Heteroatom modification represents one of the largest studied areas of research related to nanostructured carbon materials, with integrated applications stretching from energy production and storage to sustainability and medical uses. While a wide variety of dopants (boron, phosphorus, iodine, fluorine, etc.) have been studied, doping carbon structures with nitrogen ad-atoms has arguably experienced the greatest progress and brought the most attention over the last several years. Research in this field has conclusively demonstrated that nitrogen doping is an effective way to tailor the properties of carbon and tune the material for various applications of interest. This review provides a comprehensive overview of advances in the last half decade on state-of-the-art carbon modification with nitrogen heteroatoms. Improvements in well-established fabrication/modification processes are discussed as well as novel strategies. Additionally, recent theoretical and experimental findings related to the benefits and effects of nitrogen modification for specific applications in the energy and environmental fields are reviewed.

Recent progress on nitrogen/carbon structures designed for use in energy and sustainability applications

This review covers the current state of the art of using graphenes in electrochemical and optical chemical sensors and biosensors. We first discuss the various types of graphenes, graphene oxides and the like, and also give a definition for each. This is followed by a section on the use of non-modified materials (“plain graphenes”) in mainly electrochemical and optical chemical sensors and biosensors. The next section summarizes the various kinds of sensors based on composite materials containing graphenes, with subsections on electro-chemical, field-effect-transistor-based, fluorescent, chemiluminescent and colorimetric sensors. We show that the use of graphenes alone or in composite form can improve the performance of chemical sensors and biosensors, particularly with respect to dynamic ranges, lower limits of detection, selectivity and size of instrumentation. The review is based on ∼270 references, primarily from 2007–12.

Graphenes in chemical sensors and biosensors

Recent advances in polyaniline composites with metals, metalloids and nonmetals

Enhanced catalytic and dopamine sensing properties of electrochemically reduced conducting polymer nanocomposite doped with pure graphene oxide

This review (with 110 refs.) gives an overview on the progress that has been made in the past few years on the use of gold nanoparticles (AuNPs) for use in sensors and analytical tools for the determination of dopamine (DA). Both AuNPs and their composites with other organic and inorganic materials including noble metals are treated. Following an overview on the clinical significance of DA, we discuss the various analytical methods that are (a) electrochemiluminescence (ECL); (b) surface enhanced Raman scattering (SERS); (c) colorimetric probing and visual detection; and (d) the large class of electrochemical sensors. Subsections cover sensors based on plain AuNPs, bimetallic NPs, AuNP-metal@metal oxide nanocomposites, AuNP nanocomposites with organic polymers, AuNP nanocomposites with carbon nanotubes or with graphene, and finally sensors based on ternary materials containing AuNPs. The review ends with a conclusion on current challenges of sensors for DA and an outlook on future trends.

Gold nanoparticle based optical and electrochemical sensing of dopamine

Boron-doped diamond electrodes covered with a nanostructured Pt nanoparticle-polyaniline composite have been fabricated and employed as sensitive amperometric sensors with low detection limit. A highly conductive boron-doped diamond thin film (BDD) was prepared by chemical vapor deposition, and its morphology was characterized by scanning electron microscopy and transmission electron microscopy. The nanostructured composite layer was grown on the BDD electrode by electrochemical deposition of polyaniline and Pt nanoparticles. Glucose oxidase (GOx) was then adsorptively immobilized on the modified BDD electrode. The biosensor displays a large surface area, high catalytic activity of the Pt nanoparticles, efficient electron mediation through the conducting polymer, and low background current of the electrode. The biosensor exhibits an excellent response to glucose, with a broad linear range from 5.9 μM to 0.51 mM, a sensitivity of 5.5 μA·mM−1, a correlation coefficient (R) of 0.9947, and a detection limit of 0.10 μM. The apparent Michaelis-Menten constant (KMapp) and the maximum current density of the electrode are 4.1 mM and 0.021 mA, respectively. This suggests that the immobilized GOx possesses a higher affinity for glucose at the lower KMapp, and that the enzymatic reaction rate constitutes the rate-limiting step of the response.

Pt-polyaniline nanocomposite on boron-doped diamond electrode for amperometic biosensor with low detection limit

Electrochemical sensor based on Au nanoparticles decorated boron-doped diamond electrode using ferrocene-tagged aptamer for proton detection

A selective dopamine (DA) sensor was developed using gold nanoparticles (Au-NPs) dispersed overoxidized-polyaniline (PANI(ox)) based on a boron-doped diamond (BDD) thin-film electrode. The concentration of the DA was determined using voltammetry as a non-enzymatic sensor. BDD thin film has a high signal-to-noise ratio, a long-term stability, a high sensitivity, and a good reproducibility. PANI nanocomposites were directly synthesized on the BDD electrode and overoxidized using 0.5 M H(2)SO(4) solution. The overoxidized PANI film enhances selectivity and sensitivity toward DA. The Au-NPs were dispersed on the PANI nanocomposite by electrochemical deposition. The nanometer-sized Au-NPs favor the sensing of DA in the presence of ascorbic acid (AA). The combination of the PANI with the Au-NPs and the BDD electrode can create synergetic effects for the performance of the biosensor, such as a fast response time, a lower detection limit, a wider linear range, enhanced selectivity, and higher sensitivity for the determination of DA.

Dopamine Sensor Based on a Boron-Doped Diamond Electrode Modified with a Polyaniline/Au Nanocomposites in the Presence of Ascorbic Acid

Micron-sized and precise patterns of nanocrystalline CVD diamond were fabricated successfully on substrates using dispersed nanodiamond particles, charge connection by electrostatic self-assembly, and photolithography processes. Nanodiamond particles which had been dispersed using an attritional milling system were attached electrostatically on substrates as nuclei for diamond growth. In this milling process, poly sodium 4-styrene sulfonate (PSS) was added as an anionic dispersion agent to produce the PSS/nanodiamond conjugates. Ultra dispersed nanodiamond particles with a ζ-potential and average particle size of - 60.5 mV and ∼ 15 nm, respectively, were obtained after this milling process. These PSS/nanodiamond conjugates were attached electrostatically to a cationic polyethyleneimine (PEI) coated surface on to which a photoresist had been patterned in an aqueous solution of the PSS/nanodiamond conjugated suspension. A selectively seeded area was formed successfully using the above process. A hot filament chemical vapor deposition system was used to synthesize the nanocrystalline CVD diamond on the seeded area. Micron-sized, thin and precise nanocrystalline CVD diamond patterns with a high nucleation density (3.8 ± 0.4 × 10(11) cm(-2)) and smooth surface were consequently fabricated.

https://iopscience.iop.org/article/10.1088/0957-4484/21/50/505302/pdf

Direct deposition of patterned nanocrystalline CVD diamond using an electrostatic self-assembly method with nanodiamond particles.

An electrochemical biosensor was developed using Pt-nanoparticles (Pt-NPs) dispersed graphene based on a borondoped diamond thin film electrode. To compare its performances with those of other biosensors, glucose was used as a target analyte. This biosensor exhibited a wide linear range, a low detection limit and a higher sensitivity compared to other amperometric biosensors using graphene-based electrodes. In addition, the biosensor promotes a direct electron transfer between the redox enzymes and the electrode surface and detects low concentration analytes. The excellent performance of the biosensor is attributed to the synergistic effect of the Pt-NPs, graphene sheet and the BDD thin film. Therefore, it can be a promising application for electrochemical detection of analytes.

Min Jung Song

Papers

Pt-polyaniline nanocomposite on boron-doped diamond electrode for amperometic biosensor with low detection limit

Electrochemical sensor based on Au nanoparticles decorated boron-doped diamond electrode using ferrocene-tagged aptamer for proton detection

Dopamine Sensor Based on a Boron-Doped Diamond Electrode Modified with a Polyaniline/Au Nanocomposites in the Presence of Ascorbic Acid

Direct deposition of patterned nanocrystalline CVD diamond using an electrostatic self-assembly method with nanodiamond particles.

Analytical Characteristics of Electrochemical Biosensor Using Pt-Dispersed Graphene on Boron Doped Diamond Electrode