Carbon-based structures are the most versatile materials used in the modern field of renewable energy (i.e., in both generation and storage) and environmental science (e.g., purification/remediation). However, there is a need and indeed a desire to develop increasingly more sustainable variants of classical carbon materials (e.g., activated carbons, carbon nanotubes, carbon aerogels, etc.), particularly when the whole life cycle is considered (i.e., from precursor "cradle" to "green" manufacturing and the product end-of-life "grave"). In this regard, and perhaps mimicking in some respects the natural carbon cycles/production, utilization of natural, abundant and more renewable precursors, coupled with simpler, lower energy synthetic processes which can contribute in part to the reduction in greenhouse gas emissions or the use of toxic elements, can be considered as crucial parameters in the development of sustainable materials manufacturing. Therefore, the synthesis and application of sustainable carbon materials are receiving increasing levels of interest, particularly as application benefits in the context of future energy/chemical industry are becoming recognized. This review will introduce to the reader the most recent and important progress regarding the production of sustainable carbon materials, whilst also highlighting their application in important environmental and energy related fields.

Sustainable carbon materials

Carbon and graphene quantum dots (CQDs and GQDs), known as zero-dimensional (0D) nanomaterials, have been attracting increasing attention in sensing and bioimaging. Their unique electronic, fluores...

Review of Carbon and Graphene Quantum Dots for Sensing

Surface-initiated polymer brushes in the biomedical field : applications in membrane science, biosensing, cell culture, regenerative medicine and antibacterial coatings

Surface-Initiated Polymer Brushes in the Biomedical Field: Applications in Membrane Science, Biosensing, Cell Culture, Regenerative Medicine and Antibacterial Coatings

Nitrogen and sulfur codoped carbon dots (CDs) were prepared from garlic by a hydrothermal method. The as-prepared CDs possess good water dispersibility, strong blue fluorescence emission with a fluorescent quantum yield of 17.5%, and excellent photo and pH stabilities. It is also demonstrated that the fluorescence of CDs are resistant to the interference of metal ions, biomolecules, and high ionic strength environments. Combining with low cytotoxicity properties, CDs could be used as an excellent fluorescent probe for cellular multicolor imaging. Moreover, the CDs were also demonstrated to exhibit favorable radical scavenging activity.

Green Synthesis of Bifunctional Fluorescent Carbon Dots from Garlic for Cellular Imaging and Free Radical Scavenging.

Carbon nanomaterials are among the most broadly discussed, researched and applied of synthetic nanomaterials. The structural diversity of these materials provides an array of unique electronic, magnetic and optical properties, which when combined with their robust chemistry and ease of manipulation, makes them attractive candidates for sensor applications. Furthermore, the biocompatibility exhibited by many carbon nanomaterials has seen them used as in vivo biosensors. Carbon nanotubes, graphene and carbon dots have come under intense scrutiny, as either discrete molecular-like sensors, or as components which can be integrated into devices. In this review we consider recent developments in the use of carbon nanoparticles and nanostructures as sensors and consider how they can be used to detect a diverse range of analytes.

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Recent developments in carbon nanomaterial sensors

High quantum yield carbon quantum dots (CQDs) are successfully synthesized via a simple, low cost, and green hydrothermal method using bamboo leaves as carbon source for the first time. Branched polyethylenimine (BPEI)-capped CQDs (BPEI-CQDs) are prepared by coating the CQDs with BPEI via electrostatic adsorption. The BPEI-CQDs are then employed as fluorescent probes for sensitive and selective Cu 2+ detection. Experimental results show that the synthesized CQDs have average size of 3.6 nm in diameter with narrow size distribution. The biomass-based CQDs offer high quantum yield of 7.1%. The BPEI-CQDs-based sensing system renders a simple, reliable and sensitive Cu 2+ detection with limit of detection (LOD) as low as 115 nM and a dynamic range from 0.333 to 66.6 μM. In addition, the BPEI-CQDs are successfully used to detect Cu 2+ in river water, demonstrating its good selectivity and great potential for analysis of environmental water samples.

One-step green synthesized fluorescent carbon nanodots from bamboo leaves for copper(II) ion detection

Phenylboronic acid polymer brush-enabled oriented and high density antibody immobilization for sensitive microarray immunoassay.

The localized hairpin-DNA cascade reaction exhibited some fascinating merits over the traditional hairpin-DNA hybridization reaction, such as the reduced reaction time and enhanced hybridization efficiency. However, the reported localized hairpin-DNA cascade reaction usually needed the participation of expensive proteases, which limited their application. This work developed a magnetic nanobeads (MBs)-assisted highly-ordered enzyme-free localized DNA cascade reaction (HELDCR) to achieve highly efficient signal amplification. With the help of magnetically separable MBs, a novel fluorescent sensor was constructed for the ultrasensitive detection of Pb2+. In the presence of the target Pb2+, the DNAzyme chain was activated and the substrate chain was cleaved. The released DNAzyme chain could trigger the HELDCR and open the highly-ordered assembled hairpin structures (HAHs) on MBs, which promoted substantial fluorophores FAM and quenchers BHQ mutually close. The proximity of FAM and BHQ caused signal quenching, thus achieving a satisfactory performance for detecting Pb2+ with a low detection limit of 3.0 pM. The synergistic effect of the HELDCR and MBs provided an attractive and sensitive fluorescent platform for biological analysis in the homogeneous environment.

A novel magnetic beads-assisted highly-ordered enzyme-free localized DNA cascade reaction for the fluorescence detection of Pb2+

Currently reported polyfluorene-based fluorescence detection usually shows high background signal and low detection sensitivity. This work developed a novel three-dimensional (3D) DNA rolling walker via directional movement on a lipid bilayer (LB) supported by Au@Fe3O4 nanoparticles (NPs) in a polyfluorene-based fluorescence system so that it could achieve significantly improved detection sensitivity and almost zero-background signal detection for miRNA-16. First, the carboxyl-functionalized poly[(9,9-dioctylfluorenyl-2,7-diyl)-co-(1,4-benzo-{2,1',3}-thiadazole)] polymer nanoparticles (c-PFBT PNPs) covalently bonded with amino-labeled single-strand CP and further hybridized with single-strand AP to prepare AP-CP-coupled c-PFBT PNP probes. Meanwhile, Au@Fe3O4 NPs were developed as efficient fluorescence quenchers and served as the matrix for assembling the LB. The resulting Au@Fe3O4@LB assembled cholesterol-labeled orbital DNA L1 and L2 and further assembled hairpins H1 and AP-CP-coupled c-PFBT PNP probes to construct DNA nanomachines. Then, the target miRNA-16 was introduced to initiate the rolling circle amplification (RCA) reaction and form dynamic DNA rolling walkers, thus releasing single-strand CP-coupled c-PFBT PNP probes. The magnetic separation effect of Au@Fe3O4 NPs made it possible to detect the fluorescence signal from the released probes, thus achieving almost zero-background signal detection for miRNA-16 with a low detection limit of 95 aM. The flexible interfaces provided by the LB endowed the DNA rolling walkers with high binding efficiency and low derailment probability, thus achieving significantly improved detection sensitivity. The developed strategy provided an attractive polyfluorene-based fluorescence platform with high-sensitivity and low-background signals.

Dynamic 3D DNA Rolling Walkers via Directional Movement on a Lipid Bilayer Supported by Au@Fe3O4 Nanoparticles for Sensitive Detection of MiRNA-16.

Dual-emitting Iridium nanorods combining dual-regulating coreaction accelerator Ag nanoparticles for electrochemiluminescence ratio determination of amyloid-β oligomers.

Yuanyuan Zhang

Papers

One-step green synthesized fluorescent carbon nanodots from bamboo leaves for copper(II) ion detection

Phenylboronic acid polymer brush-enabled oriented and high density antibody immobilization for sensitive microarray immunoassay.

A novel magnetic beads-assisted highly-ordered enzyme-free localized DNA cascade reaction for the fluorescence detection of Pb2+

Dynamic 3D DNA Rolling Walkers via Directional Movement on a Lipid Bilayer Supported by Au@Fe3O4 Nanoparticles for Sensitive Detection of MiRNA-16.

Dual-emitting Iridium nanorods combining dual-regulating coreaction accelerator Ag nanoparticles for electrochemiluminescence ratio determination of amyloid-β oligomers.