Solid-state Substrates Research Articles

An Effective and Controllable Platform with Ag-Stepped Nanocone Arrays Serving as Stable SERS Substrate

Facile, controllable and efficient SERS substrate preparation has always been the focus project in the SERS field, especially the solid-state nanoarray substrate. Herein, a simple and convenient method for preparing a series of homogeneous Ag-stepped nanocone arrays (Ag-SNCAs) using polymer nanocompression printing is presented. By analyzing the 1162[Formula: see text]cm[Formula: see text] characteristic peak of crystal violet (CV), the relative standard deviation (RSD) of the Raman intensity was only 4.71%. The detection limit of malachite green (MG) reached 0.001[Formula: see text]ppm, and it also has good SERS detection results for drug molecules such as melamine, methadone, morphine, methamphetamine and thiabendazole. This work provides a large area uniform and controllable preparation method of sharp cone nanostructure array, which has important application in plasmonic photocatalysis and deep light field regulations.

Surface-Enhanced Raman Spectroscopy Detection for Fenthion Pesticides Based on Gold Molecularly Imprinted Polymer Solid-State Substrates.

Current label-free surface-enhanced Raman spectroscopy (SERS) assay for the detection and analysis of organophosphorus pesticides has achieved initial success, but the application still faces constraints of substrate portability and specificity. To this end, this paper demonstrates a method for portable, rapid, and specific detection of low concentrations of fenthion pesticides based on a solid substrate of gold nanoparticle monolayers combined with molecularly imprinted polymers (MIPs). The nano-monolayers were transferred to the surface of mercapto-silicon wafers by interfacial self-assembly technique to form a stable connection with S-Au bonds and, at the same time, prevent nanoparticles from dropping off during the surfactant removal process. Then, the fenthion MIPs were directly generated on the surface of the monolayer film by spin-coating with a pre-polymerization solution and ultraviolet-induced polymerization. Tests showed that the molecular imprint was able to accurately bind to fenthion, but not other molecules, in a mixture of structural analogs, achieving a low concentration detection of 10-8 mol/L. The composite substrate maintained a signal uniformity of a relative standard deviation (RSD) = 7.05% and a batch-to-batch reproducibility of RSD = 10.40%, making it a potential pathway for the extended application of SERS technology.

SERS-based pump-free microfluidic chip sensor for highly sensitive competitive immunoassay of cortisol in human sweat.

Cortisol, known as the "stress hormone", is secreted by the adrenal cortex. Measuring cortisol levels in body fluids is essential for evaluating stress levels, adrenal function, hormone imbalance, and psychological well-being. Early diagnosis and management of related conditions depend on this measurement. A rapid detection method that combines immunoassay and surface-enhanced Raman scattering (SERS) technology has become widely used in bioanalysis, offering benefits such as fast detection, high throughput, integrated microsystems, and high specificity. This study introduces a pump-free microfluidic chip integrating a solid-state SERS substrate to detect trace amounts of cortisol in bodily fluids through immunoassay. The method relies on a competitive reaction between cortisol and SERS tags with cortisol antigens immobilized on gold nanostructured substrates in a microfluidic environment. Two detection channels are used to provide controls and enhance measurement efficiency and accuracy. Solid-state gold nanostructured substrates offer a larger surface area for antibody capture and act as SERS-active substrates, which significantly enhance the Raman signal and improve the microsystem's sensitivity and applicability. Driven by a capillary pump, the sample can be loaded within 60 seconds, with the entire detection process taking less than 10 min, significantly reducing the detection time. Results indicate that the detection limit for cortisol is 10 pg mL-1, meeting clinical biomarker thresholds. The integrated SERS microfluidic chip shows great promise as an analytical tool for the rapid and sensitive diagnosis of cortisol in bodily fluids.

Size control of MoS2 quantum dots by varying the crystallographic orientation of sapphire substrates

The phenomena in size-dependent optoelectronic and catalytic properties of MoS2 quantum dots make them attractive in fabricating optoelectronic devices and processing water-splitting. However, growing monolayered MoS2 quantum dots with controlled sizes is challenging and has never been realized on a solid-state substrate. Herein, we experimentally demonstrate the size of monolayered MoS2 quantum dots can be thermodynamically manipulated by varying the orientation of the sapphire substrate from c plane, m plane to r plane and the size can be tuned from 10 nm to 2 nm. An apparent shift in the optical absorption and outstanding size-dependent electrocatalytic capability of the MoS2 quantum dots can be featured. The DFT results verify that the size modulation is associated with the interaction strength between the MoS2 quantum dots and the sapphire substrate. This work provides a new benchmark in the growth of size-tunable monolayered MoS2 quantum dots on a solid-state substrate.

Friction taper stitch welding of a duplex stainless steel

Friction taper stitch welding (FTSW) is a novel technique that uses multiple inserts to conceal surface crack in a given substrate. The inserts are rotated and forced to fill the crack as plasticized material, and forge with the substrate in solid-state. The process is well suited for alloys such as duplex stainless steel, which suffers degradation of properties during fusion welding. A detailed experimental and theoretical investigation is presented here on FTSW of a duplex stainless steel (DSS). The experimental results show the presence of a ferrite-rich phase along the interface. The results computed by the numerical process model reveal a direct influence of thermal cycle in the amount of ferrite along the joint interface. The welded joint shows near homogeneous structure and properties similar to those of the substrate.

Statistical Experimental Design as a New Approach to Optimize a Solid-State Fermentation Substrate for the Production of Spores and Bioactive Compounds from Trichoderma asperellum.

Managing organic agricultural wastes is a challenge in today's modern agriculture, where the production of different agricultural goods leads to the generation of large amounts of waste, for example, olive pomace and vine shoot in Mediterranean Europe. The discovery of a cost-effective and environment-friendly way to valorize such types of waste in Mediterranean Europe is encouraged by the European Union regulation. As an opportunity, organic agricultural waste could be used as culture media for solid-state fermentation (SSF) for fungal strains. This methodology represents a great opportunity to produce secondary metabolites like 6-pentyl-alpha-pyrone (6-PP), a lactone compound with antifungal properties against phytopathogens, produced by Trichoderma spp. Therefore, to reach adequate yields of 6-PP, lytic enzymes, and spores, optimization using specific agricultural cheap local wastes from Southeastern France is in order. The present study was designed to show the applicability of an experimental admixture design to find the optimal formulation that favors the production of 6-PP. To conclude, the optimized formulation of 6-PP production by Trichoderma under SSF contains 18% wheat bran, 23% potato flakes, 20% olive pomace, 14% olive oil, 24% oatmeal, and 40% vine shoots.

Effects of pomelo sponge fermented by Monascus ruber on cholesterol metabolism and intestinal microbiota in high-fat diet mice

The purpose of this study is to produce Monascus ruber fermented pomelo sponge products (MFPS) utilizing low-cost pomelo sponge as a solid-state fermentation substrate, and to investigate the effects of MFPS on cholesterol metabolism and gut microbiota in mice. The study of oral MFPS treatment in high-fat diet mice uncovered that a high dosage of MFPS effectively inhibited the increase of body weight, reduced the accumulation of liver and epididymal fat and improved blood cholesterol metabolism in mice. Interestingly, MFPS consumption enhanced the liver's antioxidant capacity, cleared free radicals. Furthermore, HE staining demonstrated that MFPS effectively repaired liver damage. UPLC-QTOF/MS analysis of liver metabolomics revealed that MFPS intervention exerts a substantial regulatory impact on metabolic pathways encompassing alanine, aspartate and glutamate metabolism, biosynthesis of unsaturated fatty acids, steroid hormone biosynthesis, tryptophan metabolism, glycerophospholipid metabolism, fatty acid degradation, folate biosynthesis, etc. High-throughput sequencing of 16S rRNA unveiled that MFPS mitigated the intestinal microbiota imbalance triggered by a high-fat diet, increasing the abundance of probiotics in the intestine, including Lactobacillus and Bifidobacterium. Therefore, these findings demonstrate that MFPS can improve abnormal cholesterol metabolism and balance intestinal flora, offering valuable insights for developing natural and effective cholesterol-lowering products.

Studying the Interaction between Bendamustine and DNA Molecule with SERS Based on AuNPs/ZnCl2/NpAA Solid-State Substrate.

Bendamustine (BENDA) is a bifunctional alkylating agent with alkylating and purinergic antitumor activity, which exerts its anticancer effects by direct binding to DNA, but the detailed mechanism of BENDA-DNA interaction is poorly understood. In this paper, the interaction properties of the anticancer drug BENDA with calf thymus DNA (ctDNA) were systematically investigated based on surface-enhanced Raman spectroscopy (SERS) technique mainly using a novel homemade AuNPs/ZnCl2/NpAA (NpAA: nano porous anodic alumina) solid-state substrate and combined with ultraviolet-visible spectroscopy and molecular docking simulation to reveal the mechanism of their interactions. We experimentally compared and studied the SERS spectra of ctDNA, BENDA, and BENDA-ctDNA complexes with different molar concentrations (1:1, 2:1, 3:1), and summarized their important characteristic peak positions, their peak position differences, and hyperchromic/hypochromic effects. The results showed that the binding modes include covalent binding and hydrogen bonding, and the binding site of BENDA to DNA molecules is mainly the N7 atom of G base. The results of this study help to understand and elucidate the mechanism of BENDA at the single-molecule level, and provide guidance for the further development of effective new drugs with low toxicity and side effects.

Solid-State Au Nanocone Arrays Substrate for Reliable SERS Profiling of Serum for Disease Diagnosis.

Surface-enhanced Raman scattering (SERS) is a widely used rapid and noninvasive method for detecting biological substances in serum samples and is commonly employed in disease screening and diagnosis. Solid-state nanoarray SERS substrates used in serum detection may cause spectral instability due to imperfections in the detection method. For the purpose of identifying optimal detection conditions, various dilution levels of the serum were tested in this study. The study found that a complete and stable serum SERS spectrum can be obtained when the serum is diluted by a factor of 50. The study reports the successful preparation of an Au nanocone array (Au NCA) plasmonic substrate with a uniform, controllable microstructure and high activity, achieved through a combination of PS colloidal sphere template-assisted reactive ion etching (RIE) process and magnetron sputtering deposition technology. Based on this substrate, a standard detection scheme was developed to obtain highly stable and repeatable serum SERS spectra. The study verified the reliability of the optimized serum detection scheme by comparing the SERS spectra of serum samples from healthy individuals and gastric cancer patients, and confirmed the potential benefits of the scheme for disease screening and diagnosis.

Gate-tunable resistance drops related to local superconducting gaps in thin TaS2 layers on SrTiO3 substrates

Strontium titanate [SrTiO3 (STO)], a perovskite oxide with an extremely high gate-tunable dielectric constant (ε) due to quantum paraelectric phases, is attracting considerable attention for yielding various physical phenomena when two-dimensional (2D) layers are integrated. Superconductivity is such a typical phenomenon. However, the influence of the STO substrates on enhancing transition temperatures (Tc) for (atomically) thin 2D flakes attached to them has been rarely investigated. Here, we report gate-tunable and gradual four-terminal resistance drops with critical onset T (TCR) and scanning tunneling spectroscopy (STS) spectra in devices comprising thin TaS2 flakes attached on monolayer hexagonal boron nitride (hBN) spacer/STO substrates. Observation of STS spectra confirms the presence of local superconducting gaps Δ (∼1.5 meV) with transition T (TΔC) three-times higher than previous reports of Tc under absent pressure and strong position dependence of Δ. Depending on Δ on back gate voltages (Vbg) and magnetic fields, there is a strong correlation between TCR and the onset Tc of superconductivity, implying an enhancement of approximately five times compared with the previous highest-onset Tc values without pressure as the applied Vbg increases. The high onset Tc and Δ are discussed based on screening of the long-range Coulomb interaction (CI) due to the high-ε of SrTiO3, while the short-ranged CI remains strong in the 2D limit, causing the superconductivity. Using a monolayer hBN/SrTiO3 substrate with Vbg opens doors to Tc enhancement in thin superconducting layers integrated on it and wide application due to the solid-state high-ε substrates.

Can we really detect relic neutrinos?

Detecting relic neutrinos is a longstanding goal in fundamental physics. Experimentally, this goal is extremely challenging as the required energy resolution is defined by the tiny neutrino masses (\sim∼ 10 meV). The current consensus is that sufficient statistics together with a clean spectrum could only be achieved if beta decayers are attached to a solid state substrate. However, this inevitably imposes irreducible intrinsic limitations on the energy resolution coming from Heisenberg’s uncertainty principle. This limitation appears to be critical for the currently accepted decayer - Tritium. Here, we analyze the state of the art approaches to mitigate this limitation and conclude that the most promising solution is to change Tritium for a heavier emitter. We find that the two suitable candidates are ^{171}171Tm, ^{63}63Ni.

Solvent effects and mass transfer on aroma extraction during solid-state distillation

Steam distillation is an important unit operation to extract valuable compounds from natural solid-state substrates. Solid-state distillation with steam can extract aroma from fermented solid substrate such as fermented grains of Chinese liquor fermentation. However, this procedure is still operated based on generations of empirical skills rather than a technique under process control based on scientific principles. The resulting drawback is poor mass and heat transfer with undesired consequences concerning productivity, quality and sustainability. Mathematical modelling can be a powerful tool to get insight into such an empirical process for potential rational design, optimization and control. Therefore, we established a mathematical model to describe the mass transfer based on kinetic parameters. The simulation results show that the distillation had a natural column plate structure that more effectively concentrated compounds. Furthermore, this structure resulted in a high ethanol concentration in the distillate. To evaluate subsequent effect of high ethanol concentration, we analysed aroma compounds in the distillates under simulated conditions with or without ethanol. The hydrophobic compounds were fitted well under conditions with ethanol, whereas hydrophilic compounds had similar outcomes under both conditions. The results show that ethanol could accelerate the release of hydrophobic compounds in Chinese liquor distillation. Therefore, solvent could be one of the important factors to optimize the distillation process. Our findings provide a reference for improving the extraction during solid-state distillation.

Hydrogen Loading System for Thin Films for Betavoltaics

Abstract Betavoltaics are direct conversion energy devices that are ideal for low power and long-lasting, uninterruptable applications. Betavoltaics operate similarly to photovoltaics where a radio isotope irradiates beta particles into a semiconductor p-n junction that converts the kinetic energy into electrical energy. Betavoltaics are limited by their power output from the radio isotope. However, the source power density can be increased by the selection of solid-state substrates. While tritium absorbing substrates can be simulated to estimate tritium absorption levels and surface emission energies, their viability has to be physically evaluated. A state-of-the-art hydrogen loading system developed by our research group was used to evaluate different film types to understand how they perform during the hydrogen/tritium loading process. The hydrogen loading system utilizes the Sievert technique, where the temperature and volume is constant and pressure drop of the system is used to determine hydrogen uptake of a film substrate. The hydrogen loading system procedure was verified using 250 nm thick palladium films at three loading temperatures. Results clearly show uptake of hydrogen by the thin palladium films accurate to the ideal stoichiometric ratio of one hydrogen atom to host palladium atom.

Growth performance and nutrient composition of black soldier fly larvae reared on solid-state fermentation substrates with various white rot fungi

Abstract. Fitriana EL, Jayanegara A, Astuti DA, Laconi EB. 2022. Growth performance and nutrient composition of black soldier fly larvae reared on solid-state fermentation substrates with various white rot fungi. Biodiversitas 23: 4894-4905. This study examines agricultural byproducts fermented with various rot fungi as a substrate of black soldier fly larvae. The experiment used a three-way randomized design with four replications. The first factor was substrate (cacao pod husk and oil palm frond), the second factor was fungi (Phanerochaete chrysosporium, Trametes versicolor, and Pleurotus sajor-caju), and the third factor was environment condition (light and without light). Approximately 1200 of 7-day-old larvae were added to 600 g substrate treatment. The results showed that the solid-state fermentation substrates had the highest waste reduction parameters and level of consumption. Larvae in the experiment had a crude protein level of 38.84-58.88% of dry matter. Glutamic acid is the most abundant non-essential amino acid in larvae, while leucine is the most abundant essential amino acid. Solid-state fermentation substrate could improve the fatty acid profile quality of larvae in relation to high linoleic acid, polyunsaturated fatty acid, and unsaturated fatty acid percentages, especially CPH-pc substrate. The use of solid-state fermentation in larvae rearing decreased lignin in the cacao pod husk substrate. In conclusion, cacao pod husk substrate solid-state fermented with white rot fungi is not supported the optimum growth performance of BSFL but increases fatty acid profile quality.

Co-biomass degradation of fluoranthene by marine-derived fungi; Aspergillus aculeatus and Mucor irregularis: Comprehensive process optimization, enzyme induction and metabolic analyses

The application and relevance of marine-derived fungi in the mycoremediation of environment polluted with polycyclic aromatic hydrocarbons (PAHs) is promising whilst limiting environmental hazards. The present study investigated the fluoranthene degradation efficiency of marine-derived fungal co-culture, Aspergillus aculeatus (AA) and Mucor irregularis (MI) in batch processes (Plackett-Burman experiments) enhanced with the addition of surfactants and solid-state substrates. Further optimization studies done through fractional factorial design revealed that the co-culture exhibited 98.4% fluoranthene degradation capacity after 7 days of incubation. The role played by enzymes was revealed with 93, 85 and 71% induction of laccase, lignin peroxidase and manganese peroxidase respectively during fluoranthene degradation. The Gas Chromatography-Mass Spectrometry analysis revealed the formation of five metabolites; 1,2- dihydroxyfluoranthene, 9H-fluorene-1,9-dicarboxylic acid, benzene-1,2,4-tricarboxylic acid, benzene-1,3-dicarboxylic acid and benzoic acid after fluoranthene degradation by AA + MI co-culture which was used in predicting a metabolic pathway. The findings of this study elucidated the promising potentials of marine-derived fungal co-biomass in the eco-friendly remediation of polycyclic aromatic hydrocarbons thus promoting green technology.

Soft elastic tubular reactor: An unconventional bioreactor for high-solids operations

Many bioreactors for solid state (SSF) and high-solids load fermentations have been developed in order to obtain valuable bioproducts. In general, it is emphasized the necessity for design improvements in reactor mixing, heat transfer, and gaseous mass transfer. A soft-elastic tubular reactor (SETR) was built and its behavior in terms of aeration, mixing, and temperature control was evaluated. Although soft-elastic reactors have been explored for some time, this was the first time they were thoroughly investigated for fermentation use. Depending on the applied parameters, such as aeration, mixing rate, and media characteristics (liquid viscosity, solid, sludge), KLa ranged between 1 and 40 h−1, a well-mixed state was attained between 0.3 and 60 min, and the temperature reached operational stability within 20 min. Soybeans were fermented by Bacillus subtilis subsp. natto as a proof of concept (moisture content from 66 wt% up to 80 wt%). The proposed SETR demonstrated that temperature, mixing, and aeration could be modified to meet the needs of the process, and while more research is needed, it might be regarded as a new option for solid state or high-load substrate processes.

Potential soluble substrates for transient electronics applications: A review

The excessive usage and demand of consumer electronics have caused an elevation of electronic waste. Typically, consumer electronics are produced with non-biodegradable, non-biostable, and sometimes fatal materials, resulting in global alarming biological summons. Thence, to mend the drawbacks, an emerging field—named transient electronics—takes effect where the biomaterial, device, substrate, and total systems disappear untraceably after steady-state operation. Conspicuously, transient electronics have induced immense curiosity in researchers to perform interesting investigations due to the feature of disintegration after stable operation. The idea of transient electronics has been implemented in biomedical, military, and nanotechnology fields. Although rapid development is evident in transient technology in a short period, it is believed that the technology will deliver the utmost prospects in advanced electronic applications. Essentially, in transient technology, the vital challenge is to determine the platform materials that offer stability, resistance, biocompatibility, and mainly, the solubility to accommodate the transient devices. In this Review, a detailed overview of different soluble substrates, such as organic, polymer, and solid-state substrates, is described, along with the feasibility of the fabricated devices on the respective substrates to support transient electronics. Second, the dissolving mechanism of the corresponding substrates is analyzed.

Electrophoretic Deposition and Characterization of the Doped BaCeO3 Barrier Layers on a Supporting Ce0.8Sm0.2O1.9 Solid-State Electrolyte.

In this study, the technology of electrophoretic deposition (EPD) micrometer barrier layers based on a BaCe0.8Sm0.19Cu0.1O3 (BCSCuO) protonic conductor on dense carrying Ce0.8Sm0.2O1.9 (SDC) solid-state electrolyte substrates is developed. Methods for creating conductive sublayers on non-conductive SDC substrates under EPD conditions, such as the synthesis of a conductive polypyrrole (PPy) layer and deposition of a layer of finely dispersed platinum from a suspension of its powder in isopropanol, are proposed. The kinetics of disaggregation, disperse composition, electrokinetic potential, and the effect of adding iodine to the BCSCuO suspension on these parameters as factors determining the preparation of stable suspensions and successful EPD processes are explored. Button cells based on a carrying SDC electrolyte of 550 μm in thickness with BCSCuO layers (8–35 μm) on the anode, cathode, and anode/cathode side, and Pt electrodes are electrochemically tested. It was found that the effect of blocking the electronic current in the SDC substrate under OCV conditions was maximal for the cells with barrier layers deposited on the anode side. The technology developed in this study can be used to fabricate solid oxide fuel cells with doped CeO2 electrolyte membranes characterized by mixed ionic–electronic conductivity (MIEC) under reducing atmospheres.

Insight into the Reactivity Profile of Solid-State Aryl Bromides in Suzuki–Miyaura Cross-Coupling Reactions Using Ball Milling

AbstractDespite recent advances in solid-state organic synthesis using ball milling, insight into the unique reactivity of solid-state substrates, which is often different from that in solution, has been poorly explored. In this study, we investigated the relationship between the reactivity and melting points of aryl halides in solid-state Suzuki–Miyaura cross-coupling reactions and the effect of reaction temperature on these processes. We found that aryl halides with high melting points showed significantly low reactivity in the solid-state cross-coupling near room temperature, but the reactions were notably accelerated by increasing the reaction temperature. Given that the reaction temperature is much lower than the melting points of these substrates, the acceleration effect is most likely ascribed to the weakening of the intermolecular interactions between the substrate molecules in the solid state. The present study provides important perspectives for the rational design of efficient solid-state organic transformations using ball milling.

Light‐Induced Solid‐State Protrusion of Gold Nanowires and Their Derivatives for Sensing Applications

AbstractGold nanowires (AuNWs) have been one of the key components for nanoelectronics and optoelectronic devices but the fabrication has been poorly customized for this purpose even though diverse synthetic strategies bloomed over the last decades. Here, the concept of light‐induced protrusion of AuNWs directly from solid state substrate is demonstrated, which is highly compatible for on‐chip fabrication of functional nanodevices. This is realized by irradiating the Au ion‐doped titanium dioxide (TiO2) films with continuous wave laser. The blue laser triggers the reduction and nucleation of Au(0) which grows vertically into AuNW bundles with diffusion‐controlled supply of Au ions within the TiO2 matrix. Thus, the morphology of the AuNWs can be tuned with irradiation time/power as well as the ion concentration, which can derive into Au nanorings (NRs) and NR stacks in 1D photonic crystal with reduced plasmon linewidth. Such light‐induced protrusion can also generate nanopillars by introducing Au seeds before irradiation. The surface‐enhanced Raman scattering performance of the AuNW bundles is excellent with fm detection limit. Such laser‐directed solid‐state growth technique is facile, versatile, cost‐effective site‐selective, ligand‐free, and wafer‐scalable, which opens up many promising applications in (bio)chemical sensing, photovoltaics, photocatalysis, plasmonic displays, and integrated nanoelectronic/optoelectronic devices.