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Semiconductor electrocatalysis with weak conductivity can accumulate extremely high carriers at semiconductor-electrolyte interface by self-gating effect, which strongly promotes electrocatalytic efficiency. The correlation between semiconductor carrier mobility and electrocatalysis performance is still unclear. Herein atomic-thin transition metal dichalcogenides based composites have been developed for hydrogen evolution reaction (HER) performed with on-chip microdevices. Electrical and electrochemical measurement of individual flack verified the key role of high carrier mobility for enhanced HER activity. Carrier mobility regulation further demonstrated its high dependence with HER performance under self-gating. Our study provides new insight into the carrier mobility of the semiconductor in the electrocatalysis, paving the way for designing high-performance semiconductor catalysts.

The oxygen vacancy-rich perovskite La0.9FeO3−δ was employed as an electrocatalyst to reduce nitrate to ammonia and obtained the highest NH3 yield of 1024.8 μg h−1 cm−2 at −1.0 V (vs. RHE) and a faradaic efficiency of 78.1% at −0.8 V (vs. RHE).

Machine learning approach was employed to guide the fabrication of blue carbon dots(CDs) with excellent result. The quantum yield of the CDs can increase up to 200% and can be used as fluorescent probes for bleaching teeth H2O2 detection.

Supplementary material and methods

Supplementary Table S1. Antibodies Used in the Study Supplementary Table S2. Characterization of LPD NPs Supplementary Table S3. Primers Used in the Study Supplementary Table S4. Blood Chemistry after Treatments Supplementary Figure S1. Morphology and in vivo biodistribution of LPD NPs. Supplementary Figure S2. Histology (H&E, left; IF, right; adjacent sections) of mice bearing UMUC3/3T3 tumors. Supplementary Figure S3. Calculation of DiI positive cells in each cell population within UMUC/3T3 xenograft tumors by flow cytometry (n=4). Supplementary Figure S4. In vitro transfection efficiency of sTRAIL or TRAIL loaded LPD on UMUC3 bladder cancer cell line. Supplementary Figure S5. Neighboring tumor-suppressive effect of the secreted TRAIL protein. Supplementary Figure S6. qPCR quantitation of relative mRNA levels of sTRAIL in the UMUC3/3T3 tumors after different treatments. Supplementary Figure S7. ELISA quantification of the expression and secretion of sTRAIL protein in the UMUC3/3T3 tumors after different treatments. Supplementary Figure S8. Collagen remodeling during the dose escalation of sTRAIL LPD. Supplementary Figure S9. Remodeling of tumor microenvironment after sTRAIL LPD treatment. Supplementary Figure S10. Histology (both fibroblast staining and collagen staining) of orthotopic BXPC3-Luc2 mouse xenograft. Supplementary Figure S11. sTRAIL LPD inhibited the metastasis of BXPC3-Luc2 tumors Supplementary Figure S12. Expression of GFP within different cell populations of BXPC3-Luc2 tumors after 3 doses of sTRAIL or TRAIL NPs (co-expressing GFP). Supplementary Figure S13. Collagen staining of tumors from mice treated with PBS and sTRAIL LPD NP, respectively. Supplementary Figure S14. In vivo cytotoxicity evaluation and organ distribution of sTRAIL or TRAIL LPD. Supplementary Figure S15. Apoptosis of neighboring tumor cells reduces the activation of fibroblasts.

The off-target distribution of anticancer nanoparticles to fibroblasts creates a barrier to the effective treatment of desmoplastic tumors. However, we hypothesized that this nanoparticle detriment might be exploited to target the expression of secreted cytotoxic proteins from tumor-associated fibroblasts (TAF) as an anticancer strategy. In addressing this hypothesis, plasmids encoding the secretable TNF-related factor sTRAIL were loaded into lipid-coated protamine DNA complexes and administered by infusion in a murine xenograft model of human desmoplastic bladder carcinoma. Three doses were sufficient to generate approximately 70% of TAFs as sTRAIL-producing cells. sTRAIL triggered apoptosis in tumor cell nests adjacent to TAFs. Furthermore, it reverted residual fibroblasts to a quiescent state due to insufficient activation, further compromising tumor growth and remodeling the microenvironment to favor second-wave nanotherapy. We confirmed the efficacy of this strategy in an orthotopic xenograft model of human pancreatic cancer, where the desmoplastic stroma is well known to be a major barrier to the delivery of therapeutic nanoparticles. Collectively, our results offer a proof of concept for the use of nanoparticles to modify TAFs as an effective strategy to treat desmoplastic cancers. Cancer Res; 77(3); 719–31. ©2016 AACR.

An integrated physiologically based modeling framework is presented for predicting pharmacokinetics and bioavailability of subcutaneously administered monoclonal antibodies in cynomolgus monkeys, based on in silico structure-derived metrics characterizing antibody size, overall charge, local charge, and hydrophobicity. The model accounts for antibody-specific differences in pinocytosis, transcapillary transport, local lymphatic uptake, and pre-systemic degradation at the subcutaneous injection site and reliably predicts the pharmacokinetics of five different wild-type mAbs and their Fc variants following intravenous and subcutaneous administration. Significant associations were found between subcutaneous injection site degradation rate and the antibody's local positive charge of its complementarity-determining region (R = 0.56, p = 0.0012), antibody pinocytosis rate and its overall positive charge (R = 0.59, p = 0.00063), and antibody paracellular transport and its overall charge together with hydrophobicity (R = 0.63, p = 0.00096). Based on these results, population simulations were performed to predict the relationship between bioavailability and antibody local positive charge. In addition, model simulations were conducted to calculate the relative contribution of absorption pathways (lymphatic and blood), pre-systemic degradation pathways (interstitial and lysosomal), and the influence of injection site lymph flow on antibody bioavailability and pharmacokinetics. The proposed physiologically based modeling framework integrates fundamental mechanisms governing antibody subcutaneous absorption and disposition, with structured-based physiochemical properties, to predict antibody bioavailability and pharmacokinetics in vivo.

Compared to traditional rigid-bodied robots, soft robots are constructed using physically flexible/elastic bodies and electronics to mimic nature and enable novel applications in industry, healthcare, aviation, military,etc.

Strong, reversible, and self-cleaning adhesion in the toe pads of geckos allow the lizards to climb on a variety of vertical and inverted surfaces, regardless of the surface conditions, whether hydrophobic or hydrophilic, smooth or tough, wet or dry, clean or dirty. Development of synthetic gecko-inspired surfaces has drawn a great attention over the past two decades. Despite many external-stimuli responsive mechanisms (i.e., thermal, electrical, magnetic) have been successfully demonstrated, smart adhesives controlled by light signals still substantially lag behind. Here, in this report, we integrate tetramethylpiperidinyloxyl (TEMPO)-doped polydopamine (PDA), namely, TDPDA, with PDMS micropillars using a template-assisted casting method, to achieve both improved adhesion and self-cleaning performances. To the best of our knowledge, this is the first report on PDA being used as a doping nanoparticle in bioinspired adhesive surfaces to achieve highly efficient self-cleaning controllable by light signals. Notably, the adhesion of the 5% TDPDA-PDMS sample is ∼688.75% higher than that of the pure PDMS at the individual pillar level, which helps to explain the highly efficient self-cleaning mechanism. The sample surfaces (named TDPDA-PDMS) can efficiently absorb 808 nm wavelength of light and heat up from 25 °C to 80.9 °C in 3 min with NIR irradiation. The temperature rise causes significant reduction of adhesion, which results in outstanding self-cleaning rate of up to 55.8% within five steps. The exploration of the photoenabled switching mechanism with outstanding sensitivity may bring the biomimetic smart surfaces into a new dimension, rendering varied applications, e.g., in miniaturized climbing robot, artificial intelligence programmable manipulation/assembly/filtration, active self-cleaning solar panels, including high output sensors and devices in many engineering and biomedical frontiers.

A model-based framework is presented to predict monoclonal antibody (mAb) pharmacokinetics (PK) in humans based on

There is a high demand for hydrogels with multifunctional performance (a combination of adhesive, mechanical, and electrical properties) in biological, tissue engineering, robotics, and smart device applications. However, a majority of existing hydrogels are relatively rigid and brittle, with limited stretchability; this hinders their application in the emerging field of flexible devices. In this study, cheap and abundant potato residues were used with polyacrylamide (PAM) to fabricate a multifunctional hydrogel, and chitosan was used for the design of a three-dimentional (3D) network-structured hydrogel. The as-prepared hydrogels exhibited excellent stretchability, with an extension exceeding 900% and a recovery degree of over 99%. Due to the combination of physical and chemical cross-linking properties and the introduction of dopamine, the designed hydrogel exhibits a remarkable self-healing ability (80% mechanical recovery in 2 h), high tensile strength (0.75 MPa), and ultra-stretchability (900%). The resultant products offer superior properties compared to those of previously reported tough and self-healing hydrogels for wound adhesion. Chitosan and potato residues were used as scaffold materials for the hydrogels with excellent mechanical properties. In addition, in vitro experiments show that these hydrogels feature excellent antibacterial properties, effectively hindering the reproduction of bacteria. Moreover, the ternary hydrogel can act as a strain sensor with high sensitivity and a gauge factor of 1.6. The proposed strategy is expected to serve as a reference for the development of green and recyclable conductive polymers to fabricate hydrogels. The proposed hydrogel can also act as a suitable strain sensor for bio-friendly devices such as smart wearable electronic devices and/or for health monitoring.

Geckos have the extraordinary ability to adhere and move across varied surfaces, while keeping their tiny high-aspect-ratio foot-hairs intact for thousands of attachment-detachment cycles. Inspired...

The high diffusion rate of sulfur with respect to metal oxide creates precursors that deviate from the stoichiometric ratio, leading to poor growth controllability and defects in the as-grown transition metal dichalcogenides (TMDCs). The introduction of a sulfur precursor with a high melting point is a hopeful strategy to solve these problems. Here, we first introduce sodium sulfate (Na2SO4) as a sulfur precursor, which plays roles in tuning diffusion of source precursors and balancing their mass flux based on the temperature-confined decomposition of Na2SO4. We deduced the specific growth process by characterizing the composition of intermediates; the results show that emissions of sulfur and metal sources were synchronously released and spanning the entire growth stage. This temperature-controlled source-feeding system reduced the diffusion gap between sulfur and metal, which promoted a faster kinetics for reactions. Moreover, this method has the wide applicability for producing other TMDCs.

Designing effective catalysts by controlling morphology and structure is key to improving the energy efficiency of fuel cells. A good understanding of the effects of specific structures on electrocatalytic activity, selectivity, and stability is needed. Here, we propose a facile method to synthesize PtCu bimetallic nanostructures with controllable compositions by using Cu nanowires as a template and ascorbic acid as a reductant. A further annealing process provided the alloy PtCu with tunable crystal structures. The combination of distinct structures with tunable compositions in the form of PtCu nanowires provides plenty of information for better understanding the reaction mechanism during catalysis. HClO4 cyclic voltammetry (CV) tests confirmed that various phase transformations occurred in bimetallic and alloy samples, affecting morphology and unit cell structures. Under a bifunctional synergistic effect and the influence of the insertion of a second metal, the two series of structures show superior performance toward methanol electrooxidation. Typically, the post-product alloy A-Pt14Cu86 with a cubic structure (a = 3.702 A) has better methanol oxidation reaction (MOR) catalysis performance. Density functional theory (DFT) calculations were performed to determine an optimal pathway using the Gibbs free energy and to verify the dependence of the electrocatalytic performance on the lattice structure via overpotential changes. Bimetallic PtCu has high CO tolerance, maintaining high stability. This work provides an approach for the systematic design of novel catalysts and the exploration of electrocatalytic mechanisms for fuel cells and other related applications.

Countless organisms in nature have adapted high-aspect-ratio micro-/nano-fibrillar arrays on their functional surfaces for achieving special and often optimized functionalities using earthly abundant materials. At the core of nanoscience and nanotechnology, rationally mimicking nature offers a promising route to create multifunctional superstructures that capture organisms and biological materials’ intriguing responsive and self-adjusting properties. Prior work has demonstrated that hierarchical vertically aligned multi-walled carbon nanotube (VA-MCNT) arrays can achieve ten folds of adhesive force comparing to the fibrillar structures of the gecko toe pads. However, little is known with regard to their wettability at the ultimate atomistic level, and how this may influence the adhesive performance and/or self-cleaning capabilities, despite water condensation and bridging are common phenomena at this length scale. In present study, molecular dynamics (MD) simulations were performed using Large-Scale Atomic / Molecular Massively Parallel Simulator (LAMMPS). Results indicate that commonly believed hydrophobic defect free CNTs (i.e., carbon sp2 hybridization without any dangling bonds) become super-hydrophilic at this length/temporal scale. The critical factors that influence the number of H-Bonds in water are: i) tube-tube spacing; and ii) shape/size and position of the water nanodroplet; and iii) how many droplets exists and how many nanotubes are bridged by the droplets. Chirality has little effect on the water interfacial behaviors. Future work will focus on the effect of water condensation and bridging on the adhesive and self-cleaning properties of carbon-based bio-inspired fibrillar dry adhesives considering defects and saline water.

Self-cleaning surfaces are desirable in many engineering applications where low energy consumption, reusability and sustainability are of the biggest concerns. Inspired by the gecko’s unique ‘dry self-cleaning’ hierarchical structures. Here we fabricated artificial Fe 3 O 4 /PDMS composites that show robust self-cleaning capabilities. The enhanced adhesion performance is attributable to the decrease of PDMS polymerization degree and the load transfer between PDMS matrix and Fe 3 O 4 magnetic particles. The self-cleaning surfaces showed up to 24.3% self-cleaning rate with as few as 4 steps. Simulation result indicated that the changing of cross linking between Fe 3 O 4 and PDMS is the main reason for the enhanced self-cleaning surfaces. This work reveals an alternative route of making high-performance self-cleaning smart surfaces that are applicable in the textile industry, robotic locomotion/gripping technology, outer-space explorations and tissue engineering.

Shape engineering plays a crucial role in the application of two-dimensional (2D) layered metal dichalcogenide (LMD) crystalline materials in terms of physical and chemical property modulation. How...

Fibroblast growth factor 21 (FGF21) serves as an essential biomarker for early detection and diagnosis of nonalcoholic fatty liver disease (NAFLD). It has received a great deal of attention recently in efforts to develop an accurate and effective method for detecting low levels of FGF21 in complex biological settings. Herein, we demonstrate a label-free, simple and high-sensitive field-effect transistor (FET) biosensor for FGF21 detection in a nonaqueous environment, directly utilizing two-dimensional molybdenum disulfide (MoS2) without additional absorption layers. By immobilizing anti-FGF21 on MoS2 surface, this biosensor can achieve the detection of trace FGF21 at less than 10 fg mL−1. High consistency and satisfactory reproducibility were demonstrated through multiple sets of parallel experiments for the MoS2 FETs. Furthermore, the biosensor has great sensitivity to detect the target FGF21 in complex serum samples, which demonstrates its great potential application in disease diagnosis of NAFLD. Overall, this study shows that thin-layered transition-metal dichalcogenides (TMDs) can be used as a potential alternative platform for developing novel electrical biosensors with high sensitivity and selectivity.

Present study reports a controllable phase transformation of nickel (Ni) from amorphous to cubic crystal structures on tungsten (W) substrate by electrodeposition. X-ray powder diffraction, scanning electron microscopy, transmission electron microscopy and energy dispersive spectroscopy were used to characterize the microstructure, micro-constituents and surface morphology of as-prepared Ni. The microstructure of Ni was strongly affected by the applied overpotential and deposition time. It is demonstrated that by controlling these two parameters either amorphous or cubic crystal structure of Ni on the W substrate could be obtained. The crystallization mechanism is discussed based on Gibbs crystal growth theory and Ostwald’s rule. It is concluded that W substrate, acting as a heat sink, can effectively promote the thermal stability of amorphous Ni, based on the data from differential scanning calorimetry and Kissinger’s model. This work contributes to the elucidation of the crystallization mechanism of Ni on W powder substrates, and proves that, better than alloying with other elements, incorporating powder substrates will significantly improve the crystallization temperature, hence the thermostability of amorphous Ni.

Substitutional doping has been proven to be an effective route to engineer band gap, transport characteristics, and magnetism in transition metal dichalcogenides. Herein, we demonstrate substitutio...

Two-dimensional layered molybdenum disulfide (MoS2) is a promising catalyst for hydrogen evolution reaction (HER), and a good replacement for platinum (Pt) in elelctrochemical water splitting. Most transition metal dichalcogenides (TMDs) show excellent catalytic activity, which stems from their active sites located along the edges. However, small density of the active sites in the basal plane, largely limits TMDs performance. To enhance the HER catalysis activity of MoS2, we developed an efficient and scalable approach to significantly increase the overall electrochemically active sites using mild sodium hypochlorite (NaClO) solution anisotropic etching. The effect is further enhanced by oxygen-plasma pretreatment of the material, which - upon chemical etching - leads to highly porous and highly reactive structure. The resulting chemically activated MoS2 (ca-MoS2) was systematically characterized and optimized. The optimized ca-MoS2 powder exhibits enhanced HER performance with an overpotential of 0.34 V at a current density of 0.5 mA cm−2 in this experiment due to the increasing active sites, and the Tafel slope also smaller than other samples. This chemical etching method provides new ways to design atomic structure modification, including controlling layered TMD electrochemical property and new type of transistor fabrication.