Biological application of carbon nanotubes and graphene

Carbon nanotubes (CNTs) and graphene are two representative nanomaterials comprised of purely element carbon [1,2]. Graphene is the two-dimensional, hexagonal sp2-carbon ring networks with one atomic layer thickness, while CNTs can be envisaged as one or several graphene sheets concentrically rolled up into a one-dimensional cylindrical structure, so-called singlewalled (SW) or multi-walled (MW) CNTs, respectively. Figure 12.1 shows the schematic diagram of structures of graphene, SWCNT and MWCNT. Owing to their exceptional mechanical, electrical, optical and thermal properties, CNTs and graphene have been widely considered as a new type of materials with great potentials to revolutionalize many of the biological and medical fields [3–5].

Single-walled carbon nanotube-based polymer monoliths for the enantioselective nano-liquid chromatographic separation of racemic pharmaceuticals

Many protocols have been used for extraction of DNA from Thraustochytrids. These generally involve the use of CTAB, phenol/chloroform and ethanol. They also feature mechanical grinding, sonication, N2 freezing or bead beating. However, the resulting chemical and physical damage to extracted DNA reduces its quality. The methods are also unsuitable for large numbers of samples. Commercially-available DNA extraction kits give better quality and yields but are expensive. Therefore, an optimized DNA extraction protocol was developed which is suitable for Thraustochytrids to both minimise expensive and time-consuming steps prior to DNA extraction and also to improve the yield. The most effective method is a combination of single bead in TissueLyser (Qiagen) and Proteinase K. Results were conclusive: both the quality and the yield of extracted DNA were higher than with any other method giving an average yield of 8.5 µg/100 mg biomass.

Pre-lithiation of onion-like carbon/MoS2 nano-urchin anodes for high-performance rechargeable lithium ion batteries

Hybrid urchin-like nanostructures composed of a spherical onion-like carbon (OLC) core and MoS2 nanoleaves were synthesized by a simple solvothermal method followed by thermal annealing treatment. Compared to commercial MoS2 powder, MoS2/OLC nanocomposites exhibit enhanced electrochemical performance as anode materials of lithium-ion batteries (LIBs) with a specific capacity of 853 mA h g−1 at a current density of 50 mA g−1 after 60 cycles, and a moderate initial coulombic efficiency of 71.1%. Furthermore, a simple pre-lithiation method based on direct contact of lithium foil with MoS2/OLC nano-urchins was used to achieve a very high coulombic efficiency of 97.6% in the first discharge/charge cycle, which is at least 26% higher compared to that of pristine MoS2/OLC nano-urchins. This pre-lithiation method can be generalized to develop other carbon-metal sulfide nanohybrids for LIB anode materials. These results may open up a new avenue for the development of the next-generation high-performance LIBs.

Long, vertically aligned single-walled carbon nanotubes from plasmas: Morpho-kinetic and alignment controls

The enhanced large-scale model and numerical simulations are used to clarify the growth mechanism and the differences between the plasma- and neutral gas-grown carbon nanotubes, and to reveal the underlying physics and the key growth parameters. The results show that the nanotubes grown by plasma can be longer due to the effects of hydrocarbon ions with velocities aligned with the nanotubes. We show that the low-temperature growth is possible when the hydrocarbon ion flux dominates over fluxes of other species. We have also analysed the dependencies of the nanotube growth rates on nanotube and process parameters. The results are verified by a direct comparison with the experimental data. The model is generic and can be used for other types of carbon nanostructures such as carbon nanowalls, vertical graphenes, etc.

Carbon nanotubes on nanoporous alumina: From surface mats to conformal pore filling

Control over nucleation and growth of multi-walled carbon nanotubes in the nanochannels of porous alumina membranes by several combinations of posttreatments, namely exposing the membrane top surface to atmospheric plasma jet and application of standard S1813 photoresist as an additional carbon precursor, is demonstrated. The nanotubes grown after plasma treatment nucleated inside the channels and did not form fibrous mats on the surface. Thus, the nanotube growth mode can be controlled by surface treatment and application of additional precursor, and complex nanotube-based structures can be produced for various applications. A plausible mechanism of nanotube nucleation and growth in the channels is proposed, based on the estimated depth of ion flux penetration into the channels.

Plasma-enabled carbon nanostructures for early diagnosis of neurodegenerative diseases

Carbon nanostructures (CNs) are amongst the most promising biorecognition nanomaterials due to their unprecedented optical, electrical and structural properties. As such, CNs may be harnessed to tackle the detrimental public health and socio-economic adversities associated with neurodegenerative diseases (NDs). In particular, CNs may be tailored for a specific determination of biomarkers indicative of NDs. However, the realization of such a biosensor represents a significant technological challenge in the uniform fabrication of CNs with outstanding qualities in order to facilitate a highly-sensitive detection of biomarkers suspended in complex biological environments. Notably, the versatility of plasma-based techniques for the synthesis and surface modification of CNs may be embraced to optimize the biorecognition performance and capabilities. This review surveys the recent advances in CN-based biosensors, and highlights the benefits of plasma-processing techniques to enable, enhance, and tailor the performance and optimize the fabrication of CNs, towards the construction of biosensors with unparalleled performance for the early diagnosis of NDs, via a plethora of energy-efficient, environmentally-benign, and inexpensive approaches.

Electrochemical mechanism of eugenol at a Cu doped gold nanoparticles modified glassy carbon electrode and its analytical application in food samples

A simple one-step electrodeposition method was used to construct a glassy carbon electrode (GCE), which has been modified with Cu doped gold nanoparticles (GNPs), i.e. a Cu@AuNPs/GCE. This electrode was characterized with the use of scanning electron microscopy (SEM) and X-ray diffraction (XRD) techniques. The eugenol was electrocatalytically oxidized at the Cu@AuNPs/GCE. At this electrode, in comparison with the behavior at the GCE alone, the corresponding oxidation peak current was enhanced and the shift of the oxidation potentials to lower values was observed. Electrochemical behavior of eugenol at the Cu@AuNPs/GCE was investigated with the use of the cyclic voltammetry (CV) technique, and additionally, in order to confirm the electrochemical reaction mechanism for o-methoxy phenols, CVs for catechol, guaiacol and vanillin were investigated consecutively. Based on this work, an electrochemical reaction mechanism for o-methoxy phenols was suggested, and in addition, the above Cu@AuNPs/GCE was successfully employed for the analysis of eugenol in food samples.

Multipurpose nanoporous alumina-carbon nanowall bi-dimensional nano-hybrid platform via catalyzed and catalyst-free plasma CVD

Simple, rapid, plasma-assisted synthesis of large-area arrays of vertically-aligned carbon nanowalls on highly-porous, transparent bare and gold-coated alumina membranes with the two pore sizes is reported. It is demonstrated that the complex patterns of vertically aligned nanowalls can nucleate and form different morphologies in the low-temperature plasmas. The process is stable, and the twofold change in the gas flow (10 and 20 sccm) does not noticeably influence the morphology of the nanowall pattern. Application of a thin (5 nm) gold layer to nanoporous membrane prior to the nanowall growth allows controlling the network morphology.

Using smartphones for cycling safety: A survey of riders preferences and interest in new technologies

Cyclists are among the most vulnerable road users. Many recent interventions have aimed at improving their safety on the road, such as the minimum overtaking distance rule introduced in Queensland in 2014. Smartphones offer excellent opportunities for technical intervention for road safety at a limited cost. Indeed, they have a lot of available processing power and many embedded sensors that allow analysing a rider's (or driver's) motion, behaviour, and environment; this is especially relevant for cyclists, as they do not have the space or power allowance that can be found in most motor vehicles. The aim of the study presented in this paper is to assess cyclists’ support for a range of new smartphone-based safety technologies. The preliminary results for an online survey with cyclists recruited from Bicycle Queensland and Triathlon Queensland, with N=191, are presented. A number of innovative safety systems such as automatic logging of incidents without injuries, reporting of dangerous area via a website/app, automatic notification of emergency services in case of crash or fall, and advanced navigation apps were assessed. A significant part of the survey is dedicated to GoSafeCycle, a cooperative collision prevention app based on motion tracking and Wi-Fi communications developed at CARRS-Q. Results show a marked preference toward automatic detection and notification of emergencies (62-70% positive assessment) and GoSafeCycle (61.7% positive assessment), as well as reporting apps (59.1% positive assessment). Such findings are important in the context of current promotion of active transports and highlight the need for further development of system supported by the general public.

Cycling for transport and recreation: Associations with the socio-economic, natural and built environment

This study examined associations between objective environmental attributes and, separately, transport (TC) and recreational cycling (RC). Environmental attributes were more strongly associated with TC than RC. Distances to areas with the best bicycle infrastructure and urban amenities may be key environmental factors influencing TC but not RC. Government investments in bicycle infrastructure within inner Brisbane appear to have resulted in more TC than in outer areas and to appeal to residents of both the most and least disadvantaged neighbourhoods. Extending this infrastructure to residents living in disadvantaged and advantaged neighbourhoods outside the CBD could expand TC participation.

Metal-free graphitic carbon nitride as mechano-catalyst for hydrogen evolution reaction

Graphitic carbon nitride (g-C3N4), as a promising metal-free catalyst for photo-catalytic and electrochemical water splitting, has recently attracted tremendous research interest. However, the underlying catalytic mechanism for the hydrogen evolution reaction (HER) is not fully understood. By using density functional theory calculations, here we have established that the binding free energy of hydrogen atom (ΔGH∗0) on g-C3N4 is very sensitive to mechanical strain, leading to substantial tuning of the HER performance of g-C3N4 at different coverages. The experimentally-observed high HER activity in N-doped graphene supported g-C3N4 (Zheng et al., 2014) is actually attributed to electron-transfer induced strain. A more practical strategy to induce mechanical strain in g-C3N4 is also proposed by doping a bridge carbon atom in g-C3N4 with an isoelectronic silicon atom. The calculated ΔGH∗0 on the Si-doped g-C3N4 is ideal for HER. Our results indicate that g-C3N4 would be an excellent metal-free mechano-catalyst for HER and this finding is expected to guide future experiments to efficiently split water into hydrogen based on the g-C3N4 materials.

Carbon nanodot decorated graphitic carbon nitride: New insights into the enhanced photocatalytic water splitting from ab initio studies

Interfacing carbon nanodots (C-dots) with graphitic carbon nitride (g-C3N4) produces a metal-free system that has recently demonstrated significant enhancement of photo-catalytic performance for water splitting into hydrogen [Science, 2015, 347, 970–974]. However, the underlying photo-catalytic mechanism is not fully established. Herein, we have carried out density functional theory (DFT) calculations to study the interactions between g-C3N4 and trigonal/hexagonal shaped C-dots. We find that hybrid C-dots/g-C3N4 can form a type-II van der Waals heterojunction, leading to significant reduction of band gap. The C-dot decorated g-C3N4 enhances the separation of photogenerated electron and hole pairs and the composite's visible light response. Interestingly, the band alignment of C-dots and g-C3N4 calculated by the hybrid functional method indicates that C-dots act as a spectral sensitizer in hybrid C-dots/g-C3N4 for water splitting. Our results offer new theoretical insights into this metal-free photocatalyst for water splitting.

Thermal conductivity of a new carbon nanotube analog: The diamond nanothread

Based on the non-equilibrium molecular dynamics simulations, we have studied the thermal conductivities of a novel ultra-thin one-dimensional carbon nanomaterial - diamond nanothread (DNT). Unlike single-wall carbon nanotube (CNT), the existence of the Stone-Wales transformations in DNT endows it with richer thermal transport characteristics. There is a transition from wave-dominated to particle-dominated transport region, which depends on the length of poly-benzene rings. However, independent of the transport region, strong length dependence in thermal conductivity is observed in DNTs with different lengths of poly-benzene ring. The distinctive SW characteristic in DNT provides more degrees of freedom to tune the thermal conductivity not found in the homogeneous structure of CNT. Therefore, DNT is an ideal platform to investigate various thermal transport mechanisms at the nanoscale. Its high tunability raises the potential to design DNTs for different applications, such as thermal connection and temperature management.

Roundabout design guidelines and cycling safety

Review conducted as part of a Queensland Department of Transport and Main Roads funded project ‘Roundabout design review’. The project examined: - Design guidelines - Factors that affect safety at roundabouts

Sustainable me - a pharmacist’s role in reducing the carbon footprint of healthcare delivery

Introduction Climate change has been described as the most significant global health threat of the 21st century. Already, negative impacts on human health and wellbeing are being observed. These impacts present enormous challenges for the healthcare sector and the time has come for healthcare professionals to demonstrate leadership in addressing these challenges. Since any unsustainable organizational practices of healthcare organisations may ultimately have a negative impact on human health, there is an implicit moral obligation for these organisations and the people who work in them, to deliver healthcare more sustainably. If one considers that in 2010 pharmaceuticals comprised 22% of the carbon footprint of the NHS England (equating to 4.4 million tonnes of CO2 emissions) and 3% of England’s total carbon footprint (NHS Sustainable Development Unit, 2012), by reducing the carbon footprint of pharmaceuticals used in their healthcare organisations, pharmacists can have a significant impact on reducing the organisation’s total carbon footprint and ultimately on the public’s health. Aims The engagement of pharmacists with sustainability initiatives in the workplace has been largely unreported in international and national pharmacy journals. This paper aims to highlight the important role that pharmacists can play in helping to reduce the carbon footprint of healthcare delivery. Methods Literature was reviewed to identify areas where pharmacists could influence the more sustainable use of pharmaceuticals in their organisations. Discussion Much of the carbon footprint of pharmaceuticals is embedded carbon from their manufacture and delivery. Through efficient inventory management practices, pharmacists can reduce the number of orders and potentially reduce the number of deliveries required. Pharmacists can also help to reduce the amount of pharmaceutical waste generated. Of the waste that is generated, they can help improve the segregation of waste streams to increase the amount of non-contaminated packaging waste that is recycled and reduce the amount of pharmaceutical waste being incinerated or ending up in landfill. Reference NHS Sustainable Development Unit. (2012). Sustainability in the NHS Health Check 2012. NHS Sustainable Development Unit. Cambridge, UK: NHS Sustainable Devlopment Unit.