Development of ciprofloxacin sensor using iron-doped graphitic carbon nitride as transducer matrix: Analysis of ciprofloxacin in blood samples

n the present work, we have synthesized an iron-decorated graphitic carbon nitride (Fe@g-C3N4) composite and employed it for electrochemical sensing of ciprofloxacin (CFX). The physicochemical characteristics of the Fe@g-C3N4composite were analyzed with X-ray diffraction (XRD), scanning electron microscopy (SEM), and energy-dispersive X-ray diffraction (EDX) spectroscopy methods. Further, the pencil graphite electrode (PGE) was modified with Fe@g-C3N4 composite to get PGE/Fe@g-C3N4 electrode and characterized the resultant electrode by cyclic voltammetry (CV) and electrochemical impedance spectroscopy (EIS). Differential pulse voltammetry (DPV) was employed to determine the effect of concentration and interferents. The modified PGE/Fe@g-C3N4electrode demonstrated the exceptional electrochemical performance for CFX identification and quantification with a LOD of 5.4 nM, a wide linear range of 0.001-1.0 μM, and high sensitivity of 0.0018 μA mM-1cm-2. Besides, Fe@g-C3N4 modified PGE showed remarkable recovery results in qualitative analysis of CFX in human blood specimens. This research advocates that the Fe@g-C3N4 composite acts as an excellent transducer material in the electrochemical sensing of CFX in blood and standard samples. Further, the proposed strategy deduces that the PGE/Fe@g-C3N4 sensor can be a prospective candidate for the dynamic determination of CFX in blood serum and possibly ratified as an exceptional drug sensor for therapeutic purposes

Fabrication of 1D graphene nanoribbon and malenized linseed oil-based nanocomposite: a highly impervious bio-based anti-corrosion coating material for mild steel

Graphene nanoribbon (GNR) is a flat ribbon-like 1D nanomaterial of graphene family rarely explored in the development of anti-corrosion coatings. In the present work, a bio-based anti-corrosion coating was fabricated using GNR as nanofiller in malenized linseed oil (MLO) polymer network. MLO polymer network was first prepared from commercially available linseed oil by malenization reaction at 80 degrees C using maleic anhydride. Later, GNR was synthesized from multiwalled carbon nanotube by oxidative unzipping method and incorporated into MLO polymer network to obtain the bio-based MLO-GNR nanocomposite. The as-prepared MLO and MLO-GNR coating materials were spin coated onto bare mild steel samples and cured at 80 degrees C for 24 h. The morphology and surface characteristics of coatings were studied by spectroscopic and microscopic techniques. Further, the anti-corrosion behaviour of bare and coated MS samples was investigated by potentiodynamic polarization and electrochemical impedance methods in a 3.5% NaCl medium. Among the samples, MLO-GNRcoated samples exhibited a high level of corrosion inhibition in the saline medium compared to uncoated MS sample as the damages and destruction activity were more on its surface than their counterparts. MLO-GNR nanocomposite coating exhibited robust corrosion resistance activity and showed 99.9% protection efficiency. Further, the MLO-GNR coating displayed higher stability in the saline medium as well as open-air environment establishing that the flat GNR molecule acts as excellent nanofiller in MLO polymer network to produce robust anti-corrosion activity leading to protection of mild steel. GRAPHICS]

Fabrication of ZnO/rGO and ZnO/MWCNT nanohybrids to reinforce the anticorrosion performance of polyurethane coating

Polyurethane (PU) has been widely utilized in different applications due to its unique properties. Substantial attempts have been made to enhance the corrosion resistance and mechanical properties of PU coating through the addition of nanomaterials. In this study, zinc oxide/reduced graphene oxide (ZnO/rGO) and zinc oxide/multiwalled carbon nanotube (ZnO/MWCNT) nanohybrids were synthesized and incorporated into the PU matrix to enhance the anti-corrosion property of the PU coating. The synthesized nanofillers were thoroughly characterized through Fourier transform infrared spectroscopy (FT-IR), X-ray diffraction (XRD), Raman spectroscopy, Field Emission Scanning Electron Microscopy (FE-SEM) and Energy Dispersive X-ray spectroscopy (EDX). The rGO/ZnO-PU and MWCNT/ZnO-PU nanocomposites, and also neat PU were coated on the mild steel (MS) substrate, and the surfaces of the coated samples were probed by Contact angle technique, Atomic Force Microscopy (AFM), and SEM analysis. Electrochemical impedance spectroscopy and potentiodynamic polarization tests were carried out to examine the effects of rGO/ZnO and CNT/ZnO nanofillers in improving the protection and barrier properties of pure PU coating. Electrochemical corrosion data revealed the superior anticorrosion efficiency for rGO/ZnO decorated PU coating (99.09%) compared to that of MWCNT/ZnO dispersed PU coating (95.24%). The high surface area and aspect ratio of rGO make it an effective nanofiller in reinforcing the PU matrix for anticorrosion application

Graphene nanoribbon derived from multi-walled carbon nanotube: An efficient viral gene hosting and biosensing molecular platform for the electroanalysis of HIV-1 gene

Graphene nanoribbon (GNR) is a carbon nanomaterial with strikingly distinct characteristics compared to graphene. GNRs possess high aspect ratio, variable band gap, high surface area and high density of reactive edge states which make it an emerging flat molecular platform alternative to graphene. GNR is not much explored in sensing applications compared to graphene. Here, for the first time, we are reporting the application of GNRs, derived from multiwalled carbon nanotube (MWCNT), as an efficient flat molecular platform for hosting and biosensing of Human immune deficiency virus-1 (HIV-1) gene. For the construction of HIV-1 sensor, GNRs were synthesized by unzipping of MWCNTs and deposited onto glassy carbon electrode (GCE) followed by the immobilization of HIV-1 probe (ssDNA) onto the resulting GCE/GNR platform to obtain GCE/GNR/ssDNA sensor. Subsequently, the sensor was employed in the analysis of target gene (cDNA) by measuring the voltammetric response generated from hybridization between ssDNA and cDNA. Differential pulse voltammetry (DPV) responses recorded at different target gene concentrations displayed perfect linear correlation (R2 = 0.991). The sensor exhibited low detection limit (2.3 aM), low quantification limit (7.67 aM) and high sensitivity (5.5 μA aM−1 cm−2) which is possibly due to synergic effects of GNRs. Sensor exhibited acceptable stability, repeatability and displayed good selectivity when tested with mismatched target DNA sequences. Further, sensor’s diagnostic applicability was verified by spiking target gene in human blood sample which showed high recovery (4 %) indicating its practical utility in the electroanalysis of HIV-1 gene in human blood samples

Sonochemical synthesis of graphitic carbon nitride-manganese oxide interfaces for enhanced photocatalytic degradation of tetracycline hydrochloride

The present study focuses on the sonochemical synthesis of graphitic carbon nitride-manganese oxide (GCN/MnO2) nanocomposite for photocatalytic degradation of an environmentally hazardous pharmaceutical compound, tetracycline hydrochloride (TcH). The sonochemical synthesis aided in tailoring the morphology of GCN/MnO2. The characterization results of SEM/FESEM, XRD, FTIR, UV-Vis spectra, EIS, CV, etc., revealed on the morphology, composition, crystallinity, and other photo-electro-intrinsic properties of the materials. The synergy of GCN and MnO(2)results in rapid electron transfer, efficient visible-light absorption, and slower electron-hole pair recombination through its photo-responsive traits against TcH. It was noted that similar to 93% TcH (20 mg L-1) degradation was achieved for 30-mg catalyst dose under light-emitting diode (LED) irradiation (9 W, 220 V) in 135-min duration. The TcH mineralization results were well fit to pseudo-first-order kinetics with a rate constant of 0.02 min(-1)(R-2= 0.994). In addition, the composite possessed fair reusability for consequent cycles. Hence, the as-synthesized composite applied for photocatalysis and photoelectrocatalysis fosters a fit-for-purpose and reliable system in the decontamination of TcH in environmental samples

Development of Al2O3.ZnO/GO-phenolic formaldehyde amine derivative nanocomposite: A new hybrid anticorrosion coating material for mild steel

The hybrid nanocomposites are least explored materials in anti-corrosion application. In this context, Al2O3 center dot ZnO and Al2O3 center dot ZnO/GO nanocomposites were prepared and dispersed in the synthesized phenolic formaldehyde amine derivative (PFAd) polymer. The structural and the elemental composition of the nanocomposites and PFAd were ascertained through Fourier transfer infrared spectroscopy (FT-IR), X-ray diffraction (XRD) and Energy dispersive X-ray spectroscopy (EDX) and Transition electron microscopy (TEM). The 0.2 wt.% of nanofiller was chosen as an optimum composition to obtain uniform dispersion in PFAd matrix. The surface morphology, texture and chemical composition of the coatings on mild steel (MS) surface have been studied by XRD and Scanning electron microscopy (SEM). The anti-corrosion performance of the coatings on MS in 3.5 wt.% NaCl solution was evaluated by electrochemical techniques. Electrochemical impedance spectroscopy (EIS) and potentiodynamic polarization (PP) data revealed that, Al2O3 center dot ZnO/GO dispersed PFAd shows very good R-coat (3.81 x 10(2) ohm cm(2)) and R-ct (1.84 x 10(3) ohm cm(2)) with reasonably lower i(corr) (1.233 x 10(-3 )A/cm(2)) values even after 68 days of immersion. Further, it was found that, the barrier property of the coating depends on the composition and dispersibility of the fillers in the polymer matrix

Functionalized graphene oxide-epoxy phenolic novolac nanocomposite: an efficient anticorrosion coating on mild steel in saline medium

The present paper reports the fabrication of efficient anticorrosion coating material on mild steel using epoxy phenolic novolac (EPN) polymer. The EPN was prepared by refluxing the mixture of phenol formaldehyde amine and epoxy in a 1:1 weight ratio and characterized by H-1 NMR and FT-IR spectral studies. The graphene oxide (GO) was functionalized using 2-{4-2-hydroxy-3-(propan-2-ylamino) propoxy] phenyl} acetamide and thoroughly characterized by FT-IR, Raman, and energy dispersive X-ray spectroscopies and TEM techniques. The anticorrosion performance of the coated mild steel (MS) samples was studied by electrochemical impedance spectroscopy and potentiodynamic polarization techniques in 3.5 wt% NaCl medium. The results revealed that the anticorrosion ability of EPN coating was significantly enhanced by the incorporation of functionalized graphene oxide (FGO). The corrosion inhibition efficiency of 99.99% is achieved with 0.2 wt% FGO-grafted EPN matrix. Graphical abstrac