The impermeability of the blood–brain barrier (BBB), formed by a monolayer of endothelial cells, remains a major obstacle for delivering chemotherapeutic drugs to the brain. Ultra-small nanoparticles, particularly nanoclusters smaller than 2 nm, offer a promising strategy to overcome this challenge. Here, we investigate the anti-cancer efficacy and underlying mechanisms of two sizes of platinum-based nanoparticles; platinum nanoclusters (PtNCs: 2 nm) and platinum nanoparticles (PtNPs: 10 nm), synthesized using bovine serum albumin (BSA) as a stabilizer. In this study, PtNCs and PtNPs were tested against paediatric glioblastoma (p-GBM) cells, and were shown to induce cell death, prevent cell migration, and cause cell reproductive death. The mechanism of action of the PtNCs and PtNPs was investigated and compared with cisplatin by examining oxidative stress status, DNA damage, cell cycle arrest, and cell apoptosis. PtNCs exhibited promising catalytic ability under acidic conditions and physiological temperature. They showed the ability to generate free radicals to induce oxidative stress in p-GBM cells, thus causing DNA double strand breaks and G2/M phase cell cycle arrest. Conversely, PtNPs induced S phase cell cycle arrest by causing DNA crosslinking. These findings demonstrate that the cell death mechanism of Pt-based nanoparticles is critically size-dependent. This construct therefore has the potential for an improved anti-cancer treatment for paediatric glioblastoma with negligible cytotoxicity towards the normal organs. It is suggested that PtNCs could provide a promising treatment for p-GBM, and an alternative to conventional platinum-based drugs.

Introduction: It is well known, that titanium dioxide (TiO2) nanoparticles can lead to the generation of reactive oxygen species (ROS) upon photoexcitation. Method: In this work, we investigated mesoporous surfaces based on TiO2 nanoparticles doped with 0.6-0.7% manganese (Mn), which showed reduced photoactivity and were based on the more stable rutile polymorph of titania. Result: In particular, we showed spectrophotometrically that the enzyme glucose oxidase (GOD) can be successfully adsorbed up to 80% while retaining its bioactivity in contact with the TiO2:Mn-based surface. Conclusion: We propose that this study could potentially give rise to biocompatible surfaces for biosensing applications.

Miguel Alario-Franco is recognised not only for his seminal experimental advances in the field of High Tc superconductivity but also for his incisive observations on the advances and challenges in that field. In 1995, he highlighted the need for “a new theme” to unite the chemistry and the physics of this spectacular natural phenomenon following the advance by Bednorz and Muller, that surely ranking as one of the greatest-ever discoveries in science. We review the remarkable recent advances that showed hole-pairing in the cuprates is found at temperatures above Tc; first proposed over three decades ago by Mott and Alexandrov. We highlight that the pairing itself will be ‘orbital-selective’ where holes of predominantly one specific orbital character bind to form the Cooper pairs which then condense to yield the High Tc state at a critical density and temperature. Here, a collection of friends and colleagues of Miguel from the disciplines of chemistry, physics and electronic engineering outline this as a working, chemically-intuitive model in the search for other High Tc materials.

Titanium dioxide (TiO2) nanoparticles, have been routinely used in cosmetic and sunscreen applications, due to their ability to absorb in the UV spectrum. Nevertheless, one of the main disadvantages has been the generation of reactive oxygen species (ROS), especially the hydroxyl radical, upon photoexcitation of titania. In this work, we investigate TiO2 nanoparticles doped with 0.6–0.7% manganese (Mn), based in the more stable rutile polymorph of titania. In particular, while the anatase crystal form has the ability to destroy almost any organic matter under UV illumination, rutile is less photoreactive, and with Mn doping its photoactivity is reduced further. In particular, we study its optical, structural and semiconducting properties via the Seebeck effect and show that the material displays p-type characteristics. This is very significant because it shifts the energy levels with respect to formation of hydroxyl free radicals. This ensures that for Mn doped p-type titania it is not energetically possible for the hole created in the valence band by photoexcitation to create an OH. free radical and this may explain its low photoreactivity. It also means that this material can act as a very effective scavenger for hydroxyl free radicals.

The title of this book captured my interest immediately and the summary of chapter headings looked very promising. Over the years I have lectured on the applications of nanotechnology and mostly with respect to the impacts on humans in terms of safety, diagnostics and therapy, and one of the surprises for me, has been the relative neglect for the impact on plants. This is compounded by the importance of plants for food and the environment and the fact that plants grow in soils which have a very high percentage ofmicro and nanoparticles, and they contribute to aerosol particles in the air. I have also emphasised to my students that looking for effects of nanoparticles on plant cells does not require the expensive and strict regulatory protocols that are required for animals and humans! Despite all of this, there is a shortage of textbooks to help the interested reader and I hoped that this volume would fill this gap. The book is very nicely produced, and it is readable, with very extensive references for each of the 14 chapters. A descriptive style has been adopted which requires hardly any detailed prior knowledge of physics, chemistry ormathematics. However, herein lies the biggest shortcoming: there is a lack of rigour and also a lack of critical analysis. Of the 14 chapters there is some considerable overlap between them which could have been avoided. There are two on biosensors and that topic is repeated in other chapters. However, the treatment is rather superficial and lacks good explanation of the main science behind the sensor function and measurement. There are three chapters on wastewater treatment using nanomaterials and another two on environmental remediation, all with strong overlaps. There is hardly any quantification as to the valence state of toxic metals and the concentrations that occur, apart from one table which does not employ comparable units. Although they refer to World Health Organisation and the US Environment Protection Agency guidelines, there are no actual references to where these are published. Bionanocomposites are in two main chapters and are referred to elsewhere in the book. The treatment is very descriptive, withmany references, but there is no underlying structure to the presentation.Other chapters cover antimicrobial aspects of metals and their oxides as well as pesticide control, fertilisers and growth enhancement. Opportunities have been missed for discussion as to why some of the nanoparticles show antimicrobial properties. There is a separate chapter on the impact of bionanomaterials on the food industry. This is rather brief and again there is inconsistency in the use of units. Concentrations of analytes vary between grams per litre and molar concentrations and there are no definitive references to the regulations by different agencies. To be fair, much of the book will stimulate interest to those who are very new to the field of nanotechnology. So, what is missing? There is nothing on the aspects of soil and the processes that occur in the root region and uptake of water and nutrients or unwanted nano-toxins by plants. There is nothing about the detailed photosynthesis, respiration and transpiration that occurs in leaves, along with the uptake and emission of gases and the effect of nanomaterials. These omissions detract from the value. The editors expressed the hope that this book will serve as a textbook for students and perform a reference function for professionals, scientists, researchers and academics. I fear that this is overoptimistic, but it has many useful attributes.

Peter Edwards, Peter Dobson and Gari Owen say that net-zero targets can only be met if renewable energy can be stored cost-effectively.

After his theory of Special Relativity, Einstein’s theory of General Relativity added a further revolution to the way we think about space and time. As a theory of gravity in curved space-time, it is notoriously difficult mathematically, and its physical interpretation for a long time generated a good deal of controversy. Fortunately, there are now many textbooks on the subject, although these may have varying degrees of success in communicating the material in a way that a student can follow without too much difficulty. There are also popular accounts that aim to convey the physical ideas and consequences to the more general reader. Carlo Rovelli, in his present concisely-written book, aims to bridge the gap a little. This is certainly not a popular-level book, but neither does it go into the extensive detail that a more standard text would provide. The book has three sections. The first presents a general discussion of space and time and the mathematical foundations of the theory, starting with Newton, and mentioning both the traditional tensor formulation and the more recently fashionable differential-form approach to the curved geometry. Einstein’s equations are then presented together with a discussion of physical action and symmetries. The final section describes the various physical applications, moving on to discuss quantum gravity, and loop quantum gravity, which is Rovelli’s own specialist subject in which he has made a distinguished name for himself. Of course, at this stage, we are very much in the realm of speculation. What type of reader will benefit most from this book? It has the excellent virtue of being very reasonably priced in its paperback version, and as a non-specialist with some degree of training in the subject, I have tried to place myself in the position of a potential student. Although Rovelli seeks to place a stress on concepts, the mathematics is not compromised and this means that a general physicist reader will find a good deal of the material rather difficult to follow. Although much of the writing is admirably clear in the context of the theory, it seems to me that longer pedagogical explanations would sometimes be desirable – I found the description of p-forms on page 51 particularly over-concise. Rovelli sometimes presents short exercises for the reader and I reckon that these should probably have been done in the text. On the other hand, in a treatment of this compact length it is possible to give a good overview of the subject, and Rovelli makes many interesting observations and perceptions that are capable of amplifying the reader’s understanding in a variety of ways. It seems to me that this book can be well recommended to a serious student as parallel reading to a more comprehensive text, particularly in view of its affordability, for which the publishers must be complimented. Sometimes a given text just doesn’t express a particular point too well, and here a second point of view may be just what the student needs. Rovelli may well be able to help in such cases! To understand general relativity properly requires time and effort, and this thoughtfully written book may be a very useful contribution to the teaching of the subject.

With mounting concerns over climate change, the utilisation or conversion of carbon dioxide into sustainable, synthetic hydrocarbons fuels, most notably for transportation purposes, continues to attract worldwide interest. This is particularly true in the search for sustainable or renewable aviation fuels. These offer considerable potential since, instead of consuming fossil crude oil, the fuels are produced from carbon dioxide using sustainable renewable hydrogen and energy. We report here a synthetic protocol to the fixation of carbon dioxide by converting it directly into aviation jet fuel using novel, inexpensive iron-based catalysts. We prepare the Fe-Mn-K catalyst by the so-called Organic Combustion Method, and the catalyst shows a carbon dioxide conversion through hydrogenation to hydrocarbons in the aviation jet fuel range of 38.2%, with a yield of 17.2%, and a selectivity of 47.8%, and with an attendant low carbon monoxide (5.6%) and methane selectivity (10.4%). The conversion reaction also produces light olefins ethylene, propylene, and butenes, totalling a yield of 8.7%, which are important raw materials for the petrochemical industry and are presently also only obtained from fossil crude oil. As this carbon dioxide is extracted from air, and re-emitted from jet fuels when combusted in flight, the overall effect is a carbon-neutral fuel. This contrasts with jet fuels produced from hydrocarbon fossil sources where the combustion process unlocks the fossil carbon and places it into the atmosphere, in longevity, as aerial carbon - carbon dioxide.

The demand of gold nanoparticles (AuNPs) is growing steeply as a result of the remarkable advances in the applications of this product in the healthcare and diagnostics sectors. To this end, having an efficient and sustainable production system is of paramount importance for achieving low environmental impacts and avoiding depletion of capitals. In this respect, the present work gives insights on the environmental impact and costs of the production of AuNPs for nano-enabled medical applications, by looking at two production technologies: the conventional batch production and an innovative milli-continuous flow production, currently at lab scale. Life Cycle Assessment (LCA) and cost assessment are used to evaluate the sustainability and economics of the continuous-flow technology in an anticipatory fashion; this means capturing the environmental impacts and production costs of the emerging technology before it reaches full-scale and is deployed. The aim is to prevent waste of resources in the process development and avoid having a non-optimized final system, which would lead to high costs and reduce competitiveness. The milli-continuous flow production was subjected to a scale up/out-analysis enabling the comparison with the batch production, already established at large scale. The life cycle of both production systems is described, and the results of the assessment comprise a normalisation analysis, which frames the environmental impacts of the gold nanoparticles production in the European context, a scenario analysis, a comparative analysis and a hotspot analysis. The results show that significant advantages can be gained from the adoption of the continuous-flow production in place of the batch system, both in terms of environmental impact and production costs. Specifically, the environmental impact is reduced in terms of human toxicity (cancer effect), ecotoxicity of freshwater and depletion of gold resources; these impact categories were identified as the main carrier of the environmental impact in the conventional production. The main contributors to savings for the flow production are primarily milder cleaning procedures, reduction of hazardous wastes produced, and less labour required for the operation and control of the process. Finally, the depletion of gold resources associated to the production of AuNPs emerges as a major issue. It is hardly addressable by using second-hand gold, and this calls for the necessity of recycling the product at the end of its life cycle or complementing AuNPs with alternative nano-products.

The quantum spin properties of nitrogen-vacancy defects in diamond enable diverse applications in quantum computing and communications 1 . However, fluorescent nanodiamonds also have attractive properties for in vitro biosensing, including brightness 2 , low cost 3 and selective manipulation of their emission 4 . Nanoparticle-based biosensors are essential for the early detection of disease, but they often lack the required sensitivity. Here we investigate fluorescent nanodiamonds as an ultrasensitive label for in vitro diagnostics, using a microwave field to modulate emission intensity 5 and frequency-domain analysis 6 to separate the signal from background autofluorescence 7 , which typically limits sensitivity. Focusing on the widely used, low-cost lateral flow format as an exemplar, we achieve a detection limit of 8.2 × 10 −19 molar for a biotin–avidin model, 10 5 times more sensitive than that obtained using gold nanoparticles. Single-copy detection of HIV-1 RNA can be achieved with the addition of a 10-minute isothermal amplification step, and is further demonstrated using a clinical plasma sample with an extraction step. This ultrasensitive quantum diagnostics platform is applicable to numerous diagnostic test formats and diseases, and has the potential to transform early diagnosis of disease for the benefit of patients and populations.

Hydrogen technologies and fuel cells offer an alternative and improved solution for a decarbonised energy future. Fuel cells are electrochemical converters; transforming hydrogen (or energy sources containing hydrogen) and oxygen directly into electricity. The hydrogen fuel cell, invented in 1839, permits the generation of electrical energy with high efficiency through a non-combustion, electrochemical process and, importantly, without the emission of CO2 at its point of use. Hitherto, despite numerous efforts to exploit the obvious attractions of hydrogen technologies and hydrogen fuel cells, various challenges have been encountered, some of which are reviewed here. Now, however, given the exigent need to urgently seek low-carbon paths for humankind's energy future, numerous countries are advancing the deployment of hydrogen technologies and hydrogen fuel cells not only for transport, but also as a means of the storage of excess renewable energy from, for example, wind and solar farms. Furthermore, hydrogen is also being blended into the natural gas supplies used in domestic heating and targeted in the decarbonisation of critical, large-scale industrial processes such as steel making. We briefly review specific examples in countries such as Japan, South Korea and the People's Republic of China, as well as selected examples from Europe and North America in the utilization of hydrogen technologies and hydrogen fuel cells.

Interviews conducted with 66 experts to gather their perspectives on environmental risks from nanomedicines and their responses analysed using qualitative content analysis.

Ultrasmall gold nanoparticles were synthesized without strong capping agents by using a capillary-based continuous flow system. A mixture of gold(III) chloride trihydrate and trisodium citrate flowed through capillaries at elevated temperature. The effect of capillary material (polytetrafluoroethylene, fluorinated ethylene propylene, polyetheretherketone, fused silica), surface-to-volume ratio (capillary internal diameter 0.3-1 mm), average residence time (1.5-30 min) and temperature (70-100 degrees C) were investigated. At a flow rate of 0.006 ml/min (residence time 30 min), 100 degrees C, 275 kPa back pressure, citrate/gold molar ratio 3.15 and using PTFE capillary tubing with an inner diameter of 0.3 mm, very small (1.9 +/- 0.2 nm) nanoparticles were obtained. For comparison, experiments were also performed under the same experimental conditions, but in slug flow using octane as segmenting fluid, thus isolating the reactants from the tubing wall. The synthesized particles were 17.4 +/- 1.4 nm for segmented flow, demonstrating the important effect of the capillary wall surface. The performance of these citrate-capped gold nanoparticles was tested for Surface-Enhanced Raman Scattering (SERS). The average enhancement factor (AEF) of 2 nm gold nanoparticles capped by citrate from our work (AEF = 1.54 x 10(8)) was nearly double when compared to 2 nm phosphate-capped commercial gold nanoparticles (AEF = 7.34 x 10(7)). The adsorption of analyte molecules onto citrate-capped gold surface was easier due to the weaker binding strength of the carboxylate ligand and more hotspots formed with narrower gaps between neighbouring particles, giving rise to improved enhancement. This work has been selected by the Editors as a Featured Cover Article for this issue. (C) 2018 The Authors. Published by Elsevier Ltd.

The phase transfer of quantum dots to water is an important aspect of preparing nanomaterials that are suitable for biological applications, and although numerous reports describe ligand exchange, very few describe efficient ligand encapsulation techniques. In this report, we not only report a new method of phase transferring quantum dots (QDs) using an amphiphilic protein (hydrophobin) but also describe the advantages of using a biological molecule with available functional groups and their use in imaging cancer cells in vivo and other imaging applications.

Nanotechnology is starting to play a role in a number of commercial products, though in an evolutionary, rather than revolutionary way, says Peter Dobson.

The use of gold nanoparticles (Au-NP) based medical applications is rising due to their unique physical and chemical properties. Diagnostic devices based on Au-NP are already available in the market or are in clinical trials and Au-NP based therapeutics and theranostics (combined diagnostic and treatment modality) are in the research and development phase. Currently, no information on Au-NP consumption, material flows to and concentrations in the environment are available. Therefore, we estimated prospective maximal consumption of Au-NP from medical applications in the UK and US. We then modelled the Au-NP flows post-use and predicted their environmental concentrations. Furthermore, we assessed the environment risks of Au-NP by comparing the predicted environmental concentrations (PECs) with ecological threshold (PNEC) values.

This study describes a system for quantifying paclitaxel activity using the C-terminus of α-tubulin as a biomarker. Following stabilization of microtubules with paclitaxel, a specific detyrosination reaction occurs at the C-terminus of α-tubulin which could be used to assess efficacy. A fluorescence resonance energy transfer (FRET) based biosensor was synthesized comprising a short peptide that corresponded to the C-terminus of α-tubulin, a fluorophore (Abz), and a quencher (Dnp). The fluorophore added to the end of the peptide can be released upon enzymatic detyrosination. In addition, a single fluorophore-tagged peptide was also conjugated to mesoporous silica nanoparticles to examine the feasibility of combining the drug with the peptide biomarker. As a proof of concept, we found that the degree of peptide cleavage, and therefore enzymatic activity, was directly correlated with exogenous bovine carboxypeptidase (CPA) an enzyme that mimics endogenous detyrosination. In addition, we show that cell lysates obtained from paclitaxel-treated cancer cells competed with exogenous CPA for biosensor cleavage in a paclitaxel dose-dependent manner. Our work provides strong evidence for the feasibility of combining paclitaxel with a novel biosensor in a multi-load nanoparticle.