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To deeply investigate the pivotal roles of Auxin (mainly indole-3-acetic acid, IAA), it is essential to obtain the contents of IAA in different locations of plants. It is still a challenge to quantify the levels of IAA in different sites of Arabidopsis thaliana leaves because of the small sizes. In this study, a simple paper-based electroanalytical device coupled with microsampling was used to differentiate the IAA amounts in different locations of Arabidopsis thaliana leaves. For the micro real sampling, the different areas of the thaliana leaves were retrieved by the Harris Uni-Core TM Miltex® with diameters: 1.0, 1.5, 2.5, 3.5, and 4.0 mm. The results showed that the contents of IAA can be detected from circle samples with the diameter from 1.0 to 4.0 mm. With 1.5 mm diameter sampling, the levels of IAA could be obtained in different sites of cotyledon and the first true leaf of Arabidopsis thaliana at the seedling stage. Our results suggested that the highest IAA levels were in the near petiole and lowest IAA levels in the leaf tip, which roughly agreed with those in tobacco leaves based on HPLC-MS reported before. In addition, the microsampling has a minor impact on the growth of Arabidopsis thaliana in the following especially for circle samples with the diameter 1.5 mm. This study revealed the potential application of microsampling coupled with a simple paper-based electroanalytical device for the mapping study of IAA in small plants or small tissue samples.

We report a simple and cost-effective paper-based and colorimetric dual-mode detection of As(iii) and Pb(ii) based on glucose-functionalized gold nanoparticles under optimized conditions. The paper-based detection of As(iii) and Pb(ii) is based on the change in the signal intensity of AuNPs/Glu fabricated on a paper substrate after the deposition of the analyte using a smartphone, followed by processing with the ImageJ software. The colorimetric method is based on the change in the color and the red shift of the localized surface plasmon resonance (LSPR) absorption band of AuNPs/Glu in the region of 200-800 nm. The red shift (Δ

Silver nanoparticle (AgNP)-decorated cellulose filter paper (FP), a low-cost point-of-use (POU) water disinfection system, can supply affordable and safe drinking water for people in desperate need, especially in rural areas in developing countries. However, owing to the unstable immobilization of AgNPs, silver can leach into the treated drinking water from the FP and exceed the World Health Organization (WHO) drinking water limit (

A cellulose/reduced graphene oxide/carbon fibers paper electrode exhibits high electrocatalytic performance for the oxidation of amitrole, showing high sensitivity, wide linear range and low detection limit.

This paper describes a method to fabricate microfluidic paper-based analytical devices (μPADs) using a toner laser printer. Multiple methods have been reported for the fabrication of μPADs for point-of-care diagnostics and environmental monitoring. Despite successful demonstrations, however, existing fabrication methods depend on particular printers, in-house instruments, and synthetic materials. In particular, recent discontinuation of the solid wax printer has made it difficult to fabricate μPADs with readily available instruments. Herein we reported the fabrication of μPADs using the most widely available type of printer: a toner laser printer. Heating of printed toner at 200 °C allowed the printed toner to reflow, and the spreading of the hydrophobic polymer through the filter paper was characterized. Using the developed μPADs, we conducted model colorimetric assays for glucose and bovine serum albumin (BSA). We found that heating of filter paper at 200 °C for 60 min caused the pyrolysis of cellulose in the paper. The pyrolysis resulted in the formation of aldehydes that could interfere with molecular assays involving redox reactions. To overcome this problem, we confirmed that the removal of the aldehyde could be readily achieved by washing the μPADs with aqueous bleach. Overall, the developed fabrication method should be compatible with most toner laser printers and will make μPADs accessible in resource-limited circumstances.

Herein, we report a KBr-impregnated paper substrate as a sample probe to enhance the attenuated total reflection-Fourier transform infrared (ATR-FTIR) signal strength of anionic surfactants (AS) and non-ionic surfactants (NS) in an aqueous solution. The mechanism for the sensing of AS and NS is based on the strong interaction of surfactants with the silicate groups (SiO44−) of the KBr-impregnated paper substrate. The role of SiO44− on the surface of the paper is to enhance the adsorption of AS and NS, resulting in improved IR signal intensities for the target analytes. The improved signal intensity at 1253 cm−1 (SO42−, symmetric stretching) for AS and 1114 cm−1 (C–O–C, stretching vibration) for NS were selected for quantification. SEM-EDX was employed to determine the elemental compositions of pre- and post-adsorbed AS and NS on glass fibre filter paper (GFF). The linear range for the determination of AS and NS was 10–100 μg L−1 with a method detection limit (MDL) of 4 μg L−1 and method quantification limit (MQL) of 12 μg L−1. The good relative recovery of 71.4–109.7% and the interference studies showed the selectivity of the method for the determination of AS and NS in environmental water and commodity samples. The advantages of this method include its cost-effectiveness, enhanced sensitivity, disposability and accessibility of the paper substrate.

Several studies have been conducted on textile-based TENGs (T-TENGs) with high performance and wearability, which can efficiently harvest energy based on human body motions. STENG is a self-powered device capable of supplying power to small and portable electronic devices.

One of the cardiac biomarkers, myoglobin (Mb), is important in the rapid identification of cardio-vascular disorders.

In this research, we demonstrate a facile approach for the synthesis of a graphite-analogous layer-by-layer heterostructured CuO/ZnO/carbon paper using a graphene oxide paper as a sacrificial template. Cu2+ and Zn2+ were inserted into the interlayer of graphene oxide papers via physical absorption and electrostatic effects and then, the Mn+-graphene oxide paper was annealed in air to generate 2D nanoporous CuO/ZnO nanosheets. Due to the graphene oxide template, the structure of the obtained CuO/ZnO nanosheets with an average size of ∼50 nm was duplicated from the graphene oxide paper, which displayed a layer-by-layer structure on the microscale. The papers composed of nanosheets had an average pore size of ∼10 nm. Moreover, the as-prepared CuO-ZnO papers displayed high hybridization on the nanoscale. More importantly, the thickness of the single-layer CuO/ZnO nanosheet was about 2 nm (3-4 layer atom thickness). The as-synthesized nano-hybrid material with a high specific surface area and conjunct bimodal pores could play key roles for providing a shorter diffusion path and rapid electrolyte transport, which could further facilitate electrochemical reactions by providing more active sites. As an electrode material, it displayed high performances as a non-enzymatic sensor for the detection of glucose with a low potential (0.3 V vs. SCE), high sensitivity (3.85 mA mM-1 cm-2), wide linear range (5 μM to 3.325 mM), and low detection limit of 0.5 μM.

Nowadays quantitative chemical analysis is usually costly, instrument-dependent, and time-consuming, which limits its implementation for remote locations and resource-limited regions. Inspired by the ancient papercutting art (kirigami), we herein introduce a novel cut-and-paste protocol to fabricate 3D microfluidic paper-based analytical devices (μPADs) that are suitable for on-site quantitative assay applications. The preparation of the device is fast, simple, and independent of any lithographic devices or masks. Particularly designed reaction “channels” were pre-cut from a piece of filter paper, then assembled back to the silanized, superhydrophobic paper pads. The different layers of the device were assembled using a chemically-inert adhesive spray. The fabricated device has high efficiency of liquid handling (up to 60 times faster than conventional methods) and it is particularly inexpensive. Beyond the benchtop fabrication advantage, in conjunction with a custom mobile app developed for colorimetric analysis, we were able to quantify representative environmental contaminants (i.e., the amount of Cr(VI) and nitrite ions) in various water samples with the cut-and-paste μPADs (namely kPADs). Their detection limits (0.7 μg mL−1 for Cr(VI) and 0.4 μg mL−1 for nitrite ions, respectively) are comparable with conventional spectrophotometric methods, which confirm the potential of kPADs for on-site environmental/sanitary monitoring and food toxin pre-screening.

Free-standing graphene-based composite paper electrodes with various active materials have attracted tremendous interest for next-generation lithium-ion batteries (LIBs) due to advantages such as their light weight, excellent mechanical flexibility, and superior electrochemical performance. However, despite its high theoretical energy density, SnS2 is rather difficult to composite with the graphene paper, because conventional reduction procedures for graphene oxide (GO) induce either decomposition or oxidation of SnS2. Herein, a novel solid/gas two-phase interface hydrothermal process is reported to fabricate flexible free-standing SnS2/graphene nanocomposite papers (SGP) assisted by a reducing and stabilizing agent thioacetamide aqueous solution. Such hydrothermal process not only successfully reduces SnS2/graphene oxide paper (SGOP) to SGP, but more importantly, keeps intact the paper configuration as well as the phase stability of SnS2. The as-prepared SGP electrode exhibits high reversible discharge capacity, outstanding cyclic stability and rate capability, which can be attributed to the synergistic effect of the conductive and flexible graphene matrix for accommodation of the volumetric changes of SnS2 upon cycling and the planar SnS2 nanospacers between the graphene layers introducing nanopores for penetration of electrolyte and inhibition of graphene nanosheets restacking. This report demonstrates a new strategy for more active materials with promising lithium storage properties joining the flexible graphene-based paper electrode family.

Wearable electrochemical sensors have attracted tremendous attention in recent years. Here, a three-dimensional paper-based microfluidic electrochemical integrated device (3D-PMED) was demonstrated for real-time monitoring of sweat metabolites. The 3D-PMED was fabricated by wax screen-printing patterns on cellulose paper and then folding the pre-patterned paper four times to form five stacked layers: the sweat collector, vertical channel, transverse channel, electrode layer and sweat evaporator. A sweat monitoring device was realized by integrating a screen-printed glucose sensor on polyethylene terephthalate (PET) substrate with the fabricated 3D-PMED. The sweat flow process in 3D-PMED was modelled with red ink to demonstrate the capability of collecting, analyzing and evaporating sweat, due to the capillary action of filter paper and hydrophobicity of wax. The glucose sensor was designed with a high sensitivity (35.7 μA mM−1 cm−2) and low detection limit (5 μM), considering the low concentration of glucose in sweat. An on-body experiment was carried out to validate the practicability of the three-dimensional sweat monitoring device. Such a 3D-PMED can be readily expanded for the simultaneous monitoring of alternative sweat electrolytes and metabolites.

Free-standing graphene (FSG) paper plays a vital role in a wide variety of applications as an electrode material. Specifically, the electrical properties of FSG are the most important factor affecting its use as an electrode material. Herein, the vacuum filtration technique is utilized to fabricate GO paper, which is then reductively treated with HI. Initially, the electrical conductivity is measured for GO papers with different thicknesses by varying the concentration of GO precursor as well as the reduction time. The FSG paper with a thickness of 3 microns exhibits the lowest sheet resistance and further characterization is carried out to reveal the origin of this enhancement of electrical properties. The low resistance is attributed to its crystalline nature, stacking height (Lc), in-plane crystallite size (La) and defect density (nD). Meanwhile, iodide ions intercalated into the graphene layers act as hole-carriers, and their intercalation is favoured over adsorption at the surface.

In this study, optical microfluidic paper analytical devices (μPADs) for glucose detection from whole blood samples with a small sample volume (2 μL) have been developed on a single paper. In the proposed method, a mushroom-shaped analytical device contains a sample inlet zone and a detection zone. When blood is dripped onto the inlet region of a μPAD, the plasma diffuses to the detection region. The detection region is implanted with a metallic three-dimensional (3D) polymer hydrogel vehicle. The gel vehicle consists of a copper complex that responds to oxygen changes and glucose oxidase (GOx) immobilized inside the gel as a bioactivity preservative. The phosphorescence of the copper complex is enhanced by oxygen consumed by detection of glucose with a limit of detection (S/N = 3) of 0.44 mM, and the total analysis of the sample is completed within 1 min. The validity of the proposed research is demonstrated using control samples and real-world whole blood samples of glucose concentrations ranging from 3 to 200 mM, and the detection results are shown to be in agreement with those obtained using a glucometer. Attaining a simple device for analysing glucose in human whole blood without any pretreatment procedures and having a broad sensing range while consuming a small sample volume remain challenging; thus, our new analytical device is of great interest.

Herein, a new colorimetric paper sensor based on the layer-by-layer assembled multilayers of a cationic surfactant, tetrabutylammonium bromide (TBABr), and an anionic surfactant, sodium dodecyl sulfate (SDS), modified on filter paper was developed for the determination of total antioxidant capacity (TAC). In this study, gallic acid (GA) was used as the antioxidant standard. The fabricated (TBABr/SDS)3/PAD was loaded with Fe3+ ions to obtain Fe3+/(TBABr/SDS)3/PAD, exhibiting high selectivity for the detection of GA when compared with the case of other metal ions. The interaction between GA and the Fe3+/(TBABr/SDS)3/PAD sensor occurred rapidly, and the colorimetric paper sensor changed from yellow to purple immediately. The quantitative detection of GA was enabled by taking an image using an ordinary smartphone and applying the ImageJ software based on the change in color. Under optimum conditions, a linear response was obtained between the change in the color of the sensor and the TAC value expressed in terms of gallic acid equivalents. The linear range was from 0.50 μM to 6.50 mM with the detection limit of 0.35 μM. The colorimetric paper sensor was applied to detect the TAC in three kinds of green tea and vegetable samples, which provided the good recoveries of 86.0–109.9%. The proposed sensor is simple, cheap, equipment-free, rapid and environmentally friendly. In addition, the colorimetric sensor Fe3+/(TBABr/SDS)3/PAD has potential applicability for TAC detection in real food samples.

Air filter paper with a high filtration efficiency that can remove small-size pollutant particles and toxic gases is vital for human health and the environment. We report a nanofiltration paper that is based on wood fiber filter paper with good mechanical properties and a three-dimensional network structure. The filter paper was prepared by impregnation with multi-walled carbon nanotubes (MWCNTs) and phenol-formaldehyde (PF). The results showed that MWCNTs were present on the surfaces of the fibers and between the pores, which increased the specific surface area of the fibers and enhanced the effective interception of the particles. The optimum impregnation concentration of the MWCNT was 0.1%. Compared with the cellulose fibers (CFs), the average pore diameter of the 0.1% MWCNT–CF filter paper was reduced by 8.05%, the filtration efficiency was increased by 0.64%, and the physical properties were slightly enhanced. After impregnation with PF, the mechanical properties of the air filter paper were significantly enhanced. The PF on the fiber surfaces and at the junction of the fibers covered the MWCNTs. Based on the change in the filter paper properties after impregnation, the optimal filter paper strength index and filtration performance were observed at a solid PF content of 8.4%.

With more and more applications, the mechanical strength of graphene paper (GP) has attracted significant attention in recent years. In this report, GPs were prepared by flow-induced filtration of electrochemical exfoliated graphene sheets. By adjusting the concentration of solution, we found graphene sheets fabricated in 0.1 M K2SO4 have the thinnest average thickness. And by uniaxial in-plane tensile tests operated on a self-developed in situ scanning electron microscopy (SEM) tensile stage, the corresponding GP has the best fracture strength of 192 MPa. This is due to that the thickness decrease of exfoliated graphene will increase the quantity of interlayer crosslinks, thus improving the mechanical properties of GPs. This research may open a new way to obtain high-strength GPs for applications.

The conversion of CO2 into useful chemicals can lead to the production of carbon neutral fuels and reduce greenhouse gas emissions. A key technological challenge necessary to enable such a process is the development of substrates that are active, cost effective, and selective for this reaction. In this regard, the reduction of CO2 via electrochemical means is one of the most attractive alternatives but still requires rather unique electrodes. Considering the potential of this approach, this report describes a one-step methodology for the synthesis of carbon electrodes derived from simple paper and modified with various metallic nanoparticles. Upon a preliminary selection based on the catalytic activity towards CO2 reduction, the electrodes containing CuNPs were further characterized by Raman spectroscopy, and electrical/electrochemical techniques. These electrodes were then applied for the electrochemical reduction of CO2, leading to the formation of compounds with one carbon atom (formic acid), two carbon atoms (ethenone), three carbon atoms (propanoic acid) and four carbon atoms (butanol and butanoic acid). Fil: Gomez, Federico Jose Vicente. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Mendoza. Instituto de Biología Agrícola de Mendoza. Universidad Nacional de Cuyo. Facultad de Ciencias Agrarias. Instituto de Biología Agrícola de Mendoza; Argentina Fil: Chumanov, George. Clemson University; Estados Unidos Fil: Silva, María Fernanda. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Mendoza. Instituto de Biología Agrícola de Mendoza. Universidad Nacional de Cuyo. Facultad de Ciencias Agrarias. Instituto de Biología Agrícola de Mendoza; Argentina. Clemson University; Estados Unidos Fil: Garcia, Carlos D.. Clemson University; Estados Unidos

Foodborne pathogens are responsible for hundreds of thousands of deaths around the world each year. Rapid screening of agricultural products for these pathogens is essential to reduce and/or prevent outbreaks and pinpoint contamination sources. Unfortunately, current detection methods are laborious, expensive, time-consuming and require a central laboratory. Therefore, a rapid, sensitive, and field-deployable pathogen-detection assay is needed. We previously developed a colorimetric sandwich immunoassay utilizing immuno-magnetic separation (IMS) and chlorophenol red-β-D-galactopyranoside for Salmonella detection on a paper-based analytical device (μPAD); however, the assay required many sample preparation steps prior to the μPAD as well as laboratory equipment, which decreased user-friendliness for future end-users. As a step towards overcoming these limitations in resource-limited settings, we demonstrate a reusable 3D-printed rotational manifold that couples with disposable μPAD layers for semi-automated reagent delivery, washing, and detection in 65 minutes. After IMS to clean the sample, the manifold performs pipette-free reagent delivery and washing steps in a sequential order with controlled volumes, followed by enzymatic amplification and colorimetric detection using automated image processing to quantify color change. Salmonella was used as the target pathogen in this project and was detected with the manifold in growth media and milk with detection limits of 4.4 × 102 and 6.4 × 102 CFU mL−1 respectively. The manifold increases user friendliness and simplifies immunoassays resulting in a practical product for in-field use and commercialization.

A graphene oxide paper (GOP) was irradiated with 500 keV proton for total fluence of 2 × 1013 cm−2 to 2 × 1015 cm−2 in a ground-based irradiation simulator. The spacing of layer, surface chemical composition, structural defects, thermal conductivity and electrical property of the GOP before and after irradiation was measured. The results indicated that the spacing of layer decreased after irradiation. The ratio of total carbon atom and total oxygen atom increased from 2.40 to 4.31 as well as the sp2 hybridized carbons obviously increased after 2 × 1015 cm−2 irradiation. The XPS analysis suggested the occurrence of reduction, and the Raman spectra indicated that the defects were produced after proton irradiation. Furthermore, the thermal conductivity of GOP decreased, and then increased smoothly as the irradiation fluences were increased, and the electrical property showed the similar trend. The change in the thermal and electrical properties for GOP could be attributed to the defects and the removal of oxygen-containing functional groups, which lead to the phonon conduct path and scattering centers changed under proton irradiation. This study could promote the application of GOP in future space expeditions.

Arsenic (As) as a metal ion has long-term toxicity and its presence in water poses a serious threat to the environment and human health. So, rapid and accurate recognition of traces of As is of particular importance in environmental and natural resources. In this study, a fast and sensitive colorimetric method was developed using silver nano prisms (Ag NPrs), cysteine-capped Ag NPrs, and methionine-capped Ag NPrs for accurate detection of arsenic-based on transforming the morphology of silver nanoparticles (AgNPs). The generated Ag atoms from the redox reaction of silver nitrate and As(iii) were deposited on the surface of Ag NPrs and their morphology changed to a circle. The morphological changes resulted in a change in the color of the nanoparticles from blue to purple, which was detectable by the naked eye. The rate of change was proportional to the concentration of arsenic. The changes were also confirmed using UV-Vis absorption spectra and showed a linear relationship between the change in adsorption peak and the concentration of arsenic in the range of 0.0005 to 1 ppm with a lower limit of quantification (LLOQ) of 0.0005 ppm. The proposed probes were successfully used to determine the amount of As(iii) in human urine samples. In addition, modified microfluidic substrates were fabricated with Ag NPrs, Cys-capped Ag NPrs, and methionine-capped Ag NPrs nanoparticles that are capable of arsenic detection in the long-time and can be used in the development of on-site As(iii) detection kits. In addition, silver nanowires (AgNWs) were used as a probe to detect arsenic, but good results were not obtained in human urine specimens and paper microfluidic platforms. In this study, for the first time, AgNPs were developed for optical colorimetric detection of arsenic using paper-based microfluidics. Ag NPrs performed best in both optical and colorimetric techniques. Therefore, they can be a promising option for the development of sensitive, inexpensive, and portable tools in the environmental and biomedical diagnosis of As(iii).

Carboxylated cellulose nanocrystal whisker (C-CNC) and chitosan (CTS) were used to blend and reinforce anionic starch (AS) to prepare a paper-coating agent, AS-CNC-CTS, which was coated on one side of the surface of offset paper and kraft paper. Scanning electron microscopy (SEM) showed that the AS-CNC-CTS coating agent can form a layer of dense film on the paper surface and fill the surface pores. And also, owing to the irregular pore structure of the paper, the coating agent penetrated the pores to different degrees. The structure and mechanical properties of the coated paper were analyzed using a Fourier infrared spectrometer, computer-controlled paper-tearing tester and paper tensile strength test machine. Peptide bonding interaction between C-CNC and CTS, hydrogen bonding between C-CNC and CTS, C-CNC and AS, C-CNC and paper fibers, as well as electrostatic attraction between acidified CTS and AS were found. Moreover, the coating agent also had good antibacterial properties, and no mold spots formed throughout the observation period (60d). The gas-barrier properties and oil resistance of the coated paper were further studied using a paper and paperboard air permeability tester and a paper oil-permeability tester. Results showed that the coating agent can significantly enhance the gas-barrier properties and oil resistance of paper. Furthermore, with increased C-CNC content in the coating agent, its barrier properties gradually increased. This finding indicated that the coating preparation had no effect on the crystal region of C-CNC.

A new platform has been developed for environmentally friendly C–C cross-coupling reactions via filtration of reactants through a portable Pd(II)-salen complex-embedded filter paper.

Two-dimensional vertically aligned Bi2O3 nanosheets over carbon paper (CP) were prepared via an in situ growth approach.

In search for more effective and eco-friendly adsorbent materials, this study comprehensively investigated Cd2+ adsorption onto phosphorylated cellulose paper (PCP).

Flexible energy storage devices have received great interest due to the increasing demand for wearable and flexible electronic devices with high-power energy sources. Herein, a novel hybrid flexible hexagonal boron nitride integrated graphene paper (BN/GrP) is fabricated from 2D hexagonal boron nitride (h-BN) nanosheets integrated with graphene sheets dispersion via a simple vacuum filtration method. FE-SEM indicated that layered graphene nanosheets tightly confined with h-BN nanosheets. Further, the Raman spectroscopy confirmed successful integration of BN with graphene. As-prepared BN/GrP free-standing flexible conductive paper showed high electrical conductivity of 5.36 × 104 S m−1 with the sheet resistance of 8.87 Ω sq−1. However, after 1000 continuous bending cycles, the BN/GrP sheet resistance increased just about 8.7% which indicated good flexibility of the paper. Furthermore, as-prepared BN/GrP showed excellent specific capacitance of 321.95 F g−1 at current density of 0.5 A g−1. In addition, the power and energy densities were obtained as 3588.3 W kg−1, and 44.7 W h kg−1, respectively. The stability of the prepared flexible electrode was tested in galvanostatic charge/discharge cycles, where the results showed the 96.3% retention even after 6000 cycles. These results exhibited that the proposed BN/GrP may be useful to prepare flexible energy-storage systems.

Efficient and low-cost oil/water separation remains a great challenge for industries. Natural cellulose-based filter paper, because of its abundance, low cost, biodegradability and excellent chemical stability, has been developed as an oil/water separator in recent years. In the present study, a superhydrophilic and underwater superoleophobic filter paper is successfully prepared by an aldol condensation reaction to crosslink glucose molecules with filter paper. The prepared filter paper is characterized by IR-spectroscopy, SEM spectroscopy and wettability measurements, and it has high underwater oil contact angles of over 162° for hexane, toluene and petroleum ether. It is shown that the modified filter paper has high water recovery from various oil/water mixtures, not only in a gentle environment but also in acidic, alkaline, and salty environments and at different temperatures. Moreover, the glucose modified filter paper shows excellent oil/water emulsion separation efficiency (>99%) and good recycling performance. The preparation is economic and could be easily scaled up, suggesting its great potential for large-scale industrial applications.

Designing and controlling spontaneous imbibition is becoming a key requirement for advanced devices, presenting a substantial scientific and engineering challenge. Here we describe an approach that allows directional imbibition into designed geometries. A set of custom domains based on paper microfluidics mold nano-imbibition in user-Defined shapes such as curvatures, corners, and vertices into mesoporous thin films; enabling localized chemical reactions with programmable designs. The method also achieves nano-size filtration, allows the generation and delivery of reagent gradients in a nanofluidic fashion, and it can be used as a reactor for the synthesis of patterned metallic nanoparticle arrays. By using this easyto-build hybrid platform, users can create functional nanofluidic domains in custom geometries and perform spatially shaped chemistry. The ability to integrate mesoporous nanofluidic generation and paper-based microfluidics has made the hybrid system an exciting candidate for versatile nanoflow applications. Fil: Mercuri, Magalí. Comisión Nacional de Energía Atómica; Argentina Fil: Gimenez, Rocio Aldana. Comisión Nacional de Energía Atómica; Argentina. Consejo Nacional de Investigaciones Científicas y Técnicas; Argentina Fil: Berli, Claudio Luis Alberto. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Santa Fe. Instituto de Desarrollo Tecnológico para la Industria Química. Universidad Nacional del Litoral. Instituto de Desarrollo Tecnológico para la Industria Química; Argentina Fil: Bellino, Martin Gonzalo. Consejo Nacional de Investigaciones Científicas y Técnicas; Argentina. Comisión Nacional de Energía Atómica; Argentina

This paper demonstrates a facile strategy for the development of nanosilver decorated polyaniline coated (PAg) paper-based electrodes for the fabrication of solid-state symmetrical supercapacitors. PAg based printing paper was developed through a two-step process involving initial silver nucleation and growth on the paper followed by aniline polymerization. The developed electrically conductive paper exhibited a highly porous structure and excellent mechanical stability. Further symmetrical supercapacitors having the configuration PAg/electrolyte/PAg were fabricated and evaluated for electrochemical performance such as specific capacitance (483 F g−1 and 613 F g−1 in aqueous 1 M H2SO4 and PVA–H2SO4 gel electrolytes respectively), energy density (69.56 and 85.13 W h kg−1), and power density (243.44 and 405.375 W kg−1) and cycling stability (90% of its capacitance retention even after 2000 cycles), exhibiting excellent performance under various bending conditions. All these exciting results suggest that the developed paper-based flexible solid-state energy device can serve as an efficient, sustainable, and low-cost energy storage system for portable microelectronic devices which are expected to revolutionize the perception of energy-storage devices in the electronics industry.

Geographical indications have gained increasing importance as a powerful marketing tool for highly valuable products especially foods. In this study, a unique and synergistic combination of chemical reaction arrays on paper and chemometric analysis was used to uncover geographical indication of turmerics, an important food ingredient in several cultures. The key to effective differentiation was based on the subtle differences in the compositions of compounds found in each sample, mainly curcumin and derivatives. When these compounds reacted with various reagents in the form of paper arrays, different optical and fluorescence profiles were generated, which can then be exploited by chemometrics. As a result, our strategy could provide up to 94% prediction accuracy without the need for any sophisticated instruments.

SEM images of TiO2(R) nanorods and TiO2(A) nanoflakes grown on CFP. And the corresponding catalytic performances under solely visible light, solely ultrasonic field, and the combined conditions of visible light and ultrasonic field.