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Commercialization of photoelectrochemical (PEC) water-splitting devices requires the development of large-area, low-cost photoanodes with high efficiency and photostability. Herein, we address these challenges by using scalable fabrication techniques and porous transport layer (PTLs) electrode supports. We demonstrate the deposition of W-doped BiVO 4 on Ti PTLs using successive-ionic-layer-adsorption-and-reaction methods followed by boron treatment and chemical bath deposition of NiFeOOH co-catalyst. The use of PTLs that facilitate efficient mass and charge transfer allowed the scaling of the photoanodes (100 cm 2 ) while maintaining ~90 % of the performance obtained with 1 cm 2 photoanodes for oxygen evolution reaction, that is, 2.10 mA cm -2 at 1.23 V vs. RHE. This is the highest reported performance to date. Integration with a polycrystalline Si PV cell leads to bias-free water splitting with a stable photocurrent of 208 mA for 6 h and 2.2 % solar-to-hydrogen efficiency. Our findings highlight the importance of photoelectrode design towards scalable PEC device development., (© 2023 The Authors. ChemSusChem published by Wiley-VCH GmbH.)

Textile-based sensors fabricated using the direct-coating method are the appropriate choice to meet the aspects of flexibility, non-invasiveness, and lightness for continuous monitoring of the human body. The characteristics of the sensor substrate are directly influenced by factors such as the type of weave, thread fineness, fabric density, and the type of polymeric constituent fibers. The fabric used as the sensor substrate, fabricated using the direct-coating method, must be capable of retaining the electrode paste solution, which has higher viscosity, on one surface of the fabric to avoid short circuits during the fabrication process. However, during its application, this fabric should allow the easy passage of analyte solutions with low viscosity as much as possible. Hence, an appropriate fabric construction is required to serve as the substrate for textile-based sensors to ensure the success of the fabrication process and the effectiveness of the resulting sensor's performance. The development of the structural design of the fabric to be used as a substrate for non-invasive biosensors with a multilayer concept is carried out by weaving and sewing processes utilizing polyester-viscose fibers. During the production process, variations are applied, such as weft yarn density, the characterization of wetting time, absorption rate, maximum wetted radius, spreading speed, and accumulative one-way transport index. The most suitable fabric for use as a substrate for non-invasive biosensors with a multilayer concept, such as in this research, is a fabric with a weft thread density of 70 strands per inch, along with the addition of an analyte transfer thread configuration.

Graphene oxide (GO) has attracted attention as an excellent membrane material for water treatment and desalination owing to its high mechanical strength, hydrophilicity, and permeability. In this study, composite membranes were prepared by coating GO on various polymeric porous substrates (polyethersulfone, cellulose ester, and polytetrafluoroethylene) using suction filtration and casting methods. The composite membranes were used for dehumidification, that is, water vapor separation in the gas phase. GO layers were successfully prepared via filtration rather than casting, irrespective of the type of polymeric substrate used. The dehumidification composite membranes with a GO layer thickness of less than 100 nm showed a water permeance greater than 1.0 × 10 -6 mol/(m 2 s Pa) and a H 2 O/N 2 separation factor higher than 10 4 at 25 °C and 90-100% humidity. The GO composite membranes were fabricated in a reproducible manner and showed stable performance as a function of time. Furthermore, the membranes maintained high permeance and selectivity at 80°C, indicating that it is useful as a water vapor separation membrane.

3D porous electrodes have been considered as a new paradigm shift for increasing the energy storage of pseudocapacitive micro-supercapacitors for on-chip electronics. However, the conformal deposition of active materials is still challenging when highly porous structures are involved. In this work, we have investigated the atomic layer deposition (ALD) of ruthenium dioxide RuO 2 on porous Au and Pt architectures prepared by hydrogen bubble templated electrodeposition, with area enlargement factors ranging from 400 to 10 000 cm 2 /cm 2 . Using proper ALD conditions, a uniform RuO 2 coverage has been successfully obtained on porous Au, with a specific electrode capacitance of 8.1 mF cm -2 and a specific power of 160 mW cm -2 for a minute amount of active material. This study also shows the importance of the chemical composition and reactivity of the porous substrate for achieving conformal deposition of a ruthenium oxide layer., (© 2022 IOP Publishing Ltd.)

The influence of modifying nanopowders on the spreading and crystallization of a nickel droplet on a porous steel substrate is analyzed. For this purpose, a model has been developed for the spreading of a drop of liquid metal after its high-speed collision with a heated porous substrate. Due to the high impact velocity, the process of metal crystallization is considered after the complete spreading of the drop using the model of heterogeneous nucleation and macroscopic growth of the solid phase, taking into account the size and capillary effects. The influence of the impact velocity and substrate porosity on the thickness and diameter of the formed splat, the penetration depth, and the volume of liquid that penetrated the substrate has been studied. The numerical study of heterogeneous crystallization of a metal drop has made it possible to evaluate the influence of the modifying nanoparticle parameters, the impact velocity, and substrate porosity on the heterogeneous nucleation and on the resulting splat macrostructure., (© 2022 IOP Publishing Ltd.)

A porous substrate plays an important role in constructing a thin-film composite forward osmosis (TFC-FO) membrane. To date, the morphology and performance of TFC-FO membranes are greatly limited by porous substrates, which are commonly fabricated by non-solvent induced phase separation (NIPS) or thermally induced phase separation (TIPS) processes. Herein, a novel TFC-FO membrane has been successfully fabricated by using cellulose triacetate (CTA) porous substrates, which are prepared using a nonsolvent-thermally induced phase separation (N-TIPS) process. The pore structure, permeability, and mechanical properties of CTA porous substrate are carefully investigated via N-TIPS process (CTA N-TIPS ). As compared with those via NIPS and TIPS processes, the CTA N-TIPS substrate shows a smooth surface and a cross section combining interconnected pores and finger-like macropores, resulting in the largest water flux and best mechanical property. After interfacial polymerization, the obtained TFC-FO membranes are characterized in terms of their morphology and intrinsic transport properties. It is found that the TFC-FO membrane supported by CTA N-TIPS substrate presents a thin polyamide film full of nodular and worm-like structure, which endows the FO membrane with high water permeability and selectivity. Moreover, the TFC-FO membrane supported by CTA N-TIPS substrate displays a low internal concentration polarization effect. This work proposes a new insight into preparing TFC-FO membrane with good overall performance.

In vitro intracellular delivery is a fundamental challenge with no widely adopted methods capable of both delivering to millions of cells and controlling that delivery to a high degree of accuracy. One promising method is porous substrate electroporation (PSEP), where cells are cultured on porous substrates and electric fields are used to permeabilize discrete portions of the cell membrane for delivery. A major obstacle to the widespread use of PSEP is a poor understanding of the various impedances that constitute the system, including the impedances of the porous substrate and the cell monolayer, and how these impedances are influenced by experimental parameters. In response, we used impedance measurements to develop an equivalent circuit model that closely mimics the behavior of each of the main components of the PSEP system. This circuit model reveals for the first time the distribution of voltage across the electrode-electrolyte interface impedances, the channels of the porous substrate, the cell monolayer, and the transmembrane potential during PSEP. We applied sample waveforms through our model to understand how waveforms can be improved for future studies. Our model was validated from intracellular delivery of protein using PSEP., (Copyright © 2021 Elsevier B.V. All rights reserved.)

Ion-exchange membranes (IEMs) are a core component that greatly affects the performance of electrochemical energy conversion processes such as reverse electrodialysis (RED) and all-vanadium redox flow battery (VRFB). The IEMs used in electrochemical energy conversion processes require low mass transfer resistance, high permselectivity, excellent durability, and also need to be inexpensive to manufacture. Therefore, in this study, thin-reinforced anion-exchange membranes with excellent physical and chemical stabilities were developed by filling a polyethylene porous substrate with functional monomers, and through in situ polymerization and post-treatments. In particular, the thin-reinforced membranes were made to have a high ion-exchange capacity and a limited degree of swelling at the same time through a double cross-linking reaction. The prepared membranes were shown to possess both strong tensile strength (>120 MPa) and low electrical resistance (<1 Ohm cm 2 ). As a result of applying them to RED and VRFB, the performances were shown to be superior to those of the commercial membrane (AMX, Astom Corp., Japan) in the optimal composition. In addition, the prepared membranes were found to have high oxidation stability, enough for practical applications.

Electrolytic deposition (ELD) and electrophoretic deposition (EPD) are relevant methods for creating functional layers of solid oxide fuel cells (SOFCs). This review discusses challenges, new findings and prospects for the implementation of these methods, with the main emphasis placed on the use of the ELD method. Topical issues concerning the formation of highly active SOFC electrodes using ELD, namely, the electrochemical introduction of metal cations into a porous electrode backbone, the formation of composite electrodes, and the electrochemical synthesis of perovskite-like electrode materials are considered. The review presents examples of the ELD formation of the composite electrodes based on porous platinum and silver, which retain high catalytic activity when used in the low-temperature range (400-650 °C). The features of the ELD/EPD co-deposition in the creation of nanostructured electrode layers comprising metal cations, ceramic nanoparticles, and carbon nanotubes, and the use of EPD to create oriented structures are also discussed. A separate subsection is devoted to the electrodeposition of CeO 2 -based film structures for barrier, protective and catalytic layers using cathodic and anodic ELD, as well as to the main research directions associated with the deposition of the SOFC electrolyte layers using the EPD method.

Metallization of polyethylene (PE) using thermal spray techniques has proved difficult due to its low melting point and softness. In this study, metallic coatings were applied on porous polyethylene substrates using a twin wire-arc spray process. Commercially available polyethylene sheets, 3 mm in thickness, were used as substrates. Copper (Cu), aluminum (Al), and zinc (Zn) were successfully deposited on the porous polymer, without prior surface preparation, to form coatings with thickness of about 400 µm. Coating surface morphology and cross-sections were examined using a scanning electron microscope. Individual metal splats on the porous and non-porous substrates were observed to study the differences in the bonding mechanisms. The adhesion strength and electrical resistivity of the coatings on porous PE were evaluated. It was found that the bond strength of all three metallic coatings was found to be higher than the ultimate fracture strength of the porous. These results suggest that porosity in the polymer helps to overcome the challenges of metallizing polyethylene and provides a significant reduction in the weight of the polymer. Therefore, all these properties aided in fabricating an extremely lightweight, composite material with potential use in thermal management applications., Competing Interests: Conflict of interestThe authors of this work declare that they have no conflict of interests regarding the publication of this paper., (© ASM International 2021.)

The fluorescence-based detection of biological complexes on solid substrates is widely used in microarrays and lateral flow tests. Here, we investigate thiol-ene micropillar scaffold sheets ("synthetic paper") as the solid substrate in such assays. Compared to state-of-the-art glass and nitrocellulose substrates, assays on synthetic paper provide a stronger fluorescence signal, similar or better reproducibility, lower limit of detection (LOD), and the possibility of working with lower immunoreagent concentrations. Using synthetic paper, we detected the antibiotic enrofloxacin in whole milk with a LOD of 1.64 nM, which is on par or better than the values obtained with other common tests, and much lower than the maximum level allowed by European Union regulations. The significance of these results lays in that they indicate that synthetically-derived microstructured substrate materials have the potential to improve the performance of diagnostic assays., Competing Interests: Declaration of competing interest The authors declare the following financial interests/personal relationships which may be considered as potential competing interests: Co-author Jonas Hansson is employed at Mercene Labs who holds the patent rights on synthetic paper. The other authors declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper., (Copyright © 2020 Elsevier B.V. All rights reserved.)

Three constructed wetland systems were established to treat saline sewage via high-porosity ceramsite, activated carbon, and low-porosity sand: A (ceramsite + activated carbon + sand), B (sand + activated carbon + ceramsite), and C (sand). The distribution of dissolved oxygen in these systems varied with different filling methods with the best removal efficiency of ammonium nitrogen and total nitrogen observed in system B (97.4 and 96.2%, respectively). The 16S rDNA amplicon sequencing results showed that all the systems had a high abundance of salt-tolerant denitrifiers, and the filling method significantly impacted denitrifying bacteria (e.g., Vibrio and Planctomyces) in the substrate. System B had more diverse dissolved oxygen conditions than system A and showcased aerobic nitrification-denitrification and anaerobic ammonium oxidation pathways. Therefore, the use of substrates with different porosities can improve the dissolved oxygen supply and enhance nitrogen removal efficiency in constructed wetlands., Competing Interests: Declaration of Competing Interest The authors declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper., (Copyright © 2020 Elsevier Ltd. All rights reserved.)

This study investigated the pore characterization of polyurethane (PU) foam as a necessary step in water filtration membrane fabrication. Porous material characterization is essential for predicting membrane performance, strength, durability, surface feel, and to understand the transport mechanisms using modeling and simulations. Most existing pore characterization techniques are relatively costly, time-consuming, subjective, and have cumbersome sample preparations. This study focused on using three relatively inexpensive imaging systems: a black box, Canon camera (EOS760D), and LaserJet scanner (M1132 MFP). Two standard, state-of-the-art imaging systems were used for comparison: a stereomicroscope and a scanning electron microscope. Digital images produced by the imaging systems were used with a MATLAB algorithm to determine the surface porosity, pore area, and shape factor of the polyurethane foam in an efficient manner. The results obtained established the compatibility of the image analysis algorithm with the imaging systems. The black box results were found to be more comparable to both the stereomicroscope and SEM systems than those of the Canon camera and scanner imaging systems. Indeed, the current research effort demonstrates the possibility of substrate characterization with inexpensive imaging systems.

Blood microsampling is desired in clinical, pharmaceutical and biomedical fields to overcome the challenges of conventional whole blood sampling. One of the popular methods for blood microsampling is the dried blood spot (DBS) kit and the collected sample is subsequently used for bioanalysis. The current practice of DBS is simple to use, cheap and very well standardized from sample collection to analysis. However, DBS suffers from several well documented challenges related to blood spot formation such as varying hematocrit volume, thin layer chromatography effect and subsequent bio-analysis resulting in a variable and ocassionally high failure rate. A major source of these problems is our limited understanding of blood flow in porous media under different ambient and material conditions. Therefore, it is highly desirable to understand the parameters that affect blood flow in a porous medium to enable a more robust design of DBS and generally blood microsampling kits. In this review, we discuss some existing blood microsampling techniques while focusing on the challenges associated with blood flow dynamics. We also review existing studies on the potential factors that affect the permeation (imbibition or wicking) and spreading of blood in a thin, porous substrate as means to understand and overcome the challenges in designing new DBS kits and blood microsampling devices. Thereafter, we have discussed recent advances in the design of passive flow-based devices to overcome these challenges of current blood microsampling by DBS. Finally, we present a few applications of DBS in clinical and non-clinical studies. This review can benefit researchers working at the interface of complex fluid flow, surface chemistry, and material and device design for biomedical and biological applications., (Copyright © 2019 Elsevier B.V. All rights reserved.)

The use of inkjet printing for pharmaceutical manufacturing is gaining interest for production of personalized dosage forms tailored to specific patients. As part of the manufacturing, it is imperative to ensure that the correct dose is printed. The aim of this study was to use inkjet printing for manufacturing of personalized dosage forms combined with the use of near-infrared (NIR) and Raman spectroscopy as complementary analytical techniques for active pharmaceutical ingredient (API) quantification of the inkjet-printed dosage forms. Three APIs, propranolol (0.5-4.1 mg), montelukast (2.1-12.1 mg), and haloperidol (0.6-4.1 mg) were inkjet printed in 1 cm 2 areas on a porous substrate. The printed doses were non-destructively analyzed by transmission NIR and Raman spectroscopy (both transmission and backscatter). X-ray computed microtomography (μ-CT) analysis was undertaken for porosity measurements of the substrate. The API content was confirmed using high-performance liquid chromatography (HPLC), and the content in the dosage forms was modeled from the NIR and Raman spectra using partial least squares regression (PLS). HPLC analysis revealed a linear correlation of the number of layers printed to the API content. The resulting PLS models for both NIR and Raman had R 2 values between 0.95 and 0.99. The best predictive model was obtained using NIR, followed by Raman spectroscopy. μ-CT revealed the substrate to be highly porous and optimal for inkjet printing. In conclusion, NIR and Raman spectroscopic techniques could be used complementary as fast API quantification tools for inkjet-printed medicines.

In the investigation of criminal cases involving metallic weapons such as firearms and knives, the trace metal detection test (TMDT) and the transfer detection technique are two effective and on-the-spot methods to link a suspect and a suspected metallic weapon. In general, these tests need to be conducted on suspects' hands or done by lifting trace metals from their hands within 3 days of the crime being committed. However, if no suspects are arrested within this period, neither of these two techniques is applicable. This paper presents preliminary development of a modified TMDT to overcome the intrinsic disadvantages of conventional TMDTs. The method primarily focuses on the secondary imprints on porous substrates that are transferred unconsciously from the palms of criminals after handling galvanized weapons. The modified TMDT was established by studying the effect of various factors on secondary imprints on porous substrates. We also tested the effectiveness of the modified TMDT for common porous substrates and galvanized weapons and its relative sensitivity in a depletion series. Additionally, the storage conditions of the developed secondary imprints as physical evidence were studied under different time lapses and light conditions. Finally, we proposed an improved procedure for detecting metal traces formed in the use of metallic weapons and subsequent activities at a crime scene. The modified TMDT provides a novel method for investigators to demonstrate the relationship between a suspect and a metallic weapon, thus reducing the heavy reliance of conventional TMDTs on suspects and the time limit available to visualize or lift metal traces. For this reason, it can be used as a complementary and remedial method for conventional TMDTs, especially when suspects are not arrested within 3 days of the commission of a crime. Furthermore, the improved procedure can serve as a guide for investigators to apply the TMDT series properly to solving the cases involving metallic weapons., (Copyright © 2019 Elsevier B.V. All rights reserved.)

In the process of protection and consolidation of valuable materials, the efficiency is the crucial property that needs to be considered. TiO₂/ZnAl layered double hydroxide (LDH) coating and silicate- and carbonate-based consolidants were synthesized and proposed to be used for protection and consolidation of four porous mineral substrates: brick, stone, render and mortar. The photocatalytic efficiency of TiO₂/ZnAl LDH coating, as well as consolidation efficiency of two consolidants, both applied on model substrates, were studied. The photocatalytic coating showed significant activity and performed well after the durability tests involving rinsing and freezing/thawing procedures. After treatment with both consolidants, a serious enhancement of consolidation of the used substrates was found. On the other hand, the application of TiO₂/ZnAl LDH, as well as consolidants, caused negligible changes in the water vapour permeability values and in appearance of the porous mineral substrates, indicating a high level of compatibility.

Two-ply composite membranes with separation layers from chitosan and sulfoethylcellulose were developed on a microporous support based on poly(diphenylsulfone- N -phenylphthalimide) and investigated by use of X-ray diffraction and scanning electron microscopy methods. The pervaporation properties of the membranes were studied for the separation of aqueous alcohol (ethanol, propan-2-ol) mixtures of different compositions. When the mixtures to be separated consist of less than 15 wt % water in propan-2-ol, the membranes composed of polyelectrolytes with the same molar fraction of ionogenic groups (-NH₃⁺ for chitosan and -SO₃ - for sulfoethylcellulose) show high permselectivity (the water content in the permeate was 100%). Factors affecting the structure of a non-porous layer of the polyelectrolyte complex formed on the substrate surface and the contribution of that complex to changes in the transport properties of membranes are discussed. The results indicate significant prospects for the use of chitosan and sulfoethylcellulose for the formation of highly selective pervaporation membranes.

At the core of translational challenges in tissue engineering is the mechanistic understanding of the underpinning biological processes and the complex relationships among components at different levels, which is a challenging task due to the limitations of current tissue culture and assessment methodologies. Therefore, we proposed a novel scale-down strategy to deconstruct complex biomatrices into elementary building blocks, which were resembled by thin modular substrate and then evaluated separately in miniaturised bioreactors using various conventional microscopes. In order to investigate cell colonisation within porous substrate in this proof-of-concept study, TEM specimen supporters (10-30 μm thick) with fine controlled open pores (100∼600 μm) were selected as the modular porous substrate and suspended in 3D printed bioreactor systems. Noninvasive imaging of human dermal fibroblasts cultured on these free-standing substrate using optical microscopes illustrated the complicated dynamic processes used by both individual and coordinated cells to bridge and segment porous structures. Further in situ analysis via SEM and TEM provided high-quality micrographs of cell-cell and cell-scaffold interactions at microscale, depicted cytoskeletal structures in stretched and relaxed areas at nanoscale. Thus this novel scaled-down design was able to improve our mechanistic understanding of tissue formation not only at single- and multiple-cell levels, but also at micro- and nanoscales, which could be difficult to obtain using other methods., (© 2017 The Authors. Journal of Microscopy published by John Wiley & Sons Ltd on behalf of Royal Microscopical Society.)

To evaluate the in vivo foreign body reaction to bio-inert 2-methacryloyloxyethyl phosphorylcholine (MPC) polymers, MPC polymer-coated porous substrates, with large surface area, were implanted subcutaneously in mice for 7 and 28 days, and the surrounding tissue response and cells infiltrating into the porous structure were evaluated. The MPC polymer surface induced low angiogenesis and thin encapsulation around the porous substrate, and slightly suppressed cell infiltration into the porous substrate. M1-type macrophage specific gene (CCR7) expression was suppressed by the MPC polymer surface after 7 days, resulting in the suppression of inflammatory cytokine/chemokine gene expression. However, the expression of these genes on the MPC polymer surface was higher than on the non-coated surface after 28 days. These findings suggest that MPC polymer surfaces successfully inhibit inflammatory responses during the early stage of tissue response, and seem to retard its occurrence over time.

For the correct interpretation of results of tangential electrokinetic measurements with porous materials, in particular, composite/asymmetric membranes on porous supports, it is necessary to have the data available for various channel heights. In some kinds of equipment, the variation of channel height is technically possible only for a range of relatively large heights. This communication shows that under these conditions, the fluid flow can become undeveloped and the conventional approaches to the interpretation of electrokinetic measurements should be modified accordingly. In particular, the dependence of streaming-current coefficient on the channel height becomes sub-linear. If the experimental data are available only for larger channel heights, this can be mistakenly taken for the manifestation of contribution of porous sub-structure to the streaming current. In this communication, we investigate electrokinetic phenomena in undeveloped flows both numerically and experimentally. We confirm that the aforementioned sub-linearity occurs for nonporous as well as porous substrates. We also demonstrate that the channel heights estimated from the volume flow rate by using numerical simulations of undeveloped flows are in very good agreement with the reference values obtained from the electrical conductance (in contrast to the values estimated by using the conventional approach of Hagen-Poiseuille equation). The numerical fitting of channel-height dependences of streaming-current coefficient enables us to separate the contributions of external surface and porous sub-structure (in case of porous substrates) and obtain quite reasonable values of (effective) zeta-potentials in both cases. Nonetheless, the accuracy of experimental data deteriorates with increasing channel height, so it is generally advisable to vary the heights within a range below 100-150 μm., (Copyright © 2013 Elsevier Inc. All rights reserved.)