Graphene Oxide Carbon Nanotubes Research Articles

Computational analysis of ternary cation perovskite based solar cells employing transition metal chalcogenide, graphene derivatives, and SWCNT as hole transport layers

In this study, a numerical modelling on device configurations composed of Cs3Bi2I9 as the absorber material is performed by choosing diverse hole transport layers (HTLs) such as Cu2Te, graphene oxide (GO), reduced graphene oxide (rGO) and single walled carbon nanotube (SWCNT). All device configurations exhibit excellent PCE when the design parameters of perovskite, charge transport materials are optimized. The PCE of the device configurations with Cu2Te, GO, rGO and SWCNT as HTL is estimated as 10.81%, 10.87%, 9.99% and 11% respectively on optimizing design parameters of layers of the device. The perovskite solar cell (PSC) design is further optimized for suitable back metal contact and the device with rGO as the HTL shows an enhancement in PCE from 9.99% to 11.62% when Au is replaced by Se with a work function of 5.9 eV. Among the device configurations with distinct HTLs analysed, the FTO/ZnO/Cs3Bi2I9/rGO/Se configuration achieves the maximum PCE of 11.62%, indicating that rGO is the most suitable HTL material among the chosen ones. All modelled devices exhibit a gradual decline in PCE with temperature, except the PSC with SWCNT as the HTL, which shows a sudden performance degradation with temperature.

One-step solvent thermal synthesis of 3D networked MOF composites for preparation of anultrasensitive chemosensor for hydroquinone and catechol.

Pharmaceuticals and personal care products (PPCPs) have a significant impact on the environment and human health, due to their sometimestoxic and carcinogenic characteristics. Therefore, an innovative chemosensor was constructed for ultrasensitive determinationof two typical PCCPs (hydroquinone (HQ) and catechol (CC)) in several minutes. The homemade chemosensor (UiO-67@GO/MWCNTs) consisted of MOF(UiO-67), graphene oxide (GO), and multi-walled carbon nanotubes (MWCNTs) composites; it was a networked, structurally sparse, porosity-rich, homogeneous octahedral composite, and had ultra-high electrical conductivity, which provided lots of active adsorption sites, promote charge transfer, and enrich lots of molecules to be measured in a few minutes. The prepared electrochemical sensor showed good long-term stability, applicability, reproducibility, and immunity to interference for the determination of HQ and CC, with a wide linear range of response of 5.0 ~ 940µM for both HQ and CC, and a low limit of detection with satisfactory recoveries. In addition, a new strategy of using MOF composites as the basis for electrochemical determination of organic small molecules was established, and a new platform was constructed for the quantitative determination of organic small molecules in various environmental samples.

Effect of graphite, graphene oxide, and multi-walled carbon nanotubes on the physicochemical characteristics and biocompatibility of chitosan/hyaluronic acid/hydroxyapatite scaffolds for tissue engineering applications

Bone tissue engineering (BTE) is a promising alternative approach to the repair of damaged bone tissue. This study aims to fabricate and characterize scaffolds composed of chitosan (CS), hyaluronic acid (HA), hydroxyapatite (HAp), and a combination of graphite (Gr), graphene oxide (GO), and multi-walled carbon nanotubes (MWCNT) for BTE applications. The Gr and MWCNT were functionalized by acid oxidation, while the GO was synthesized using the improved Hummers' method. The scaffolds were prepared by lyophilization, and the physical, chemical, and biological properties were evaluated. Scanning electron microscopy (SEM), energy-dispersive x-ray spectroscopy (EDS), Fourier transform infrared (FTIR) spectroscopy, mechanical testing, water contact angle, degradation, and biocompatibility assays were used to characterize the scaffolds. The degradation rate was determined using the liquid displacement method. Pores of different sizes were present on the surface of and throughout the scaffold. According to the FTIR results, the scaffolds contained functional groups that promote cell differentiation and proliferation. These scaffolds have compressive strength, Young's modulus, and toughness similar to cancellous bone, with reasonable porosity and controllable degradation rates. Biocompatibility testing confirmed that the scaffolds support cell proliferation and differentiation.

Graphene oxide–carbon nanotube composite membrane for enhanced removal of organic pollutants by forward osmosis

Composite membranes constructed using both graphene oxide and carbon nanotubes (CNTs) were designed to strengthen the forward osmosis (FO) technology for the removal of organic contaminants. The nano-membrane was chemically treated with organic acids, which were citric acid in this case for more efficiency in permeability and pollutant removal. The efficiency of the composite membranes in organic pollutants removal was estimated by checking the levels of COD (chemical oxygen demand), TKN (total nitrogen analysis), and (TOC) organic carbon in the water sample before and after applying the technology. The analysis of the study recommends that the nano-membranes may be appropriately used to reduce organic pollutants significantly, to 98.20% efficiency, in addition to elevating water quality standards. This was caused by the higher degree of selectivity and permeability of the membranes that was consequent to the treatment of the organic acid. In brief, the employment of citric acid in the pre-treatment procedures for the preparation of composite graphene oxide-carbon nanotube membranes for FO technology could take water cleaning technologies a step ahead toward sustainable technology. The application of the composite membrane with graphene oxide and carbon nanotubes is not only efficient in cleaning out organic contaminants but it has a lot of added benefits. These membranes are easily manufactured with a long lifespan which, in turn, makes them cost-effective and environmentally friendly. Also, forward osmosis technology reduces the energy demand compared to other water remediation methods, making it a more sustainable solution. The final point of this article is that the using of composite graphene oxide-carbon nanotube membranes treated with an organic acid, such as citric acid, in FO technology not only assists with the water treatment problem but also elevates sustainablility due to its effectiveness and is environmentally friendly.

Photothermal Hydrogel Composites Featuring G4-Carbon Nanomaterial Networks for Staphylococcus aureus Inhibition.

Microbial infections represent a significant health risk, often leading to severe complications and, in some cases, even fatalities. As a result, there is an urgent need to explore innovative drug delivery systems and alternative therapeutic techniques. The photothermal therapy has emerged as a promising antibacterial approach and is the focus of this study. Herein, we report the successful synthesis of two distinct supramolecular composite hydrogels by incorporating graphene oxide (GO) and single-walled carbon nanotubes (SWNTs) into guanosine quadruplex (G4) based hydrogels containing covalently bound β-cyclodextrin (β-CD). The G4 matrix was synthesized through a two-step process, establishing a robust network between G4 and β-CDs, followed by the encapsulation of either GO or SWNTs. Comprehensive characterization of these composite hydrogels were conducted using analytical techniques, including circular dichroism, Raman spectroscopy, rheological investigations, X-ray diffraction, and scanning electron microscopy. A notable discovery from the conducted research is the differential photothermal responses exhibited by the hydrogels when exposed to near-infrared laser irradiation. Specifically, SWNT-based hydrogels demonstrated superior photothermal performance, achieving a remarkable temperature increase of up to 52 °C, in contrast to GO-based hydrogels, which reached a maximum of 34 °C. These composite hydrogels showed good cytotoxicity evaluation results and displayed synergistic antibacterial activity against Staphylococcus aureus, positioning them as promising candidates for antibacterial photothermic platforms, particularly in the context of wound treatment. This study offers a valuable contribution to the development of advanced and combined therapeutic strategies for combating microbial infections and highlights the potential of carbon nanomaterial-enhanced supramolecular hydrogels in photothermal therapy applications.

Demulsification of water-in-crude oil emulsion via novel Fe3O4@ ethylene oxide–propylene oxide copolymer decorated graphene oxide or multiwall carbon nanotubes magnetic nanodemulsifiers

Demulsification of water-in-crude oil emulsion via novel Fe3O4@ ethylene oxide–propylene oxide copolymer decorated graphene oxide or multiwall carbon nanotubes magnetic nanodemulsifiers

Preparation high-performance SiC ceramic reinforced with 3D hybrid graphene oxide-carbon nanotube by direct ink writing and liquid silicon infiltration

This paper proposes the preparation of a silicon carbide ceramic matrix composite toughened with three-dimensional graphene oxide-carbon nanotubes (3D GO-CNT) using direct ink writing and liquid silicon infiltration processes. The research focuses on the microstructure and mechanical properties of the composite, emphasizing the toughening impact of varied GO-CNT ratios. When the GO-CNT ratio was 1:2, the mechanical properties of the material were optimal, with a flexural strength of 337.4 MPa and a fracture toughness of 4.58 MPa · m1/2, which were enhanced by 40.9% and 34.7%, respectively, compared to that of the pure silicon carbide matrix. Graphene oxide and carbon nanotubes can act as dispersants for each other enabling them to be uniformly distributed in the matrix. Key toughening mechanisms include GO/CNT pull-out, multiple microcracks, crack bridging, deflection, and branching. This study promises to significantly improve the mechanical properties of 3D printed SiC composites, assisting their potential applications in aerospace engineering.

Tube-on-rod structure of MWCNTs-ammonium cobalt vanadium oxide/ammonium vanadium oxide; evaluation of electrochemical hydrogen storage capacity

Carbon nanostructures have lately been widely used in energy storage systems. This study examines the impact of ammonium cobalt vanadium oxide/ammonium vanadium oxide as electrode materials in hydrogen storage which modifying with carbon nanostructures. The poor conductivity of vanadate-based materials may be improved by adding zero to two-dimensional carbon nanomaterials, such as graphene quantum dots (GQDs), graphene oxide (GO), and multiwall carbon nanotubes (MWCNTs). Electrode materials based on (NH4)2V12O27·xH2O/(NH4)2Co2V10O28·16H2O/NH4V3O8 were synthesized by hydrothermal method in the presence of PEG with engineered morphology of one dimensional (ID) nanorods. The carbonous nanocomposites based on GQDs, MWCNTs and GO exhibit a capacity 203, 438 and 28 mAhg−1 after 15 cycles at a current density of 1 mA. The hydrogen storage performance is influenced by various amount of MWCNTs. Increasing the percentage of MWCNTs led to decreasing the capacity. Therefore, optimum electrode materials fabricated in the presence of 5 % MWCNTs which has 1055 mAhg−1 capacity. Therefore, 1D/1D structure of Tube-on-Rod can improve the performance of hydrogen storage in the ammonium cobalt vanadium oxide/ammonium vanadium oxide electrodes.

Enhancing the performance of thermal energy storage by adding nano-particles with paraffin phase change materials

Abstract Phase change materials (PCMs) are now being extensively used in thermal energy storage (TES) applications. Numerous researchers conducted experiments using various circumstances and materials to optimize storage performance. A study was conducted to compare the numerical research of the melting process of paraffin wax using a hybrid nano-integrated paraffin PCM with graphene oxide (GO) and single-walled carbon nanotubes (SWCNTs) in a TES unit. Hence, this research focuses on a sustainable TES system using hybrid nanomaterials (PCM + GO, PCM + SWCNTs, PCM + GO + SWCNT) with varying concentrations of nanoparticles. The objective is to improve the thermal characteristics of PCMs. The main aim of this study is to examine the numerical analysis of the system inside a TES that has a rectangular form. The numerical experiments were conducted using the finite-volume solver Ansys Fluent. The obtained findings show the thermophysical characteristics fluctuations with respect to the solid volume fractions, liquid fraction, temperature, and velocity inside the TES system. Implementing an effective heat transfer mechanism from the point of capture to storage and later consumption necessitates the employment of a heat transfer fluid. The inclusion of SWCNT particles at a concentration of just 10% has been seen to expedite the melting phenomenon. Furthermore, incorporating GO in conjunction with SWCNT alleviates this phenomenon, resulting in a melting behavior that resembles that of unadulterated paraffin. Additionally, the introduction of just 1% GO, combined with SWCNT, leads to a rapid alteration in surface heat transfer coefficient compared to the scenario with single SWCNT and paraffin. These insights hold practical relevance for the development of TES systems in various applications.

A hemin/rGO/MWCNT nanocomposite-based dual signal electrochemical aptasensor for sensitive detection of NSE.

Neuron-specific enolase (NSE), a tumor marker of small cell lung cancer (SCLC), has high application value in the early diagnosis of SCLC. In this study, a dual signal electrochemical aptasensor for NSE was constructed based on hemin/reduced graphene oxide/multi-walled carbon nanotube (H-rGO-MWCNT) nanocomposites. Hemin played a dual role, functioning not only as an in situ electrochemical probe but also exhibiting excellent peroxidase-like properties, effectively catalyzing the electroreduction of H2O2. Reduced graphene oxide and multi-walled carbon nanotubes exhibited excellent conductivity. Through their binding with hemin, the nanocomposites achieved a larger specific surface area, providing numerous active sites for capturing the NSE aptamer. In the presence of NSE, the specific adsorption between the antigen and the aptamer formed a stable antigen-aptamer structure, which inhibited the performance of hemin, resulting in the weakening of the electrochemical signals of hemin and H2O2. Leveraging these characteristics, the sensitive and cost-effective dual-signal electrochemical aptasensor has been fabricated for the detection of NSE. One signal corresponded to differential pulse voltammetry (DPV) of hemin, while the other signal was derived from chronoamperometry, capturing the catalytic reduction of H2O2. The linear ranges for NSE were 1 pg mL-1 to 1 μg mL-1 and 100 pg mL-1 to 100 ng mL-1 with the limit of detection (LOD) of 0.21 pg mL-1 and 11.22 pg mL-1 by DPV and chronoamperometry, respectively. In addition, this aptasensor exhibited good reproducibility, stability and specificity. The recovery of NSE in human blood serum samples was from 89% to 131%. It provided a promising strategy for the detection of NSE in clinical diagnostics.

Electrochemical sensors based on the composite of reduced graphene oxide and a multiwalled carbon nanotube-modified glassy carbon electrode for simultaneous detection of hydroquinone, dopamine, and uric acid.

Using a simple drop-casting technique, we successfully fabricated a sensitive electrochemical sensor based on the composite of reduced graphene oxide (RGO) and multiwalled carbon nanotubes (MWCNT) deposited on the surface of a glassy carbon electrode (GCE) for individual and simultaneous measurements of hydroquinone (HQ), dopamine (DA), and uric acid (UA). The nanocomposite of RGO/MWCNT was further characterized in terms of its structural properties, surface morphology, and topography using Raman, FT-IR spectroscopy, SEM, HRTEM, and AFM. Then, the proposed sensor for simultaneous measurement of HQ, DA, and UA based on RGO/MWCNT-modified GCE was investigated for its electrochemical behavior and electroanalytical performances using cyclic voltammetry (CV) and electrochemical impedance spectroscopy (EIS), and differential pulse voltammetry (DPV). In addition, the composition ratio between RGO and MWCT was 1 : 1 showing the highest electrochemical response for simultaneous detection of HQ, DA, and UA. Owing to the synergistic effect between RGO and MWCNT leading to excellent conductivity properties, the proposed sensor exhibited improved electrochemical response at pH 7 toward the oxidation processes of HQ, DA, and UA on the surface of modified electrode. The proposed sensor demonstrated three well-defined anodic peaks of these analytes with their linear concentrations ranges of 3.0-150.0 μM for HQ, 4.0-100.0 μM for DA, and 2.0-70.0 μM for UA. The limit of detection values for the simultaneous detection of HQ, DA, and UA were found as follows 0.400 ± 0.014, 0.500 ± 0.006, and 0.300 ± 0.016 μM, respectively. The additional features of this proposed sensor are high reproducibility and stability for the simultaneous detection of HQ, DA, and UA with negligible interference effect from interferents such as Mg2+, K+, Cl-, ascorbic acid, and glucose. An acceptable percentage of recovery was also shown by this sensor for simultaneous measurements of HQ, DA, and UA using 6 samples of human urine. In summary, the RGO/MWCNT nanocomposite has been shown to be a promising platform for rapid, simple, and reliable determination of simultaneous measurements of HQ, DA, and UA in practical applications.

Novel Surface-Enriched Spiky Ball With Spines NiCo2S4@GO/CNT Electrode Material for a High-Performance Flexible Asymmetric Supercapacitor

Nickel cobalt sulfide (NiCo2S4) nanoparticles on graphene oxide GO sheets and carbon nanotube (CNT) were fabricated successfully via a simple solvothermal route. Most NiCo2S4 nanoparticles cover both sides of the GO sheets, and the carbon nanotubes are arranged at the edge of the composite, creating a Spiky ball structure that effectively prevents the accumulation of GO. Synthesized hybrid nanocomposite (NiCo2S4/GO/CNT) has an optimum specific surface area and pore nature, and the coupling between CNT and GO enhances the electrochemical properties of NiCo2S4. The structural, morphological, and spectral characteristics were analysed using diffraction, microscopy, and spectroscopy techniques. To determine the electrochemical activity, cyclic voltammetry (CV), galvanostatic charge-discharge spectroscopy, and electrochemical impedance spectroscopy (EIS) were performed in a 3 M KOH electrolyte solution, the prepared sample was evaluated as an active electrode material for the supercapacitor. It delivers a very high specific capacitance of 845 Fg−1 at a current density of 2 Ag −1 as compared with NiCo2S4 (423 Fg−1). Coin cell was fabricated and tested using NiCo2S4/GO/CNT as cathode and graphite as an anode. The device exhibited an excellent energy density of 30.8 Wh kg−1, a power density of 3691 Wkg−1, and good cyclic stability with 82% retention after 1000 cycles.

Synthesis and applications of metal nanoparticles (Au, Ag)@C-graphene oxide and carbon nanotubes hybrid nanoarchitectures

In this work, we made an effort to use dopamine hydrochloride and the solid state method to anchor the gold and silver metallic nanoparticles over the graphene oxide-carbon nanotubes to improve the metal nanoparticles' interaction with the support materials. Because the hybrid nanoarchitectures of graphene-CNT provide enhanced electron transfer ability, which facilitates the catalytic activity more quickly and enhances the rate. Additionally, carbon nanotubes–graphene oxide-metal nanoparticles based hybrid catalyst was developed in a similar fashion. The formation of metallic nanoparticles in a size range of 3–15 nm is visible in the micrographs. These particles developed as nano-islands. The excess reductant formed as polydopamine acts as a stabilizer, and further, we utilise this polydoapmine into carbon by the calcination process. It results that carbonous materials will enhance the interaction between metal and support (CNT/GO). This leads to improved catalytic activity towards the reduction of 4-nitrophenol and catalytic decolorization of methylene blue at room temperature. The suggested technique for synthesizing metal nanoparticles over carbon nanostructures is simple and environmentally friendly.

Functionalization of Graphene-Nanotube Nanostructures by BaO Nanoparticles for Devices with Field Electron Emission

A technology has been developed for the functionalization of hybrid nanostructures (HNS) from reduced graphene oxide (rGO) and single-walled carbon nanotubes with BaO nanoparticles. Quantum methods have been used to numerically establish patterns of reduction in the work function of the HNS. It is established that the emission current of functionalized HNSs increases by more than 40 times compared to non-functionalized samples. Such HNS can be promising for devices with a current density of at least 2 A/cm2.

Crafting advanced supercapacitor electrodes with calcium manganese oxide in synergy with rGO and MWCNTs

Despite significant progress in developing metal oxide composite electrodes, methods to improve conductivity and integrate them with carbon nanocomposites remain scarce. Herein, we have synthesized carbon variants – metal oxide composite electrodes with reduced graphene oxide (rGO) and multi-walled carbon nanotubes (MWCNTs). This study outlines the process of synthesizing CaMn3O6 microbeads (∼0.4 μm), which are dispersed within reduced graphene oxide (rGO) sheets and carbon nanotubes (CNTs). The synthesis involves a hydrothermal reaction followed by a calcination process. The synthesized samples are fabricated as a pouch type asymmetric supercapacitor device. The electrodes labelled as CMO–G and CMO–M were tested in three electrode system wherein CMO–M delivered a capacitance of 483 F/g and CMO-G delivered a capacitance of 356 F/g. Low resistance, excellent cycling stability makes CMO–M a suitable electrode for practical applications. The device CMO–M||AC delivered capacitance of 140 F/g and showed a capacity retention up to 84 % even after 20,000 cycles. CMO–M||AC device delivered energy density of 43.81 Wh kg−1 at 750 W kg−1 power density. Our results distinctly demonstrate the significant potential achieved through the synergistic effect in CaMn3O6 and carbon variants. This understanding could prove valuable in the creation of advanced energy storage solutions.

Obtaining nanocomposites based on recycled polystyrene from urban solid waste with carbon nanostructures: graphene oxide and multi-wall carbon nanotubes, modified with organic acids

The excessive use of polystyrene has caused great environmental problems at a global level, an alternative to reduce this problem is recycling, in order to obtain new products from waste, so the objective of this manuscript is to obtain nanocomposites (NCs) from recycled polystyrene with the integration of graphene oxide (OG) and multiple walled carbon nanotubes (NTCPM) previously modified with benzoic acid at concentrations of 0.33 and 5% respectively. Low toxicity solvent was used. The materials obtained were characterized by infrared spectroscopy (FTIR), thermogravimetric analysis (TGA) and light microscopy, finding by FTIR that the chemical structure of the polystyrene was not affected after the integration of the nanostructures and processing, which suggests that they are maintained the properties, regarding the optical micrographs, it can be observed that the NCs with the modified nanostructures presented a homogeneous dispersion, with respect to the thermogravimetric analysis, they increased 27 ° C in thermal stability.

Bioengineered Smart Nanocarriers for Breast Cancer Treatment: Adorned Carbon-Based Nanocomposites with Silver and Palladium Complexes for Efficient Drug Delivery.

Biocompatible and bioactive carbon-based nanocomposites are ingeniously designed and fabricated with the aim of enhancing drug delivery applicability in breast cancer treatment. Reduced graphene oxide (rGO) and multiwalled carbon nanotubes (MWCNTs) are utilized as nanocarriers for increasing penetrability into cells and the loading capacity. What sets our study apart is the strategic incorporation of the two different complexes of silver (AgL2) and palladium (PdL2) with the carboxamide-based ligand C9H7N3OS (L), which have been synthesized and decorated on nanocarriers alongside doxorubicin (DOX) for stabilizing DOX by π-π interactions and hydrogen bonding. Although DOX is a well-known cancer therapy agent, the efficacy of DOX is hindered owing to drug resistance, poor internalization, and limited site specificity. Aside from stabilizing DOX on nanocarriers, our carbon-based nanocarriers are tailored to act as a precision-guided missile, strategically by adorning with target-sensitive complexes. Based on the literature, carboxamide ligands can connect to overexpressed receptors on cancerous cells and inhibit them from proliferation signaling. Also, the complexes have an antibacterial activity that can control the infection caused by decreasing white blood cells and necrosis of cancerous cells. A high-concentration cytotoxicity assay revealed that decorating PdL2 on a DOX-containing nanocarrier not only increased cytotoxicity to breast cancerous cell lines (MDA-MB-231 and MCF-7) but also revealed higher cell viability on a normal cell line (MCF-10A). The drug release screening results showed that the presence of PdL2 led to 72 h correlate release behavior in acidic and physiological pH profiles, while the AgL2-containing nanocomposite showed an analogue behavior for just 6 h and the release of DOX continued and after about 100 h hit the top.

Long-term stability of lithium–sulfur batteries via synergistic integration of nitrogen-doped graphitic carbon-coated cobalt selenide nanocrystals within porous three-dimensional graphene-carbon nanotube microspheres

Three-dimensional porous microspheres consist of highly conductive reduced graphene oxide-carbon nanotube (rGO‒CNT) framework with well-embedded cobalt selenide (CoSe2) nanocrystals coated with N-doped graphitic carbon (NGC) were synthesized (referred as “P–CoSe2@NGC/rGO‒CNT” microspheres) and utilized as an electrocatalytic interlayer to enhance the performance of lithium-sulfur (Li–S) batteries. The incorporation of the NGC layer and rGO‒CNT framework not only enhances the electronic conductivity significantly but also offers numerous conductive pathways (primary and secondary) for efficient electron transport. Macropores (φ = 100 nm) formed by the decomposition of PS nanobeads (φ = 200 nm) guarantee effective electrolyte penetration and short diffusion pathways. Moreover, the CoSe2 nanocrystals offer a multitude of polar active sites that effectively anchor polysulfide intermediates, reducing the loss of active material. Benefiting from the nanostructure merits, Li–S cells featuring a P–CoSe2@NGC/rGO‒CNT-coated separator and a conventional sulfur electrode demonstrated outstanding rate capability (up to 2.0 C) and remarkable cycling stability (1000 cycles at 2.0 C). Even under more demanding cell conditions, such as high sulfur content (71 %), high sulfur loading (4.6 mg cm−2), and low E/S (5.6 μL mg−1) ratio, the cell exhibits impressive cycling stability with 420 cycles at 0.1 C, along with feasible rate performance up to 0.3 C.

New electrodes based on composites of polyphenothiazine with carbon nanomaterials

The goal of this research is to obtain new electrode hybrid coatings for electrochemical devices applications. Nanocomposites based on unsubstituted polyphenothiazine (PPTA) and carbon nanomaterials (CNM) were prepared for the first time. Reduced graphene oxide (RGO), single-walled and multi-walled carbon nanotubes (SWCNT and MWCNT) were used as CNM. Hybrid nanocomposites were prepared by two methods: via oxidative polymerization of PTA in the presence of CNM (CNM/PPTA-1), or from pre-synthesized polymer solution in DMF containing CNM followed by solvent removal (CNM/PPTA-2). The structure and morphology of PPTA-derived nanocomposites were studied by means of FTIR spectroscopy, X-ray diffraction, and FE-SEM. The nanocomposite composition dependence of conductivity was demonstrated. Electrochemical behavior of the electrode coatings prepared on the basis of the said polymer and CNM/PPTA nanocomposites thereof was studied by CV methods. All the samples were found to be electroactive in 1 M sulfuric acid. An addition of carbon nanomaterials was shown to improve reversibility of the electrode processes that is related to formation of nanocarbon conductive framework in the composite with a highly developed surface filled with thin layers of the polymer. CNM/PPTA nanocomposites exhibit the electrocatalytic effect to the redox behavior of ferro/ferricyanide couple in 1 M H2SO4.

Covalent organic framework-based immunosensor to detect plasma Latexin reveals novel biomarker for coronary artery diseases

It is a great challenge to develop an efficient and rapid method to detect of biomarkers of cardiovascular disease. In this research, a differential pulse voltammetry (DPV)-based ultrasensitive immunosensor for the detection of plasma Latexin (LXN) has been established. With the aim to increase the surface area of the bare glassy carbon electrode (GCE), multi-walled carbon nanotube-graphene oxide has been developed. Covalent organic frameworks (COFs) are dropped with gold nanoparticles (AuNPs), secondary antibody and thionine (Thi-Ab2-Au-COFs) act as the signal probe with high electronic conductivity. Under the ideal conditions, the immunosensor displayed a broad linear response range from 0.01 ng mL−1 to 100 ng mL−1, with a detection limit of 50 pg mL−1 (S/N = 3). The immunosensor also demonstrates outstanding sensitivity, repeatability, and stability. Finally, we utilized the designed immunosensor to detect plasma LXN in coronary artery disease (CAD) patients, and the data showed that plasma LXN was significantly increased in CAD patients with a good performance of ROCAUC (AUC 0.871, 95 % CI 0.725–1.0, p = 0.002), indicating plasma LXN is a potential biomarker of cardiovascular disease. This immunosensor is a promising strategy for screening CAD patients in clinical practice.