Electroactive Properties Research Articles

Nanoclay composites in electrochemical sensors

Nanoclays are layered structures in the nanoscale range with widespread application due to their unique properties such as swelling, cation exchange capacity, and ease of functionalisation using metals, metal oxides, and organic compounds such as carbon paste, polymers, and other biomolecules that form nanoclay composites. Nanoclay functionalisation with silver (Ag), zinc oxide (ZnO), and bimetallic silver–gold (Ag–Au) using hydrophilic and hydrophobic clays is here evaluated and discussed. The composites’ synthesis and morphological, crystallinity, and electroactive properties in comparison with pure nanoclay are also assessed. The layered structure and crystallinity of all these nanoclay composites were slightly changed. The clumped layered structures on the surface of the nanocomposites had dispersed white spots that indicated possible surface modification. The nano-films of the composites’ electroactivity were comparatively high, as seen from the increase in current in the cyclic voltammetry characterisation voltammograms and the differential pulse voltammograms of the pharmaceutical detection. Efavirenz, nevirapine, and zidovudine detection was improved by modification of the nanocomposite with human serum albumin (HSA), as shown by the higher current, thus indicating improved conductivity of the composites compared to the pure nanoclays. Applying HAS-modified nanocomposites in the analysis of efavirenz, nevirapine, and zidovudine on a glassy carbon electrode (GCE) showed good linearity and acceptable detection limits comparable to those of previous studies. Therefore, it has potential for application in pharmaceutical quality control and environmental monitoring.

Amperometric Determination of Dopamine and Ascorbic Acid with a Carbon Paste‐Yttrium Oxide Electrode

AbstractThis report presents a new application for yttrium oxide (YOX) in the modification of carbon paste electrodes with excellent electroactivity for the independent detection of dopamine (DA) and ascorbic acid (AA). The surface of the YOX‐modified electrode was characterized with SEM and EDS. The electroactive properties of DP and AA were studied with cyclic voltammetry (CV), square wave voltammetry (SWV) and amperometry (Am). The activity of DA and AA increased by more than 100 % when YOX/CPE was used, which allowed us to obtain detection limits of 0.04 and 0.06 μmol/L for DA and AA, respectively. The usefulness of YOX/CPE was tested with real human urine, fresh orange juice and vitamin C tablets, and the results were acceptable.

Spray-coated PDA-wrapped carboxylic CNT/PES membrane to augment fouling mitigation, organic removal, and membrane stability in electrochemical membrane filtration

This study introduces robust and conductive polydopamine (PDA)-wrapped carboxylic carbon nanotube (C-CNT)-coated polyethersulfone (PES) membrane for electrochemical membrane filtration to treat greywater. Self-polymerized dopamine was prepared directly under oxidative conditions on the CNT strands, followed by their immobilizations on the surface of the PES membrane through a novel spray-coating technique. The spraying coating technique improved both the durability of the coating layer and membrane permeability by 27 % higher than that prepared by the conventional vacuum filtration method. The spraying coating technique enhanced the electroactive properties of the PDA/C-CNT membrane so that the fouling rate was reduced more effectively than the C-CNT membrane or bare PES membrane. Fouling mitigation of the PDA/C-CNT membrane was attributed to the combined effect of electrostatic repulsions between the foulants and the conductive membrane surface along with degradation of organic compounds by electrochemical oxidation. The constant current density profile also confirmed the structural stability of the conductive layer on the membrane under both cathodic and anodic conditions. Furthermore, the fouling layer formed by membrane filtration was removed effectively by in-situ anodic cleaning. Over 80% of water permeability was recovered without losing the membrane integrity up to 3 consecutive anodic cleaning cycles.

Composite PEDOT-PSS based highly sensitive electrochemical sensors for sensing glucose from human saliva

Here we report two composites, especially two different 2D materials and Au nanoparticle composite with conducting polymer PEDOT-PSS as electrodes for highly sensitive, cost effective and reliable biosensors. Conducting polymer composite electrodes of AuNP/WS2/PEDOT-PSS and AuNP/GO/PEDOT-PSS were prepared by electrochemical deposition and were studied using various structural and electrochemical techniques. XRD, FTIR and SEM have been used for structural characterization which confirmed the elemental compositions of these composite electrodes. Electrochemical Impedance Spectroscopy (EIS) and Cyclic Voltammetry (CV) were used to examine the charge transfer kinetics and electroactive properties of the modified electrodes. Impedance spectra analysis had shown the reduced charge transfer resistance and diffusive property of AuNP/WS2/PEDOT-PSS electrodes compared to AuNP/GO/PEDOT-PSS. To demonstrate biosensing advantages of these electrodes, interaction between covalently immobilized glucose oxidase (GlOx) enzyme and D-glucose was monitored via chronoamperometry and CV. GlOx/AuNP/WS2/PEDOT-PSS/ITO yielded wider linear range from 0.74 to 440.67 µM towards the oxidation of glucose with high selectivity and lower limit of detection (LOD) of 1 µM. AuNP/GO/PEDOT-PSS/ITO composite electrode exhibited linearity in the range 3.84–373.33 µM and LOD 2.33 µM. Better sensitivity and wider linear range of GlOx/AuNP/WS2/PEDOT-PSS/ITO has been assigned to special layered structure as sheets formed by incorporation of WS2 to PEDOT-PSS. Validation of the glucose sensors has shown satisfactory results using real saliva samples. Study suggests use of conducting polymer, 2D layered material and metal nanoparticle composite electrodes based sensors offer wider linearity range and higher sensitivity for stable, reliable, cost- effective sensor electrodes which can be used easily in non-clinical diagnostics.

Role of Annealing with Electric Field Toward Improvement of Ferroelectric and Electroactive Properties of PVDF Copolymer and Terpolymer Thin Films.

The present study elucidates the role of annealing with electric field on lamellar crystalline structure and molecular orientation of polymer chains in ferroelectric copolymer (P(VDF-TrFE)) and ferroelectric terpolymer (P(VDF-TrFE-CFE)) spin-coated thin films. The ferroelectric polymer thin films annealed under an electric field support the growth of nanostructure with an "edge-on" lamellar crystalline structure having in-plane molecular chain orientation. The poled P(VDF-TrFE) thin films have higher remnant polarization (Pr) ≈6.2µCcm-2 and saturation polarization (Ps) ≈8.2µCcm-2 at an applied electric field of 250 MV/m compared to unpoled thin films having Pr ≈4.7 and Ps ≈6.2µCcm-2. Also, poled P(VDF-TrFE) thin films show lower coercive field (Ec) ≈94 MV/m compared to an unpoled thin film having Ec ≈105 MV/m. Similarly, poled PVDF-TrFE-CFE thin film shows better ferroelectric properties having Pr ≈0.4 and Ps ≈5.7µCcm-2 at an applied electric field of 200 MVm-1 compared to unpoled thin films having Pr ≈0.4 and Ps ≈4.1µCcm-2. The storage energy efficiency of unpoled and poled P(VDF-TrFE-CFE) thin films is measured to be ≈75% and 80%. Annealing of ferroelectric P(VDF-TrFE) polymer thin films under an electric field demonstrates improved ferroelectric and electroactive properties.

Modeling solid-state reaction processes: application for the archaeometric study of potteries from Venus Fisica Temple in Pompeii (Italy)

AbstractThis research employs the voltammetry of immobilized microparticles (VIMP) methodology to analyze a collection of ceramic samples from the temple of Venus Fisica in the archaeological site of Pompeii. The primary objective is to discern their origins and manufacturing processes by the solid-state analysis of the electroactive properties of iron minerals, particularly hematite, extensively investigated for its electrochemical and catalytic characteristics. In our study, we propose a model to elucidate the electrochemical processes involved, building upon prior logistic and nucleation formulations. In this model, we consider the possibility of two superimposed pathways. This approach provides a nuanced understanding of composition changes and mineral crystallinity, factors that can induce significant variations in the voltammetric signal. Consequently, it becomes an effective means to discriminate between different provenances and manufacturing techniques of different potteries. The outcomes of this research contribute valuable insights into the intricate realm of ancient ceramic materials, casting light on their origins and production processes within the historical context of Pompeii.

Electroadsorption of La3+ and Ce3+ from aqueous media with a carbon paste electrode modified with HMS-CMPO

This work deals with the electroadsorption of rare earths cerium and lanthanum in aqueous solution by using a carbon paste electrode modified with a silica mesoporous material functionalized with carbamoyl methyl phosphine oxide (CMPO). This functionalization was carried out in a two-step synthesis, the intermediate product was synthesized by attaching N-(2-aminoethyl)-3-aminopropyltrimethoxysilane (APTMS) to the surface of the HMS by a grafting method synthesis, then this intermediate was modified by CMPO, in a further condensation reaction. The final product CMPO obtained was characterized by diffuse reflectance infrared Fourier transform spectroscopy (DRIFTS), thermal gravimetric analysis (TGA) and N2 adsorption/desorption isotherms using BJH and BET models. Showing thermal stability, a surface area higher than 450m2g-1 and mesoporous properties. The CMPO material was used to modify the mixture of the carbon paste electrode producing an enhancement in the interaction between the electrode surface and the lanthanides studied, at the same time it produces and improvement in the electroactive area by over two orders of magnitude. The modified carbon paste electrode (CMPO-CPE) developed in this work shows an increase in the conductivity, observed with the electrochemical impedance spectroscopy studies, and an increase in the electroactive area of 47 % was calculated from cyclic voltammetry experiments. CMPO-CPE was used to extract La3+ and Ce3+ from aqueous solution using NaNO3 as support electrolyte, by using a fixed potential program over time, measuring the obtained current by Chronoamperometric method. The adsorption and desorption results were corroborated with Inductively coupled plasma atomic emission spectroscopy (ICP-OES) demonstrated the capacity of extraction of the electrode were 74 μg after ten cycles for La3+ at pH 5.0 and 15 μg after ten cycles for Ce3+ at pH 6.0, using a CMPO modified electrode of small surface (3 mm radius). This electrode was tested for over 50 cycles without losing their electroactive properties under tested electrochemical conditions.

Multifunctional piezoelectric surfaces enhanced with layer-by-layer coating for improved osseointegration and antibacterial performance

Implant failure is primarily caused by poor osseointegration and bacterial colonization, which demands readmissions and revision surgeries to correct it. A novel approach involves engineering multifunctional interfaces using piezoelectric polyvinylidene fluoride (PVDF) materials, which mimic bone tissue’s electroactive properties to promote bone integration and provide antibacterial functionality when mechanically stimulated. In this study, PVDF films were coated with antibacterial essential oil nanoparticles and antibiofilm enzymes using a layer-by-layer (LBL) approach to ensure antibacterial properties even without mechanical stimulation. The experimental results confirmed the LBL build-up and demonstrated notable antibiofilm properties against Pseudomonas aeruginosa and Staphylococcus aureus while enhancing pre-osteoblast cell proliferation under mechanical dynamic conditions in a bioreactor that replicated the real-life environment of implants within the body. The findings highlight the potential of PVDF-coated surfaces to prevent biofilm formation and boost cell proliferation through the piezoelectric effect, paving the way for advanced implantable devices with improved osseointegration and antibacterial performance.

A facile fabricated electrochemical sensor based on dual-shell Sn4CoO9.3 microspheres for simultaneous detection of Pb2+ and Hg2+

The presence of heavy metal ions poses significant health hazards to humans, necessitating an urgent demand for a rapid and efficient detection method. Electrochemical sensing offers a promising approach that enables high sensitivity and selectivity in detecting heavy metal ions. In this study, a novel bimetallic oxide, Sn4CoO9.3, with dual shells and multiple pores was developed by a simple template-free method. The unique dual-shell structure and multiple pores greatly enhance its adsorption capacity for heavy metal ions, while the mesoporous pores facilitate electrolyte and ion diffusion. A sensor based on Sn4CoO9.3/CS-ERGO with the excellent electroactive properties and outstanding absorption capacity was fabricated for the simultaneous detection of different heavy metal ions (Pb2+ and Hg2+). By harnessing the benefits of Sn4CoO9.3 and graphene sheets, the sensors that were created exhibited exceptional sensitivity, stability, and minimal interference when detecting Pb2+ and Hg2+ in real samples. These results suggest promising prospects for utilizing the sensor in environmental water quality monitoring applications.

Impact of aliovalent La-doping on zinc oxide – A wurtzite piezoelectric

The development of high-performance low-cost electroactive films for energy conversion and electronic device applications is a key goal of current advanced materials and condensed matter physics research. Here, using solution-based scalable chemical spray pyrolysis, high-quality electroactive lanthanum-doped zinc oxide (i.e., Zn1-xLaxO) thin films are grown on silicon substrates, and the impact of aliovalent lanthanum doping is investigated using a suite of microstructural, optical and nanoscale scanning probe microscopy techniques. The synthesized polycrystalline thin films show hexagonal wurtzite crystal structure with an increased unit cell volume, crystallite size, and conductivity with lanthanum doping up to 4 at.% beyond which the thin films (6 at.%), however, exhibit a change in dominant crystalline orientation from (101) to (002) plane. Concurrently, at this optimal dopant concentration of 4–6 at.%, the electromechanical performance is enhanced by about 20 %, and polarity-dependent nanoscale electronic transport behaviour is revealed. Our study, therefore, provides key insights into the impact of the rare earth aliovalent lanthanum dopant on the electroactive and electronic properties of low-cost, functional thin films for sustainable energy and sensing applications.

Coupling various in-situ methods to reveal the peculiar semi-crystalline morphology of melt-processed fluorinated copolymers

Poly(vinylidene fluoride-co-trifluoroethylene) (P(VDF-co-TrFE)) copolymer and poly(vinylidene fluoride-ter-trifluoroethylene-ter-chlorotrifluoroethylene) P(VDF-ter-TrFE-ter-CTFE) terpolymer thin films are usually produced by solvent-casting followed by annealing to enhance their electroactive properties in electronic devices. In this study, we investigate the effect of a different thermal treatment, namely crystallization from the melt, on the crystalline structure and morphology of P(VDF-ter-TrFE-ter-CTFE) terpolymers with varying CTFE content (ranging from 0 to 8.3 mol %) using a combination of different in-situ techniques. First, in-situ Wide-Angle X-Ray Scattering (WAXS) shows the different crystal-crystal transitions during cooling for all the samples. For the terpolymers, two sharp Bragg peaks ((110) and (200) family of planes) of the low temperature crystalline phase can be detected. Their sharpness reflects a high lateral extension of the crystalline domains. Moreover, coupled morphological studies by in-situ Small-Angle X-Ray Scattering (SAXS) and Atomic Force Microscopy (AFM) show that the crystallization starts with the formation of very extended semi-crystalline domains with a sub-micrometric thickness that contributes to the SAXS signal. For significant amounts of CTFE, crystallization is spread out, leading to the appearance of increasingly finer lamellar stacks during cooling, filling the spaces left unoccupied during crystallization at higher temperatures. This contrasts with the very rapid crystallization observed in the polymer with 0 mol % of CTFE. Finally, the Curie transition is clearly visible in the AFM mechanical images, providing an original method for detecting the structural transitions occurring in these polymers.

Hexakis[p-(hydroxymethyl)phenoxy]cyclotriphosphazene as an Environmentally Friendly Modifier for Polyurethane Powder Coatings with Increased Thermal Stability and Corrosion Resistance.

Protection against fire and the corrosion of metals is necessary to ensure human safety. Most of the fire and corrosion inhibitors do not meet the ecological requirements. Therefore, effective and ecological methods of protecting metals are currently a challenge for researchers. In this work, the influence of hexakis(4-(hydroxymethyl)phenoxy)cyclotriphosphazene (HHPCP) on the characteristics of powder coatings was examined. The coatings' properties were investigated by measuring the roughness, hardness, adhesion to the steel surface, cupping, gloss, scratch resistance, and water contact angle. The thermal stability was studied by furnace test and TGA analysis. The corrosion resistance test was carried out in a 3.5% NaCl solution. The distribution of phosphazene-derived segments in the coating was examined by GD-EOS analysis. Modified coatings show better corrosion and thermal resistance and can be used for the protection of the steel surface. Their better corrosion resistance is due to the electroactive properties of the phosphazene ring and its higher concentration at the coating surface, confirmed by GD-EOS analysis. The increase in thermal resistance is due to the effect of the formation of phosphoric metaphosphoric and polyphosphoric acids during the decomposition of HHCPC, which remain in the condensed char phase and play a crucial role in surface protection.

Electrochemical Investigation of Lithium Perchlorate-Doped Polypyrrole Growing on Titanium Substrate

Lithium perchlorate-doped polypyrrole growing on titanium substrate (LiClO4-PPy/Ti) has been fabricated to act as electroactive electrode material for feasible electrochemical energy storage. A theoretical and experimental investigation is adopted to disclose the conductivity, electroactivity properties and interfacial interaction-dependent capacitance of LiClO4-PPy/Ti electrode. The experimental measurement results disclose that LiClO4-PPy/Ti reveals lower ohmic resistance (0.2226 Ω cm−2) and charge transfer resistance (2116 Ω cm−2) to exhibit higher electrochemical conductivity, a more reactive surface, and feasible ion diffusion to present higher double-layer capacitance (0.1930 mF cm−2) rather than LiClO4/Ti (0.3660 Ω cm−2, 65,250 Ω cm−2, 0.0334 mF cm−2). LiClO4-PPy/Ti reveals higher Faradaic capacitance caused by the reversible doping and dedoping process of perchlorate ion on PPy than the electrical double-layer capacitance of LiClO4/Ti caused by the reversible adsorption and desorption process of the LiClO4 electrolyte on Ti. Theoretical simulation calculation results prove that a more intensive electrostatic interaction of pyrrole N···Ti (2.450 Å) in LiClO4-PPy/Ti rather than perchlorate O···Ti (3.537 Å) in LiClO4/Ti. LiClO4-PPy/Ti exhibits higher density of states (57.321 electrons/eV) at Fermi energy and lower HOMO-LUMO molecule orbital energy gap (0.032 eV) than LiClO4/Ti (9.652 electrons/eV, 0.340 eV) to present the enhanced electronic conductivity. LiClO4-PPy/Ti also exhibits a more declined interface energy (−1.461 × 104) than LiClO4/Ti (−5.202 × 103 eV) to present the intensified interfacial interaction. LiClO4-PPy/Ti accordingly exhibits much higher specific capacitances of 0.123~0.0122 mF cm−2 at current densities of 0.01~0.10 mA cm−2 rather than LiClO4/Ti (0.010~0.0095 mF cm−2, presenting superior electroactivity and electrochemical capacitance properties. LiClO4-PPy/Ti could well act as the electroactive supercapacitor electrode for feasible energy storage.

An innovative aluminium foil electrode modified with Al nanoparticles and EDTA for lead detection in biological samples

This study presents a novel Aluminium foil-based electrode characterized by its affordability, flexibility, and ease of modification with carboxylic moiety-containing organic molecules. Upon foil modification with Aluminium nanoparticles and EDTA (AlNP-EDTA/AlE), the modified electrode exhibits remarkable activity in the oxidation of lead at potentials around −0.4 V. The lead signal is derived from the oxidation of lead deposited on the electrode surface using anodic stripping voltammetry (ASV). The addition of EDTA to AlNP/AlE increased the anodic peak current of lead by more than 500 %. The surface characterization of the electrode was performed by scanning electron microscopy (SEM) and infrared spectroscopy (IR), while its electroactive properties were evaluated by cyclic voltammetry (CV) and electrical impedance spectroscopy (EIS). Optimal operating parameters include pH 2.1, square-wave voltammetry (SWV) with an accumulation time of 60 s and an accumulation potential of −0.8 V. A low detection limit of 0.20 µmol/L and a relative standard deviation (RSD) of 3.0 % were achieved using five different electrodes. The effectiveness of AlNP-EDTA/AlE was further demonstrated with consistent results in biological samples spiked with Pb.

Superior nanocomposites of phosphonium-based poly(ionic liquid) with halloysite and graphene oxide: Electrorheological investigations

Phosphonium-based poly(ionic liquid) (PPIL) as well as its nanocomposites with halloysite (HNT) and graphene oxide (GO) were synthesized in this study. PPIL structure was engineered to be poly[(4-vinylbenzyl) trimethyl phosphonium trifluoromethane sulfonate] for high electrorheological (ER) performance. To improve ER properties of PPIL, HNT clay with strong mechanical, thermal, and insulating properties and GO with strong dielectric properties were introduced into the PPIL structure by covalent bonding. The synergistic electroactive effect of HNT and GO in the hybrid nanocomposites were investigated by comparing PPIL, HNT/PPIL and HNT/GO/PPIL structures. Structural, thermal, and morphological characterizations approved the successful synthesis of samples. Dielectric and ER flow tests of dispersions of the engineered structures in insulating silicone oil (SO) indicated that PPIL (Δε′ = 1.80 and τy = 250 Pa, EReff = 35, G′ = 33 kPa at 2.0 kV mm-1) and HNT/PPIL (Δε′ = 1.55 and τy = 260 Pa, EReff = 51, G′ = 100 kPa at 2.0 kV mm-1) have similar electroactive properties whereas the highest polarizability and ER response are achieved with HNT/GO/PPIL hybrid nanocomposite (Δε′ = 2.50 and τy = 410 Pa, EReff = 67, G′ = 790 kPa at 2.0 kV mm-1). The findings indicated that electrical stability and electric field induced polarizability of PPIL have been improved by the presence of HNT and GO, respectively. When compared with the previously reported ER studies for ammonium-based poly(ionic liquid)s, PPIL and its nanocomposites of HNT/PPIL and HNT/GO/PPIL exhibited better ER properties, as projected. The application of electric field resulted in the switchable viscoelastic character for PPIL/SO, HNT/PPIL/SO and HNT/GO/PPIL/SO dispersions. Similar to the ER flow properties, the best electroactive viscoelastic properties were obtained for the dispersion of triple HNT/GO/PPIL hybrid nanocomposite. Overall, new ER dispersions of phosphonium-based poly(ionic liquid) and its superior nanocomposites were introduced to the literature.

Electroactive properties of EABs in response to long-term exposure to polystyrene microplastics/nanoplastics and the underlying adaptive mechanisms

Given widespread presence of polystyrene (PS) microplastics/nanoplastics (MPs/NPs), the electroactive responses and adaptation mechanisms of electroactive biofilms (EABs) exposed long-term to PS-containing aquatic environments remain unclear. Therefore, this study investigated the impacts of PS MPs/NPs on electroactivity of EABs. Results found that EABs exhibited delayed formation upon initially exposure but displayed an increased maximum current density (Imax) after subsequent exposure for up to 55 days. Notably, EABs exposure to NH2PS NPs (EAB-NH2PSNPs) demonstrated a 50% higher Imax than the control, along with a 17.84% increase in viability and a 58.10% increase in biomass. The cytochrome c (c-Cyts) content in EAB-NH2PSNPs rose by 178.35%, benefiting the extracellular electron transfer (EET) of EABs. Moreover, bacterial community assembly indicated the relative abundance of electroactive bacteria increased to 87.56% in EAB-NH2PSNPs. The adaptability mechanisms of EABs under prolonged exposure to PS MPs/NPs predominantly operate by adjusting viability, EET, and bacterial community assembly, which were further confirmed a positive correlation with Imax through structural equation model. These findings provide deeper insights into long-term effects and mechanisms of MPs/NPs on the electroactive properties of EABs and even functional microorganisms in aquatic ecosystems.

Revealing the roles of biochar derived from iron-rich fermented sludge residue in anaerobic digestion

Anaerobic biological treatment of waste activated sludge (WAS) is proven as a low-carbon footprint technology with dual advantages of bio-fuel recovery and sludge stabilization. However, sludge residue after anaerobic biological treatment has been a serious obstacle to build waste-free cities. In this study, sludge residue, iron-rich sludge residue, and iron-rich fermented sludge residue were selected as the raw materials of biochar and the roles of prepared biochar in anaerobic digestion of WAS were investigated. Results indicated that the prepared biochar improved methane production and biochar derived from iron-rich fermented sludge residue (PFF-BC) obtained the best performance, with an increment of 23.4%. Mechanism analysis illustrated that the structural characteristics of PFF-BC were updated, including iron species, defect levels, and specific surface area, which played positive roles in the conversion of intermediate metabolites. Meanwhile, the compositions and electro-activity properties of extracellular polymeric substances were both stimulated by PFF-BC. Correspondingly, the activities of electron transport system and cytochrome c increased by 23.4% and 36.7%, respectively. For microbial communities, the abundances of electroactive microorganisms (such as Anaerolineaceae, Syntrophomonas and Methanosaeta) increased and direct interspecies electron transfer might be established, improving CO2-reduction and acetoclastic methanogenesis pathways. These findings will provide important references for stepwise resource recovery and final disposal of WAS.

Engineering Proteins for PEDOT Dispersions: A New Horizon for Highly Mixed Ionic-Electronic Biocompatible Conducting Materials.

Poly (3,4-ethylenedioxythiophene) (PEDOT) doped with polystyrene sulfonate (PSS) is the most used conducting polymer from energy to biomedical applications. Despite its exceptional properties, there is a need for developing new materials that can improve some of its inherent limitations, e.g., biocompatibility. In this context, doping PEDOT is propose with a robust recombinant protein with tunable properties, the consensus tetratricopeptide repeated protein (CTPR). The doping consists of an oxidative polymerization, where the PEDOT chains are stabilized by the negative charges of the CTPR protein. CTPR proteins are evaluated with three different lengths (3, 10, and 20 identical CTPR units) and optimized varied synthetic conditions. These findings revealed higher doping rate and oxidized state of the PEDOT chains when doped with the smallest scaffold (CTPR3). These PEDOT:CTPR hybrids possess ionic and electronic conductivity. Notably, PEDOT:CTPR3 displayed an electronic conductivity of 0.016Scm-1, higher than any other reported protein-doped PEDOT. This result places PEDOT:CTPR3 at the level of PEDOT-biopolymer hybrids, and brings it closer in performance to PEDOT:PSS gold standard. Furthermore, PEDOT:CTPR3 dispersion is successfully optimized for inkjet printing, preserving its electroactivity properties after printing. This approach opens the door to the use of these novel hybrids for bioelectronics.

Ag nanorod@PEI-Ag nanohybrid as an excellent signal label for sensitive and rapid detection of serum HER2

The accurate detection of Human epidermal growth factor receptor-2 (HER2) as a critical breast cancer biomarker can be essential for the early selection of therapeutic approaches. HER2 is a prominent component of a signaling network. Overexpression of the HER2 protein due to amplification of its gene leads to the development of an aggressive subtype of breast cancer. Patients with tumors that overexpress HER2 are eligible for treatment that significantly reduces mortality rates. Herein, we present a fast and simple method for detecting serum HER2. A new electrochemical label has been developed using charged Ag nanorod@ polyethylenimine-Ag (Ag NR@ PEI-Ag) nanohybrid. The synthesized Ag NR@PEI-Ag nanohybrid simultaneously has the electroactive property of silver and the large surface area of the PEI, which results in the enhancement of the detection signal. So, using Ag NR@PEI-Ag nanohybrid as the electrochemical label, a simple, fast, and sensitive electrochemical biosensor was designed to detect HER2. This way, after immobilizing HER2 aptamer on the Au electrode surface, HER2 or human serum was exposed to the aptamer. Then, the positively charged Ag NR@PEI-Ag nanohybrid was adsorbed onto the negatively charged aptamer-HER2 complex, and the current that was produced due to the Ag/AgCl reaction was measured as the electrochemical signal. The aptasensor shows a broad linear response from 10–12 to 10–7 g, a low detection limit (LOD) of 10 pg, and a total assay time of ~ 30 min.

Electroactive Prussian Blue Analogues/TiO2 Nanocomposites Obtained through SILAR Assembly in Mesoporous Nanoarchitectures

AbstractThe preparation of nanomaterials for energy applications such as intercalation batteries and materials that can act as substrates for water oxidation is a subject of major interest nowadays. In this work, we report the deposition of Prussian blue (PB) and its cobalt analogue (CoPBA) on mesoporous titania thin films (MTTF) using the successive ionic layer adsorption reaction (SILAR) technique under soft conditions. A bifunctional ligand, 1,10‐phenanthroline‐5,6‐dione (pd), was used to functionalize the titania surface and promote the growth of PB and CoPBA. The resulting PB@MTTF and CoPBA@MTTF nanocomposites were characterized using several techniques and it was determined that PB and CoPBA grow in a controlled and sequential manner, maintaining the mesoporous architecture. Both PB@MTTF and CoPBA@MTTF demonstrated very good electroactive properties, while CoPBA@MTTF exhibited water oxidation capabilities. The flexibility of this PBA@MTTF platform allows the incorporation of any labile transition metal ion or fragment into the structure of the coordination polymer embedded into a mesoporous matrix, opening the door for (photo)electrochemical devices and catalysts.