Nanoparticle Hybrid Films Research Articles

A Tunable Threshold Colorimetric DNA Logic Gate for Intuitive Assessment of Chemical Contaminant Exceedance.

Current molecular logic gates are predominantly focused on the qualitative assessment of target presence, which has certain limitations in scenarios requiring quantitative assessment, such as chemical contaminant monitoring. To bridge this gap, we have developed a novel DNA logic gate featuring a tunable threshold, specifically tailored to the limits of contaminants. At the core of this logic gate is a DNA-gold nanoparticle (AuNP) hybrid film that incorporates aptamer sequences to selectively bind to acetamiprid (ACE) and atrazine (ATR). Upon interaction with these contaminants, the film degrades, releasing AuNPs that, in the presence of Hg2+, catalyze the oxidation of TMB, resulting in a visible blue coloration on test paper. This aptamer-enabled process effectively establishes an OR logic gate, with ACE and ATR as inputs and the appearance of blue color as the output. A key innovation of our system is its tunable input threshold. By adjusting the concentration of Hg2+, we can fine-tune the color mutation points to match the input threshold to predefined limits, such as Maximum Residue Limits (MRLs). This alignment allows semiquantitative assessment of contaminant levels, providing intuitive visual feedback of contaminant exceedance. Validation experiments with spiked samples confirm its accuracy and reliability by closely matching HPLC results. Therefore, our colorimetric DNA logic gate is emerging as a promising tool for easy and semiquantitative monitoring of chemical contaminants across diverse applications.

3D porous graphene/double-walled carbon nanotubes/gold nanoparticles hybrid film for modifying electrochemical electrode

3D porous graphene/carbon nanotubes (Gr/CNTs) hybrid films containing nanoparticles have introduced new possibilities for the development of high-performance electrochemical sensors. Herein, we developed a novel technique for the fabrication of 3D porous graphene/double-walled carbon nanotubes/gold nanoparticles (Gr/DWCNTs/AuNPs) hybrid film on copper foils by using the thermal chemical vapor deposition (CVD) method. On these porous films, DWCNTs, Gr winkles, and a homogeneous AuNP covering were observed. These prepared 3D porous films were then transferred onto the surface of screen-printed electrodes (SPE) to investigate the electrochemical properties by using cyclic voltammetry (CV) technique. Consequently, 3D porous Gr/DWCNTs/AuNPs film modified electrodes exhibited good electrochemical characteristics with an active surface area of 2.76 times higher than that of Gr/DWCNTs film. This is due to the use of AuNPs, which improves the conductivity and surface area of the porous film.

Ultra-thin free-floating carbon nanotube/gold nanoparticle hybrid film prepared with self-assembly protein of α-synuclein

Fabrication of ultra-thin 2D film of carbon nanotubes (CNTs) is achieved by employing a self-assembly protein of α-synuclein (αS). Electron energy loss spectroscopy-transmission electron microscopy and circular dichroism spectroscopy analyses indicate that αS binds to the hydrophobic surface of CNT through its N-terminal region by forming α-helix. 1H-15N heteronuclear single-quantum coherence correlation-nuclear magnetic resonance spectra show that the acidic C-terminus of αS is exposed outward from the CNT surface. Following a slow vacuum filtration of the CNTs complexed with αS through a polycarbonate membrane filter, chloroform is used to unleash the free-floating ultra-thin CNT film from the substrate by causing unique αS-αS interactions of the enhanced anti-parallel β-sheet and α-helix formation. To make a graphically patterned CNT film stable in the free-floating state, gold nanoparticles (AuNPs) encapsulated with αS are employed to generate the αS-mediated CNT/AuNP hybrid film. The CNT-AuNP hybrid pattern is also directly transferred onto a thermo-responsive hydrogel sheet and sandwiched with a passive polymer layer. The resulting triply structure exhibits a shape deformation upon the light exposure. The light-responsive controllable soft material, therefore, has been suggested to be utilized in various areas including not only soft robotics but also human-machine interface by providing stimuli-responsive electroconductive and biocompatible matrix.

A fractional calculus approach to study mechanical relaxations on hybrid films of Fe2O3 nanoparticles and polyvinyl butyral

Polymeric hybrid magnetic films composed of iron oxide nanoparticles and polyvinyl butyral (PVB) were synthesized and studied by a fractional calculus approach. Iron oxide nanoparticles were synthesized in situ from a polymeric hybrid precursor composed of Fe+2 and PVB. These polymeric hybrid magnetic films (PVB/Fe2O3) could carry out functions as actuators or sensors in electronic or mechatronic devices. But, for this purpose, it is required a study of the mechanical relaxation processes displayed in the polymer matrix. The synthesis of iron oxide nanoparticles into PVB was confirmed by HRTEM, XRD and FTIR analysis. The main goal of this work is the study of the effect of iron oxide nanoparticles on the α-relaxation for three PVB samples with a different mass average molar mass. Experimental measurements of the complex modulus, $$\left( {E^{*} = E^{{\prime }} + iE^{\prime \prime } } \right)$$, were obtained by dynamic mechanical analysis (DMA) to identify the α-relaxation for each analyzed sample. Experimental isochronal curves of $$E^{\prime }$$ and $$E^{\prime \prime }$$ were compared with theoretical curves of $$E^{\prime } \left( T \right)$$ and $$E^{\prime \prime } \left( T \right)$$ computed by the fractional Zener model (FZM). An agreement between experiments and fractional model predictions has been achieved. The effect of fractional parameters ($$a$$ and $$b$$) of the FZM was related to molecular motions associated with this relaxation process. The cooperative motions of chains segments were observed in all analyzed samples, and $$b > a$$; this means that when temperature increases, the molecular mobility (energy dissipation) also increases. The matching between PVB matrix and the Fe2O3/PVB films showed that Fe2O3 nanoparticles decreases the molecular mobility of PVB; this effect is more pronounced at temperatures above $$T_{\text{g}}$$.

High-Performance Printed Circuit Board Materials Based on Benzoxazine and Epoxy Blend System

Epoxy resin has been used as an industrial printed circuit board (PCB) material based on its excellent mechanical strength and adhesion property to metal. Silica nanoparticle is employed as a component of hybrid matrix material with epoxy resin due to its superior electrical insulating properties. In this study, benzoxazine, which has attracted attention as a new generation of electrically insulating material and displays extraordinary thermal stability, was investigated as a candidate for PCB material. Benzoxazine and epoxy/silica nanoparticle hybrid films were prepared to achieve low dissipation factor and improved mechanical stability. Two types of benzoxazines, monobenzoxazine, and linear polybenzoxazine were investigated; for monobenzoxazine-based film, the blend with epoxy resin was required to improve physical property because monobenzoxazine film showed brittle nature which limited the application as a film with proper mechanical strength. Films with higher content of monobenzoxazine over epoxy resin resulted in lower dissipation factor around 0.005 frequency/10 GHz, however, the mechanical property of the film did not meet the condition as a PCB material. On the contrary, the linear polybenzoxazine-based film demonstrated enhanced mechanical stability but showed limitations in adhesion to the copper layer probably due to the lack of polar functional groups. To overcome the drawbacks, linear polybenzoxazine and epoxy blend systems were prepared to produce films with good adhesion and excellent electrical insulation property with the dissipation factor around 0.006 frequency/10 GHz.

Enhanced electrocatalytic activity of reduced graphene oxide-Os nanoparticle hybrid films obtained at a liquid/liquid interface

Hybrid films of reduced graphene oxide-osmium nanoparticles (rGO-Os NPs) synthesized at a liquid/liquid interface are explored for their electrocatalytic activity towards the oxidation of rhodamine B (RhB), a popular colourant found in textile industry effluents and a non-permitted food colour. The free-standing nature of the films enables them to be lifted directly on to electrodes without the aid of any binders. The films consist of aggregates of ultra-small Os NPs interspersed with rGO layers. The hybrid film exhibits enhanced RhB oxidation when compared to its constituents arising from the synergic effect between rGO and Os NPs, Os contributing to electrocatalysis and rGO contributing to high surface area and conductance as well as stabilization of Os nanoparticles. The electrochemical sensor based on rGO-Os NP hybrid film on pencil graphite electrode shows a remarkable performance for the quantitative detection of RhB with a linear variation in a wide range of concentrations, 4–1300 ppb (8.3 nM–2.71 μM). The modified electrode presents good stability over more than 6 months, reproducibility and anti-interference capability. The use of developed sensor for adequate detection of RhB in real samples such as food samples and pen markers is also demonstrated.

In situ self-assembly of polarizing chromogen nanofibers catalyzed with hybrid films of gold nanoparticles and cellulose

Hybrid materials of metal nanoparticles and biopolymers with catalytic properties are very promising to be used as detectors in biochemical reactions. In this work, the catalytic properties and relevant in situ self-assembly abilities of hybrid films of gold nanoparticles (GNPs) and cellulose for the oxidation of benign chromogen 3,3′,5,5′-tetramethylbenzidine (TMB) with hydrogen peroxide (H2O2) are revealed for the first time. The peroxidase-like properties of hybrid films are inherited from those of colloidal GNPs and increase with their contents of GNPs. It is discovered that the oxidized products of TMB grow in situ and assemble into rod-like and tumbleweed-like nanofiber assemblies on hybrid films. The rod-like nanofibers show a magnificent polarizing phenomenon under polarized light because of polycrystalline globular nanoparticles inside. The in situ self-assembly of polarizing nanofibers of chromogen catalyzed with hybrid films creates an opportunity for the synthesis of novel organic nanomaterials and the enhanced detection of biochemical products under polarized light.

Scalable Fabrication of Photochemically Reduced Graphene-Based Monolithic Micro-Supercapacitors with Superior Energy and Power Densities.

Micro-supercapacitors (MSCs) hold great promise as highly competitive miniaturized power sources satisfying the increased demand of smart integrated electronics. However, single-step scalable fabrication of MSCs with both high energy and power densities is still challenging. Here we demonstrate the scalable fabrication of graphene-based monolithic MSCs with diverse planar geometries and capable of superior integration by photochemical reduction of graphene oxide/TiO2 nanoparticle hybrid films. The resulting MSCs exhibit high volumetric capacitance of 233.0 F cm-3, exceptional flexibility, and remarkable capacity of modular serial and parallel integration in aqueous gel electrolyte. Furthermore, by precisely engineering the interface of electrode with electrolyte, these monolithic MSCs can operate well in a hydrophobic electrolyte of ionic liquid (3.0 V) at a high scan rate of 200 V s-1, two orders of magnitude higher than those of conventional supercapacitors. More notably, the MSCs show landmark volumetric power density of 312 W cm-3 and energy density of 7.7 mWh cm-3, both of which are among the highest values attained for carbon-based MSCs. Therefore, such monolithic MSC devices based on photochemically reduced, compact graphene films possess enormous potential for numerous miniaturized, flexible electronic applications.

Influence of Quantum Dot Concentration on Carrier Transport in ZnO:TiO₂ Nano-Hybrid Photoanodes for Quantum Dot-Sensitized Solar Cells.

Zinc oxide nanowire and titanium dioxide nanoparticle (ZnO:TiO2 NW/NP) hybrid films were utilized as the photoanode layer in quantum dot-sensitized solar cells (QDSSCs). CdSe quantum dots (QDs) with a ZnS passivation layer were deposited on the ZnO:TiO2 NW/NP layer as a photosensitizer by successive ion layer adsorption and reaction (SILAR). Cells were fabricated using a solid-state polymer electrolyte and intensity-modulated photovoltage and photocurrent spectroscopy (IMVS/PS) was carried out to study the electron transport properties of the cell. Increasing the SILAR coating number enhanced the total charge collection efficiency of the cell. The electron transport time constant and diffusion length were found to decrease as more QD layers were added.

Tunnelling conductive hybrid films of gold nanoparticles and cellulose and their applications as electrochemical electrodes

Conductive hybrid films of metal nanoparticles and polymers have practical applications in the fields of sensing, microelectronics and catalysis, etc. Herein, we present the electrochemical availability of tunnelling conductive hybrid films of gold nanoparticles (GNPs) and cellulose. The hybrid films were provided with stable tunnelling conductive properties with 12 nm GNPs of 12.7% (in weight). For the first time, the conductive hybrid films were used as substrates of electrochemical electrodes to load calmodulin (CaM) proteins for sensing of calcium cations. The electrodes of hybrid films with 20 nm GNPs of 46.7% (in weight) exhibited stable electrochemical properties, and showed significant responses to calcium cations with concentrations as low as 10−9 M after being loaded with CaM proteins.

Degradation of pollutant and antibacterial activity of waterborne polyurethane/doped TiO2 nanoparticle hybrid films

The waterborne polyurethane/doped TiO2 nanoparticle hybrid films were prepared. Nd, I doped TiO2 was prepared with a 50 nm particle size firstly. The hybrid film was prepared by mixing doped TiO2 with waterborne polyurethane, followed by heat treatment. The presence and nanometric distribution of doped TiO2 nanoparticles in prepared membranes is evident according to SEM images. The photocatalytic activities of doped TiO2 were significantly enhanced compared with pure TiO2 powders. After the hybrid film fabrication, the photocatalytic activities were almost the same as the pure catalysts with kMB of 0.046. In the antibacterial testing, the hybrid films can inhibit E. coli growth. A significant decrease in membrane fluidity and increase of permeability of E. coli were observed.

Characteristics of novel transparent poly(methyl methacrylate)/silica nanoparticle hybrid film prepared based on entanglement-agglomeration transition mechanism

Using polydisperse poly(methyl methacrylate) (PMMA) and SiO2 nanoparticles with an average particle diameter of ~15 nm, transparent PMMA/SiO2 hybrid films could be fabricated based on the agglomeration mechanism of nanoparticles in the suspension. The calculated distance between the particles in the transparent films was ~30 nm, corresponding to the actual measured value of 31 nm obtained from the small-angle X-ray scattering intensity. Upon heating the transparent hybrid films to 140 °C, above the glass-transition temperature of PMMA, the transmittance of UV light decreased significantly with the heating time for hybrid films with Mw=9.6 × 104 and a critical molecular weight (Mc) of 3 × 104 or greater, at which PMMA chains show effective entanglement. However, for hybrid films with Mw=0.3 × 104 and with the Mc or a lower molecular weight, the initial high transmittance was sustained over the entire wavelength range even after a long period of heating, and no agglomeration of the SiO2 nanoparticles was observed. Such molecular weight dependence was also observed for monodisperse PMMA/SiO2 hybrid films, leading to an examination of the difference in the rates of polymer chain entanglement and disentanglement. The critical molecular weight (Mc), at which the entanglement effect of the PMMA chain occurs is ~3 × 104. When the PMMA molecular weight in the hybrid suspension and film is such that Mc < Mw, such formation of molecular chain entanglements acts as a driving force for the agglomeration of SiO2 particles. In cases in which the PMMA molecular weight in the hybrid suspension and film is such that Mw< Mc, because no effective entanglements are formed, there is no driving force for the agglomeration of the SiO2 nanoparticles.

Electronic Tongue Based on Nanostructured Hybrid Films of Gold Nanoparticles and Phthalocyanines for Milk Analysis

The use of gold nanoparticles combined with other organic and inorganic materials for designing nanostructured films has demonstrated their versatility for various applications, including optoelectronic devices and chemical sensors. In this study, we reported the synthesis and characterization of gold nanoparticles stabilized with poly(allylamine hydrochloride) (Au@PAH NPs), as well as the capability of this material to form multilayer Layer‐by‐Layer (LbL) nanostructured films with metal tetrasulfonated phthalocyanines (MTsPc). Film growth was monitored by UV‐Vis absorption spectroscopy, atomic force microscopy (AFM), and Fourier transform infrared spectroscopy (FTIR). Once LbL films have been applied as active layers in chemical sensors, Au@PAH/MTsPc and PAH/MTsPc LbL films were used in an electronic tongue system for milk analysis regarding fat content. The capacitance data were treated using Principal Component Analysis (PCA), revealing the role played by the gold nanoparticles on the LbL films electrical properties, enabling this kind of system to be used for analyzing complex matrices such as milk without any prior pretreatment.

Construction of hybrid films of silver nanoparticles and polypyridine ruthenium complexes on substrates.

Hybrid films of functional molecules and metal nanoparticles have been considered to be novel photo-functional devices. Here we have successfully constructed hybrid films of silver nanoparticles and ruthenium polypyridine derivatives on substrates. In order to hybridise them on a surface, a self-assembled monolayer method via chemical bond formation and electro-reductive polymerisation (thick layers) via physical attachment have been employed. These methods have the advantage of convenient and reproducible fabrication of complicated hybrid films. Furthermore, it has been clarified that these hybrid films show unique photo-functional behaviours, such as enhanced photocurrent generation.

A facile fabrication of large-scale reduced graphene oxide–silver nanoparticle hybrid film as a highly active surface-enhanced Raman scattering substrate

Larger-scale reduced graphene oxide–silver nanoparticle hybrid film can serve as a novel SERS-active substrate for detecting R6G and MA.

Fabrication of novel nitrogen-doped graphene-hollow AuPd nanoparticle hybrid films for the highly efficient electrocatalytic reduction of H2O2.

Hollow AuPd (hAuPd) alloy nanoparticles (NPs) were prepared through simultaneous reduction of HAuCl4 and Na2PdCl4 using Co NPs as sacrificial template (i.e., reductant). Then, the hAuPd NPs were assembled on nitrogen-doped graphene (NG) to prepare an NG-hAuPd hybrid film. The obtained NG-hAuPd composite showed higher electrocatalytic activity toward the reduction of H2O2, compared with graphene-hAuPd hybrid, NG-solid AuPd hybrid, and hAuPd NPs. The enhanced performance was related to the hollow structure of hAuPd NPs and the synergistic effect between NG and hAuPd NPs. Under optimum conditions, the NG-hAuPd hybrid film showed a linear response to H2O2 in the range of 0.1-20 μM, with a sensitivity of 5095.5 μA mM(-1) cm(-2)and a comparable detection limit of 0.02 μM (S/N = 3). These results demonstrated that the NG-hAuPd composite was a promising electrocatalytic material for constructing sensors, etc.

Electrochemical aptasensor for mucin 1 based on dual signal amplification of poly(o-phenylenediamine) carrier and functionalized carbon nanotubes tracing tag

Mucin 1 (MUC 1), as a most studied mucin, has become a useful marker for identifying breast cancer in the early stages. In this work, a novel method for the determination of MUC 1 in serum was developed based on a sandwich-type electrochemical aptasensor, which combined a dual signal amplification strategy of poly(o-phenylenediamine)–Au nanoparticles (PoPD–AuNPs) hybrid film as carrier and AuNPs functionalized silica/multiwalled carbon nanotubes core–shell nanocomposites (AuNPs/SiO2@MWCNTs) as tracing tag. The PoPD–AuNPs film provides a suitable microenvironment for stabilizing the primary aptamer (Apt) assembly, and the AuNPs/SiO2@MWCNTs enhances the surface area for immobilizing abundant secondary Apts as well as load large amounts of electrochemical probe thionine (Thi). In the presence of MUC 1, the sandwich-type recognition reacted on the aptasensor surface, and the Thi-AuNPs/SiO2@MWCNTs nanoprobes were captured onto the electrode surface to form biocomplex. AuNPs and MWCNTs could facilitate the electron transfer from Thi to the electrode, thus amplifying the detection response. Under the optimized experimental conditions, the proposed sensing strategy provided a wider linear dynamic range over three orders of magnitude with the detection limit down to 1pM. Moreover, the aptasensor demonstrated good precision, acceptable stability and reproducibility.

Thermal degradation of transparent poly(methyl methacrylate)/silica nanoparticle hybrid films

Using thermogravimetric (TG/DTG) analysis, we evaluated the thermal degradation characteristics of transparent poly(methyl methacrylate) (PMMA)/silica nanoparticle hybrid films obtained by well dispersing surface-unmodified silica (SiO2) nanoparticles, of average particle size approximately 15 nm, in poly(methyl methacrylate), of weight-average molecular weight (Mw) 9.6 × 104 as synthesized by radical solution polymerization of methyl methacrylate (MMA). The TG/DTG curve of a secondary aggregated opaque hybrid film, comprising SiO2 nanoparticles of size greater than several hundreds of nanometers, was in substantial agreement with that of pure PMMA. What was surprising, however, was that in the transparent hybrid, weight reduction due to cleavage of head-to-head bonds in PMMA occurring around 200 °C was nearly completely absent, and DTG peaks originating from cleavage of head-to-tail bonds and allylic-position cleavage of terminal vinylidene double bonds increased. These thermal degradation behaviors can be explained by the hypothesis of a specific chemical reaction between tertiary terminal macroradicals produced by cleavage of head-to-head bonds and silanol (SiOH) on the SiO2 nanoparticle surface.

Ultrasensitive enzyme-free electrochemical immunoassay for free thyroxine based on three dimensionally ordered macroporous chitosan–Au nanoparticles hybrid film

The measurement of free thyroxine concentration in serum is considered to be an essential indicator of thyroid function. Here, a novel enzyme-free sandwich electrochemical immunosensor for the detection of FT4 antigen based on the immobilization of primary antibody (Ab1) on three dimensional ordered macroporous chitosan–Au nanoparticles hybrid (3DOM CS–AuNPs) film electrode, and magnetic multiwall carbon nanotubes (MMWCNTs) were used as label of secondary antibody (Ab2). The 3DOM CS–AuNPs film electrode was constructed by one-step electrodeposition of CS–AuNPs composite onto Au electrode with silica opal template. MMWCNTs were prepared by chemical co-precipitation of Fe2+ and Fe3+ salts on carboxylated MWCNTs. Ru(bpy)32+ labeled anti-FT4 (Ru(bpy)32+–Ab2) was covalently attached to MMWCNTs through the formation of amide bond between the carboxylic groups of MWCNTs and the amine groups of antibody. Under the optimal conditions, FT4 was detected in a concentration range from 0.71fgmL−1 to 1.15pgmL−1 with a correlation coefficient of 0.998 and a detection limit of 0.20fgmL−1. Moreover, the immunosensor showed excellent selectivity, good stability, satisfactory reproducibility and regeneration. Importantly, the developed method was used to assay clinical serum specimens, achieving a good relation with those obtained from the commercialized electrochemiluminescent method.

Enhanced light–matter interaction of graphene–gold nanoparticle hybrid films for high-performance SERS detection

We demonstrate enhanced light–matter interactions in graphene–Au nanoparticle hybrid films and the application for high-quality SERS detection.