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Summary Despite the high energy density, the lithium metal electrode has been plagued for decades with a dendrite growth problem that can result in a battery thermal runaway. Here, we introduce anisotropic spatially heterogeneous three dimensional (3D) current collectors that prevent lithium deposition on the insulating electrolyte-facing surface and accommodate lithium deposition inside the spacious voids. The anisotropic spatial heterogeneity was introduced by a line-of-sight deposition of a thin SiO2 layer onto a carbon-fiber paper. The deposited SiO2 was later converted into SiC by a magnesiothermic reaction. The SiO2 and SiC decorated 3D current collectors were confirmed dendrite-free by ex situ SEM observation after a deep lithium deposition of 28.8 C cm−2 at a high current density of 4 mA cm−2. A high lithium cycling efficiency of 94% was achieved over deep deposition (14.4 C cm−2) and stripping cycles in a carbonate based organic electrolyte, demonstrating the superiority of the novel current collector for dendrite control and lithium cycling. This strategy opens new avenues to address the dendrite problem by rationally designed current collectors and for the creation of a high energy density electrode.

This research is supported by the Advanced Manufacturing Program (No. 1927623) from the National Science Foundation and by the McIntire-Stennis Cooperative Forestry Research Program (No. 1020630) from the USDA National Institute of Food and Agriculture. The authors also thank WestRock Paper Company for donated the wood pulp used in this research. Open access funding is enabled and organized by CERN. Cellulose-based paper electronics is an attractive technology to meet the growing demands for naturally abundant, biocompatible, biodegradable, flexible, inexpensive, lightweight and highly miniaturizable sensory materials. The price reduction of industrial carbon nanotube (CNT) grades offers opportunities to manufacture electrically conductive papers whose resistivity is responsive to environmental stimuli, such as the presence of water or organic solvents. Here, a highly sensitive paper nanocomposite is developed by integrating CNTs into a hierarchical network of pulp fibers and nanofibrillated cellulose. The aqueous-phase dynamic web forming process enables the scalable production of sensory paper nanocomposites with minimal nanoparticle loss due to the tailored interfacial bonding between CNT and cellulose components. The resulting materials are applied as multifunctional liquid sensors, such as leak detection and wave monitoring. The sensitivity to liquid water spans an outstanding four orders of magnitude even after 30 cycles and 6-month natural aging, due to the hydroexpansion of the hierarchical cellulose network, which alters the intertube distance between neighboring CNTs. The re-organization of percolated CNTs modifies the electron transport in wet areas of the sheet, which can be predicted by an equivalent circuit of resistors for the rapid detection and quantification of various liquids over large surfaces. (c) 2021 Published by Elsevier Ltd. National Science Foundation [1927623]; USDA National Institute of Food and Agriculture [1020630]; CERN; Div Of Civil, Mechanical, & Manufact Inn; Directorate For Engineering [1927623] Funding Source: National Science Foundation

Graphene is a two dimensional (2D) planar and hexagonal array of carbon atoms and has been studied extensively as advanced nanomaterials for important technological applications. This review summarizes the recent developments in chemistry, materials and energy applications of graphene, doped graphene and their composites with nanoparticles (NPs). It first highlights the new chemistry used to synthesize high quality graphene. It then outlines the methodologies developed to dope graphene with heteroatoms to modify and control graphene properties. It further describes the general approaches to graphene–NP composites via either direct NP growth onto graphene or self-assembly of the pre-formed NPs on graphene surface. These graphene–NP composites provide some ideal systems for studying synergistic effects between graphene and NPs on catalysis. The review focuses on applications of graphene–NP composites in increasing electrochemical energy storage density and in catalyzing chemical reactions with much desired electrochemical efficiencies.

Summary Graphene microcircuits have been successfully created on graphene oxide films via direct femtosecond laser reduction process according to preprogrammed patterns. Atomic force microscopy (AFM) characterization shows that surface height of the micropatterns was lower than the rest of the film due to the loss of oxygen confirmed by XPS and XRD techniques. The electric resistivity and conductivity of as-reduced graphene have strong dependences on output power of femtosecond laser. Moreover, current–voltage curves of graphene microcircuits show typical linear relationship, indicating the stable conductivities. The micro-nanoprocessing of graphene through femtosecond laser technologies might open the door for applications of graphene-based materials in electronic microdevices.

Summary Ultrasound technology in combination with echogenic particles is currently having a considerable effect on the modern medical field, not only as a conventional diagnostic modality but also as a methodology that administers therapeutics to various lesions. The diagnostic and therapeutic effects of ultrasound technologies on diseased sites are governed by several primary factors such as the ultrasound technique itself and the physicochemical properties of echogenic particles. Therefore, rational design and a good combination of echogenic particles with the ultrasound technique are the most decisive factors in achieving optimal diagnostic and therapeutic goals. In this respect, great research advances in design and engineering of echogenic particles to meet these diagnostic and therapeutic demands have consistently been made. Since echogenic particles exhibit quite different behaviors in response to ultrasound, the most important issue in achieving maximal therapeutic efficacy must be the establishment of technical rationales that depend on these particles’ biomedical uses, from the selection of shell materials and gas types to the manufacturing techniques used to make particles of the proper diameter. Several attempts have been made to develop highly effective theranostic echogenic particles that have the proper particle size and yet can sustain intense echo signals for long enough to circulate repeatedly through the body, a primary requirement for targeting and accumulating at a diseased site. However, a very important challenge has been the technical barrier between the most favorable in vivo nano-size for desirable biodistribution and the obtaining of a strong echo intensity. In this review paper, the present status and the critical issues for developing theranostic echogenic particles as an ultrasound contrast agent and drug delivery vehicle will be described. Firstly, conventional micro-sized echogenic particles are comprehensively introduced with their research history, diagnostic applications and intrinsic limitations. Then recent progress in developing more advanced echogenic particles for diagnostic and therapeutic purposes will be described. Most importantly, in this review paper, the design criteria for developing promising theranostic echogenic particles to satisfy recent research and clinicians’ demands will be given, with special emphasis on overcoming the conflicting and insuperable size issue of echogenic particles.

This paper describes large positive cooperative effects of two orders of magnitude in the tunneling rates across molecular junctions of mixed self-assembled monolayers (SAMs) of rectifying (ferrocenyl undecanethiol HS(CH2)11Fc) and non-rectifying molecules with different terminal groups (11-undecanethiol and its derivatives, denoted as HS(CH2)11X, where X = -H, -NH2 or -NO2). By gradually diluting the surface fraction of HS(CH2)11Fc in the mixed SAM, it is found that the large positive cooperative effect is only important in the coherent tunneling regime but not in the incoherent tunneling regime. Density functional theory (DFT) shows that the measured cooperative effects in the tunneling rates in these binary systems are caused by Fc---X van der Waals interactions which increase in the order of -H< -NH2< -NO2. These strong cooperative effects dramatically alter the operation of a molecular diode, further highlighting the importance of taking cooperative effects into account, in this case driven by van der Waals interactions, in the rational design of electronic devices working at tunneling regime.

Water pollution worldwide has already endangered health and environment. At places of rapid population growth and urbanization, traditional technologies for wastewater treatment and polluted water reclamation are approaching their limits. Nanomaterials of small particle sizes, huge specific surface areas and abundant reactive sites are ideal for adsorbing pollutants, but semiconducting nanoparticles that can harness sunlight to catalyze advanced oxidation processes are especially effective for eliminating refractory water contaminants. This paper reviews the guiding principles of nanomaterial adsorption and photocatalysis for advanced water treatment, and calls attention to low-cost, high-performance nanomaterials that are well positioned for large-scale water treatment. Black titania (BT) capable of full-spectrum solar photon absorption and three-dimensional graphene (3DG) with an unparalleled combination of electrical conductivity, mechanical strength/flexibility and surface activity and functionality are especially promising. Hybrids of BT and 3DG have been successfully field-tested for large-area remediation of contaminated water in its natural setting, and the lessons learned will lead to further advances in this technology, including ones that integrate wastewater treatment with energy conversion and storage.

This review focuses on the generation of energetic (hot) electrons in plasmonic metastructures and nanomaterials, and their characterization through time-resolved spectroscopy. Excitation of hot electrons under illumination occurs in any metal or conductor, but their number will vary for each type of nanostructure. While plasmonic resonances are well described classically, the excitation of hot electrons (HEs) is a quantum process and its description requires further elaboration. Some potential applications for HEs lie in the fields of photo-catalysis and optoelectronics, and their study constitutes a very active interdisciplinary research direction that involves chemistry, physics and device engineering. Here we focus on some particular developments enabling the use of hot carriers for these applications. Particularly, we discuss the approaches and structures required to create hot carriers, the temporal dynamics of hot carrier formation and relaxation, and relevant theoretical methods used to compute the HE dynamics. The observations presented here support the conclusion that the shape of the nanostructure matters. Although metastructures with infrared gap plasmons can exhibit spatially extended hot spots and anomalously large numbers of non-thermalized HEs, most excited carriers in a plasmonic nanostructure typically have small excitation energies. Here we discuss ways to strongly increase the number of high-energy electrons, highlighting the role of hot spots, system size, geometry and resonant frequencies. To generate HEs efficiently, we can take advantage of special geometries with hot spots, such as metamaterial absorbers with ultra-narrow gaps or nanostars. Furthermore, we discuss the applications in ultrafast electronics based on plasmon-enhanced photoemission and tunneling in the nonlinear regime. Considering the longer timescale phenomena, we also present studies on the coherent dynamics in a nanostructure after electron thermalization, showing acoustic breathing modes. In this paper, we review some key developments in the field of ultra-fast plasmonic dynamics and provide a perspective for its possible next steps.

Piezoelectric and triboelectric nanogenerators are the two recently developed technologies for effective harvesting of ambient mechanical energy for self-powered systems. The work herein briefly reports the trends and impacts of research based on piezoelectric and triboelectric nanogenerators. For the first time, a statistical study of publication trends in piezo- and triboelectric nanogenerators is used to investigate the current state of the research. We investigate the status of the research in these fields, based on their S-shaped history, as a description of their growth in size over time, considering the number of citations and published papers that use these two novel technologies. A brief discussion of the outlook for these technologies and their potential impact on everyday life is presented, particularly in the development of future ‘smart’ cities.

Over the last decade, lithium–sulfur (Li–S) batteries have been extensively studied because of the abundance of sulfur, their environmental benignity, and high gravimetric (2600 W h kg−1) and volumetric (2800 W h L−1) energy densities. However, their unique electrochemical behavior involving the formation of dissolved polysulfide intermediate species and the insulating nature of sulfur and Li2S are the main drawbacks that must still be overcome. To tackle these limitations, solutions such as appropriate cathode architecture design, electrolyte optimization, and lithium metal stabilization have been proposed. Recently, high areal sulfur loading, a high sulfur content, and a high electrolyte-to-sulfur ratio have also become prominent issues for the commercialization of the Li–S batteries. This paper reviews a wide range of reports on the design of structural and functional nanomaterials for Li–S batteries and suggests future research directions.

Virus labeling is an ideal strategy to explore the interaction between virus and host cells. However, existed probes are limited in in vivo studies due to the poor imaging effects caused by tissue-depth and autofluorescence. Lanthanide-doped upconversion nanoparticles (UCNP) can be effectively excited in deeper bio-tissues, and its long fluorescence life-time is suitable for in vivo imaging using time-resolved luminescence imaging technology. In this study, lanthanide-doped UCNP was used to label viral envelope and nucleic acid, which could be used for in vitro and in vivo virus tracking. The in vitro results demonstrated that the UCNP-labeled Influenza A virus (UCNP-IAV) could be used for the study of virus internalization kinetics, and proved that the movement of UCNP labeled IAV was lysosome- and microtube-dependent. For in vivo study, pre-labeling and in situ labeling strategies were implemented to monitor the IAV infection. The results showed that the UCNP probe could provide high-quality images using time-gated strategy to effectively monitor the viral infection in vivo. Further, simultaneous tracking of IAV and adenovirus type-5 (Ad5) labeled by UCNP with different life-time was realized using time-resolved luminescence imaging technology. Hence, this paper provided a novel labeling method for virus tracking using UCNP, which was optimal to study the mechanism of virus infection in vitro and in vivo.

One-dimensional plasmonic nanoparticle arrays have intriguing optical properties that can be utilized in a number of applications, including molecular sensing. In this paper, firstly, we studied the plasmonic coupling behavior in chains of gold and silver plasmonic nanocubes of 21 nm edge length arranged in both face-to-face and edge-to-edge configurations at large separation distance (8.5 nm), where the classical electromagnetic coupling is dominant. Interestingly, an increase in the sensitivity factor was observed when increasing the number of nanocubes in the chain and by orienting them in edge-to-edge configuration, with a few exceptions. Additionally, linear chains of edge-to-edge and face-to-face assembled gold nanocube with sub-nanometer interparticle distances (0.2 nm), where the effect of tunneling-induced charge transfer plasmons (tCTPs) becomes significant, was studied using a quantum-corrected model. In comparison to the face-to-face orientation, the changes in optical properties were more prominent in the edge-to-edge configuration. Our results suggest that plasmonic coupling in linearly assembled nanoparticles becomes extremely important at sub-nanometer interparticle distances. It can significantly modify the optical properties of the nanocubes chains, especially spectral line shape and electric-field distribution, which might help designing more advanced sensing devices for chemical and bio-sensing applications.

Two-dimensional (2D) semiconductors have attracted considerable attentions from electronic-engineering community due to their unique electronic properties. Especially, the inherent advantage of scaling semiconductor into atomic thickness has raised the prospect of possible extension of the Moore’s law. To achieve 2D electronics, a full comprehension of semiconductor defect physics and chemistry is indispensable due to its controlling electrical performance of 2D materials and functionalizing their devices. In this review, first we explain why 2D semiconductors is important for nanoelectronics and optoelectronics. Second, we elucidate how native defects or intentional impurities affect and control electrical characteristic in 2D semiconductors, such as carrier concentration and their conductive type. In this section, experimental pictures of defects and several updated theoretical methods to evaluate carrier ionization energies of defects and their conductive type are introduced in detail. Third, typical device experiments are shown to demonstrate a direct role of defects to functionalize 2D electronic device. Furthermore, a database of popular defects and their electrical properties in current popular 2D semiconductors is summarized for references. Last, we discuss the challenges and potential prospects of defect engineering for 2D devices. The present paper offers important viewpoints from semiconductor defects to design the emerging 2D electronics.

In the field of nanoscience and nanotechnology, Nano Today continuously provides a platform for researchers from all over the world to present their latest valuable and creative research outcome. We here celebrate the journal’s 15th year’s birthday by combing through its achievements in the past, which may provide a reflection on the developmental trend of nanoscience and nanotechnology. With the aid of bibliometric analytical methods, we looked at annual publication volume, the most prolific countries/affiliations/authors, the top-cited papers, major research domains and disciplines in Nano Today using Web of Science Core Collection database. Since 2020, the inclusion of primary research articles enables more time-sensitive and dynamic research advances appearing in Nano Today. It is anticipated that more exciting and dynamic research advances will appear in the journal.

International audience; The notorious PM2.5 (2.5 μm diameter particulate matters) that can reach human lungs, considered as responsible for most deleterious effects of air pollution, are now unmasked. Anthropogenic carbon nanotubes and other carbon nanoparticles have been unambiguously identified as the major components of PM2.5 in alveolar macrophages of Parisian children. Soot and diesel particulate matter have recognized detrimental health effects. However, information on the health effects of anthropogenic carbon nanotubes, which are the main components of PM2.5 found within human alveolar cells, is still lacking. While nanotechnologists are focused on applications with a profit, notably in the field of nano-biomedicine, the health effects of nano-particulate pollutants attract little of their attention. In an attempt to bridge the research gaps between cutting-edge nanotechnologies, environmental studies and biomedical approaches, this opinion paper attempts to inform the nanotechnology community about critical issues related to airborne anthropogenic carbon nanotubes. The question that has to be urgently addressed is whether carbon nanotubes are the main culprit or act only as nano-vectors of carcinogenic polycyclic aromatic hydrocarbons and other toxic gaseous pollutants.

In cancer, one of the main barriers to effective chemotherapy is inefficient drug delivery. The delivery of drugs to solid tumors involves various biochemical, biophysical, and mechanical processes, occurring over a wide range of length and time scales. Nanotechnology-based research in targeted drug delivery to solid tumors has led to a breakthrough in cancer treatment. However, many challenges remain related to inadequate tissue penetration, ineffective tumoral distribution, insufficient accumulation of drugs, loss of targeting ability, and various safety concerns. Mathematical and computational modeling allows for controlled study of these processes which is often not possible, or not economical, through empirical methods. Different computational models have been used to simulate nano-sized-drug delivery to solid tumors in order to investigate efficacy, understand biological phenomena, and select optimal anticancer treatment strategies. These models are classified as: discrete (quantum mechanics, molecular dynamics, Monte Carlo, and coarse-grained), continuous (pharmacokinetic/pharmacodynamics, finite element, and finite volume), or hybrid models. Using in vivo and in silico models, this paper reviews several key issues related to the use of nanoparticles as anticancer drug delivery vehicles: specifically, injection into the circulatory system, transvascular extravasation, distribution in the interstitium, cellular uptake, and drug release from nanocarriers. Adjustable nanocarrier design parameters, static targeting strategies (active/passive), and dynamic targeting strategies (internal/external stimuli-responsive) for nano-sized-drug delivery systems are discussed. Further, endogenous- and exogenous-based stimuli-responsive nano-engineered drug delivery systems are introduced for timed, destination-specific drug release. Clinical translation of nanomedicine can be accelerated through the integration of mathematical modeling techniques with modern imaging techniques and in vitro technologies.

Tumor metastasis and recurrence is one of the biggest problems in curing cancers. Due to the difficulty in complete removal of the primary tumor in traditional surgeries and the poor drug delivery efficiency of traditional chemotherapy, the residual tumor cells/tissues may further develop and result in tumor recurrence and/or distant metastasis. Nanoparticles with targeting probes and payload chemo-drugs are expected to conquer this problem, because they can efficiently accumulate at tumor sites to effectively inhibit the proliferation and metastasis of the primary tumor cells by themselves or via combination with other therapies, such as photothermal therapy, photodynamic therapy, chemotherapy, gene silencing, gene editing, etc. Meanwhile, they can also capture circulating tumor cells (CTCs), concentrate in targeted organs/lymph nodes that were invaded by metastatic tumor cells, and inhibit tumor metastasis and recurrence. From material science point of view, the functions of nanomedicines could be roughly divided into different categories, such as serving as nanocarriers for delivery of theranostic probes/chemotherapy drugs, as image contrast enhancers/radiosensitizers, diagnostic agents, or therapeutic agents. From a disease point view, tumor treatment can be roughly divided into different stages, including diagnosis, destruction of primary tumors, prevention of metastasis/recurrence, and clinical applications. In this paper, we review the use of nanomaterials in the treatment of tumors with a focus on those related to the inhibition of tumor metastasis/recurrence as well as clinical applications. We analyze the mechanisms and methods of using functional nanoparticles to destroy primary tumors and explore the abilities of functional nanoparticles on the inhibition of growth, spread, and recurrence of metastatic tumors. We also summarize the literature reported ongoing oncological trials in clinics using nanomedicines. Finally, we offer analysis and an outlook on the current research status, and highlight challenges and perspectives for the future development of nanomedicines.

Graphical Abstract Point-of-care diagnostics for infectious diseases.ga1, The current widespread of COVID-19 all over the world, which is caused by SARS-CoV-2 virus, has again emphasized the importance of development of point-of-care (POC) diagnostics for timely prevention and control of the pandemic. Compared with labor- and time-consuming traditional diagnostic methods, POC diagnostics exhibit several advantages such as faster diagnostic speed, better sensitivity and specificity, lower cost, higher efficiency and ability of on-site detection. To achieve POC diagnostics, developing POC detection methods and correlated POC devices is the key and should be given top priority. The fast development of microfluidics, micro electro-mechanical systems (MEMS) technology, nanotechnology and materials science, have benefited the production of a series of portable, miniaturized, low cost and highly integrated POC devices for POC diagnostics of various infectious diseases. In this review, various POC detection methods for the diagnosis of infectious diseases, including electrochemical biosensors, fluorescence biosensors, surface-enhanced Raman scattering (SERS)-based biosensors, colorimetric biosensors, chemiluminiscence biosensors, surface plasmon resonance (SPR)-based biosensors, and magnetic biosensors, were first summarized. Then, recent progresses in the development of POC devices including lab-on-a-chip (LOC) devices, lab-on-a-disc (LOAD) devices, microfluidic paper-based analytical devices (μPADs), lateral flow devices, miniaturized PCR devices, and isothermal nucleic acid amplification (INAA) devices, were systematically discussed. Finally, the challenges and future perspectives for the design and development of POC detection methods and correlated devices were presented. The ultimate goal of this review is to provide new insights and directions for the future development of POC diagnostics for the management of infectious diseases and contribute to the prevention and control of infectious pandemics like COVID-19.

The rapid development of flexible and wearable nanodevices for a variety of commercial applications has identified a pressing need for targeted research on nanomaterials for use as building blocks in the fabrication of functional devices via bottom-up assembly. In the search for new fabrication technology, nanojoining or nanowelding has been selected as a promising method in this bottom-up approach. While there are a number of methods that can be used for nanojoining, laser processing is of interest because laser nanojoining combines high-precision property with a flexible manufacturing platform. In this review we discuss how this technology can be implemented in practical applications and outline the advantages and limitations of laser-induced nanojoining. We emphasize how laser nanojoining introduces reliability and reproducibility to the joining process, and show that this is due to precise control over heat-input in nanoscale dimensions. We also review the ways in which laser nanojoining can be integrated with other commercial fabrication operations in practical applications. To illustrate the flexibility of laser nanojoining, we give a detailed summary of joining involving a wide variety of multidimensional heterogeneous nanomaterials in the form of zero-dimension, one-dimension and two-dimension as well as the hybrid combination of these building blocks. We also discuss how laser processing can be used to generate hybrid materials with new functionalities as electrodes for various devices, optical systems and in functional circuits. The mechanisms and strategies in laser-induced joining of nanomaterials are systematically discussed in this paper along with a review of the properties and applications of the joined nanostructures. We also review some challenges in the implementation of this technology and discuss some possible directions for future research into laser-induced nanojoining.

Developments in nanotechnology oblige technology regulators and other stakeholders to manage unfamiliar and unpredictable human health and environmental risks. When technological achievement stretches the limits of understanding of risk and safety, the desire to ensure protection can produce unnecessarily prohibitive and costly regulatory policy. This lack of knowledge, referred within this paper as ‘governance gaps,’ requires safety-by-design to overcome lingering governance challenges. However, the fundamentals of safety-by-design are not developed. We propose translating the methodological framing of safety-by-design and related nanotechnology risk governance into a mathematical framing of Multi-Criteria Decision Analysis (MCDA) to illustrate how safety-by-design might be operationalized. This framing provides a more thorough understanding of technology governance gaps and can help focusing technology development on implementable and safe alternatives. Ultimately, addressing each governance gap can help technology development and technology risk governance keep pace with one another, thereby allowing innovation to flourish while protecting society from undue risks.

As one of important approaches of light emission, chemiluminescence (CL) induced by chemical reactions has evoked considerable interest for its potential applications in chemical detection, bioanalysis, and cold light source. Carbon dots (CDs) are one kind of emerging carbon nanomaterials for promising CL due to their unique luminescent properties, such as high fluorescence quantum yield, tunable emission wavelength, high photostability, etc. With the special physicochemical property, CDs can take part in the CL reaction as oxidants, emitting species, energy acceptors of chemical reaction energy or even catalysis involving in different CL systems. With these novel influences in CL reaction, these CD-related CL systems have been applied in a broad range of areas. For the reason, CL CDs and their applications such as CL emitting species, catalyst, sensor, information encryption, photodynamic therapy and in-vitro and in-vivo bioimaging/biosensor are reviewed and discussed in this paper. Meanwhile, the challenges and future prospects of the CL CDs have been discussed and proposed.

With the increased aging population and economic climate, people's demand for healthcare has changed from seeking medical treatment after illness to maintaining active health into later years. Flexible electronic technological advancements have now given us the potential to develop wearable, next-generation implantable medical devices. However, before flexible electronic technology is expected to be commonplace for medical devices, safety and effectiveness in their intended clinical uses must first be proven. This paper summarizes the latest developments in flexible electronic technology in the context of medicine and healthcare, with emphasis on the requirements for safety and effectiveness evaluation of such innovations for medical devices from the perspective of regulatory science. Herein, we attempt to establish a standardized evaluation system suitable for the characteristics of flexible electronic technology, with the goal to help expedite the development of innovative medical devices based on flexible electronic technology from the laboratory to clinically approved products.

In-situ quantitative structure-property relationship (QSPR) characterization between nanomorphology and physicochemical parameters is essential for revealing the growth mechanism and guiding the optimization of functional nanomaterials. However, extracting the interrelated physicochemical parameters in the process of nanomorphology observation is still challenging. Herein, this paper demonstrates an advanced chip-scale platform for in-situ QSPR characterization by integrating a gravimetric resonant microcantilever sensor within a transmission electron microscopy (TEM) microreactor. The microcantilever measures the thermodynamic and kinetic parameters, such as enthalpy (ΔH°), activation energy (Ea) and reaction rate (v), by monitoring the reaction-induced mass change of functional nanomaterials. Simultaneously, the low-stress SiNx films as electron transparent windows allow in-situ nanomorphology observation. Using such a QSPR characterization platform, the three-stage sulfuration mechanism based on nano Kirkendall effect for the gas-solid reaction of H2S and Cu nanowires is revealed, and the different molecule-interaction behaviors of SO2 on ZnO nanowires at various temperatures are distinguished for the first time. It is believed that the in-situ QSPR microreactor can be widely used for elucidating the underlying interfacial thermodynamic/kinetic reaction mechanism, and guiding the controllable synthesis and precise optimization of functional nanomaterials.

Nanoparticle polymer composites have wide-ranging applications in fields such as catalysis, optoelectronics, drug delivery and biochemical sensing. In recent years, the use of noble metal nanoparticle polymer composites for plasmonic sensing has attracted much attention. Because several fabrication methodologies for such nanocomposites have already been established, resulting in a substantial collection of plasmon-active sensing devices, it would be timely to review the progress made so far and discuss future research directions. Although the synthesis and applications of a variety of nanoparticle polymer composites have been described in general and at length in several earlier reviews, no review to date has been dedicated to noble metal nanoparticle polymer composites on solid substrates fabricated for plasmonic sensing. One of the greatest advantages of nanoparticle polymer composites on solid substrates is their convenient utilization in practical applications, as they can be readily produced on gold and silicon substrates, glass and even paper. This makes them more suitable than solution phase nanoparticle polymer composites for device integration, bringing them closer to commercialization and consumer use. To facilitate rapid technology transfers in the near future, an in-depth understanding of the subject matter as well as an update of the state-of-the-art is therefore necessary, prompting this review. This review begins by describing the assembly techniques used to obtain such nanoparticle polymer composites before discussing their applications in plasmonic sensing based on localized surface plasmon resonance (LSPR) and surface enhanced Raman spectroscopy (SERS).

The surface engineering on various functional nanomaterials has enabled the creation of diverse nanocomposites that possess pre-designed architectures with improved and complementary properties. Magnetic porous materials with core-shell structures have recently received great attentions due to the combination of the respective properties of cores and shells that achieves cooperatively boosted performance. Core-shell magnetic nanoparticles are well-known for their outstanding properties of enhanced stability, being able to protect the active species from harsh environments, improved physical, chemical and photoelectric properties, and easiness of surface functionalization, etc. All of their exciting synergistic properties are heavily depending on the controllable and ingenious design towards cores and shells, and precise regulation of the interaction between them. In this paper, different surface engineering strategies, based on sol-gel chemistry and confined interfacial coating, for the construction of iron oxide-mesoporous core-shell materials have been reviewed. Attentions are paid not only on the selection of promising candidates for cores or porous shells and the creation of different shapes, but also more importantly on the synthetic principles and mechanisms for interfacial control in achieving perfectly adjustment of porous shells with various compositions, different pore sizes, pore structures and functionalities. Following the methods and principles presented in the review, it is very easy even for new beginners to synthesize various magnetic porous materials with well-defined core-shell structure and integrated functionalities for various applications.

Summary It is generally agreed that the United States National Nanotechnology Initiative (NNI) has significantly influenced global nanotechnology development since its inception in 2000. The far-reaching impact of NNI and nanotechnology development, as evidenced by publications in high impact journals, has been rising rapidly over the last 10 years. Recently, the global nanotechnology community witnessed China's ascent in nanotechnology. With increased governmental funding and improved research infrastructure, China has made significant advances and currently has the fastest growing nanotechnology publications and related industrialization. On the one hand, the Chinese government, like the American government, continues to build and support a fertile nanotechnology community. On the other hand, efforts appear less organized in the European Union. Although the gap in nanotechnology impact between the USA and China has narrowed significantly over recent years, the two countries have evolved with their own research focuses. Yet, China is still left behind American nanotechnology in terms of average citations per papers and publications in high-impact journals. It is hopeful that competition and collaboration between the two countries in this field will positively advance the global nanotechnology development.

Three-dimensional interconnected carbon networks (3DCNs) materials have the advantages of large specific surface area, high porosity, and high electronic and ionic conductivity. Especially, 3DCNs can combine with other nanomaterials to achieve the synergistic effect in numerous applications, such as energy storage, catalysis, and structural engineering. For the synthesis of 3DCNs, the hard template strategy is the most popular method due to its efficient and versatile process and controllable production. This paper summarized the recent progress in the approaches to constructing 3DCNs by using hard templates including metals, inorganic non-metals, etc. The composites based on 3DCNs with multi-dimensional reinforcements, such as 0D nanoparticles, 1D nanotubes/nanofibers, and 2D nanosheets are introduced. The applications of these 3DCNs composites towards energy storage and conversion devices are reviewed. Furthermore, the challenges on the hard-templated 3DCNs are discussed based on the current progress.

Summary The hollow nanoparticles, which contain catalytic species inside the cavity enclosed by a porous nanoshell, are considered an ideal framework for the nanoreactor that efficiently catalyzes the transformation of the selectively transferred substrate molecules with little loss of activity and surface area of entrapped catalysts even in harsh reaction conditions or during the recycling process. In the performance of the hollow nanoreactor, the selectively functionalized interior cavity is the most vital component which allows chemical reactions to occur within the confines of the protected cavity. Therefore, selective and differential functionalization of the internal space of the hollow nanoshell is the important and challenging topic which is demanded for fully exploiting the potential of the hollow nanoparticle in the nanoreactor application. In this context, this review paper intends to make a survey on the synthetic strategies of functionalizing the interior cavity of the hollow nanoparticles and their employment as nanoreator systems which catalyze the chemical reactions and template the growth of nanocrystals.

he paper reviews physical concepts related to the collective dynamics of plasmon excitations in metal nanocrystals with a focus on the photogeneration of energetic carriers. Using quantum linear response theory, we analyze the wave function of a plasmon in nanostructures of different sizes. Energetic carriers are efficiently generated in small nanocrystals due to the non-conservation of momentum of electrons in a confined nanoscale system. On the other hand, large nanocrystals and nanostructures, when driven by light, produce a relatively small number of carriers with large excitation energies. Another important factor is the polarization of the exciting light. Most efficient generation and injection of high-energy carriers can be realized when the optically induced electric current is along the smallest dimension of a nanostructure and also normal to its walls and, for efficient injection, the current should be normal to the collecting barrier. Other important properties and limitations: (1) intra-band transitions are preferable for generation of energetic electrons and dominate the absorption for relatively long wavelengths (approximately >600 nm), (2) inter-band transitions efficiently generate energetic holes and (3) the carrier-generation and absorption spectra can be significantly different. The described physical properties of metal nanocrystals are essential for a variety of potential applications utilizing hot plasmonic electrons including optoelectronic signal processing, photodetection, photocatalysis and solar-energy harvesting. © 2014 Elsevier Ltd.

Summary Plasma etching, a conventional technique in semiconductor industry, has exhibited great potentials in fabricating nanoscale patterns by taking advantage of its high anisotropic nature and fine controllability. Thus far, various gas mixtures and chemistries have been practically developed for etching a wide variety of materials, including semiconductors, oxides, glass, metals and polymers, to fabricate a broad range of vertical nanostructure arrays (VNAs). In this review paper, we will summarize the recent achievements in fabricating VNAs by plasma etching processes and their applications in biology, energy and electronics. The strategies in conjunction with microlithography or natural templates for fabricating various VNAs are outlined and the VNAs-based applications in diverse fields such as DNA sensors, biomimetic structures, solar cells, gas sensors, SERS, drug delivery, and field emission will be discussed in detail. Finally, the perspective of future studies is proposed. The widespread applications of the VNAs provide the conventional process of plasma etching a new opportunity to strut in the forefront of materials science.

Summary Due to exceptional photo-physical properties, up-converting nanoparticles (UCNPs) are promising and advantageous alternative to conventional fluorescent labels used in many bio-medical applications. The first part of this review aims at presenting these properties as well as the current state-of-the-art in the up-conversion enhancement, NPs surface functionalization and bioconjugation. In the second part of the paper, the applications of UCNPs and currently available detection instrumentation are discussed in the view of the distinctive properties of these markers. Because the growing widespread use of the biofunctionalized NPs, scarce instrumentation for up-conversion detection is reviewed. Finally, the challenges and future perspectives of the UCNPs are discussed.

Summary Titania is one kind of important materials, which has been extensively investigated because of its unique electronic and optical properties. A large number of efforts have been made to synthesize mesoporous TiO2 materials with high surface area and uniform pore size, as well as apply them in many fields. In this review paper, we focus on the ordered mesoporous TiO2 materials. We summarize the synthesis pathways, morphology, doping, as well as crystallization of the mesoporous TiO2 in synthesis section. And we introduce the applications in photocatalysis, solar cells, lithium-ion batteries, sensors and catalyst supports. Besides, we also mention several nanostructured TiO2 materials.

Summary In the past decade, atomic force microscopy (AFM) has become a powerful technology for nanofabrication due to its low cost, simplicity in operation, and unique atomic-level manipulation capabilities. Although a wide range of nanoscale components, devices, and systems have been fabricated by AFM, three major challenges in the further enhancement of its capability, reliability and productivity are still remaining in AFM nanofabrication. In this paper, following an overview of the recent advances in AFM nanofabrication technology, the recent efforts made to cope with these challenges are examined and the potential challenges on further capability advancement, especially on those processes having tips loaded with multiple energy sources, are discussed. Then, specific approaches for improving the repeatability by equipment automation and for enhancing its throughput or productivity by parallel processing and speed increasing are evaluated and the potential improvements are suggested. Finally, concluding remarks summarizing the major challenges and the potential solutions in AFM fabrication are included.

Summary Research on Janus nanoparticles has been thriving over the past few years, focusing both on novel preparation strategies and on investigations of their unique properties. In this paper we review the main contributions to this field reported in the literature, dividing Janus nanoparticles into three main categories, depending on the route followed for their preparation. The first group of Janus nanoparticles is those obtained via self-assembly, of, e.g. , block copolymers, and mixtures of ligands that in some cases show competitive adsorption on the surfaces of the nanoparticles. The second group comprises Janus nanoparticles obtained through a masking step, in which particles are trapped at the interface between two phases, so that a modification to the particle surface is made only on one side. Preparation of the third group of Janus nanoparticles relies on the phase separation of two different substances, usually either two polymers, or a polymer and an inorganic material. The peculiar properties of Janus nanoparticles, derived from their asymmetric structure, allow for their controlled self-assembly and surface activity. As a result of the simultaneous presence of two different regions in Janus nanoparticles, which can be designed to have different hydrophobicity and thereby mimic the behavior of surfactants, they can form stable clusters with defined size, and substantially reduce the interfacial tension between two different phases. Additionally, Janus nanoparticles can bring together different materials in a segregated manner at the nanoscale, thus combining widely different properties in single entity, as in the case of heterodimers.

Summary This paper reviews recent advances in the synthesis of porous hollow nanoparticles (PHNPs) of iron oxide and Au for biomedical applications. It first summarizes the synthesis and characterization of various PHNPs of iron oxide and Au. It then outlines the common chemistry applied to make these PHNPs biocompatible and target-specific. Finally the review presents several representative examples to highlight the applications of these PHNPs for drug delivery and for hyperthermia cancer therapy.

Summary Self-assembly of nanocrystals has been a subject of comprehensive studies including preparation, characterization and manipulation. In this paper, we summarize recent research reports in self-assembled superlattices consisting of non-spherical nanocrystals such as nanocubes, nanooctahedra, nanorods and nanoplates, and discuss their superstructures. Compared with spherical nanocrystals which are randomly oriented when being assembled into a superlattice, the non-spherical nanocrystals can form more abundant and complex superlattices and may offer certain enhanced characteristics with their anisotropic assemblies. In each type of faceted shape, synthesis, superlattice structure as well as formation conditions are discussed. With a brief review of novel properties generated from non-spherical superlattices, this article aims to provide an outline of various shape-induced superlattices that could serve as potential new device metamaterials in future.

Summary Intense interests on surfaces with micro- and nano-patterns originated from abundant applications in optics, electronics, tissue engineering, biomedical sensors, etc. Searching for ways to create small patterns in both organic and inorganic materials at reduced operation time and cost is one of the challenges in nanotechnology. This paper reviews recent advances in patterning of thin films by using electrohydrodynamic instabilities, a simple and cost-effective bottom-up method. Challenges and future directions are also discussed from the point of view of both fundamental understanding and technological applications of the pattern formation induced by the electric field.

Summary Tissue engineering and regenerative medicine aim to develop biological substitutes that restore, maintain, or improve damaged tissue and organ functionality. While tissue engineering and regenerative medicine have hinted at much promise in the last several decades, significant research is still required to provide exciting alternative materials to finally solve the numerous problems associated with traditional implants. Nanotechnology, or the use of nanomaterials (defined as those materials with constituent dimensions less than 100 nm), may have the answers since only these materials can mimic surface properties (including topography, energy, etc.) of natural tissues. For these reasons, over the last decade, nanomaterials have been highlighted as promising candidates for improving traditional tissue engineering materials. Importantly, these efforts have highlighted that nanomaterials exhibit superior cytocompatible, mechanical, electrical, optical, catalytic and magnetic properties compared to conventional (or micron structured) materials . These unique properties of nanomaterials have helped to improve various tissue growth over what is achievable today. In this review paper, the promise of nanomaterials for bone, cartilage, vascular, neural and bladder tissue engineering applications will be reviewed. Moreover, as an important future area of research, the potential risk and toxicity of nanomaterial synthesis and use related to human health are emphasized.

Summary A fascinating phenomenon which characterizes semiconductors in the nanoscale regime is the ability to control the physical properties of the system through its dimensionality, as was demonstrated for a large number of systems including 2D quantum wells, 1D nanowires, and 0D quantum dots. Heterostructured nanorods, which are composed of two or more semiconductors, present an exciting example for a system in which the physical properties are strongly influenced by the 1D nature of the entire particle, but also incorporate the effects of the dimensionality, dimensions, and composition of each component on its own. The ongoing progress in colloidal synthesis of nanocrystals allows nowadays to synthesize a variety of heterostructured nanorods with different compositions and structures, ranging from seeded nanorods to rods with asymmetric spatial compositions. The unique properties of these systems, with reduced and mixed dimensionality, attract a growing interest from the scientific point of view, and are also attractive for a range of applications including solid state lighting, lasers, light emitting diodes, flat panel displays, bio-labeling, and solar cells. In this paper we review the growing family of heterostructured nanorods, analyze the factors which determine their physical properties and in particular their optical characteristics, and discuss the potential applications of these systems in different technologies.

(Murr et al., 2009). No slight was intended, and our omission completely unintentional, as we have always had the highestregard for their seminal work.The observations of Croce et al. (2007) and those reported in our publication illustrate the importance of the remark-able pathway for the hierarchical self-assembly of the silicatein subunits and the consequent emergence of the properties(exhibited by the resulting protein filament) of structure-directing catalytic synthesis and templating of inorganic materials.We again sincerely apologize to Drs. Croce et al. for our inadvertent omission of their 2007 paper, which we recognize as animportant elaboration of their earlier publication (Croce et al., 2004) that we cited.