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This study demonstrates that the therapeutic efficacy of inorganic nanomaterials can be optimized by employing different thermal treatment atmospheres.

Micelles as nanocarriers not only offer new opportunities for early diagnosis and treatment of malignant cancers but also encounter numerous barriers in the path of efficient delivery of drugs to diseased areas in the body. To address these issues, we developed a pH/GSH responsive nano-prodrug micelle (NLG919/PGA-Cys-PPA@Gd) with a high drug-loading ratio and controlled drug release performance for MRI-guided tumor photodynamic therapy (PDT) and immune synergistic therapy. Under normal conditions, theranostic nanomicelles remained stable and in a photo-quenched state. Upon accumulation in the tumor site, however, the micelles demonstrated tumor microenvironment (TME) triggered photoactive formed-PPA (a photosensitizer) and NLG919 (an indoleamine 2,3-dioxygenase (IDO) inhibitor) release because the amide bonds of PGA-Cys-PPA and the disulfide linkage of Cys were sensitive to pH and GSH, respectively. More importantly, these micelles could avoid the undesired PPA leakage in blood circulation due to the conjugation between PPA and polymers. Furthermore, the obtained micelles could also enhance the contrast of

Wearable sensor industry is on the rise, because it can achieve real-time monitoring, intervention and prediction functions in the field of personal health management. To date, although remarkable progress has been made and laboratory-based theoretical researches have also been confirmed, there are still only a handful of sensors that have been commercialized or clinically available due to the immaturity of technologies. Here, we make an up-to-date Review of wearable and biodegradable sensors. First, we introduce the basic concepts and transduction mechanisms of four physical sensors based on piezoresistive, capacitive, piezoelectric and triboelectric effects. Then, we survey the latest research advances in terms of wearable and biodegradable sensors, focusing our attention on material option, structure design and application exploration. In particular, the implantable sensors made from biocompatible and biodegradable materials are emphasized, which may become the mainstream research direction of green electronic products. Finally, we debate the current challenges and future trends of wearable and biodegradable sensors.

Perusing redox nanozymes capable of disrupting cellular homeostasis offers new opportunities to develop cancer-specific therapy, but remains challenging, because most artificial enzymes lack enzyme-like scale and configuration. Herein, for the first time, we leverage a defect engineering strategy to develop a simple yet efficient redox nanozyme by constructing enzyme-mimicking active centers and investigated its formation and catalysis mechanism thoroughly. Specifically, the partial Fe doping in MoOx (donated as Fe-MoOv) was demonstrated to activate structure reconstruction with abundant defect site generation, including Fe substitution and oxygen vacancy (OV) defects, which significantly enable the binding capacity and catalytic activity of Fe-MoOv nanozymes in a synergetic fashion. More intriguingly, plenty of delocalized electrons appear due to Fe-facilitated band structure reconstruction, directly contributing to the remarkable surface plasmon resonance effect in the near-infrared (NIR) region. Under NIR-II laser irradiation, the designed Fe-MoOv nanozymes are able to induce substantial disruption of redox and metabolism homeostasis in the tumor region via enzyme-mimicking cascade reactions, thus significantly augmenting therapeutic effects. This study that takes advantage of defect engineering offers new insights into developing high-efficiency redox nanozymes.

Tumor hypoxia severely limits the therapeutic effects of photodynamic therapy (PDT). Although many methods for oxygen generation exist, substantial safety concerns, spatiotenporal uncontrollability, limited efficacy and complicated procedures have compromised their practical application. Here, we demonstrate the feasibility of a biocompatiable all-in-one organic semiconductor to provide a photoxidation catalysis mechanism of action to combat these challenges. A one-step and facile method is developed to produce gram-level C5N2 nanoparticles (NPs)-based organic semiconductor. Under 650 nm laser irradiation, the semiconductor split water to generate O2 and simultaneously produced singlet oxygen (1O2), revealing that the photocatalyst for O2 evolution and the photosensitizer (PS) for 1O2 generation could be synchronously achieved in one organic semiconductor. Furthermore, the inherent nucleus targeting capacity endows it with direct and efficient DNA photocleavage. These findings pave the way for developing organic semiconductor-based cancer therapeutic agents.

Intracellular targeting has the same potential as tissue targeting to increase therapy efficacy, especially for drugs that are toxic to DNA. By adjusting intracellular traffic, we developed a novel direct-nucleus-delivery platform based on C5 N2 nanoparticles (NPs). Supramolecular interactions of C5 N2 NPs with the cell membrane enhanced cell uptake; abundant edge amino groups promoted fast and effective rupture of early endosomes; and the appropriate size of the NPs was also crucial for size-dependent nuclear entry. As a proof of concept, the platform was not only suitable for the effective delivery of molecular drugs/dyes (doxorubicin, hydroxycamptothecine, and propidium iodide) and MnO2 nanoparticles to the nucleus, but was also photoresponsive for nucleus-targeting photothermal therapy (PTT) and photodynamic therapy (PDT) to further greatly increase anticancer efficacy. This strategy might open the door to a new generation of nuclear-targeted enhanced anticancer therapy.

Appropriate disposal of radioactive iodine in spent nuclear fuel reprocessing represents an acknowledged challenging topic. Currently, most solid sorbents for radioactive iodine treatment are suffering from the risk of fire and explosion due to the presence of nitrogen oxides in the exhaust stream. Herein, we reported for the first time the use of porous hexagonal boron nitride (porous BN) to capture radioactive iodine and further studied its practicability and iodine-removal performance. A series of tests, such as flammability, acid leaching durability and so on, revealed the excellent thermal stability, acid-resistance, anti-oxidation activity and hydrophobic properties of porous BN. It should be highlighted that porous BN exhibits outstanding flame-retardant ability, which is superior to that of well-studied MOF and POP iodine-removal materials. These merits will enormously reduce the risk of fire and explosion in the exhaust stream and endow this material with great potential in practical radioactive waste reprocessing. Benefiting from the porous properties and Lewis acid–base interaction, porous BN demonstrated 213 wt% adsorption capacity for iodine vapor, which is a considerably high value among inorganic materials. The iodine removal performance of porous BN was further demonstrated by a column test under simulated reprocessing. Combining its superb physicochemical properties with iodine removal capacity, porous BN is thereby a promising iodine sorbent for safe and effective radioactive iodine capture in practical applications.

Nanotheranostic agents that can simultaneously provide real-time tracking and accurate treatment at tumor sites are playing an increasingly important role in medicine. Herein, a novel polypyrrole (PPy)-based theranostic agent containing double rare-earth elements (PPy@BSA-Gd/Dy NPs) was successfully synthesized via an integrated strategy combining biomineralization and oxidation polymerization. The obtained PPy@BSA-Gd/Dy NPs with a diameter of approximately 59.48 ± 6.12 nm exhibited excellent solubility, long-term stability, superior biocompatibility, and negligible toxicity. Importantly, due to its intrinsic paramagnetic and strong X-ray attenuation ability, this agent demonstrated brilliant imaging performance in both T1/T2-weighted magnetic resonance imaging (MRI) and X-ray computed tomography (CT) imaging in vitro and vivo. Additionally, with an excellent photothermal conversion efficiency (26.61%) upon irradiation by an 808 nm laser, this theranostic agent showed significant photothermal cytotoxicity against HeLa cells and 4T1 cells in vitro and antitumor efficacy through intravenous injection in vivo. Meanwhile, biodistribution and blood circulation were also used to explore its fate in vivo. In summary, this study highlighted the versatility and practicability of PPy@BSA-Gd/Dy NPs and also suggested that the agent may be a promising candidate for T1/T2-weighted MRI/CT tri-modal imaging guided photothermal cancer therapy.

Severe side effects and poor therapeutic efficacy are the main drawbacks of current anticancer drugs. These problems can be mitigated by targeting, but the targeting efficacy of current drugs is poor and urgently needs improvement. Taking this into consideration, this Review first summarizes the current targeting strategies for cancer therapy in terms of cancer tissue and organelles. Then, we analyse the systematic targeting of anticancer drugs and conclude that a typical journey for a targeted drug administered by intravenous injection is a CTIO cascade of at least four steps. Furthermore, to ensure high overall targeting efficacy, the properties of a targeting drug needed in each step are further analysed, and some guidelines for structure optimization to obtain effective targeting drugs are offered. Finally, some viewpoints highlighting the crucial problems and potential challenges of future research on targeted cancer therapy are presented. This review could actively promote the development of precision medicine against cancer.

X-ray computed tomography (CT) is one of the most widely used imaging modalities in the clinic. Current commercialized CT contrast agents are mainly small iodinated molecules. These contrast agents suffer from drawbacks such as short circulation times in vivo . Recent advance highlight the importance of nano-sized CT imaging probes that exhibit good biocompatibility and long circulation time. Most importantly, their surface features enable the design of multifunctional imaging probes. This review provides a comprehensive introduction to recent development of nano-sized CT imaging probes and some future directions are presented.

The direct monitoring of trace water in real time during electrochemical cycles is of vital importance because water impurities are one of the causes of reduced lifetimes and capacity fading in Li-ion batteries. However, the most common Karl-Fischer titration lacks the ability to perform real-time monitoring of trace water while the battery is operating. Here, we demonstrate the use of nanosized coordination polymers as a sensing platform for the rapid and highly sensitive detection of water molecules, which gives a distinguishable turn-on fluorescence (FL) response toward water with a quantifiable detection range from 0 to 1.2% v/v, offering a novel opportunity to monitor trace water during electrochemical cycles. To demonstrate the practical value of our platform, we designed an in situ measurement system using nanosized coordination polymers as an electrolyte additive. Within the platform, the findings indicate that trace water is indeed generated during the first discharge process, in which the FL intensity shows a linear increase over time along with the gradual formation of water. We believe that this strategy provides new insights into the in situ monitoring of complex electrochemical processes, and it may help to pave the way for the development of new operando analytical techniques for lithium-ion batteries.

Carbon nanotubes-supported non-precious metal nanoparticles emerge as promising catalyst candidate for fuel cell. Although it is well known that carbon nanotubes can influence the catalytic activity of transition metal nanoparticles, insights into whether the unrolling of carbon nanotubes can be exploited to enhance the oxygen reduction performance are lacking. Herein we demonstrate the transformation from FeS/Fe3C nanoparticles coupled S, N dual doped carbon nanotubes (FeS/Fe3C@S, N-C) to nanosheets can yield the improved oxygen reduction performance. Under a glucose protective strategy, the walls of FeS/Fe3C@S, N-C nanotubes were unrolled and extended, creating FeS/Fe3C nanoparticles coupled S, N dual doped carbon nanosheets (FeS/Fe3C@S, N-C g(50)) with larger surface area and higher doping level, which allowed for the exposure of sufficient accessible active sites. Consequently, FeS/Fe3C@S,N-C g(50) exhibited an onset potential of 0.938 V, together with low peroxide yield, good selectivity and durability. Our investigations showed that the carbon matrix with an opened structure and abundant accessible active sites is critical to the electrocatalysts. Furthermore, the synergetic effect of the S, N dual doped carbon nanosheets and FeS/Fe3C nanoparticles contributed to the enhanced oxygen reduction activity. We expect the presented structure–activity relationship can provide guidance for future design of advanced electrocatalysts.

Early detection of ovarian cancer, the most lethal type of gynecologic cancer, can dramatically improve the efficacy of available treatment strategies. However, few screening tools exist for rapidly and effectively diagnosing ovarian cancer in early stages. Here, we present a facile "lock-key" strategy, based on rapid, specific detection of plasma lysophosphatidic acid (LPA, an early stage biomarker) with polydiacetylenes (PDAs)-based probe, for the early diagnosis of ovarian cancer. This strategy relies on specifically inserting LPA "key" into the PDAs "lock" through the synergistic electrostatic and hydrophobic interactions between them, leading to conformation transition of the PDA backbone with a concomitant blue-to-red color change. The detailed mechanism underlying the high selectivity of PDAs toward LPA is revealed by comprehensive theoretical calculation and experiments. Moreover, the level of LPA can be quantified in plasma samples from both mouse xenograft tumor models and patients with ovarian cancer. Impressively, this approach can be introduced into a portable point-of-care device to successfully distinguish the blood samples of patients with ovarian cancer from those of healthy people, with 100% accuracy. This work provides a valuable portable tool for early diagnosis of ovarian cancer and thus holds a great promise to dramatically improve the overall survival.

Nanotechnology-mediated antioxidative therapy is emerging as a novel strategy for treating a myriad of important diseases through scavenging excessive reactive oxygen and nitrogen species (RONS), a mechanism critical in disease development and progression. However, similar to antioxidative enzymes, currently studied nano-antioxidants have demonstrated scavenging activity to specific RONS, and sufficient antioxidative effects against multiple RONS generated in diseases remain elusive. Here we propose to develop bioinspired melanin nanoparticles (MeNPs) for more potent and safer antioxidative therapy. While melanin is known to function as a potential radical scavenger, its antioxidative mechanisms are far from clear and its applications for the treatment of RONS-associated diseases have yet to be well explored. In this study, we provide for the first time exhaustive characterization of the activities of MeNPs against multiple RONS including O2•−, H2O2, •OH, •NO, and ONOO−, the main toxic RONS generated in diseases. The potential of MeNPs for antioxidative therapy has also been evaluated in vitro and in a rat model of ischemic stroke. In addition to the broad defense against these RONS, MeNPs can also attenuate the RONS-triggered inflammatory responses through suppressing the expression of inflammatory mediators and cytokines. In vivo results further demonstrate that these unique multi-antioxidative, anti-inflammatory and biocompatible features of MeNPs contribute to their effective protection of ischemic brains with negligible side effects.

Inorganic layered ion-exchangers have received extensive attention in the field of environmental remediation due to their high chemical, thermal and radiolytic stability, large surface areas, and excellent ion exchange capacities. These materials have been widely investigated as adsorbents for decontamination of toxic metal pollutants, such as heavy metals and nuclear waste related metal ions in aquatic systems. In this review, we describe the most important inorganic layered ion-exchangers including layered double hydroxides, layered metal oxides, and layered metal sulfides in terms of their structural features and ion exchange properties as well as potential applications in remediation of metal polluted aquatic systems. Furthermore, the future challenges and outlooks for these materials are also discussed.

In this paper, we designed a novel near-infrared aptamer-mediated fluorescence “turn off–on” nanosensor for highly sensitive and selective detection of kanamycin based on CuInS2 quantum dots (QDs)@graphene oxide (GO) nanocomposites. The carboxy groups on the surface of CuInS2 QDs (modified with mercaptopropionic acid) were conjugated with amino terminal kanamycin-binding Ky2 aptamer to form the Ky2-CuInS2 QDs in the presence of 1-(3-dimethylaminopropyl)-3-ethylcarbodiimide hydrochloride and N-hydroxysuccinimide. Then, the Ky2-CuInS2 QDs were facilely immobilized on the surface of GO through π–π stacking interaction between the nucleobases and GO, which caused the fluorescence of Ky2-CuInS2 QDs “turned off”. In the presence of kanamycin, the Ky2-CuInS2 QDs desorb from the surface of GO and bind to kanamycin with high affinity and specificity. As a result, the quenched fluorescence “turned on”. Under the optimum conditions, there was a good linear relationship between I/I0 (I and I0 were the fluorescence intensity of Ky2-CuInS2 QDs@GO in the presence and absence of kanamycin, respectively) and kanamycin concentration in the range of 0.3–45 nmol L−1 (0.174–26.1 μg L−1), with the detection limit of 0.12 nmol L−1 (0.070 μg L−1). The present nanosensor was utilized to detect kanamycin in the human serum, urine and milk samples with satisfactory results.

Developing non-precious metal electrocatalysts (NPMCs) for the oxygen reduction reaction (ORR) is of paramount importance for commercial implementation of several clean energy techniques (e.g. proton exchange membrane fuel cells). However, limited understanding of the ORR catalytic mechanism of NPMCs greatly hinders the progress in the precise fabrication of NPMCs at the molecular or atomic level. Recently, an increasing number of studies have demonstrated the crucial role of a carbon matrix in exposing, stabilizing, and activating the catalytic sites, thus providing a platform to identify the nature of NPMCs. Herein, the unique structural effects of a carbon matrix in NPMCs are first reviewed to inspire the development of more advanced NPMCs for the ORR.

X-ray computed tomography (CT) has been widely used as a powerful diagnostic tool in clinics because it can provide high-resolution 3D tomography of the anatomic structure based on the distinctive X-ray absorptions between different tissues. Currently, CT contrast agents are mainly small iodinated molecules, which suffer from drawbacks such as short bloodretention time, nonspecific in vivo biodistribution, and renal toxicity. Utilization of nanoparticles as potential CT contrast agents to overcome the aforementioned issues has advanced rapidly. In this mini review, we introduce current research efforts in the development of nanoparticulate CT contrast agents and discuss the challenges for additional breakthroughs in this field.

Nitrogen-doped species (NDs) are theoretically accepted as a determinant of the catalytic activity of metal-free N-doped carbon (NC) catalysts for oxygen reduction reaction (ORR). However, direct relationships between ND type and ORR activity have been difficult to extract because the complexity of carbon matrix impairs efforts to expose specific NDs. Herein, we demonstrate the fabrication of a 3D hierarchically porous NC catalyst with micro-, meso-, and macroporosity in one structure, in which sufficient exposure and availability of inner-pore catalytic sites can be achieved due to its super-high surface area (2191 cm(2) g(-1) ) and interconnected pore system. More importantly, in-situ formation of graphitic-N species (GNs) on the surface of NC stimulated by KOH activation enables us to experimentally reveal the catalytic nature of GNs for ORR, which is of great significance for the design and development of advanced metal-free NC electrocatalysts.

Frequent oil spillages and the industrial discharge of organic solvents have not only caused severe environmental and ecological damage, but also create a risk of fire and explosion. Therefore, it is imperative, but also challenging, to find high-performance absorbent materials that are both effective and less flammable. Here we present a superior superhydrophobic sponge that exhibits excellent absorption performance through a combination of its superhydrophobicity, high porosity, and robust stability. More importantly, it inherits the intrinsic flame-retardant nature of the raw melamine sponge, and is thus expected to reduce the risk of fire and explosion when being used as an absorbent for flammable oils and organic compounds. Moreover, the fabrication of this sponge is easy to scale up, since it does not use a complicated process or sophisticated equipment. These characteristics make the sponge a much more competitive product than the commercial absorbent, nonwoven polypropylene fabric.

A facile and efficient strategy is described for the fabrication of soluble reduced graphene oxide (rGO) sheets. Different from the conventional strategies, the proposed method is based on the reduction of graphene oxide by an endogenous reducing agent from a most widely used and cost-effective solvent, without adding any other toxic reducing agent. Simultaneously, this solvent can serve as an effective stabilizer, avoiding complicated and time-consuming modification procedures. The as-prepared rGO sheets not only exhibit high reduction level and conductivity, but also can be well dispersed in many solvents. Of particular significance is that rGO sheets can be produced in large quantities. These advantages endow this proposed synthetic approach great potential applications in the construction of high-performance graphene-based devices at low cost, as demonstrated in our study of NO gas sensing.

Ordered porous metal nanomaterials have current and future potential applications, for example, as catalysts, as photonic crystals, as sensors, as porous electrodes, as substrates for surface-enhanced Raman scattering (SERS), in separation technology, and in other emerging nanotechnologies. Methods for creating such materials are commonly characterized as "templating", a technique that involves first the creation of a sacrificial template with a specific porous structure, followed by the filling of these pores with desired metal materials and finally the removal of the starting template, leaving behind a metal replica of the original template. From the viewpoint of practical applications, ordered metal nanostructures with hierarchical porosity, namely, macropores in combination with micropores or mesopores, are of particular interest because macropores allow large guest molecules to access and an efficient mass transport through the porous structures is enabled while the micropores or mesopores enhance the selectivity and the surface area of the metal nanostructures. For this objective, colloidal crystals (or artificial opals) consisting of three-dimensional (3D) long-range ordered arrays of silica or polymer microspheres are ideal starting templates. However, with respect to the colloidal crystal templating strategies for production of ordered porous metal nanostructures, there are two challenging questions for materials scientists: (1) how to uniformly and controllably fill the interstitial space of the colloidal crystal templates and (2) how to generate ordered composite metal nanostructures with hierarchical porosity. This Account reports on recent work in the development and applications of ordered macroporous bimetallic nanostructures in our laboratories. A series of strategies have been explored to address the challenges in colloidal crystal template techniques. By rationally tailoring experimental parameters, we could readily and selectively design different types of ordered bimetallic nanostructures with hierarchical porosity by using a general template technique. The applications of the resulting nanostructures in catalysis and as substrates for SERS are described. Taking the ordered porous Au/Pt nanostructures as examples for applications as catalysts, the experimental results show that both the ordered hollow Au/Pt nanostructure and the ordered macroporous Au/Pt nanostructure exhibit high catalytic ability due to their special structural characteristics, and their catalytic activity is component-dependent. As for SERS applications, primary experimental results show that these ordered macroporous Au/Ag nanostructured films are highly desirable for detection of DNA bases by the SERS technique in terms of a high Raman intensity enhancement, good stability, and reproducibility, suggesting that these nanostructures may find applications in the rapid detection of DNA and DNA fragments.

Shape-controlled synthesis of metal nanostructures has opened many new possibilities to design ideal building blocks for future nanodevices. In this work, new types of monodisperse silver nanoplates with complex shapes, namely, a disklike shape and flowerlike shapes, were controllably synthesized in high yield by reducing [Ag(NH3)2]+ with ascorbic acid in the presence of silver seed at room temperature. Unlike previous methods for synthesizing the silver nanoplates in the presence of cetyltrimethylammonium bromide (CTAB) micelles, the use of the precursor [Ag(NH3)2]+, other than Ag+, provides a flexible strategy to control the procession of the reduction reaction in a mild way. These silver nanoplates with shapes of disk and flower were shown to possess surface plasmon resonance (SPR) that directly relates to their geometric shapes. As a result of their high anisotropy in shape, the flowerlike silver nanoplates exhibit excellent surface-enhanced Raman scattering (SERS) enhancement ability relative to sphe...

We describe the small-biomolecule (glycyl glycine)-directed synthesis of single-crystalline silver nanoplates, and different experimental conditions have been explored for a more thorough understanding of the growth mechanism. The yield of silver nanoplates relative to the total number of nanoparticles formed was as high as ∼80%. It was found that the ratio of glycyl glycine to AgNO3 was the key to forming Ag nanoplates.

We report an alternative procedure to incorporate gold nanoparticles into 3D ordered colloidal crystal film. The size of gold nanoparticles within the films can be controlled from about 10 nm to about 60 nm by simply varying the gold plating time. The application of the as-prepared films in surface-enhanced Raman spectroscopy (SERS) is investigated by using Rhodamine 6G (R6G) as probe molecules. It is found that the resultant gold-coated 3D ordered colloidal crystal films can be used as SERS substrates, exhibiting excellent enhancement ability.

Selective crystallization of BaF2 crystals under a compressed Langmuir monolayer of behenic acid [CH3(CH2)20COOH] has been studied by using X-ray diffraction, X-ray photoelectron spectroscopy, scanning electron microscopy, and energy-dispersive X-ray analysis. It was found that, in the absence of a monolayer, three kinds of crystals (Ba2ClF3, BaClF, and BaF2) can be obtained by mixing BaCl2 with a NH4F solution. However, in the presence of the monolayer of behenic acid, only BaF2 crystals appear at the monolayer−subphase interface and crystals have a special crystal face (100). During this process of crystallization, the monolayer plays a very important role and acts as a template that can preferentially select a special crystal and a special crystal face. The above results can be explained in terms of a specific molecular interaction between ions and the headgroups of the monolayer and specific electrostatic, geometric, and stereochemical interactions at the organic−inorganic interface.

α-Fe2O3 nanoparticulate films could be formed on the surface of α-Fe2O3 hydrosol after aging of the hydrosol or by compressing of the nanoparticles on the sol surface, in which a three-dimensional ordered structure was constructed by the Langmuir−Blodgett technique and colloid chemical methods. The structure of the LB film was characterized by AFM, TEM, XPS, and UV−vis spectra and small-angle X-ray diffraction. Gas-sensing measurement shows that the LB film has good sensitivity to alcohols at room temperature.

Berlin green FeFe(CN)6 microcubic crystals have been successfully prepared by a simple hydrothermal process between K3[Fe(CN)6] with Na2S2O3 aqueous solution, free of any surfactant or template. The experimental results clearly show that the molar ratio of K3[Fe(CN)6] to Na2S2O3 and their concentrations are the dominant processing factors in controlling the size, morphology, and composition of the resulting products.

X-ray computed tomography (CT) is one of the most powerful noninvasive diagnostic imaging techniques in modern medicine. Nevertheless, the iodinated molecules used as CT contrast agents in the clinic have relatively short circulation times in vivo, which significantly restrict the applications of this technique in target-specific imaging and angiography. In addition, the use of these agents can present adverse. For example, an adult patient typically receives approximately 70 mL of iodinated agent (350 mg I/mL) because of iodine's low contrast efficacy. Rapid renal clearance of such a large dose of these agents may lead to serious adverse effects. Furthermore, some patients are hypersensitive to iodine. Therefore, biomedical researchers have invested tremendous efforts to address these issues. Over the past decade, advances in nanoscience have created new paradigms for imaging. The unique properties of nanomaterials, such as their prolonged circulating half-life, passive accumulation at the tumor sites, facile surface modification, and integration of multiple diverse functions into a single particle, make them advantageous for in vivo applications. However, research on the utilization of nanomaterials for CT imaging has lagged far behind their applications for other imaging techniques such as MRI and fluorescence imaging because of the challenges in the preparation of cost-effective nanoparticulate CT contrast agents with excellent biocompatibility, high contrast efficacy, long in vivo circulation time, and long-term colloidal stability in physiological environments. This Account reviews our recent work on the design and in vivo applications of nanoparticulate CT contrast agents. By optimizing the contrast elements in the nanoparticles according to the fundamental principles of X-ray imaging and by employing the surface engineering approaches that we and others have developed, we have synthesized several nanoparticulate CT contrast agents with excellent imaging performance. For example, a novel Yb-based nanoparticulate agent provides enhanced contrast efficacy compared to currently available CT contrast agents under normal operating conditions. To deal with special situations, we integrated both Ba and Yb with great differential in K-edge value into a single particle to yield the first example of binary contrast agents. This agent displays much higher contrast than iodinated agents at different voltages and is highly suited to diagnostic imaging of various patients. Because of their prolonged in vivo circulation time and extremely low toxicity, these agents can be used for angiography.

A new approach to the preparation of large palladium nanoparticles with diameters between 25 and 100 nm is presented. In this approach PdCl42− ions are reduced on the surface of performed 12-nm-diameter gold “seeds” by the introduction of ascorbic acid. The resultant particles exhibit improved monodispersity relative to previous work. Interestingly, these nanoparticles possess Au–Pd core–shell structures. The method can be scaled up to produce 50–110 mg of large palladium nanoparticles.

Ultra-small superparamagnetic particles of iron oxides (USPIO) have been developed as intravenous organ/tissue-targeted contrast agents to improve magnetic resonance imaging (MRI) in vivo. However, their potential toxicity and effects on metabolism have attracted particular attention. In the present study, uncoated and dextran-coated USPIO were investigated by analyzing both rat urine and plasma metabonomes using high-resolution NMR-based metabonomic analysis in combination with multivariate statistical analysis. The wealth of information gathered on the metabolic profiles from rat urine and plasma has revealed subtle metabolic changes in response to USPIO administration. The metabolic changes include the elevation of urinary alpha-hydroxy-n-valerate, o- and p-HPA, PAG, nicotinate and hippurate accompanied by decreases in the levels of urinary alpha-ketoglutarate, succinate, citrate, N-methylnicotinamide, NAG, DMA, allantoin and acetate following USPIO administration. The changes associated with USPIO administration included a gradual increase in plasma glucose, N-acetyl glycoprotein, saturated fatty acid, citrate, succinate, acetate, GPC, ketone bodies (beta-hydroxybutyrate, acetone and acetoacetate) and individual amino acids, such as phenylalanine, lysine, isoleucine, glycine, glutamine and glutamate and a gradual decrease of myo-inositol, unsaturated fatty acid and triacylglycerol. Hence USPIO administration effects are reflected in changes in a number of metabolic pathways including energy, lipid, glucose and amino acid metabolism. The size- and surface chemistry-dependent metabolic responses and possible toxicity were observed using NMR analysis of biofluids. These changes may be attributed to the disturbances of hepatic, renal and cardiac functions following USPIO administrations. The potential biotoxicity can be derived from metabonomic analysis and serum biochemistry analysis. Metabonomic strategy offers a promising approach for the detection of subtle physiological responses on mammalian metabolism, and can be employed to investigate the potential adverse effects of other nanoparticles and nanomaterials on the environment and human health.

The color change induced by triple hydrogen-bonding recognition between melamine and a cyanuric acid derivative grafted on the surface of gold nanoparticles can be used for reliable detection of melamine. Since such a color change can be readily seen by the naked eye, the method enables on-site and real-time detection of melamine in raw milk and infant formula even at a concentration as low as 2.5 ppb without the aid of any advanced instruments.

A low-cost and high-performance carbon material for supercapacitors is fabricated via a simple yet versatile strategy using a renewable natural resource: bean dregs. Owing to the natural properties of the heteroatom-enriched resource and the uniqueness of the fabrication approach, an optimized sample with plentiful heteroatoms (mainly O and N), well developed hierarchical porosity and highly ion-accessible surface area is obtained. The synergetic function of the heteroatom doping and the unique structural characteristics endows the as-prepared sample with an excellent combination of electric double layer capacitance and pseudo-capacitance, thus remarkably improving its electrochemical performance. As expected, it exhibits superior capacitive performance, including high specific capacitance, impressive rate performance, and excellent cycle stability. Considering the facile procedure and the easy-availability of raw material, this environmental-friendly and cost-effective method can be expected to perform extraordinarily in the widespread application of supercapacitors.

The development of fuel cells is highly dependent on the exploration of the efficient electrocatalyst. However, up to now, constructing high-quality hybrids with large electrochemical surface area (ECSA) through a facile method has remained a great challenge. In this paper, a novel approach for producing three dimensional porous graphene/PtPd bimetallic hybrids was developed by combining the solvothermal strategy with the ice template technique. First, a simple solvothermal route were employed for preparing PtPd bimetallic nanoparticle supported on graphene (PPG) hybrids by simultaneously forming bimetallic nanoparticles and reducing graphene oxide (GO). Then, three dimensional porous graphene/PtPd bimetallic hybrids are obtained via the ice templation of an aqueous suspension comprised of the PPG and phthalic acid diethylene glycol diacrylate (PDDA). The as-prepared 3D PPG were characterized by transmission electron microscopy (TEM), high-resolution TEM (HRTEM), X-ray diffraction XRD, scanning electron microscopy (SEM), X-ray photoelectron spectroscopy (XPS), Raman spectroscopy and electrochemical technique. It is interesting to find that the loading of PtPd bimetallic nanoparticles on the surface of graphene could be controlled by simply changing the initial weight ratio of the precursors. Furthermore, the hydrophilicability of PDDA plays an important role on the fabrication of 3D porous graphene/PtPd bimetallic hybrids. Most importantly, this special morphology endows the 3D PPG hybrids with larger ECSA and more catalytic sites compared with the PPG and commercial E-TEK Pt/C catalysts, and thus leads to much higher catalytic activity towards methanol oxidation reaction. The details are shown as follows. (a) The ECSA value of the as-prepared 3D PPG hybrids is tested to be 98.7 m(2).g(-1), while the ECSA values of PPG and E-TEK Pt/C catalysts are tested to be 61.3 and 46.5 m(2).g(-1), respectively. (b) The mass current density for methanol oxidation in 3D PPG hybrids is higher than those of PPG and E-TEK Pt/C catalysts and the corresponding potential on 3D PPG hybrids is much lower than that on PPG and E-TEK Pt/C catalysts at a given oxidation current density. (c) The as-prepared 3D PPG hybrids catalyst exhibits greater poisoning tolerance than the PPG and E-TEK Pt/C catalysts during methanol oxidation. All results reveal that these 3D PPG hybrids can provide a new and versatile platform for the development of high-performance electrocatalyst for methanol oxidation.

A new type of nanoscale coordination particles (NCPs) are successfully synthesized on a large scale through a coordination-induced self-assembling process. The as-prepared NCPs exhibit fascinating fluorescence properties including large stokes shifts, strong photoluminescence (PL) intensity, high photochemical stability, as well as tunable emission spectra. Excitingly, this new type of NCPs enable rapid, sensitive and modification-free detection of H2S as its fluorescence can be selectively quenched in the presence of H2S. With this NCPs-based detection system, the lowest concentration to quantify H2S can be down to 2 ppm, which is five times lower than the permissible exposure limit value set by the US National Institute for Occupational Safety and Health (NIOSH). Importantly, NCPs can serve as ‘inks’ for writeable detection of H2S. The ability to directly write the H2S-sensitive NCPs under ambient conditions is really convenient and offers promising perspectives for real-time monitoring H2S.

A facile and green strategy based on a redox reaction between potassium permanganate and ascorbic acid was developed to synthesize mesoporous manganese oxide walnuts (MPMOW) for supercapacitors. The formation procedure was performed in a one-step fashion. The as-prepared samples were fully characterized to study the morphology, chemical composition and physical properties. An N2 adsorption-desorption test indicated that the surface area of the materials is up to 128 m2 g−1. When used as electrode materials for supercapacitors, this mesoporous manganese oxide electrode materials possessed high capacitance and good cyclic stability even after 2000 cycles at a relatively high current density (833.33 mA g−1) in three alkali metal sulfate neutral aqueous electrolytes (Li2SO4, Na2SO4 and K2SO4). Moreover, the charge storage mechanisms have been discussed in detail.

A cotton-assisted preparation method of mesoporous manganese oxides for supercapacitors is reported. The samples were fully characterized to study the morphology, chemical composition, surface area and pore structure. The results of the electrochemical tests show that these electrode materials possessed good capacitive nature and long cycling life after 3000 cycles.

Large, monodisperse core-shell Au-Ag nanoparticles with Ag-like optical properties have been prepared by the seeding growth method in micellar media.

(100)-oriented NH4MnF3 perovskite with different morphologies have been obtained in situ via an organic template; experimental results can be rationalized in terms of electrostatic interactions and lattice matching between the organic template and the ions undergoing nucleation.

Catalytic degradation of organic dye molecules has attracted extensive attention due to their high toxicity to water resources. In this paper, we propose a novel method for the fabrication of uniform silver-coated ZnO nanowire arrays. The degradation of typical dye molecule rhodamine 6G (R6G), as an example, is investigated in the presence of the as-prepared silver-coated ZnO nanowire arrays. The experimental results show that such composite nanostructures exhibit high catalytic activity, and the reaction follows pseudo-first-order kinetics. Furthermore, these nanowire arrays are desirable SERS substrates for monitoring the catalytic degradation of dye molecules. Compared with traditional UV-visible spectroscopy, SERS technology can reflect more truly the catalytic degradation process occurring on the surface of the catalysts.

In this paper we report the rational design and fabrication of high-quality core-shell Au-Pt nanoparticle film. Such film shows highly efficient catalytic properties and excellent surface-enhanced Raman scattering (SERS) ability.

A facile strategy for the in situ synthesis of terbium complex-silica nanocomposites is described. The resultant spherical nanocomposites possess good monodispersity and exhibit luminescent properties of terbium complex.