Nanoplasmonic Sensor Detects Preferential Binding of IRSp53 to Negative Membrane Curvature

Flexible and Ultra Low Weight Energy Harvesters Based on 2D Phosphorene or Black phosphorus (BP): Current and Futuristic Prospects

Phosphorene, or two-dimensional (2D) black phosphorus, has recently emerged as a competitor of graphene as it offers several advantages, including a tunable band gap, higher on/off current ratio, piezoelectric nature, and biocompatibility. Researchers have succeeded in obtaining several forms of phosphorene, such as nanosheets, nanorods, nanoribbons, and quantum dots, with satisfactory yields. Nanostructures with various controlled properties have been fabricated in multiple devices for energy production. These phosphorene-based devices are lightweight, flexible, and efficient, demonstrating great potential for energy-harvesting applications in sensors and nanogenerators. While ongoing exploration and advancements continue for these lightweight energy harvesters, it is essential to review the current progress in order to develop a future roadmap for the potential use of these phosphorene-based energy harvesters in space programs. They could be employed in applications such as wearable devices for astronauts, where ultralow weight is a vital component of any integrated device. This review also anticipates the growing significance of phosphorene in various emerging applications such as robots, information storage devices, and artificial intelligence.

Electrolytes for Sodium Ion Batteries: The Current Transition from Liquid to Solid and Hybrid systems

Sodium-ion batteries (NIBs) have recently garnered significant interest in being employed alongside conventional lithium-ion batteries, particularly in applications where cost and sustainability are particularly relevant. The rapid progress in NIBs will undoubtedly expedite the commercialization process. In this regard, tailoring and designing electrolyte formulation is a top priority, as they profoundly influence the overall electrochemical performance and thermal, mechanical, and dimensional stability. Moreover, electrolytes play a critical role in determining the system's safety level and overall lifespan. This review delves into recent electrolyte advancements from liquid (organic and ionic liquid) to solid and quasi-solid electrolyte (dry, hybrid, and single ion conducting electrolyte) for NIBs, encompassing comprehensive strategies for electrolyte design across various materials, systems, and their functional applications. The objective is to offer strategic direction for the systematic production of safe electrolytes and to investigate the potential applications of these designs in real-world scenarios while thoroughly assessing the current obstacles and forthcoming prospects within this rapidly evolving field.

Construction of an electrochemical pH sensor using one-pot synthesis of a molybdenum diselenide/nitrogen doped graphene oxide screen-printed electrode

In this study, a one-pot synthesis of a molybdenum diselenide/nitrogen-doped graphene oxide (MoSe2/NGO) composite was demonstrated and used for the fabrication of an electrochemical pH sensor. The MoSe2/NGO composite was characterized using powder X-ray diffraction, infrared spectroscopy, Raman spectroscopy, X-ray photoelectron spectroscopy, thermogravimetric analysis, scanning electron microscopy, transmission electron microscopy, energy-dispersive X-ray spectroscopy, and Brunauer-Emmett-Teller analysis. The electrochemical behavior at different pH values was determined by recording the open-circuit potential. When applied for pH detection, the MoSe2/NGO modified screen-printed electrode (SPE) showed good linearity with a sensitivity of 61.3 mV pH-1 over a wide pH range of 2-14. In addition, the pH sensor exhibited a remarkably stable response, high reproducibility, and selectivity. The sensor was used to measure the acidity or alkalinity of real food and beverage samples. The results for these samples showed a relative error of less than 10% compared with the results obtained with the commercial pH meter. The portable sensor produced by screen printing electrodes paves the way for the development of simple, cost-effective, real-time, and robust pH sensors for the pH analysis of various sample matrices for clinical diagnostics, biosensing, and cost-effective applications.

Combining high energy ball milling and liquid crystal templating method to prepare magnetic ordered mesoporous silica. A physico-chemical investigation

The physico-chemical investigation of superparamagnetic MCM41 like materials prepared by the novel combination of high energy ball milling and a liquid crystal templating method is presented. Structural, morphological, textural, thermal, and preliminary magnetic characterization demonstrated the successful combination of the two synthesis techniques, avoiding the problems associated with the current methods used for the preparation of magnetic ordered mesoporous silica. MCM41 like materials with high specific surface area values (625-720 m2 g-1) and high mesopore volumes in the range 1-0.7 cm3 g-1 were obtained. The ordered mesoporous structure and accessible pores were maintained after the inclusion of increasing amounts of the magnetic component in the silica structure. All the samples showed superparamagnetic behaviour.

Recovery of potassium salt by acidification of crude glycerol derived from biodiesel production

Crude glycerol (CG) is a major byproduct of biodiesel production. Most of it cannot be utilized due to major impurities. The CG generally contains alkalis, which generate the residual salts in a series of its purification stages. This study aims to obtain the optimum process conditions and acid molar ratio to produce a higher potassium salt yield while improving the purity of glycerol by a simple acidification procedure. The CG was obtained from the transesterification of palm oil using a catalyst based on potassium carbonate. A phosphoric acid (85%) is utilized at various molar ratios and the process temperature is 60-80 °C. The strong acid was slowly added to the CG and heated for 30 minutes with a mixing speed of 250 rpm. The optimum acidification process occurred at a temperature of 70 °C with a molar crude glycerol ratio to phosphoric acid of 1 : 0.5. The glycerol purity was increased from 43.3% to 67.63% (w/w). It effectively obtains a potassium phosphate salt with a yield of 6.78%. The functional group infrared (IR) and X-ray fluorescence (XRF) spectra identified the salt residue as potassium dihydrogen phosphate (KH2PO4). This is composed predominantly of potassium oxide (K2O) and phosphorus pentoxide (P2O5), 50% and 47.9%, respectively.

Glycerol carbonate synthesis via transesterification of enriched glycerol and dimethyl carbonate using a Li-incorporated MCM-41 framework

Waste crude glycerol was successfully enriched and utilized as an inexpensive source for producing value-added chemicals, such as glycerol carbonate (GC) - a valuable compound with extensive industrial applications. The Li/MCM-41 heterogeneous catalyst was synthesized and used for the transesterification of enriched glycerol and dimethyl carbonate (DMC) to produce GC. The catalyst's physicochemical properties were characterized using thermogravimetric, Hammett indicator, inductively coupled plasma-optical emission spectroscopy, nitrogen adsorption-desorption, X-ray diffractometry, scanning electron microscopy, and Fourier-transform infrared spectroscopy analyses. Reaction conditions were optimized using response surface methodology and analysis of variance, yielding an accurate quadratic model to predict the GC yield under different transesterification variables. The results revealed that 5%Li/MCM-41 served as the optimal catalyst, achieving the highest TOF of 4.72 h-1. The DMC: enriched glycerol molar ratio had the greatest impact on the GC yield, with an R2 = 0.9743 and adjusted R2 = 0.9502. The optimal GC yield (58.77%) with a final purity of 78% was attained at a 5.15 wt% catalyst loading relative to the initial amount of enriched glycerol, DMC: enriched glycerol molar ratio of 4.24 : 1, and a reaction temperature of 86 °C for 165 min. The 5%Li/MCM-41 heterogeneous catalyst could be reused for four cycles with a decreased GC yield from 58.77% to 45.72%. Thus, the Li/MCM-41 catalyst demonstrated a remarkable efficiency and potential as a heterogeneous catalyst for synthesizing GC. This method not only contributes to environmental sustainability by making use of a byproduct from biodiesel production but also aligns with the principles of a circular economy.

The chimera of 2D- and 1D-graphene magnetization by hydrogenation or fluorination: critically revisiting old schemes and proposing new ones by ab initio methods

Graphene is an ideal candidate material for spintronics due to its layered structure and peculiar electronic structure. However, in its pristine state, the production of magnetic moments is not trivial. A very appealing approach is the chemical modification of pristine graphene. The main obstacle is the control of the geometrical features and the selectivity of functional groups. The lack of a periodic functionalization pattern of the graphene sheet prevents, therefore, the achievement of long-range magnetic order, thus limiting its use in spintronic devices. In such regards, the stability and the magnitude of the instilled magnetic moment depending on the size and shape of in silico designed graphane islands and ribbons embedded in graphene matrix will be computed and analysed. Our findings thus suggest that a novel and magneto-active graphene derivative nanostructure could become achievable more easily than extended graphone or nanoribbons, with a strong potential for future spintronics applications with a variable spin-current density.

Charge transporting and thermally activated delayed fluorescence materials for OLED applications

The design and synthesis of effective charge transporting (CT) and thermally activated delayed fluorescence (TADF) materials are in high demand to obtain high-performing OLED devices. Recently, the significant development in the field of OLEDs has led to the creation of numerous charge transporting and TADF materials with diverse structures. To further improve the device performance, a better understanding of the structural characteristics and structure-property relationships of these materials is essential. Moreover, to enhance the efficiency of OLEDs, all the electrogenerated excitons should be constrained in EMLs. The TADF mechanism can theoretically register 100% IQE through a potent up-conversion method from non-radiative triplet excitons to radiative singlet excitons. In this review, the structural importance, classification, physical properties, and electroluminescence data of some recent charge transporting and TADF materials are summarized and discussed. Moreover, their molecular structural dependence on functional groups and linkers is classified, which can enhance their charge transporting or emitting ability. To offer a potential roadmap for the further development of charge transporting and TADF materials, it is hoped that this study will encourage researchers to acknowledge their important role in OLEDs.

Supramolecular interaction of PCBM with porphyrins in solution: Photophysical insights

This work reports the self-assembly between [6,6]-phenyl C71 butyric acid methyl ester (PCBM) and 2,3,7,8,12,13,17,18-octaethyl-21H,23H porphyrin (1)(and/2,3,7,8,12,13,17,18-octaethyl-21H,23H porphyrin Zn(II) (2) in toluene. Ground state intermolecular interaction is evidenced from absorption spectrophotometric measurements. New absorption bands are observed in the visible region which may be identified due to charge transfer (CT). Several important physicochemical factors are enumerated for PCBM-1 and PCBM-2 systems. Fluorescence investigations elicit complex formation of PCBM with porphyrins (with both 1 and 2) and reveal considerable magnitude of binding constant (K) for PCBM-2 system, i.e., KPCBM-2 = 80,435 dm3⋅mol-1 compared to PCBM-1 system, i.e., KPCM-1 = 12,600 dm3·mol-1 as well as highly ratio of selectivity in binding (KPCBM-2/KPCBM-1 ∼ 6.4). Time resolved fluorescence experiments reveal that photoexcited decay from the excited singlet state of porphyrins (i.e., 1* and 2*) by PCBM is statically controlled compared to dynamic path. Magnitude of solvent reorganization energy indicates possibility of faster charge recombination in case of PCBM-2 system. Both 1H and 13C NMR measurements provide substantial support behind complexation of PCBM with porphyrins (both 1 and 2) in solution. Ab initio calculations in vacuo support the trend in K for PCBM-1 and PCBM-2 systems and establish the proper orientation of PCBM towards 1 (and/ 2) during complexation. Transient absorption measurements establish two different mode of energy transfer pathway from porphyrin to PCBM in toluene.

Advancing mesoporous carbon synthesis for supercapacitors: a systematic investigation of cross-linking agent effects on pore structure and functionality

Soft-templating synthesis provides an effective route to prepare ordered mesoporous carbons (MCs) that can be used for supercapacitors. During this process, the cross-linking of carbon precursors is critical to obtain tailored pore structural MCs, thus careful selection of appropriate cross-linking agents is required. Despite the shift from the prevailing cross-linker formaldehyde to its more environmentally friendly alternatives, detailed understanding on the influence of different cross-linking agents on templating synthesis is still lacking. Therefore, it remains challenging to draw a conclusion regarding which cross-linker can effectively enable an ideal cross-linking and a robust templating synthesis of ordered MCs. This work presents a systematic study, by comparing three typical cross-linkers (formaldehyde, glyoxal, and glyoxylic acid), on the pore architecture, surface functionality, and electrochemical performance of resulting MCs. Both the type of cross-linker and its ratio with precursor monomer were found to be crucial for the pore architecture and electrochemical performance of resulting MCs. Glyoxal showed to be a promising cross-linker for easily generating ordered mesopores between 3.3-6.1 nm when the molar ratio between cross-linker and carbon precursor ranged from 1 to 2, whereas glyoxylic acid and formaldehyde induced interrupted or disordered mesopores. When the resulting MCs were used as supercapacitor electrodes, those cross-linked with glyoxal also led to overall higher capacitance in both 6 M KOH aqueous and ionic liquid [N2220][NTf2]/acetonitrile electrolytes thanks to the dominance of ordered mesopore channels, especially MC prepared at glyoxal/precursor molar ratio of 1.5. These findings on the effect of cross-linking on templating synthesis can be used to guide the customisation of MCs for supercapacitors and other applications by smartly choosing a suitable cross-linking agent and its ratio with the precursor.

Fundamental Limitation in Electrochemical Methane Oxidation to Alcohol: A Review and Theoretical Perspective on Overcoming It

The direct conversion of gaseous methane to energy-dense liquid derivatives such as methanol and ethanol is of profound importance for the more efficient utilization of natural gas. However, the thermo-catalytic partial oxidation of this simple alkane has been a significant challenge due to the high C-H bond energy. Exploiting electrocatalysis for methane activation via active oxygen species generated on the catalyst surface through electrochemical water oxidation is generally considered as economically viable and environmentally benign compared to energy-intensive thermo-catalysis. Despite recent progress in electrochemical methane oxidation to alcohol, the competing oxygen evolution reaction (OER) still impedes achieving high faradaic efficiency and product selectivity. In this review, an overview of current progress in electrochemical methane oxidation, focusing on mechanistic insights on methane activation, catalyst design principles based on descriptors, and the effect of reaction conditions on catalytic performance are provided. Mechanistic requirements for high methanol selectivity, and limitations of using water as the oxidant are discussed, and present the perspective on how to overcome these limitations by employing carbonate ions as the oxidant.

Structural investigations of Au-Ni aerogels: morphology and element distribution

The physical properties of nanomaterials are determined by their structural features, making accurate structural control indispensable. This carries over to future applications. In the case of metal aerogels, highly porous networks of aggregated metal nanoparticles, such precise tuning is still largely pending. Although recent improvements in controlling synthesis parameters like electrolytes, reductants, or mechanical stirring, the focus has always been on one particular morphology at a time. Meanwhile, complex factors, such as morphology and element distributions, are studied rather sparsely. We demonstrate the capabilities of precise morphology design by deploying Au-Ni, a novel element combination for metal aerogels in itself, as a model system to combine common aerogel morphologies under one system for the first time. Au-Ni aerogels were synthesized via modified one- and two-step gelation, partially combined with galvanic replacement, to obtain aerogels with alloyed, heterostructural (novel metal aerogel structure of interconnected nanoparticles and nanochains), and hollow spherical building blocks. These differences in morphology are directly reflected in the physisorption behavior, linking the isotherm shape and pore size distribution to the structural features of the aerogels, including a broad-ranging specific surface area (35-65 m2 g-1). The aerogels were optimized regarding metal concentration, destabilization, and composition, revealing some delicate structural trends regarding the ligament size and hollow sphere character. Hence, this work significantly improves the structural tailoring of metal aerogels and possible up-scaling. Lastly, preliminary ethanol oxidation tests demonstrated that morphology design extends to the catalytic performance. All in all, this work emphasizes the strengths of morphology design to obtain optimal structures, properties, and (performances) for any material application.

Direct electrochemical CO2 conversion using oxygen-mixed gas on a Cu network cathode and tailored anode

Electrochemical CO2 reduction (eCO2R) by direct introduction of 60% air-containing CO2 mixed gas was demonstrated using a porous Cu network cathode formed on a hydrophobic gas diffusion layer (Cu/P-GDL). Cu/P-GDL exhibited eCO2R using the mixed gas with a remarkable faradaic efficiency of 85% for the production of C2+ chemicals, whereas a Cu cathode constructed on a conventional carbon gas diffusion layer (Cu/C-GDL) produced neither eCO2R products nor H2. Furthermore, the electrolyzer with Cu/P-GDL and optimized anode configuration achieved a partial current density of 132 mA cm-2 for C2+ chemicals even in the presence of 12% O2. Demonstration of eCO2R with impure CO2 gas would greatly expand its future applications.

Ultrasonic-Assisted Electrochemical Nanoimprint Lithography: Forcing Mass Transfer to Enhance the Localized Etching Rate of GaAs

Electrochemical nanoimprint lithography (ECNL) has emerged as a promising technique for fabricating three-dimensional micro/nano-structures (3D-MNSs) directly on semiconductor wafers. This technique is based on a localized corrosion reaction induced by the contact potential across the metal/semiconductor boundaries. The anodic etching of semiconductor and the cathodic reduction of electron acceptors occur at the metal/semiconductor/electrolyte interface and the Pt mold surface, respectively. However, the etching rate is limited by the mass transfer of species in the ultrathin electrolyte layer between the mold and the workpiece. To overcome this challenge, we introduce the ultrasonics effect into the ECNL process to facilitate the mass exchange between the ultrathin electrolyte layer and the bulk solution, thereby improving the imprinting efficiency. Experimental investigations demonstrate a positive linear relationship between the reciprocal of the area duty ratio of the mold and the imprinting efficiency. Furthermore, the introduction of ultrasonics improves the imprinting efficiency by approximately 80 %, irrespective of the area duty ratio. The enhanced imprinting efficiency enables the fabrication of 3D-MNSs with higher aspect ratios, resulting in a stronger light trapping effect. These results indicate the prospective applications of ECNL in semiconductor functional devices, such as photoelectric detection and photovoltaics.

Stable trapping of multiple proteins at physiological conditions using nanoscale chambers with macromolecular gates

The possibility to detect and analyze single or few biological molecules is very important for understanding interactions and reaction mechanisms. Ideally, the molecules should be confined to a nanoscale volume so that the observation time by optical methods can be extended. However, it has proven difficult to develop reliable, non-invasive trapping techniques for biomolecules under physiological conditions. Here we present a platform for long-term tether-free (solution phase) trapping of proteins without exposing them to any field gradient forces. We show that a responsive polymer brush can make solid state nanopores switch between a fully open and a fully closed state with respect to proteins, while always allowing the passage of solvent, ions and small molecules. This makes it possible to trap a very high number of proteins (500-1000) inside nanoscale chambers as small as one attoliter, reaching concentrations up to 60 gL-1. Our method is fully compatible with parallelization by imaging arrays of nanochambers. Additionally, we show that enzymatic cascade reactions can be performed with multiple native enzymes under full nanoscale confinement and steady supply of reactants. This platform will greatly extend the possibilities to optically analyze interactions involving multiple proteins, such as the dynamics of oligomerization events.

Fabrication of FRET based nano sensor from biomass-derived fluorescent carbon quantum dots and naphthalimide for ratiometric detection of nitric oxide: To examine nitrite levels in meat samples

Nitric oxide (NO) is a ubiquitous, gaseous, free radical signaling molecule which plays a key role in physiological and pathological processes. Literature reports revealed that the conventional methods such as colorimetry, electron paramagnetic resonance (EPR), electrochemical etc. to detect NO are costly, time consuming and lack resolution, particularly in aqueous or biological system. Thus, in this context, herein we have developed covalently linked biomass derived carbon quantum dots (CQDs) and naphthalimide based nano sensor system for FRET based ratiometric detection of nitric oxide (NO) in pure aqueous media. The CQDs derived from orange peels were characterized using UV-visible absorption, fluorescence spectroscopy, PXRD, TEM, FT-IR and zeta potential studies. Further, the obtained CQDs were functionalized with amine functionality, and subsequently linked with naphthalimide derivative (5) using terephthaldehyde through covalent bond formation. The conjugation of naphthalimide (5) and functionalized CQDs was studied using DLS, zeta potential, FT-IR and time resolved fluorescence spectroscopy. The excitation of developed nano sensor system at λ_ex 360 nm results in fluorescence emission at λ_em 530 nm which establishes the FRET pair between the CQDs and naphthalimide unit. However, in the presence of NO, the observed FRET pair abolishes due to the cleavage of NO susceptible imine bond. The developed sensor demonstrates high selectivity towards NO with limit of detection (LOD) and limit of quantification (LOQ) of 15 nM and 50 nM respectively. Further, the developed sensor system was also utilized for indirect detection of nitrite (NO₂^-) in food samples for food safety and monitoring.

Efficacy of modified carbon molecular sieve with iron oxides or choline chloride-based deep eutectic solvent for the separation of CO2/CH4

It is necessary to separate CO2 from biogas to improve its quality for the production of biomethane. Herein, an improvement in the separation of CO2/CH4via adsorption was achieved by modifying the surface of CMS. The surface modification of CMS was performed by impregnation with metal oxide (Fe3O4) and N-doping (DES-[ChCl:Gly]). Subsequently, the efficacy of the surface-modified CMS was investigated. This involved CMS modification, material characterization, and performance analysis. The uptake of CO2 by CMS-DES-[ChCl:Gly] and CMS-Fe3O4 was comparable; however, their performance for the separation of CO2/CH4 was different. Consequently, CMS-DES-[ChCl:Gly] and CMS-Fe3O4 exhibited ca. 1.6 times enhanced CO2 uptake capacity and ca. 1.70 times and 1.55 times enhanced CO2/CH4 separation, respectively. Also, both materials exhibited similar repeatability. However, CMS-DES-[ChCl:Gly] was more difficult to regenerate than CMS-Fe3O4, which is due to the higher adsorption heat value of the former (59.5 kJ).

Development of nanozyme based sensors as diagnostic tools in clinic applications: a review

Since 1970, many artificial enzymes that imitate the activity and structure of natural enzymes have been discovered. Nanozymes are a group of nanomaterials with enzyme-mimetic properties capable of catalyzing natural enzyme processes. Nanozymes have attracted great interest in biomedicine due to their excellent stability, rapid reactivity, and affordable cost. The enzyme-mimetic activities of nanozymes may be modulated by numerous parameters, including the oxidative state of metal ions, pH, hydrogen peroxide (H2O2) level, and glutathione (GSH) concentration, indicating the tremendous potential for biological applications. This article delivers a comprehensive overview of the advances in the knowledge of nanozymes and the creation of unique and multifunctional nanozymes, and their biological applications. In addition, a future perspective of employing the as-designed nanozymes in biomedical and diagnostic applications is provided, and we also discuss the barriers and constraints for their further therapeutic use.

A NanoCurvS platform for quantitative and multiplex analysis of curvature-sensing proteins

The cell membrane is characterized by a rich variety of topographical features such as local protrusions or invaginations. Curvature-sensing proteins, including the Bin/Amphiphysin/Rvs (BAR) or epsin N-terminal homology (ENTH) family proteins, sense the bending sharpness and the positive/negative sign of these topographical features to induce subsequent intracellular signaling. A number of assays have been developed to study curvature-sensing properties of proteins in vitro, but it is still challenging to probe low curvature regime with the diameter of curvature from hundreds of nanometers to micrometers. It is particularly difficult to generate negative membrane curvatures with well-defined curvature values in the low curvature regime. In this work, we develop a nanostructure-based curvature sensing (NanoCurvS) platform that enables quantitative and multiplex analysis of curvature-sensitive proteins in the low curvature regime, in both negative and positive directions. We use NanoCurvS to quantitatively measure the sensing range of a negative curvature-sensing protein IRSp53 (an I-BAR protein) and a positive curvature-sensing protein FBP17 (an F-BAR protein). We find that, in cell lysates, the I-BAR domain of IRSp53 is able to sense shallow negative curvatures with the diameter-of-curvature up to 1500 nm, a range much wider than previously expected. NanoCurvS is also used to probe the autoinhibition effect of IRSp53 and the phosphorylation effect of FBP17. Therefore, the NanoCurvS platform provides a robust, multiplex, and easy-to-use tool for quantitative analysis of both positive and negative curvature-sensing proteins.

Distilling universal activity descriptors for perovskite catalysts from multiple data sources via multi-task symbolic regression

Developing activity descriptors via data-driven machine learning (ML) methods can speed up the design of highly active and low-cost electrocatalysts. Despite the fact that a large amount of activity data for electrocatalysts is stored in the literature, data from different publications are not comparable due to different experimental or computational conditions. In this work, an interpretable ML method, multi-task symbolic regression, was adopted to learn from data in multiple experiments. A universal activity descriptor to evaluate the oxygen evolution reaction (OER) performance of oxide perovskites free of calculations or experiments was constructed and reached high accuracy and generalization ability. Utilizing this descriptor with Bayesian-optimized parameters, a series of compelling double perovskites with excellent OER activity were predicted and further evaluated using first-principles calculations. Finally, the two ML-predicted nickel-based perovskites with the best OER activity were successfully synthesized and characterized experimentally. This work opens a new way to extend machine-learning material design by utilizing multiple data sources.

A novel test device and quantitative colorimetric method for the detection of human chorionic gonadotropin (hCG) based on Au@Zn-salen MOF for POCT applications

The human chorionic gonadotropin (hCG) hormone is a biomarker that can predict tumors and early pregnancy; however, it is challenging to develop sensitive qualitative-quantitative procedures that are also effective, inventive, and unique. In this study, we used a novel easy in situ reaction of an organic nano-linker with Zn(NO₃)₂·6H₂O and HAuCl₄·3H₂O to produce a gold-zinc-salen metal-organic framework composite known as Au-Zn-Sln-MOF. A wide variety of micro-analytical instruments and spectroscopic techniques were used in order to characterize the newly synthesized Au-Zn-Sln-MOF composite. Disclosure is provided for a novel swab test instrument and a straightforward colorimetric approach for detecting hCG hormone based on an Au-Zn-Sln-MOF composite. Both of these methods are easy. In order to validate a natural enzyme-free immunoassay, an Au-Zn-Sln-MOF composite was utilized in the role of an enzyme; a woman can use this gadget to determine whether or not she is pregnant in the early stages of the pregnancy or whether or not her hCG levels are excessively high, which is a symptom that she may have a tumor. This cotton swab test device is compatible with testing of various biological fluids, such as serum, plasma, or urine, and it can be easily transferred to the market to commercialize it as a costless kit, which will be 20-30% cheaper than what is available on the market. Additionally, it can be used easily at home and for near-patient testing (applications of point-of-care testing (POCT)).

Enhancing the performance of Ni nanoparticle modified carbon felt towards glycerol electrooxidation: impact of organic additive

Organic additives are widely used in the deposition baths of metals and alloys thanks to their special function which affects the growth and the building of the crystal. This study investigates the effect of glycerol on Ni deposition onto carbon felt (CF) and its effect on the catalytic activity towards glycerol electrooxidation. The impact of glycerol on the morphology, distribution, and particle size of the electrodeposited Ni is disclosed using a scanning electron microscope (SEM). X-ray diffraction (XRD), X-ray photoelectron spectroscopy (XPS), and cyclic voltammetry (CV) techniques were used to probe the possible changes of the electrodeposited Ni oxide phases. Electrochemical measurements show that the as-synthesized Ni_0.05@CF electrocatalyst prepared in the presence of 50 mM glycerol has a marked activity towards glycerol electrooxidation, as confirmed by the impressive increase of the oxidation current by about 1.6 times concurrently with a favorable negative shift of its onset potential. Moreover, the charge transfer resistance (R _ct) is much reduced from 140 to 87 ohm. The addition of glycerol to the deposition bath is believed to retard the growth of the formed Ni deposits while enhancing the nucleation rate and thus increases the particle density and, consequently, the distribution of deposited Ni over the entire CF is improved along with increasing the surface concentration and surface-active sites. This assumption is supported by density functional theory (DFT) calculations.

BODIPY-GO nanocomposites decorated with a biocompatible branched ethylene glycol moiety for targeted PDT

The properties of graphene oxide (GO) have received much attention and been applied to the exploration of potential applications in disease-related diagnostics and non-invasive therapy. One application, photodynamic therapy (PDT), involves the killing of cancer cells where singlet oxygen is generated with light irradiation of the appropriate wavelength. In this work, three new BODIPY derivatives (13-15), decorated with carbohydrate moieties for active targeting and branched ethylene glycol for biocompatibility, and their GO based nanocarriers were designed to study the singlet oxygen production and PDT efficiency. First, BODIPYs were prepared, followed by the fabrication of GO layers with BODIPY dyes via a non-covalent method. Detailed characterizations of the materials were carried out with mass spectrometry, FT-IR spectroscopy, ¹H NMR, ¹³C NMR, elemental analysis, Raman spectroscopies, EDX analysis and TEM and AFM microscopies. The efficiency of singlet oxygen generation in organic and water-based solutions was determined by photobleaching with 1,3-diphenylisobenzofuran (DPBF) and 9,10-anthracenediyl-bis(methylene)dimalonic acid (ABDA), respectively. The results in in vitro PDT analysis against K562 human cancer cells indicate the prepared materials are highly promising in PDT anticancer therapy and the IC₅₀ values of GO loaded BODIPY derivatives bearing heavy atoms, GO-14 and GO-15, were calculated as 40.59 nM and 39.21 nM, respectively.

Identification of geographic origins of Morus alba Linn. through surfaced enhanced Raman spectrometry and machine learning algorithms

The leaves of Morus alba Linn., which is also known as white mulberry, have been commonly used in many of traditional systems of medicine for centuries. In traditional Chinese medicine (TCM), mulberry leaf is mainly used for anti-diabetic purpose due to its enrichment in bioactive compounds such as alkaloids, flavonoids and polysaccharides. However, these components are variable due to the different habitats of the mulberry plant. Therefore, geographic origin is an important feature because it is closely associated with bioactive ingredient composition that further influences medicinal qualities and effects. As a low-cost and non-invasive method, surface enhanced Raman spectrometry (SERS) is able to generate the overall fingerprints of chemical compounds in medicinal plants, which holds the potential for the rapid identification of their geographic origins. In this study, we collected mulberry leaves from five representative provinces in China, namely, Anhui, Guangdong, Hebei, Henan and Jiangsu. SERS spectrometry was applied to characterize the fingerprints of both ethanol and water extracts of mulberry leaves, respectively. Through the combination of SERS spectra and machine learning algorithms, mulberry leaves were well discriminated with high accuracies in terms of their geographic origins, among which the deep learning algorithm convolutional neural network (CNN) showed the best performance. Taken together, our study established a novel method for predicting the geographic origins of mulberry leaves through the combination of SERS spectra with machine learning algorithms, which strengthened the application potential of the method in the quality evaluation, control and assurance of mulberry leaves.

Dual-gate thin film transistor lactate sensors operating in the subthreshold regime

Organic thin-film transistors (TFTs) with an electrochemically functionalized sensing gate are promising platforms for wearable health-monitoring technologies because they are light, flexible, and cheap. Achieving both high sensitivity and low power is highly demanding for portable or wearable devices. In this work, we present flexible printed dual-gate (DG) organic TFTs operating in the subthreshold regime with ultralow power and high sensitivity. The subthreshold operation of the gate-modulated TFT-based sensors not only increases the sensitivity but also reduces the power consumption. The DG configuration has deeper depletion and stronger accumulation, thereby further making the subthreshold slope sharper. We integrate an enzymatic lactate-sensing extended-gate electrode into the printed DG TFT and achieve exceptionally high sensitivity (0.77) and ultralow static power consumption (10 nW). Our sensors are successfully demonstrated in physiological lactate monitoring with human saliva. The accuracy of the DG TFT sensing system is as good as that of a high-cost conventional assay. The developed platform can be readily extended to various materials and technologies for high performance wearable sensing applications.

Guest Binding with Sulfated Cyclodextrins: Does the Size of Cavity Matter?

Sulfated cyclodextrins have recently emerged as potential candidates for producing host-induced guest aggregation with properties better than p-sulfonatocalixarenes that have previously shown numerous applications involving the phenomena of host-induced guest aggregation. In the class of sulfated cyclodextrins (SCD), sulfated β-cyclodextrin (β-SCD) remains the most extensively investigated host molecule. Although it is assumed that the host-induced guest aggregation is predominantly an outcome of interaction of the guest molecule with the charges on the exterior of SCD cavity, it has not been deciphered whether the variation in the cavity size will make a difference in the efficiency of host-induced guest-aggregation process. In this investigation, we present a systematic study of host-induced guest aggregation of a cationic molecular rotor dye, Thioflavin T (ThT) with three different sulfated cyclodextrin molecules, α-SCD, β-SCD and γ-SCD, which differ in their cavity size, using steady-state emission, ground-state absorption and time-resolved emission measurements. The obtained photophysical properties of ThT, upon interaction with different SCD molecules, indicate that the binding strength of ThT with different SCD molecules correlate with the cavity size of the host molecule, giving rise to the strongest complexation of ThT with the largest host molecule (γ-SCD). The binding affinity of ThT towards different host molecules has been supported by molecular docking calculations. The results obtained are further supported with the temperature and ionic strength dependent studies performed on the host-guest complex. Our results indicate that for host-induced guest aggregation, involving oppositely charged molecules, the size of the cavity also plays a crucial role beside the charge density on the exterior of host cavity.

Tailor-designed binary Ni-Cu nano dendrites decorated 3D-carbon felts for efficient glycerol electrooxidation

Herein, 3D-Carbon Felt (CF) are decorated with nickel-copper (Ni-Cu@CF) bimetallic nanostructures through either sequential or co-electrodeposition tactics. Their catalytic activity towards glycerol electrooxidation is investigated by employing cyclic voltammetry (CV) and linear sweep voltammetry LSV. The morphology and composition of the various Ni-Cu@CF are investigated using X-ray diffraction (XRD) and field emission scanning electron microscopy (FE-SEM) together with various electrochemical measurements (e.g., CV, chronoamperometry, LSV). The co-deposition of Ni-Cu shows a dendritic-like structure with higher electrocatalytic activity towards glycerol electrooxidation compared to the monometallic counterparts. Interestingly, the best electrode (NiCu@CF Ni particles as the top layer) prepared by sequential electrodeposition shows 1.6-fold higher glycerol oxidation activity, manifested in oxidation current, compared to Ni-coated CF due to Ni particles covering the surface of dendritic copper uniformly. Thus, the surface concentration of Ni is increased and at the same time a synergistic effect occurs between Ni and Cu by the simple addition of Cu which reinforces the surface concentration of Ni from 3.4 × 10-8 to 1.1 × 10-7 mol cm-2.

Optical performance analysis of InP nanostructures for photovoltaic applications

In this article, we have performed a comparative analysis of six different types of nanostructures that can improve photon management for photovoltaic applications. These nanostructures act as anti-reflective structures by improving the absorption characteristics and tailoring the optoelectronic properties of the associated devices. The absorption enhancement in indium phosphide (InP) and silicon (Si) based cylindrical nanowires (CNWs) and rectangular nanowires (RNWs), truncated nanocones (TNCs), truncated nanopyramids (TNPs), inverted truncated nanocones (ITNCs), and inverted truncated nanopyramids (ITNPs) are computed using the finite element method (FEM) based commercial COMSOL Multiphysics package. The influence of geometrical dimensions of the investigated nanostructures such as period (P), diameter (D), width (W), filling ratio (FR), bottom W and D (W_bot/D_bot), and top W and D (W_top/D_top) on the optical performance are analyzed in detail. Optical short circuit current density (J_sc) is computed using the absorption spectra. The results of numerical simulations indicate that InP nanostructures are optically superior to Si nanostructures. In addition to this, the InP TNP generates an optical short circuit current density (J_sc) of 34.28 mA cm⁻², which is ∼10 mA cm⁻² higher than its Si counterpart. The effect of incident angle on the ultimate efficiency of the investigated nanostructures in transverse electric (TE) and transverse magnetic (TM) modes is also explored. Theoretical insights into the design strategies of different nanostructures proposed in this article will act as a benchmark for choosing the device dimensions of appropriate nanostructures for the fabrication of efficient photovoltaic devices.

The optical performance of different indium phosphide (InP) nanostructures are investigated using Wave Optics Module of COMSOL Multiphysics. Our results indicate that InP based nanostructures outperform silicon based nanostructures.

Intramolecular crankshaft-type rearrangement in a photoisomerised glycoconjugate†

High-resolution NMR spectroscopy revealed that a novel glycoconjugate, consisting of two β-glucopyranoses attached to a quinazolinone-like structure, exhibited photoisomerization around the –N–N <svg xmlns="http://www.w3.org/2000/svg" version="1.0" width="13.200000pt" height="16.000000pt" viewBox="0 0 13.200000 16.000000" preserveAspectRatio="xMidYMid meet"><metadata> Created by potrace 1.16, written by Peter Selinger 2001-2019 </metadata><g transform="translate(1.000000,15.000000) scale(0.017500,-0.017500)" fill="currentColor" stroke="none"><path d="M0 440 l0 -40 320 0 320 0 0 40 0 40 -320 0 -320 0 0 -40z M0 280 l0 -40 320 0 320 0 0 40 0 40 -320 0 -320 0 0 -40z"/></g></svg> and CH–C– bonds of the –N–NCH–C– linkage in the same timeframe (the so-called “crankshaft rotation”) upon exposure to UV light. Experimental NMR data combined with DFT calculations discovered that the attachment of carbohydrate residues to photoactive compounds significantly changed the isomerization process and intramolecular rearrangement compared to the unglycosylated system, while the overall molecular structure remained virtually unchanged.

A reversible photoinduced intramolecular crankshaft-type rearrangement in a glycoconjugate proceeds simultaneously at both the –N–N and CH–C– bonds.

Methanol extract of Black soldier fly (Hermetia illucens) prepupae against Aeromonas and Staphylococcus aureus bacteria in vitro and in silico

Background

Staphylococcus and Aeromonas bacteria are pathogens in humans and animals. The therapy disrupts the virulence structure of the bacteria, resulting in bacterial death. Currently, chemical drugs have resulted in many resistant bacteria, so it is necessary to find alternative natural materials that are not toxic and do not quickly induce resistance.

Aims

This study aimed to analyze the potential of methanol extract from Black soldier fly (BSF) prepupae as an antibacterial agent against Staphylococcus aureus and Aeromonas through in silico and in vitro tests.

Methods

The BSF prepupae methanol extract was analyzed for protein and fatty acid contents. Disc diffusion method, minimal inhibitory concentration, and minimum bactericidal concentration test were used for in vitro tests against Staphylococcis and Aeromonas. Molecular docking of the active ingredients (defensin, chitin, and chitosan as well as fatty acids) in BSF was downloaded from the NCBI database and docked by the Hex Cuda version 8.0 program with Correlation type parameters Shape + Electro and Grid Dimension version 0.6. Docking results were analyzed using the Discovery Studio program version 21.1.1.

Results

The highest fatty acid contents in the extract were palmitic acid and myristic acid. Methanol extract from BSF prepupae acted as a bactericidal agent against S. aureus at a concentration of 320 mg/ml, in contrast to Aeromonas, which still showed bacterial growth. The results of the in silico test showed that defensin-aerolysin and defensin-hemolysin was bound to the same active site area. However, the amount of binding energy produced by 69-Defensin-83-aerolysin was higher than all defensin types in BSF against Aeromonas. Chitin and chitosan showed a bond on the active site of aerolysin and hemolysin, but chitosan had a stronger bond than chitin. In silico study also showed the strongest binding affinity of BSF fatty acids to isoleucyl-tRNA synthetase of S. aureus.

Conclusion

The study showed that methanol extract from BSF prepupae had potential capability as an antibacterial agent against S. aureus than Aeromonas in vitro and in silico.

Visible light-induced photoredox catalyzed C-N coupling of amides with alcohols

A visible-light-mediated method for the construction of N-monoalkylated products from easily available benzamides and benzyl alcohol in the presence of eosin Y has been developed. The reaction proceeded smoothly, for a wide range of derivatives of benzamides and benzyl alcohols, to give the desired products in good to excellent yields. Biological studies, such as those on drug-likeness and molecular docking, are carried out on the molecules.

Synergy of R-(-)carvone and cyclohexenone-based carbasugar precursors with antibiotics to enhance antibiotic potency and inhibit biofilm formation

The widespread use of antibiotics in recent decades has been a major factor in the emergence of antibiotic resistances. Antibiotic-resistant pathogens pose increasing challenges to healthcare systems in both developing and developed countries. To counteract this, the development of new antibiotics or adjuvants to combat existing resistance to antibiotics is crucial. Glycomimetics, for example carbasugars, offer high potential as adjuvants, as they can inhibit metabolic pathways or biofilm formation due to their similarity to natural substrates. Here, we demonstrate the synthesis of carbasugar precursors (CSPs) and their application as biofilm inhibitors for E. coli and MRSA, as well as their synergistic effect in combination with antibiotics to circumvent biofilm-induced antibiotic resistances. This results in a biofilm reduction of up to 70% for the CSP rac-7 and a reduction in bacterial viability of MRSA by approximately 45% when combined with the otherwise ineffective antibiotic mixture of penicillin and streptomycin.

Cu-functionalised porous boron nitride derived from a metal-organic framework

Porous boron nitride (BN) displays promising properties for interfacial and bulk processes, e.g. molecular separation and storage, or (photo)catalysis. To maximise porous BN's potential in such applications, tuning and controlling its chemical and structural features is key. Functionalisation of porous BN with metal nanoparticle represents one possible route, albeit a hardly explored one. Metal-organic frameworks (MOFs) have been widely used as precursors to synthesise metal functionalised porous carbon-based materials, yet MOF-derived metal functionalised inorganic porous materials remain unexplored. Here, we hypothesise that MOFs could also serve as a platform to produce metal-functionalised porous BN. We have used a Cu-containing MOF, i.e. Cu/ZIF-8, as a precursor and successfully obtained porous BN functionalised with Cu nanoparticles (i.e. Cu/BN). While we have shown control of the Cu content, we have not yet demonstrated it for the nanoparticle size. The functionalisation has led to improved light harvesting and enhanced electron-hole separation, which have had a direct positive impact on the CO₂ photoreduction activity (production formation rate 1.5 times higher than pristine BN and 12.5 times higher than g-C₃N₄). In addition, we have found that the metal in the MOF precursor impacts porous BN's purity. Unlike Cu/ZIF-8, a Co-containing ZIF-8 precursor led to porous C-BN (i.e. BN with a large amount of C in the structure). Overall, given the diversity of metals in MOFs, one could envision our approach as a method to produce a library of different metal functionalised porous BN samples.

Electronically Conductive Hydrogels by in Situ Polymerization of a Water-Soluble EDOT-Derived Monomer

Electronically conductive hydrogels have gained popularity in bioelectronic interfaces because their mechanical properties are similar to biological tissues, potentially preventing scaring in implanted electronics. Hydrogels have low elastic moduli, due to their high water content, which facilitates their integration with biological tissues. To achieve electronically conductive hydrogels, however, requires the integration of conducting polymers or nanoparticles. These “hard” components increase the elastic modulus of the hydrogel, removing their desirable compatibility with biological tissues, or lead to the heterogeneous distribution of the conductive material in the hydrogel scaffold. A general strategy to transform hydrogels into electronically conductive hydrogels without affecting the mechanical properties of the parent hydrogel is still lacking. Herein, a two‐step method is reported for imparting conductivity to a range of different hydrogels by in‐situ polymerization of a water‐soluble and neutral conducting polymer precursor: 3,4–ethylenedioxythiophene diethylene glycol (EDOT‐DEG). The resulting conductive hydrogels are homogenous, have conductivities around 0.3 S m−1, low impedance, and maintain an elastic modulus of 5–15 kPa, which is similar to the preformed hydrogel. The simple preparation and desirable properties of the conductive hydrogels are likely to lead to new materials and applications in tissue engineering, neural interfaces, biosensors, and electrostimulation.

Investigating the effect of N-doping on carbon quantum dots structure, optical properties and metal ion screening

Carbon quantum dots (CQDs) derived from biomass, a suggested green approach for nanomaterial synthesis, often possess poor optical properties and have low photoluminescence quantum yield (PLQY). This study employed an environmentally friendly, cost-effective, continuous hydrothermal flow synthesis (CHFS) process to synthesise efficient nitrogen-doped carbon quantum dots (N-CQDs) from biomass precursors (glucose in the presence of ammonia). The concentrations of ammonia, as nitrogen dopant precursor, were varied to optimise the optical properties of CQDs. Optimised N-CQDs showed significant enhancement in fluorescence emission properties with a PLQY of 9.6% compared to pure glucose derived-CQDs (g-CQDs) without nitrogen doping which have PLQY of less than 1%. With stability over a pH range of pH 2 to pH 11, the N-CQDs showed excellent sensitivity as a nano-sensor for the highly toxic highly-pollutant chromium (VI), where efficient photoluminescence (PL) quenching was observed. The optimised nitrogen-doping process demonstrated effective and efficient tuning of the overall electronic structure of the N-CQDs resulting in enhanced optical properties and performance as a nano-sensor.

Complexities in Modeling Organic Aerosol Light Absorption

Aerosol particles dynamically evolve in the atmosphere by physicochemical interactions with sunlight, trace chemical species, and water. Current modeling approaches fix properties such as aerosol refractive index, introducing spatial and temporal errors in the radiative impacts. Further progress requires a process-level description of the refractive indices as the particles age and experience physicochemical transformations. We present two multivariate modeling approaches of light absorption by brown carbon (BrC). The initial approach was to extend the modeling framework of the refractive index at 589 nm (nD), but that result was insufficient. We developed a second multivariate model using aromatic rings and functional groups to predict the imaginary part of the complex refractive index. This second model agreed better with measured spectral absorption peaks, showing promise for a simplified treatment of BrC optics. In addition to absorption, organic functionalities also alter the water affinity of the molecules, leading to a hygroscopic uptake and increased light absorption, which we show through measurements and modeling.

DNA-aptamer-nanographene oxide as a targeted bio-theragnostic system in antimicrobial photodynamic therapy against Porphyromonas gingivalis

The aim of this study was to design and evaluate the specificity of a targeted bio-theragnostic system based on DNA-aptamer-nanographene oxide (NGO) against Porphyromonas gingivalis during antimicrobial photodynamic therapy (aPDT). Following synthesis and confirmation of NGO, the binding of selected labeled DNA-aptamer to NGO was performed and its hemolytic activity, cytotoxic effect, and release times were evaluated. The specificity of DNA-aptamer-NGO to P. gingivalis was determined. The antimicrobial effect, anti-biofilm potency, and anti-metabolic activity of aPDT were then assessed after the determination of the bacteriostatic and bactericidal concentrations of DNA-aptamer-NGO against P. gingivalis. Eventually, the apoptotic effect and anti-virulence capacity of aPDT based on DNA-aptamer-NGO were investigated. The results showed that NGO with a flaky, scale-like, and layered structure in non-cytotoxic DNA-aptamer-NGO has a continuous release in the weak-acid environment within a period of 240 h. The binding specificity of DNA-aptamer-NGO to P. gingivalis was confirmed by flow cytometry. When irradiated, non-hemolytic DNA-aptamer-NGO were photoactivated, generated ROS, and led to a significant decrease in the cell viability of P. gingivalis (P < 0.05). Also, the data indicated that DNA-aptamer-NGO-mediated aPDT led to a remarkable reduction of biofilms and metabolic activity of P. gingivalis compared to the control group (P < 0.05). In addition, the number of apoptotic cells increased slightly (P > 0.05) and the expression level of genes involved in bacterial biofilm formation and response to oxidative stress changed significantly after exposure to aPDT. It is concluded that aPDT using DNA-aptamer-NGO as a targeted bio-theragnostic system is a promising approach to detect and eliminate P. gingivalis as one of the main bacteria involved in periodontitis in periopathogenic complex in real-time and in situ.

Oxygenating Biocatalysts for Hydroxyl Functionalisation in Drug Discovery and Development

C-H oxyfunctionalisation remains a distinct challenge for synthetic organic chemists. Oxygenases and peroxygenases (grouped here as "oxygenating biocatalysts") catalyse the oxidation of a substrate with molecular oxygen or hydrogen peroxide as oxidant. The application of oxygenating biocatalysts in organic synthesis has dramatically increased over the last decade, producing complex compounds with potential uses in the pharmaceutical industry. This review will focus on hydroxyl functionalisation using oxygenating biocatalysts as a tool for drug discovery and development. Established oxygenating biocatalysts, such as cytochrome P450s and flavin-dependent monooxygenases, have widely been adopted for this purpose, but can suffer from low activity, instability or limited substrate scope. Therefore, emerging oxygenating biocatalysts which offer an alternative will also be covered, as well as considering the ways in which these hydroxylation biotransformations can be applied in drug discovery and development, such as late-stage functionalisation (LSF) and in biocatalytic cascades.

From Light to Structure: Photo Initiators for Radical Two-Photon Polymerization

Two-photon polymerization (2PP) represents a powerful technique for the fabrication of precise three-dimensional structures on a micro- and nanometer scale for various applications. While many review articles are focusing on the used polymeric materials and their application in 2PP, in this review the class of two-photon photo initiators (2PI) used for radical polymerization is discussed in detail. Because the demand for highly efficient 2PI has increased in the last decades, different approaches in designing new efficient 2PIs occurred. This review summarizes the 2PIs known in literature and discusses their absorption behavior under one- and two-photon absorption (2PA) conditions, their two-photon cross sections (σ_TPA ) as well as their efficiency under 2PP conditions. Here, the photo initiators are grouped depending on their chromophore system (D-π-A-π-D, D-π-D, etc.). Their polymerization efficiencies are evaluated by fabrication windows (FW) depending on different laser intensities and writing speeds.

New Mechanism for Long Photo-Induced Enhanced Raman Spectroscopy in Au Nanoparticles Embedded in TiO2

The photo-induced enhanced Raman spectroscopy (PIERS) effect is a phenomenon taking place when plasmonic nanoparticles deposited on a semiconductor are illuminated by UV light prior to Raman measurement. Results from the literature show that the PIERS effect lasts for about an hour. The proposed mechanism for this effect is the creation of oxygen vacancies in the semiconductor that would create a path for charge transfer between the analyte and the nanoparticles. However, this hypothesis has never been confirmed experimentally. Furthermore, the tested structure of the PIERS substrate has always been composed of plasmonic nanoparticles deposited on top of the semiconductor. Here, gold nanoparticles co-deposited with porous TiO₂ are used as a PIERS substrate. The deposition process confers the nanoparticles a unique position half buried in the nanoporous semiconductor. The resulting PIERS intensity is among the highest measured until now but most importantly the duration of the effect is significantly longer (at least 8 days). Cathodoluminescence measurements on these samples show that two distinct mechanisms are at stake for co-deposited and drop-casted gold nanoparticles. The oxygen vacancies hypothesis tends to be confirmed for the latter, but the narrowing of the depletion zone explains the long PIERS effect.

A Kinetically Superior Rechargeable Zinc-Air Battery Derived from Efficient Electroseparation of Zinc, Lead, and Copper in Concentrated Solutions

Zinc electrodeposition is currently a hot topic because of its widespread use in rechargeable zinc-air batteries. However, Zn deposition has received little attention in organic solvents with much higher ionic conductivity and current efficiency. In this study, a Zn-betaine complex is synthesized by using ZnO and betainium bis[(trifluoromethyl)sulfonyl]imide and its electrochemical behavior for six organic solvents and electrodeposited morphology are studied. Acetonitrile allowed dendrite-free Zn electrodeposition at room temperature with current efficiencies of up to 86 %. From acetonitrile solutions in which Zn, Pb, and Cu complexes are dissolved in high concentrations, Zn and Pb/Cu are efficiently separated electrolytically under potentiostatic control, allowing the purification of solutions prepared directly from natural ores. Additionally, a highly flexible Zn anode with excellent kinetics is obtained by using a carbon fabric substrate. A rechargeable zinc-air battery with these electrodes shows an open-circuit voltage of 1.63 V, is stable for at least 75 cycles at 0.5 mA cm^-2 or 33 cycles at 20 mA cm^-2 , and allows intermediate cycling at 100 mA cm^-2 .