High-sensitivity paracetamol sensor based on Pd/graphene oxide nanocomposite as an enhanced electrochemical sensing platform

Chemical analysis in saliva and the search for salivary biomarkers – a tutorial review

A review of the uses of saliva biomarkers, detection methods and requirements for new biomarkers.

An ultra-sensitive electrochemical sensor for the detection of acetaminophen in the presence of etilefrine using bimetallic Pd–Ag/reduced graphene oxide nanocomposites

In this study we report a one-step procedure for the fabrication of Pd–Ag bimetallic nanoparticles on the surface of a graphene oxide (rGO) support.

Facile synthesis of MnO2-embedded flower-like hierarchical porous carbon microspheres as an enhanced electrocatalyst for sensitive detection of caffeic acid

Tailored designs/fabrications of hierarchical porous advanced electrode materials are of great importance for developing high-performance electrochemical sensors. Herein, we demonstrate a simple and low-cost in situ chemical approach for the facile synthesis of MnO₂-embedded hierarchical porous carbon microspheres (MnO₂/CM). By the characterizations of scanning electron microscopy, X-ray photoelectron spectroscopy, X-ray powder diffraction and energy dispersive spectroscopy, we evidenced that the synthesized product were flower-like carbon microspheres (CM) assembled by the bent flakes with thickness of about several nanometers and MnO₂ nanorods were highly dispersed and successfully decorated on the CM layers, resulting in a rough surface and three-dimensional microstructure. The greatest benefit from the combined porous CM with MnO₂ nanorods is that the MnO₂/CM modified electrode has the synergetic catalysis effect on the electro-oxidation of caffeic acid, leading to the remarkable increase in the electron transfer rate and significant decrease in the over-potential for the caffeic acid oxidation in contrast to the bare electrode and CM modified electrode. This implies that the prepared MnO₂/CM can be employed as an enhanced electrocatalyst for the sensitive detection of caffeic acid. Under the optimum conditions, the anodic peak current of caffeic acid is linear with its concentration in the range of 0.01-15.00 μmol L^-1, and a detection limit of 2.7 nmol L^-1 is achieved based on S/N = 3. The developed sensor shows good selectivity, sensitivity, reproducibility, and also excellent recovery in the detections of real samples, revealing the promising practicality of the sensor for the caffeic acid detection.

Pd nanospheres decorated reduced graphene oxide with multi-functions: Highly efficient catalytic reduction and ultrasensitive sensing of hazardous 4-nitrophenol pollutant

We illustrate a facile approach for in situ synthesis of Pd-gum arabic/reduced graphene oxide (Pd-GA/RGO) using GA as the reducing agent, which favors the instantaneous reduction of both Pd ions and GO into Pd nanoparticles (NPs) and RGO. From the morphological analysis of Pd-GA/RGO, we observed highly dispersed spherical 5nm Pd NPs decorated over RGO. The as-synthesized Pd-GA/RGO composite was employed for the catalytic reduction and the electrochemical detection of 4-nitrophenol (4-NP), respectively. The catalytic reduction of 4-NP was highly pronounced for Pd-GA/RGO (5min) when compared to Pd NPs (140min) and Pd/RGO (36min). This enhanced catalytic activity was attributed to the synergistic effect of Pd NPs and the presence of various functional groups of GA. Significantly, the fabricated sensor offered a low detection limit (9fM) with a wider linear range (2-80 pM) and long-term stability. The simple construction technique, high sensitivity, and long-term stability with acceptable accuracy in wastewater samples were the main advantages of the developed sensor. The results indicated that the as-prepared Pd-GA/RGO exhibited better sensing ability than the other graphene-based modified electrodes. Therefore, the proposed sensor can be employed as a more convenient sensing platform for environmental and industrial pollutants.

Electrochemical carbon based nanosensors: A promising tool in pharmaceutical and biomedical analysis

Nanotechnology has become very popular in the sensor fields in recent times. It is thought that the utilization of such technologies, as well as the use of nanosized materials, could well have beneficial effects for the performance of sensors. Nano-sized materials have been shown to have a number of novel and interesting physical and chemical properties. Low-dimensional nanometer-sized materials and systems have defined a new research area in condensed-matter physics within past decades. Apart from the aforesaid categories of materials, there exist various materials of different types for fabricating nanosensors. Carbon is called as a unique element, due to its magnificent applications in many areas. Carbon is an astonishing element that can be found many forms including graphite, diamond, fullerenes, and graphene. This review provides an overview of some of the important and recent developments brought about by the application of carbon based nanostructures to nanotechnology for both chemical and biological sensor development and their application in pharmaceutical and biomedical area.

Reviews of the toxicity behavior of five potential engineered nanomaterials (ENMs) into the aquatic ecosystem

Presently, engineered nanomaterials (ENMs) are used in a wide variety of commercial applications, resulting in an uncontrolled introduction into the aquatic environment. The purpose of this review is to summarize the pathways and factors that controlling the transport and toxicity of five extensively used ENMs. These toxicological pathways are of great importance and need to be addressed for sustainable implications of ENMs without environmental liabilities. Here we discuss five potentially utilized ENMs with their possible toxicological risk factors to aquatic plants, vertebrates model and microbes. Moreover, the key effect of ENMs surface transformations by significant reaction with environmental objects such as dissolved natural organic matter (DOM) and the effect of ENMs surface coating and surface charge will also be debated. The transformations of ENMs are subsequently facing a major ecological transition that is expected to create a substantial toxicological effect towards the ecosystem. These transformations largely involve chemical and physical processes, which depend on the properties of both ENMs and the receiving medium. In this review article, the critical issues that controlling the transport and toxicity of ENMs are reviewed by exploiting the latest reports and future directions and targets are keenly discussed to minimize the pessimistic effects of ENMs.

Dendritic unzipped carbon nanofibers enable uniform loading of surfactant-free Pd nanoparticles for the electroanalysis of small biomolecules

Illustration of the mechanisms of SCNF and preparation of Pd/GNF composites and Pd/GNF sensors for the simultaneous determination of small biomolecules.

Fabrication of highly sensitive and selective nanocomposite film based on CuNPs/fullerene-C60/MWCNTs: An electrochemical nanosensor for trace recognition of paracetamol

Designing an electrochemical sensor for versatile clinical applications is a sophisticated task and how dedicatedly functionalized composite materials can perform on this stage is a challenge for today and tomorrow's Nanoscience and Nanotechnology. In the present work, we demonstrate a new strategy for the development of novel electrochemical sensor based on catalytic nanocomposite film. Fullerene-C60 and multi-walled carbon nanotubes (MWCNTs) were dropped on the pre-treated carbon paste electrode (CPE) and copper nanoparticles (CuNPs) electrochemically deposited on the modified CPE to form nanocomposite film of CuNPs/C60/MWCNTs/CPE. In this work, an electrochemical method based on square wave voltammetry (SWV) employing CuNPs/C60/MWCNTs/CPE has been presented for the recognition and determination of paracetamol (PT). Developed electrochemical sensor was characterized using cyclic voltammetry (CV), electrochemical impedance spectroscopy (EIS), and chronocoulometry. The composite film made the fabricated sensor to display high sensitivity and good selectivity for PT detection. The influence of the optimization parameters such as pH, accumulation time, deposition potential, scan rate and effect of loading of composite mixture of C60-MWCNTs and CuNPs on the electrochemical performance of the sensor were evaluated. A linear range from 4.0 × 10(-9) to 4.0 × 10(-7) M for PT detection was obtained with a detection limit of 7.3 × 10(-11) M. The fabricated sensor was successfully applied to the detection of PT in biological samples with good recovery ranging from 99.21 to 103%.

2-Dimensional graphene as a route for emergence of additional dimension nanomaterials

Dimension has a different and impactful significance in the field of innovation, research and technologies. Starting from one-dimension, now, we all are moving towards 3-D visuals and try to do the things in this dimension. However, we still have some very innovative and widely applicable nanomaterials, which have tremendous potential in the form of 2-D only i.e. graphene. In this review, we have tried to incorporate the reported pathways used so far for modification of 2-D graphene sheets to make is three-dimensional. The modified graphene been applied in many fields like supercapacitors, sensors, catalysis, energy storage devices and many more. In addition, we have also incorporated the conversion of 2-D graphene to their various other dimensions like zero-, one- or three-dimensional nanostructures.

A combination risk assessment of paracetamol: electrochemical oxidation behavior and cytotoxic effect evaluation of paracetamol in the presence of N1,N2-dibenzylethane-1,2-diamine

Simulation of the reaction of paracetamol in the presence of a diamine in the liver using an electrochemical cell.

Selective electrochemical detection of dopamine in the presence of uric acid and ascorbic acid based on a composite film modified electrode

An electrochemical dopamine sensor based on vanadium-substituted polyoxometalates, copper oxide and chitosan–palladium was fabricated by the LBL technique.

Facile synthesis of 3D porous nitrogen-doped graphene as an efficient electrocatalyst for adenine sensing

We demonstrate a simple, low-cost and eco-friendly strategy for the convenient preparation of three-dimensional porous nitrogen-doped graphene (3D-N-GN) for the highly sensitive detection of adenine.

Electrochemical sensors based on carbon nanomaterials for acetaminophen detection: A review

This study describes the advancements made over the last five years in the development of electrochemical sensors and biosensors for acetaminophen detection. This study reviews the different configurations based on unmodified and chemically modified carbon nanotubes and graphene. The influence of various modifiers on the two types of materials is presented along with their role on the enhancement of the selectivity and sensitivity of (bio)sensors. The review is focused on a comparative description of the applications of carbon-based nanomaterials towards acetaminophen detection and presents the results in a critical manner.

Pulicaria glutinosa extract: a toolbox to synthesize highly reduced graphene oxide-silver nanocomposites

A green, one-step approach for the preparation of graphene/Ag nanocomposites (PE-HRG-Ag) via simultaneous reduction of both graphene oxide (GRO) and silver ions using Pulicaria glutinosa plant extract (PE) as reducing agent is reported. The plant extract functionalizes the surfaces of highly reduced graphene oxide (HRG) which helps in conjugating the Ag NPs to HRG. Increasing amounts of Ag precursor enhanced the density of Ag nanoparticles (NPs) on HRG. The preparation of PE-HRG-Ag nanocomposite is monitored by using ultraviolet–visible (UV-Vis) spectroscopy, powder X-ray diffraction (XRD), and energy dispersive X-ray (EDX). The as-prepared PE-HRG-Ag nanocomposities display excellent surface-enhanced Raman scattering (SERS) activity, and significantly increased the intensities of the Raman signal of graphene.

Preparation of β-cyclodextrin functionalized reduced graphene oxide: application for electrochemical determination of paracetamol

A sensitive electrochemical sensor of paracetamol was developed based on a β-CD/reduced graphene oxide modified electrode.

One-pot in situ synthesis of a CoFe2O4nanoparticle-reduced graphene oxide nanocomposite with high performance for levodopa sensing

We demonstrate that a new nanocomposite of CoFe₂O₄-reduced graphene oxide can be used as an enhanced electrochemical sensing platform for levodopa.