Search Results (19)

Hierarchical porous N-doped carbon spheres featuring a combination of micropores, mesopores and macropores as well as tuneable properties were synthesised using dopamine as a carbon precursor and triblock copolymers (F127, P123 and F127/P123 composites) as templates via direct polymerisation-induced self-assembly. The structures and textures of these materials were characterised using X-ray diffraction, scanning electron microscopy, transmission electron microscopy, N₂ adsorption–desorption isotherm analysis, Fourier-transform infrared spectroscopy, Raman spectroscopy and X-ray photoelectron spectroscopy. The sample synthesised at an F127:P123 molar ratio of 1:3 (NCS-FP3) exhibited the highest surface area (463 m²/g) and pore volume (0.27 cm³/g). The hydrophobic/hydrophilic molar ratios of the templates were adjusted to control the morphology of the corresponding micelles and hence the porous structures and morphologies of the carbon spheres, which exhibited high CO₂ capture capacities (2.90–3.46 mmol/g at 273 K and 760 mmHg) because of their developed microporous structures and N doping. Additionally, NCS-FP3 exhibited an outstanding electrochemical performance, achieving a high specific capacitance (328.3 F/g at a current density of 0.5 A/g) and outstanding cycling stability (99.2% capacitance retention after 10,000 cycles). These high CO₂ capture and electrochemical performances were ascribed to the beneficial effects of pore structures and surface chemistry features. Full article

Vitamins are crucial micro-nutrients for overall well-being, making continuous monitoring essential. There are demands to provide an alternative detection, especially using a portable detection or a point-of-care-testing (POCT) device. One promising approach is employing an in situ electro-polymerised MIP (eMIP), which offers a straightforward polymerisation technique on screen-printed electrodes (SPEs). Here, we report a review based on three databases (PubMed, Scopus, and Web of Science) from 2014 to 2024 using medical subject heading (MeSH) terms “electrochemical polymerisation” OR “electropolymerisation” crossed with the terms “molecularly imprinted polymer” AND “vitamin A” OR “vitamin D” OR “vitamin E” OR “vitamin K” OR “fat soluble vitamin” OR “vitamin B” OR “vitamin C” OR “water soluble vitamin”. The resulting 12 articles covered the detection of vitamins in ascorbic acid, riboflavin, cholecalciferol, calcifediol, and menadione using monomers of catechol (CAT), 3,4-ethylenedioxythiophene (EDOT), o-aminophenol (oAP), o-phenylenediamine (oPD), pyrrole, p-aminophenol (pAP), p-phenylenediamine (pPD), or resorcinol (RES), using common bare electrodes including graphite rod electrode (GRE), glassy carbon electrode (GCE), gold electrode (GE), and screen-printed carbon electrode (SPCE). The most common electrochemical detections were differential pulse voltammetry (DPV) and linear sweep voltammetry (LSV). The imprinting factor (IF) of the eMIP-modified electrodes were from 1.6 to 21.0, whereas the cross-reactivity was from 0.0% to 29.9%. Several types of food and biological samples were tested, such as supplement tablets, poultry and pharmaceutical drugs, soft drinks, beverages, milk, infant formula, human and calf serum, and human plasma. However, more discoveries and development of detection methods needs to be performed, especially for the vitamins that have not been studied yet. This will allow the improvement in the application of eMIPs on portable-based detection and POCT devices. Full article

A class of hybrid molecularly imprinted polymeric nanoparticles (nanoMIPs) comprising the in situ formation of gold nanoparticles (AuNPs) immobilised in a molecularly imprinted D-gluconate polymer has been designed with the objective of attempting the electrochemical quantification of gluconic acid (GA) in a wine setting. The imprinted polymers were synthesised in the presence of AuNP precursors in a pre-polymerisation mixture, which were confined to one another during the polymerisation of the chains. This allowed the formation of hybrid electroactive responsive imprinted nanoparticles (hybrid AuNPs@GA-nanoMIP), which exhibited enhanced electron conductivity. The morphological characterisation of the produced nanoMIPs revealed a fully decorated Au spherical surface of 200 nm in diameter. This resulted in a large active surface area distribution, as well a pronounced electrochemical peak response at the commercial screen-printed platinum electrode (SPPtE), accompanied by enhanced electron kinetics. The AuNPs@GA-nanoMIP sensor demonstrated the ability to detect a broad range of GA concentrations (0.025–5 mg/mL) with exceptional selectivity and reproducibility. The calibration curves were fitted with different isotherm models, such as the Langmuir, Freundlich and Langmuir–Freundlich functions. Moreover, the efficacy of the detection method was demonstrated by the recovery rates observed in real samples of Italian red wine. This research contributes to the development of a robust and reliable electrochemical sensor for the on-site determination of gluconic acid in food analysis. Full article

The need for sustainable energy solutions is steering research towards green fuels. One promising approach involves electrocatalytic gas conversion, which requires efficient catalyst surfaces. This study focuses on developing and testing a hydrophobic octadiene (OD) coating for potential use in electrocatalytic gas conversion. The approach aims to combine a plasma-deposited hydrophobic coating with air-trapping micro- and nanotopographies to increase the yield of electrocatalytic reactions. Plasma polymerisation was used to deposit OD films, chosen for their fluorine-free non-polar properties, onto titanium substrates. We assessed the stability and charge permeability of these hydrophobic coatings under electrochemical conditions relevant to electrocatalysis. Our findings indicate that plasma-deposited OD films, combined with micro-texturing, could improve the availability of reactant gases at the catalyst surface while limiting water access. In the presence of nanotextures, however, the OD-coated catalyst did not retain its hydrophobicity. This approach holds promise to inform the future development of catalyst materials for the electrocatalytic conversion of dinitrogen (N₂) and carbon dioxide (CO₂) into green fuels. Full article

Herein, chemometric-assisted synthesis of electrochemical sensors based on electropolymerised ion-imprinted polymeric (e-IIP) films was explored. Co(II)-IIPs sensors were prepared by performing electropolymerisation procedures of polymerisation mixtures comprising varying concentrations of an electroactive o-aminophenol (o-AP) monomer and Co(II) ions, respectively, according to the Taguchi L9 experimental design, exploiting the simultaneous evaluation of other controlled parameters during electrosynthesis. Each e-IIP developed from Taguchi runs was compared with the respective non-imprinted polymer (NIP) films and fitted according to Langmuir–Freudlich isotherms. Distinctive patterns of low and high-affinity films were screened based on the qualities and properties of the developed IIPs in terms of binding kinetics (KD), imprinting factor, and the heterogeneity index of produced cavities. These results can provide a generic protocol for chemometric-assisted synthesis of e-IIPs based on poly-o-AP, providing highly stable, reproducible, and high-affinity imprinted polymeric films for monitoring purposes. Full article

Polypyrrole films are commonly prepared as conductive electrode surfaces for a variety of applications. Recently, there has been increasing interest in improving the adhesive properties and biocompatibility of polypyrrole electrodes via the incorporation of bioinspired polydopamine within the polymer scaffold. However, very little is currently known about the structural effects of polydopamine incorporation during the electropolymerisation of hybrid films. In this work, we combine electrochemical quartz crystal microbalance studies, fundamental electrochemical characterisation, atomic force microscopy, and a suite of spectroscopic techniques in order to correlate changes in the structure and performance of polypyrrole–polydopamine films to the structural modifications of the nanostructure induced by polydopamine incorporation. The results indicate that polydopamine incorporation greatly increases the rate of hybrid film deposition, as well as improving adhesion, surface homogeneity, and wettability, with no compromise in charge transfer properties. Polydopamine incorporation is strongly suggested to occur in non-connected domains within a predominantly polypyrrole-like scaffold. We propose a two-step model of co-polymerisation and the subsequent surface adhesion of hybrid films. Results are expected to be of broad general interest to researchers utilizing polypyrrole and polydopamine to prepare tailor-made electrodes for biosensing and catalysis. Full article

Three novel dibenzo-18-crown-6 aldimines were successfully synthesised and structurally characterised via various spectroscopic methods (¹H,¹³H NMR, FT-IR) and their solution phase lead binding behaviours probed via absorption spectroscopy, the results are supported by Density Functional Theoretical (DFT) modelling. These methods revealed that the asymmetric nature of these compounds is such that at equilibrium the ether cavity adopts an open configuration where the constituent oxygen atoms exhibit a highly negative electrostatic potential; hence, they spontaneously (ΔG~−58 kJ mol⁻¹) interact/bind aqueous lead ions to form stable 2:1 metal–ligand complexes. As indicated by cyclic and square voltammetry studies, all compounds are redox active and polymerise relatively easily onto a platinum surface to form a multi-layered lead Ion-selective Membrane (ISM), the structure of which is confirmed by Scanning Electron Microscopy (SEM) and Electrochemical Impedance Spectroscopy (EIS). These novel Ion-selective Electrodes (ISEs), as characterised by Differential Pulse Anodic Stripping Voltammetry (D PASV), allow selective electrochemical detection and quantification of lead at concentrations as low as 10 ppm, over a range of 15–60 ppm, with only minimal interference from mercury(II) and aluminium(III) ions at a 1:1 analyte-interferent ratio. Full article

Although zinc (Zn) is one of the elements with the greatest potential for biodegradable uses, pure Zn does not have the ideal mechanical or degrading properties for orthopaedic applications. The current research aims at studying the microstructure and corrosion behaviour of pure Zn (used as a reference material) and Zn alloyed with 1.89 wt.% magnesium (Mg), both in their extruded states as well as after being coated with polymethyl methacrylate (PMMA). The grafting-from approach was used to create a PMMA covering. The “grafting-from” method entails three steps: the alkali activation of the alloys, their functionalization with an initiator of polymerization through a phosphonate-attaching group, and the surface-initiated atom transfer radical polymerisation (SI-ATRP) to grow PMMA chains. Electrochemical and immersion corrosion tests were carried out in a simulated body fluid (SBF), and both confirmed the enhanced corrosion behaviour obtained after coating. The electrochemical test revealed a decrease in the degradation rate of the alloy from 0.37 ± 0.14 mm/y to 0.22 ± 0.01 mm/y. The immersion test showed the ability of complete protection for 240 h. After 720 h of immersion, the coated alloy displays minute crevice corrosion with very trivial pitting compared to the severe localized (galvanic and pitting) corrosion type that was detected in the bare alloy. Full article

Rutin (RU) is one of the best-known natural antioxidants with various physiological functions in the human body and other plant species. In this work, an efficient voltammetric sensor to detect RU in food samples was explicated using a poly (glutamic acid)-modified graphene paste electrode (PGAMGPE). In order to detect RU, the proposed sensor diminishes material resistance and overpotential while increasing kinetic rate, peak currents, and material conductance. Using differential pulse voltammetry (DPV) and cyclic voltammetry (CV), the analysing efficiency of a PGAMGPE and a Bare graphene paste electrode (BGPE) was evaluated in 0.2 M phosphate buffer (PB) at an ideal pH of 6.5. in a potential window of −0.25 V to 0.6 V. Electrochemical impedance spectroscopy (EIS) was used to analyse the prepared electrode materials’ conductivity, charge transfer resistance, and the kinetics of electron transport. Field emission scanning electron microscopy (FE-SEM) images were considered to compare the exterior morphology of the PGAMGPE and the BGPE. It was discovered that the PGAMGPE and the BGPE have electroactive surfaces of 0.062 cm² and 0.04 cm², respectively. It was determined that two protons and two electrons participated in the redox process. The resultant limit of detection (LOD) was found to be 0.04 µM and 0.06 µM, respectively, using DPV and CV methods. In spite of common interferents such as metal ions and chemical species, the developed sensor’s selectivity for RU detection was impressive. For the simultaneous analysis of RU in the presence of caffeine (CF), the PGAMGPE affords a good electrochemical nature for RU with good selectivity. Due to the good stability, repeatability, reproducibility, and ease of use of the present RU sensor, it is useful for real sample analysis such as food and medicinal samples with recovery ranging from 94 to 100%. Full article

This paper is to discuss the potential of using CuZn in an electrical biosensor drug carrier for drug delivery systems. CuZn is the main semiconductor ingredient that has great promise as an electrochemical detector to trigger releases of active pharmaceutical ingredients (API). This CuZn biosensor is produced with a green metal of frameworks, which is an anion node in conductive polymers linked by bioactive ligands using metal–polymerisation technology. The studies of Cu, Zn, and their oxides are highlighted by their electrochemical performance as electrical biosensors to electrically trigger API. The three main problems, which are glucose oxidisation, binding affinity, and toxicity, are highlighted, and their solutions are given. Moreover, their biocompatibilities, therapeutic efficacies, and drug delivery efficiencies are discussed with details given. Our three previous investigations of CuZn found results similar to those of other authors’ in terms of multiphases, polymerisation, and structure. This affirms that our research is on the right track, especially that related to green synthesis using plant extract, CuZn as a nanochip electric biosensor, and bioactive ligands to bind API, which are limited to the innermost circle of the non-enzymatic glucose sensor category. Full article

Coating conducting polymers onto active cathode materials has been proven to mitigate issues at high current densities stemming from the limited conducting abilities of the metal-oxides. In the present study, a carbon coating was applied onto nickel-rich NMC622 via polymerisation of furfuryl alcohol, followed by calcination, for the first time. The formation of a uniform amorphous carbon layer was observed with scanning- and transmission-electron microscopy (SEM and TEM) and X-ray photoelectron spectroscopy (XPS). The stability of the coated active material was confirmed and the electrochemical behaviour as well as the cycling stability was evaluated. The impact of the heat treatment on the electrochemical performance was studied systematically and was shown to improve cycling and high current performance alike. In-depth investigations of polymer coated samples show that the improved performance can be correlated with the calcination temperatures. In particular, a heat treatment at 400 °C leads to enhanced reversibility and capacity retention even after 400 cycles. At 10C, the discharge capacity for carbon coated NMC increases by nearly 50% compared to uncoated samples. This study clearly shows for the first time the synergetic effects of a furfuryl polymer coating and subsequent calcination leading to improved electrochemical performance of nickel-rich NMC622. Full article

Conductive hydrogel-based materials are attracting considerable interest for bioelectronic applications due to their ability to act as more compatible soft interfaces between biological and electrical systems. Despite significant advances that are being achieved in the manufacture of hydrogels, precise control over the topographies and architectures remains challenging. In this work, we present for the first time a strategy to manufacture structures with resolutions in the micro-/nanoscale based on hydrogels with enhanced electrical properties. Gelatine methacrylate (GelMa)-based inks were formulated for two-photon polymerisation (2PP). The electrical properties of this material were improved, compared to pristine GelMa, by dispersion of multi-walled carbon nanotubes (MWCNTs) acting as conductive nanofillers, which was confirmed by electrochemical impedance spectroscopy and cyclic voltammetry. This material was also confirmed to support human induced pluripotent stem cell-derived cardiomyocyte (hPSC-CMs) viability and growth. Ultra-thin film structures of 10 µm thickness and scaffolds were manufactured by 2PP, demonstrating the potential of this method in areas spanning tissue engineering and bioelectronics. Though further developments in the instrumentation are required to manufacture more complex structures, this work presents an innovative approach to the manufacture of conductive hydrogels in extremely low resolution. Full article

The easy and rapid spread of bacterial contamination and the risk it poses to human health makes evident the need for analytical methods alternative to conventional time-consuming laboratory-based techniques for bacterial detection. To tackle this demand, biosensors based on isothermal DNA amplification methods have emerged, which avoid the need for thermal cycling, thus facilitating their integration into small and low-cost devices for in situ monitoring. This review focuses on the breakthroughs made on biosensors based on isothermal amplification methods for the detection of bacteria in the field of food safety and environmental monitoring. Optical and electrochemical biosensors based on loop mediated isothermal amplification (LAMP), rolling circle amplification (RCA), recombinase polymerase amplification (RPA), helicase dependent amplification (HDA), strand displacement amplification (SDA), and isothermal strand displacement polymerisation (ISDPR) are described, and an overview of their current advantages and limitations is provided. Although further efforts are required to harness the potential of these emerging analytical techniques, the coalescence of the different isothermal amplification techniques with the wide variety of biosensing detection strategies provides multiple possibilities for the efficient detection of bacteria far beyond the laboratory bench. Full article

Polypyrrole is a classical, well-known conjugated polymer that is produced from a simple heterocyclic system. Numerous pyrrole derivatives exhibit biological activity, and the repeat unit is a common building block present in the chemical structure of many polymeric materials, finding wide application, primarily in optoelectronics and sensing. In this work, we focus on the variety of copolymers and their material properties that can be produced electrochemically, even though all these systems are obtained from mixtures of the “simple” pyrrole monomer and its derivatives with different conjugated and non-conjugated species. Full article

Two novel low band gap donor–acceptor (D–A) copolymers, poly[9,10-bis(4-(dodecyloxy)phenyl)-2,6-anthracene-alt-5,5-(4′,7′-bis(2-thienyl)-2′,1′,3′-benzothiadiazole-N-5,6-(3,7-dimethyloctyl)dicarboxylic imide)] (PPADTBTDI-DMO) and poly[9,10-bis(4-(dodecyloxy)phenyl)-2,6-anthracene-alt-5,5-(4′,7′-bis(2-thienyl)-2′,1′,3′-benzothiadiazole-5,6-N-octyl-dicarboxylic imide)] (PPADTBTDI-8) were synthesized in the present work by copolymerising the bis-boronate ester of 9,10-phenylsubstituted anthracene flanked by thienyl groups as electron–donor units with benzothiadiazole dicarboxylic imide (BTDI) as electron–acceptor units. Both polymers were synthesized in good yields via Suzuki polymerisation. Two different solubilizing alkyl chains were anchored to the BTDI units in order to investigate the impact upon their solubilities, molecular weights, optical and electrochemical properties, structural properties and thermal stability of the resulting polymers. Both polymers have comparable molecular weights and have a low optical band gap (E_g) of 1.66 eV. The polymers have low-lying highest occupied molecular orbital (HOMO) levels of about −5.5 eV as well as the similar lowest unoccupied molecular orbital (LUMO) energy levels of −3.56 eV. Thermogravimetric analyses (TGA) of PPADTBTDI-DMO and PPADTBTDI-8 did not prove instability with decomposition temperatures at 354 and 313 °C, respectively. Powder X-ray diffraction (XRD) studies have shown that both polymers have an amorphous nature in the solid state, which could be used as electrolytes in optoelectronic devices. Full article