high‐index and negative‐index meta‐materials are reviewed. In the second part, the meta‐surfaces will be briefly described including fundamental principle and some of the key potential applications. Finally, the recent experimental progress of high‐precision self‐assembly for the meta‐surface fabrication will be discussed. [ABSTRACT FROM AUTHOR]

The role of plasmon resonance on the optical efficiency of nanoantennas for tip-enhanced Raman spectroscopy (TERS) is reviewed. Technical details on surface plasmon polaritons (SPP), localized surface plasmon resonance (LSPR), and the plasmon gap mode are provided. Nanotechnology engineering is necessary to adequate the nanoantenna's size, shape and composition to match resonance conditions with the exciting radiation source. Computational simulation guides the development of new types of plasmonic nanoantennas with different materials and morphologies, specially designed to reach target applications. An overview on a recently developed nanoantenna composed by a truncated micropyramidal body with a nanopyramid end is presented. The characteristic length $L$ of the nanopyramid tip is dimensioned to fine-tune LSPR modes, giving rise to the so-called plasmon-tunable tip pyramid (PTTP). The plasmonic properties of this type of probe were investigated by electron energy loss spectroscopy and computational simulations, reveling that PTTPs act as monopole nanoantennas. TERS results obtained with the PTTPs demonstrate the achievement of unprecedent levels of field enhancement mediated by LSPR with excellent reproducibility rate. [ABSTRACT FROM AUTHOR]

Background: Bionic surface nanopatterns of titanium (Ti) materials have excellent antibacterial effects in vitro for infection prevention. To date, there is a lack of knowledge about the in vivo bactericidal outcomes of the nanostructures on the Ti implant surfaces. Methods: A systematic review was performed using the PubMed, Embase, and Cochrane databases to better understand surface nanoscale patterns’ in vivo antibacterial efficacy. The inclusion criteria were preclinical studies (in vivo) reporting the antibacterial activity of nanopatterns on Ti implant surface. Ex vivo studies, studies not evaluating the antibacterial activity of nanopatterns or surfaces not modified with nanopatterns were excluded. Results: A total of five peer-reviewed articles met the inclusion criteria. The included studies suggest that the in vivo antibacterial efficacy of the nanopatterns on Ti implants’ surfaces seems poor. Conclusions: Given the small number of literature results, the variability in experimental designs, and the lack of reporting across studies, concluding the in vivo antibacterial effectiveness of nanopatterns on Ti substrates’ surfaces remains a big challenge. Surface coatings using metallic or antibiotic elements are still practical approaches for this purpose. High-quality preclinical data are still needed to investigate the in vivo antibacterial effects of the nanopatterns on the implant surface.

The energy conversion efficiency (ECE) (η), current density (Jsc), open-circuit voltage (Voc), and fill factor (ff) of perovskite solar cells were studied by using the transmittance of a nanopatterned mesoporous TiO2 (mp-TiO2) thin-film layer. To improve the ECE of perovskite solar cells, a mp-TiO2 thin-film layer was prepared to be used as an electron transport layer (ETL) via the nanoimprinting method for nanopatterning, which was controlled by the aspect ratio. The nanopatterned mp-TiO2 thin-film layer had a uniform and well-designed structure, and the diameter of nanopatterning was 280 nm. The aspect ratio was controlled at the depths of 75, 97, 127, and 167 nm, and the perovskite solar cell was fabricated with different depths. The ECE of the perovskite solar cells with the nanopatterned mp-TiO2 thin-film layer was 14.50%, 15.30%, 15.83%, or 14.24%, which is higher than that of a non-nanopatterned mp-TiO2 thin-film layer (14.07%). The enhancement of ECE was attributed to the transmittance of the nanopatterned mp-TiO2 thin-film layer that is due to the improvement of the electron generation. As a result, better electron generation affected the electron density, and Jsc increased the Voc, and ff of perovskite solar cells.

• A one-dimensional nanopattern was transferred onto the sol–gel film through the soft-imprint technique. • Unlike conventional alignment films, the alignment direction of liquid crystal molecules can be converted by controlling the ratio of InO to SnO. • In addition, the low permeability and weak anchoring energy of InO and the resulting low orientation stability were improved through SnO doping. • The improved anchoring energy reaches a level similar to that of rubbed PI, and is expected to develop into a liquid crystal alignment system. The alignment layer process, which is a key element for liquid crystal (LC) displays, was investigated for efficiency improvement and for suggesting a new mode. To produce alignment films that can be used in both twisted-nematic (TN) and vertical alignment (VA) configurations, InO solution is doped with SnO. Then, the pattern was transferred by attaching a one-dimensional soft-imprint mold, and pattern and orientation analyses were performed in accordance with the SnO ratio. The horizontal orientation performance improved as the SnO ratio increased, and the best orientation performance was observed for a film doped with 70% SnO. Further, the thermal stability improved and anchoring energy increased, which was measured to be very close to that of the rubbed polyimide film. The low transmittance of InO was overcome by doping with SnO, which has high transmittance. In the film doped with 80% SnO, the LC molecules were aligned in a vertical direction and were suitable for VA mode operation. By simple adjustment of the doping ratio, differences are observed with respect to the existing films in that the performance of the alignment layer is improved and the pretilt angles of the LC molecules can be changed. These convertible characteristics are expected to play a revolutionary role in the development of new LC driving modes. [ABSTRACT FROM AUTHOR]

Nanopattern replication of complex structures by plastic injection is a challenge that requires simulations to define the right processing parameters. Previous work managed to simulate replication for single cavities in 2D and 3D, showing high performance requirements of CPU to simulate periodic trenches in 2D. This paper presents two ways to approach the simulation of replication of complex 3D hydrophobic surfaces. The first approach is based on previous CFD Ansys Fluent and compared to FE based CFD Polyflow software for the analysis of laminar flows typical in polymer processing and glass forming as well as other applications. The results showed that Polyflow was able to reduce computing time from 72 h to only 5 min as desired in the project. Furthermore, simulations carried out with Polyflow showed that higher injection and mold temperature lead to better replication of hydrophobicity in agreement with the experiments. Polyflow simulations are proved to be a good tool to define process parameters such as temperature and cycle times for nanopattern replication.

Abstract We present a facile and scalable coating method based on controlled airbrushing, which is suitable for conformal resin coating in continuous roll-to-roll (R2R) nanoimprint lithography (NIL) process. By controlling the concentration of UV-curable polymeric resin with mixing the volatile solvent and its airbrushing time, the coated resin film thickness can be readily tuned. After R2R NIL using a flexible nanoscale line pattern (nanograting) mold is conducted upon the airbrushed resin film, a large-area uniform nanograting pattern is fabricated with controlled residual layer thickness (RLT) based on the initial film thickness. We investigate the faithful airbrushing condition that can reliably create the uniform thin films as well as various nanopatterns with controlled morphologies. Using more diluted resin and shorter airbrushing time can reduce the RLTs favourably for many applications, yet is apt to induce the nanoscale pores and discontinued lines. We also discuss how to further improve the quality and scalability of resin airbrushing and its potential applications particularly requiring high-speed and conformal coating on highly topographic and flexible surfaces.

Developing simple and cost‐efficient methods for fabricating molecular patterns is of great importance in the field of nanoscience and nanotechnology. Here, a simple and convenient method was developed for fabricating nanopatterns composed of positively charged silane molecules by using silver nanowires as templates. The as‐obtained silane pattern copies the shape of the silver nanowires and is only 0.7 nm thick, which can later be used for templated assembly of small molecules and nanoparticles of opposite charges. As a proof of concept, the resultant assembly could be further used for surface‐enhanced Raman scattering. [ABSTRACT FROM AUTHOR]

Abstract Intensive research on lead halide perovskites over the last decade led to highly efficient perovskite thin-film photovoltaics. Further enhancement in power conversion efficiency (PCE) of this technology is expected from improved light management. In this simulation-based study, nanophotonic perovskite absorber layers are designed in order to enhance the short-circuit current density (J SC) of perovskite solar cells. The enhancement in J SC is beneficial in one of two ways. Firstly, optimized nanophotonic perovskite layers lead to an enhancement in J SC by 5–6% assuming a constant perovskite absorber volume, which correlates to a similar improvement in PCE and annual energy yield (EY). Secondly, optimized nanophotonic perovskite layers can alternatively allow a high J SC to be maintained at reduced perovskite absorber volumes. The latter approach results in about one third of the harmful lead content being mitigated in conventional perovskite solar cells, for an initial perovskite layer thickness of ~300 nm. This study evaluates and analyzes in detail the design of nanophotonic perovskite layers that can be fabricated by nanoimprint lithography. Various design parameters of the nanophotonic perovskite layers such as the period (150–750 nm), the geometrical filling fraction (0.2–0.6) and the depth (0–500 nm) of the nanostructures are studied. A broad optimum to enhance J SC is found for a period of 400 nm. Finally, the angular stability of simulated nanophotonic perovskite solar cells is shown and their excellent light harvesting for realistic irradiation conditions is demonstrated by EY modelling. Highlights • Nanophotonic perovskite solar cells enhance the short circuit current density and thereby improve the device efficiency and energy yield by around 5–7% relative by coupling light to guided modes in the absorber layer. • High short-circuit currents can be maintained at reduced perovskite absorber volumes, which allows mitigating around 1/3 of environmental harmful lead. • A broad and experimentally feasible optimum of geometrical parameters is found for nanophotonic perovskite solar cells. [ABSTRACT FROM AUTHOR]

The p‐type semiconducting copper oxides (CuO and Cu2O) are promising materials for gas sensors, owing to their characteristic oxygen adsorption properties and low operation temperature. In this study, the sensing performance of a CuO‐based chemiresistor is significantly enhanced by incorporating Ag nanoparticles on high‐resolution p‐type CuO/Cu2O nanopattern channels. The high‐resolution CuO/Cu2O/Ag nanochannel is fabricated using a unique top‐down nanolithographic approach. The gas response (ΔR/Ra) of the CuO/Cu2O/Ag gas sensor increases by a maximum factor of 7.3 for various volatile organic compounds compared with a pristine CuO/Cu2O gas sensor. The sensors exhibit remarkable sensitivity (ΔR/Ra = 8.04) at 125 parts per billion (ppb) for acetone analytes. As far as it is known, this is the highest sensitivity achieved for p‐type metal oxide semiconductor (MOS)‐based gas sensors compared to previous studies. Furthermore, the outstanding gas responses observed in this study are superior to the most of n‐type MOS‐based gas sensors. The high sensitivity of the sensor is attributed to i) the high resolution (≈30 nm), high aspect ratio (≈12), and ultrasmall grain boundaries (≈10 nm) of the CuO/Cu2O nanopatterns and ii) the electronic sensitization and chemical sensitization effects induced by incorporating Ag nanoparticles on the CuO/Cu2O channels.For the first time, a 10‐nm scale CuO/Cu2O/Ag nanopattern as gas‐sensing channel materials is reported. With unique top‐down nanolithographic approaches, an ideal metal oxide semiconductor–noble metal heterojunction is achieved for electronic and chemical sensitizations with fully exposed nanochannel structures. Using this, the sensors report the best CH3COCH3‐sensing performances among previously reported p‐type metal oxide semiconductor sensors. [ABSTRACT FROM AUTHOR]

The effective production of nanopatterned films generally requires a nanopatterned roll mold with a large area. We report on a novel system to fabricate large-area roll molds by recombination of smaller patterned areas in a step-and-repeat imprint lithography process. The process is accomplished in a method similar to liquid transfer imprint lithography (LTIL). The stamp roll with a smaller area takes up the liquid resist by splitting from a donor substrate or a donor roll. The resist is then transferred from a stamp roll to an acceptor roll and stitched together in a longitudinal and, if necessary, in a circumferential direction. During transfer, the nanostructured resist is UV-exposed and crosslinked directly on the acceptor roll. The acceptor roll with the stitched and recombined stamp patterns is ready to be used as a large-area roll mold for roll-based imprinting. A system for this purpose was designed, and its operation was demonstrated taking the example of an acceptor roll of 1 m length and 250 mm diameter, which was covered by 56 patterned areas. Such a system represents an elegant and efficient tool to recombine small patterned areas directly on a large roll mold and opens the way for large-area roll-based processing.

Abstract: The smooth surface structure of intracortical microelectrodes implanted within the nanometer‐scale architecture of brain tissue may contribute to the foreign body response. Here, the neuroinflammatory response to nanopatterning surface grooves etched directly on nonfunctional Michigan‐style microelectrodes is explored. Rats implanted with nanopatterned silicon microelectrodes are compared to smooth control implants to observe the effects the grooves have on neuroinflammation. Histology and real‐time PCR at 2 and 4 weeks postimplantation quantify glial cell reactivity and activation, inflammation, oxidative stress, and neuronal survival. Histological observations of glial cells and blood–brain barrier permeability do not show appreciable differences between the nanopatterned and control implants. However, silicon microelectrodes with nanopatterned grooves have more high mobility group box 1 (HMGB1) gene expression at 2 weeks and less nitric oxide synthase (NOS2) gene expression at 4 weeks compared to control surfaces. Control samples have increased NOS2, HMGB1, and tumor necrosis factor gene expression from 2 to 4 weeks, while nanopatterned implants have significant decrease in CD14 gene expression from 2 to 4 weeks. Collectively the results indicate that etching nanopatterned grooves do not reduce histological markers of neuroinflammation compared to control implants, but gene expression results encourage further investigation. [ABSTRACT FROM AUTHOR]

Friction and wear become significant at small scale lengths, particularly in MEMS/NEMS. Nanopatterns are regarded as a potential approach to solve these problems. In this paper, we investigated the friction behavior of nanopatterned silicon surfaces with a periodical rectangular groove array in dry and wear-less single-asperity contact at the nanoscale using molecular dynamics simulations. The synchronous and periodic oscillations of the normal load and friction force with the sliding distance were determined at frequencies defined by the nanopattern period. The linear load dependence of the friction force is always observed for the nanopatterned surface and is independent of the nanopattern geometry. We show that the linear friction law is a formal Amontons' friction law, while the significant linear dependence of the friction force-versus-real contact area and real contact area-versus-normal load captures the general features of the nanoscale friction for the nanopatterned surface. Interestingly, the nanopattern increases the friction force at the nanoscale, and the desired friction reduction is also observed. The enlargement and reduction of the friction critically depended on the nanopattern period rather than the area ratio. Our simulation results reveal that the nanopattern can modulate the friction behavior at the nanoscale from the friction signal to the friction law and to the value of the friction force. Thus, elaborate nanopatterning is an effective strategy for tuning the friction behavior at the nanoscale. [ABSTRACT FROM AUTHOR]

This study presents the characterization and antibacterial activity of nanostructured Si by plasma treatment method using a tetrafluoromethane (CF 4 ) and hydrogen (H 2 ) mixture. Nanostructured-Si is a synthetic nanomaterial that contains high aspect ratio nanoprotrusions on its surface, produced through a reactive-ion etching process. We have shown that the nanoprotrusions on the surfaces produce a mechanical bactericidal effect. Nanostructured-Si exhibited notable activity against three different microorganisms: Gram-negative ( Escherichia coli ), Gram-positive ( Staphylococcus aureus ) and spore-forming bacteria ( Bacillus cereus ) producing a > 5 log 10 reduction after 24 h of incubation. Scanning electron microscopy was used to analysis the structure and morphology character of different surfaces evidencing the physical bactericidal activity of the Nanostructured-Si. These results provide excellent prospects for the development of a new generation of antibacterial surfaces. [ABSTRACT FROM AUTHOR]

[Display omitted] • Selectivity during Ru area-selective deposition on nanopatterns was determined by a single non-destructive measurement. • Accumulation of Ru near pattern edges influences selectivity on different nanopattern geometries. • Uniformity of Ru area-selective deposition was assessed on 300 mm nanopatterned wafers. • Area-selective deposition cycles with passivation, deposition and short etch are preferred over passivation and deposition. Area-selective deposition (ASD) is a possible enabler for the fabrication of various future semiconductor devices. However, it remains challenging to characterize and optimize ASD processes in patterns with nanoscale dimensions, as required for semiconductor device applications. Therefore, we study Ru ASD on different types of nanopatterns on 300 mm-wafers and assess the role of the pattern geometry and density on selectivity. As selectivity is often improved by means of passivation-deposition-etch cycles, we investigate an ASD cycle consisting of passivation by (N,N-dimethylamino)trimethylsilane, deposition by (ethylbenzyl)(1-ethyl-1,4-cyclohexadienyl)Ru/O 2 atomic layer deposition (ALD) and an O/Cl plasma etch. On line-space patterns with a 32 nm critical dimension, the passivation-deposition-etch cycle yields a lower defectivity level than the passivation-deposition approach for a given Ru ASD thickness. The comparison of Ru ASD on line-space and hole nanopatterns reveals the pattern-dependent selectivity, that is explained by accumulation of Ru nanoparticles at pattern edges. 300 mm-wafer uniformity is also investigated and related to reactor design. The investigation of ASD on nanopatterned 300 mm-wafers is enabled by ASD-specific developments of X-ray photoelectron spectroscopy, optical critical dimension scatterometry, and scanning electron microscopy. This research highlights the possibilities and challenges in developing ASD processes in an industrial setting. [ABSTRACT FROM AUTHOR]

Extracellular matrix remodeling plays a pivotal role during mesenchyme patterning into different lineages. Tension exerted from cell membrane receptors bound to extracellular matrix ligands is transmitted by the cytoskeleton to the cell nucleus inducing gene expression. Here, we used dendrimer-based arginine−glycine−aspartic acid (RGD) uneven nanopatterns, which allow the control of local surface adhesiveness at the nanoscale, to unveil the adhesive requirements of mesenchymal tenogenic and osteogenic commitments. Cell response was found to depend on the tension resulting from cell−substrate interactions, which affects nuclear morphology and is regulated by focal adhesion size and distribution.

Cell membrane receptors bind to extracellular ligands, triggering intracellular signal transduction pathways that result in specific cell function. Some receptors require to be associated forming clusters for effective signaling. Increasing evidences suggest that receptor clustering is subjected to spatially controlled ligand distribution at the nanoscale. Herein we present a method to produce in an easy, straightforward process, nanopatterns of biomolecular ligands to study ligand–receptor processes involving multivalent interactions. We based our platform in self-assembled diblock copolymers composed of poly(styrene) (PS) and poly(methyl methacrylate) (PMMA) that form PMMA nanodomains in a closed-packed hexagonal arrangement. Upon PMMA selective functionalization, biomolecular nanopatterns over large areas are produced. Nanopattern size and spacing can be controlled by the composition of the block-copolymer selected. Nanopatterns of cell adhesive peptides of different size and spacing were produced, and their impact in integrin receptor clustering and the formation of cell focal adhesions was studied. Cells on ligand nanopatterns showed an increased number of focal contacts, which were, in turn, more matured than those found in cells cultured on randomly presenting ligands. These findings suggest that our methodology is a suitable, versatile tool to study and control receptor clustering signaling and downstream cell behavior through a surface-based ligand patterning technique.

Recently, high-resolution patterned metal oxide semiconductors (MOS) have gained considerable attention for enhanced gas sensing performance due to their polycrystalline nature, ultrasmall grain size (~5 nm), patternable properties, and high surface-to-volume ratio. Herein, we significantly enhanced the sensing performance of that patterned MOS by galvanic replacement, which allows for selective functionalization on ultrathin Cu2O nanopatterns. Based on the reduction potential energy difference between the base channel material (Cu2O) and the decorated metal ion (Pt2+), Pt could be selectively and precisely decorated onto the desired area of the Cu2O nanochannel array. Overall, the Pt-decorated Cu2O exhibited 11-fold higher NO2 (100 ppm) sensing sensitivity as compared to the non-decorated sensing channel, the while the channel device with excessive Pt doping showed complete loss of sensing properties.

Invadopodia are proteolytic structures formed by cancer cells. It is not known whether their cellular distribution can be regulated by the organization of the extracellular matrix or the organization of the golgi complex or whether they have an adhesion requirement. Here, we used electron beam lithography to fabricate fibronectin (FN) nanodots with isotropic and gradient micrometer scale spacings on K-casein and laminin backgrounds. Investigating cancer cells cultured on protein nanopatterns, we showed that (i) presence of FN nanodots on a K-casein background decreased percent of cells with neutral invadopodia polarization compared to FN control surfaces; (ii) presence of a gradient of FN nanodots on a K-casein background increased percent of cells with negative invadopodia polarization compared to FN control surfaces; (iii) polarization of the golgi complex was similar to that of invadopodia in agreement with a spatial link; (iv) local adhesion did not necessarily appear to be a prerequisite for invadopodia formation. [ABSTRACT FROM AUTHOR]

A shape-controlled method for the nanoscale patterning of cerium oxide thin films was demonstrated in this work. An ultraviolet-curable precursor-containing resin was newly developed for samarium-doped and undoped cerium oxide films, and ultraviolet nanoimprint lithography was employed for the nanopatterning. Various nanostructure shapes such as lines, circular pillars, and circular holes were fabricated, and a minimum feature width of 45 nm was realized by patterning and subsequently shrinking the structures. The fabricated film was confirmed to be cerium dioxide, both undoped and doped with Sm. The effects of the annealing temperature on the crystallinity of the nanostructure and the controllability of the doping ratio were investigated. We believe that this work will provide a new path for preparing nanostructured cerium oxide for energy applications and a basic platform for analyzing the relationship between the structure and performance of size-controlled nanostructures. [ABSTRACT FROM AUTHOR]

Arginine-glycine-aspartic acid (RGD) dendrimer-based nanopatterns on poly(L-lactic acid) were used as bioactive substrates to evaluate the impact of the RGD local surface density on the chondrogenic induction of adult human mesenchymal stem cells. During chondrogenic commitment, active extracellular matrix (ECM) remodeling takes place, playing an instructive role in the differentiation process. Although three-dimensional environments such as pellet or micromass cultures are commonly used for in vitro chondrogenic differentiation, these cultures are rather limited with respect to their ability to interrogate cells in cell-ECM interactions. In the present study, the nanopatterns of the tunable RGD surface density were obtained as a function of the initial dendrimer concentration. The local RGD surface density was quantified through probability contour plots for the minimum interparticle distance, constructed from the corresponding atomic force microscopy images, and correlated with the cell adhesion and differentiation response. The results revealed that the local RGD surface density at the nanoscale acts as a regulator of chondrogenic commitment, and that intermediate adhesiveness of cells to the substrates favors mesenchymal cell condensation and early chondrogenic differentiation. [ABSTRACT FROM AUTHOR]

In this paper, microphase behavior of an ABC triblock copolymer, polystyrene-block-poly(2-vinylpyridine)-block-poly( ethylene oxide), namely PS- b-P2VP- b-PEO, was systematically studied during spin-coating and solvent vapor annealing based on various parameters, including the types of the solvent, spin speed and thickness. The morphological features and the microdomain location of the different blocks were characterized by atomic force microscope (AFM) and high resolution transmission electron microscopy (HRTEM). With increasing thickness, the order-order transition from nanopores array to the pattern of nanostripes was observed due to microdomain coarsening. These processes of pattern transformation were based on the selectivity of toluene for different blocks and on the contact time between solvent molecules and the three blocks. This work provides different templates for preparation of gold nanoparticle array on silicon wafer, which can be adopted as an active surface-enhanced Raman scattering (SERS) substrate for poly(3-hexylthiophene) (P3HT). [ABSTRACT FROM AUTHOR]

We present a facile and scalable coating method based on controlled airbrushing, which is suitable for conformal resin coating in continuous roll-to-roll (R2R) nanoimprint lithography (NIL) process. By controlling the concentration of UV-curable polymeric resin with mixing the volatile solvent and its airbrushing time, the coated resin film thickness can be readily tuned. After R2R NIL using a flexible nanoscale line pattern (nanograting) mold is conducted upon the airbrushed resin film, a large-area uniform nanograting pattern is fabricated with controlled residual layer thickness (RLT) based on the initial film thickness. We investigate the faithful airbrushing condition that can reliably create the uniform thin films as well as various nanopatterns with controlled morphologies. Using more diluted resin and shorter airbrushing time can reduce the RLTs favourably for many applications, yet is apt to induce the nanoscale pores and discontinued lines. We also discuss how to further improve the quality and scalability of resin airbrushing and its potential applications particularly requiring high-speed and conformal coating on highly topographic and flexible surfaces. [ABSTRACT FROM AUTHOR]

We fabricated titanium dioxide (TiO2)-silica (SiO2) nanocomposite structures with controlled morphology by a simple synthetic approach using cooperative sol-gel chemistry and block copolymer (BCP) self-assembly. Mixed TiO2-SiO2 sol-gel precursors were blended with amphiphilic poly(styrene-block-ethylene oxide) (PS-b-PEO) BCPs where the precursors were selectively incorporated into the hydrophilic PEO domains. Changing the volumetric ratio of TiO2-SiO2 sol-gel precursor from 5% to 20%, a stepwise structural inversion occurred from nanodot arrays to discrete nanowires. Template free hybrid inorganic nanostructures were produced after the removal of PS-b-PEO by irradiation of UV light. The morphological evolution and photophysical properties were investigated by microscopic studies, UV-visible absorption and photocatalytic properties.

Although metallic materials are widely used in biomedical devices, most of them have no antibacterial property and exhibit corrosion-related problems in physiological environments. This study aimed to develop a biocide-free chitosan coating to inhibit bacterial adhesion and corrosion. First, a chitosan coating fabricated through nanotopography was formed on the surface of carbon steel by using soft imprinting technology. Next, hexanal was grafted onto the chitosan by using a Schiff base reaction. Nanomorphological assessments using scanning electron microscopy, confocal laser scanning microscopy, and cross-sectional transmission electron microscopy confirmed a concave width, depth, and bottom thickness of approximately 666, 242, and 208 nm, respectively. Fourier-transform infrared spectroscopy and nuclear magnetic resonance spectroscopy confirmed that hexanal was successfully grafted to chitosan. Finally, the surface hydrophobic properties, antibacterial adhesion, and electrochemical corrosion resistance of chitosan coatings with and without nanopatterning and hexanal grafting were investigated. The results indicated that the hydrophobic angle of chitosan with both nanopatterning and hexanal grafting exceeded 120° and that the hysteresis angle was only 20°, which may help inhibit the attachment of Staphylococcus aureus and Escherichia coli. During an electrochemical corrosion test, chitosan with both nanopatterning and hexanal grafting exhibited the highest corrosion potential and the lowest corrosion current density, indicating improved corrosion resistance. These results suggest that imparting nanopatterning and alkylation properties to chitosan solves not only the problem of bacterial attachment to bare metal substrates but also the problem of corrosion. [Display omitted] • The chitosan coating has a hydrophobic property via nanotopography and alkylation. • Good antibacterial property of chitosan coating at high concentration inoculation • The chitosan coating slowed down the corrosion of carbon steel. [ABSTRACT FROM AUTHOR]

The development of high-performance volatile organic compound (VOC) sensor based on a p-type metal oxide semiconductor (MOS) is one of the important topics in gas sensor research because of its unique sensing characteristics, namely, rapid recovery kinetics, low temperature dependence, high humidity or thermal stability, and high potential for p-n junction applications. Despite intensive efforts made in this area, the applications of such sensors are hindered because of drawbacks related to the low sensitivity and slow response or long recovery time of p-type MOSs. In this study, the VOC sensing performance of a p-type MOS was significantly enhanced by forming a patterned p-type polycrystalline MOS with an ultrathin, high-aspect-ratio (∼25) structure (∼14 nm thickness) composed of ultrasmall grains (∼5 nm size). A high-resolution polycrystalline p-type MOS nanowire array with a grain size of ∼5 nm was fabricated by secondary sputtering via Ar+ bombardment. Various p-type nanowire arrays of CuO, NiO, and Cr2O3 were easily fabricated by simply changing the sputtering material. The VOC sensor thus fabricated exhibited higher sensitivity (ΔR/Ra = 30 at 1 ppm hexane using NiO channels), as well as faster response or shorter recovery time (∼30 s) than that of previously reported p-type MOS sensors. This result is attributed to the high resolution and small grain size of p-type MOSs, which lead to overlap of fully charged zones; as a result, electrical properties are predominantly determined by surface states. Our new approach may be used as a route for producing high-resolution MOSs with particle sizes of ∼5 nm within a highly ordered, tall nanowire array structure. [ABSTRACT FROM AUTHOR]

A triboelectric nanogenerator (TENG) based on the contact-separation mode can be used as a portable power source to harvest the triboelectrification which arises between contacting films. However, a general challenge is that the charge generation is usually limited. The performance of a TENG can be enhanced by modifying the surface morphologies of the triboelectric materials. In this study, we demonstrate morphologies with line, pillar and hexagonal cone shapes on the surfaces of PDMS and PMMA to enhance the charge production in a TENG. A contact and subsequent separation operation between the two surfaces of triboelectric materials is then carried out to generate the charge. Experiments reveal that the maximum output power, voltage and current density of a TENG with 300-nm hexagonal cone patterns on the contacting surfaces are nearly 22, three and six times greater than a TENG without any patterns, respectively. In addition, the results showed that pillar patterns with a smaller width generate higher output voltage, current and power levels compared to those with larger widths. As a result, the generation of the surface charge density in a TENG is augmented by the creation of nanopatterns on its contacting elements. This result will be applicable to the fabrication of a self-powered nanosystem with high efficiency at a low cost. [ABSTRACT FROM AUTHOR]

Although localized surface plasmon reson-ance (LSPR) transducers can be optically interrogated without the need of light couplers, normally they need tailor-made optical assemblies for signal monitoring. This fact limits the application of LSPR biosensors in laboratories due to lack of specific optical setups. If commercial equipment like common spectrophotometers were suitable for LSPR interrogation, the LSPR technology could be applied more often in detection applications. In this paper, a universal LSPR cuvette has been developed in order to use a commercial spectrophotometer as a real-time biosensor without the need of any extra optical component. By measuring the changes in absorbance at constant wavelength, the equipment provides sensograms where real-time response is monitored. The cuvette, fully compatible with spectrophotometers, is an LSPR flow-cell (volume less than 10 mL) where a gold nanopatterned surface is emplaced as a window. Gold nanopatterns (period 600 nm) based on lines and pillars were simulated, fabricated, measured, and compared. The resolutions of 1.8\cdot 10^-4 and 6.7\cdot 10^-5 refractive index units were found for nanolines and nanopillars, respectively. The label-free detection of an antibody (anti-IgG) was carried out in the LSPR system with a limit of detection of 1.9 nM. The biosensing protocol was rapid and reproducible and allows the reuse of the surface for multiple sample measurements. The achieved analytical features are comparable with other reported LSPR sensors with tailor-made optical setups. These results indicate that the system (LSPR \text cuvette + \text spectrophotometer ) can be a useful analytical tool to biosensing applications. [ABSTRACT FROM PUBLISHER]

Bulk heterojunction (BHJ) films with nanopattern structure have been fabricated using a stamping transfer process with polyurethane acrylate (PUA) replica film based on 3-dimensional colloidal crystals. The uniformly arrayed nanostructure of the PUA film was investigated by SEM analysis. Compared to the organic photovoltaic cells wtih plain BHJ of poly(3-hexylthiophene-2,5-diyl) (P3HT) and indene-C bisadduct (ICBA), the device from the nanopatterned BHJ exhibit improved E-field distribution intensity, as assessed using a finite-difference time-domain (FDTD) method. The current density ( J ) and power conversion efficiency (PCE) of the device were respectively increased by up to 27% and 20% due to the enhanced interfacial contact area and plasmonic effect, which can brought about effective light harvesting between the BHJ active layer and cathode. Through a simple low-temperature transfer process using a PUA mold, we can fabricate reproducible nanopatterned BHJ devices that have improved light absorption within the active layer of the devices. [ABSTRACT FROM AUTHOR]

We studied podosome formation and development in activated monocytes (THP1) at ICAM1 (intercellular adhesion molecule 1) nanopatterns of circular and ring-shaped domains and show that cellular binding to a preclustered ICAM1 nanopattern requires ligand patches of at least 200 nm (corresponding to 14 or more integrins). Podosome-like adhesion formation depends on the structure of the ligand pattern under the developing podosome with larger single domains promoting adhesion in a single patch and multiple smaller domains allowing podosome formation by integration of at least 2 smaller domains on either side of the podosome core. Maturation to rosette structures and recruitment of proteases were only observed with macroscopic ICAM1 presentation. [ABSTRACT FROM AUTHOR]

The performance of organic solar cell is greatly determined by the nanoscale heterojunction morphology, and finding a practical method to achieve advantageous nanostructure remains a challenge. We demonstrate here that ordered bulk heterojunction (OBHJ) solar cell can be fabricated assisted by a simple, cost-effective nanoimprinting lithography method using patterned silk fibroin film mold at room temperature. The P3HT nanogratings were achieved by nanoimprinting lithography (NIL) process, and phenyl-C61-butyric acid methyl ester (PCBM) was spin-coated on the top of P3HT nanogratings. The conducting capacity of P3HT nanograting film has little difference compared with the unimprinted film in the vertical direction, due to the same edge-on chain alignment. However, it can be found that the fabrication of OBHJ nanostructure using room temperature NIL technique with patterned silk fibroin mold is able to promote optical absorption, interfacial area, and bicontinuous pathway. Therefore, the ordered heterojunction morphology plays an important part in improving device performance due to efficient exciton diffusion, dissociation, and reducing charge recombination rate. [ABSTRACT FROM AUTHOR]

Miniaturization of the sensor active areas to length scales of the order of the analyte has been sought as means to reduce device footprints, and to capitalize on the novel optical and electronic enhancements that arise at this scale. However, little is known on what to expect of the sensor behaviour if the sensor footprints are shrunk to the dimensions of the order of analyte themselves. Our results demonstrate the densities and kinetics of adsorption of analyte to significantly increase with decrease in the sensor footprints to dimensions of the order of few multiples of analyte dimensions. Such increase is found to be generic, irrespective of the nature of interactions that drive adsorption, exhibiting qualitative similarity for electrostatic adsorption of nanoparticles, chemisorption of primary oligonucleotides, or complementary base pairing with target nucleotides. The carryover of these benefits onto a macroscopic sensor however requires high density nanopatterns exhibiting significant fill factors withtout compromising inter-feature isolation. The impact of feature dimensions, pattern fill factors, analyte concentrations, presence of convective flow, or the density of receptors are investigated using quantitative and real-time measurements of the nanostructure-analyte interactions using nanopatterned QCM sensors. The results indicate significant opportunities for rational design of nanopatterned macroscopic sensors, as well as nanoscopic sensors with sensor active areas of the order of analyte dimensions, e.g., electromagnetic hot-spots, or nanowire sensors. • Miniaturizing sensor active areas to the order of analyte strongly impacts adsorption. • Nanopatterns profoundly enhance density and kinetics of adsorption. • Adsorption enhancement is qualitatively similar for nanoparticles or oligonucleic acids. • Nanopatterns on QCM sensors measure nanostructure-analyte interactions. • Nanopatterns with high geometric control prepared by molecular self-assembly. [ABSTRACT FROM AUTHOR]