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This study aims to investigate the effect of glucosinolate (GSL) degradation on the volatile odor of rapeseed oil (RO) during roasting. Volatile compounds of RO and individual GSL contents in the seeds were identified and measured during roasting, separately. Total GSL content decreased by 30.47-84.44%. Nitriles were the key volatile compounds that were negatively correlated with GSLs for all samples. Results indicate that GSL degradation significantly affects the volatile odor of RO and tends to produce low-carbon nitriles. Furthermore, the thermal degradation pathways of GSLs were explored according to the structure of individual GSLs and nitriles. These results provide information for the thermal degradation pathways of GSLs and the formation mechanism of nitriles during seed roasting.

Immunomagnetic micro/nanoparticles (IMNs) have been widely used to isolate rare circulating tumor cells (CTCs) from blood samples for early diagnosis of cancers. However, when entering into biofluids, IMNs nonspecifically adsorb biomolecules and the in situ formed biomolecule corona covers IMN surface ligands and weakens the targeting capabilities of IMNs. In this work, we demonstrated that by surface coating of IMNs with red blood cell (RBC)-derived vesicles, the obtained biomimetic particles (RBC-IMNs) basically adsorb no biomolecules and maintain the CTC targeting ability when exposed to plasma. Compared to IMNs, RBC-IMNs exhibited an excellent cell isolation efficiency in spiked blood samples, which was improved to 95.71% from 60.22%. Furthermore, by using RBC-IMNs, we successfully isolated CTCs in 28 out of 30 prostate cancer patient blood samples and further showed the robustness of RBC-IMNs in downstream cell sequencing. The work presented here provides a new insight into developing targeted nanomaterials for biological and medical applications.

Although anti-PD-1 immunotherapy is widely used to treat melanoma, its efficacy still has to be improved. In this work, we present a therapeutic method that combines immunotherapy and starvation therapy to achieve better antitumor efficacy. We designed the CMSN-GOx method, in which mesoporous silica nanoparticles (MSN) are loaded with glucose oxidase (GOx) and then encapsulate the surfaces of cancer cell membranes to realize starvation therapy. By functionalizing the MSN's biomimetic surfaces, we can synthesize nanoparticles that can escape the host immune system and homologous target. These attributes enable the nanoparticles to have improved cancer targeting ability and enrichment in tumor tissues. Our synthetic CMSN-GOx complex can ablate tumors and induce dendritic cell maturity to stimulate an antitumor immune response. We performed an in vivo analysis of these nanoparticles and determined that our combined therapy CMSN-GOx plus PD-1 exhibits a better antitumor therapeutic effect than therapies using CMSN-GOx or PD-1 alone. Additionally, we used the positron emission tomography imaging to measuring the level of glucose metabolism in tumor tissues, for which we investigate the effect with the cancer therapy in vivo.

The efficient capture and high-activity release of circulating tumor cells (CTCs) remain a challenge for the microfluidic chip. We have fabricated a dual-mode gelatin-polydimethylsiloxane (PDMS) microfluidic chip with a sawtooth columnar microstructure of channels that can capture the efficiency of this substrate up to 95%. Increasing the gelatin temperature to physiologic temperature (37 °C) with a baking table facilitates the overall release of CTCs. With melting of the gelatin substrate, the cells will enter into the PDMS corresponding channel; however, the released cells will be wrapped by a layer of gelatin, which may affect further proliferation of the cells. Another way to release CTCs is to use a matrix metalloproteinase-9 (MMP-9) enzyme to dissolve the gelatin and release the tumor cells with high cellular viability. This dual-mode microfluidic chip has been applied successfully to capturing and releasing CTCs, thus serving as a powerful clinical tool that facilitates the subsequent bioanalysis of CTCs for clinical and biological research.

Tin oxide (SnO2) electron selective layers (ESLs) processed by low-temperature plasma-enhanced atomic layer deposition (PEALD) hold promise for fabricating lightweight and efficient flexible lead halide perovskite solar cells (PVSCs). However, the as-synthesized SnO2 ESLs typically lead to flexible PVSCs with lower open-circuit voltage (VOC) and fill factor (FF) as well as a higher degree of current density–voltage (J–V) hysteresis, compared to PVSCs fabricated on rigid substrates. Here, we report that facile water vapor treatment of PEALD-synthesized SnO2 ESLs can effectively improve the VOC and FF while reducing the degree of J–V hysteresis. The improvement in device performance is mainly attributed to the improved conductivity and electrical mobility of SnO2 ESLs enabled by water vapor treatment. With such treatment, our best flexible PVSC fabricated on a commercial substrate shows a power conversion efficiency of 18.36 (17.12)% when measured under a reverse (forward) voltage scan and a stabilized effi...

Among many photovoltaic conversion technologies, perovskite solar cells have received significant research interests as effective photovoltaic materials owing to their high solar conversion efficiencies and low cost. However, the performance of perovskite solar cells is limited by the instability of CH3NH3PbI3 to water and ambient moisture. To address this issue, in this study, we introduced a new fundamental approach that utilizes 4-tert-butylpyridine (tBP) as the surface modification agent to enhance the performance and stability of CH3NH3PbI3-based perovskite solar cells fabricated in ambient air. The tertiary butyl group in tBP is highly hydrophobic, leading to the formation a hydrophobic layer on the surface of CH3NH3PbI3, thus increasing the moisture stability of perovskite solar cells. With this strategy, the performance of perovskite solar cells prepared at even >50% RH in ambient air was tremendously enhanced by as much as 200% compared to that without tBP additive. Besides, the stability of pero...

Nanoporous submicron TiO2 spheres of diameters around 200 nm are synthesized by a hydrothermal process and used as a scaffold layer for improving light absorption, charge transportation, as well as photovoltaic performance in hole-transport-layer free perovskite solar cells employing carbon counter electrodes. The TiO2 submicron spheres show a porous feature with high specific surface area, which is essential for perovskite infiltration, charge extraction, and transportation in mesoscopic perovskite solar cells. Furthermore, big spheres exhibit better light scattering property compared to traditional TiO2 nanoparticles, thus enhancing light absorption in corresponding devices. The present perovskite solar cells employ a TiO2 scaffold layer of optimized thickness of about 600 nm and show an average power conversion efficiency of 13.46 ± 0.41%, which is 18.4% higher than that of counterparts based on TiO2 nanoparticle (11.37 ± 0.40%). The champion cell exhibits an impressive efficiency of 14.3%, which is ve...

A perovskite solar cell with a thin TiO2 compact film prepared by thermal oxidation of sputtered Ti film achieved a high efficiency of 15.07%. The thin TiO2 film prepared by thermal oxidation is very dense and inhibits the recombination process at the interface. The optimum thickness of the TiO2 compact film prepared by thermal oxidation is thinner than that prepared by spin-coating method. Also, the TiO2 compact film and the TiO2 porous film can be sintered at the same time. This one-step sintering process leads to a lower dark current density, a lower series resistance, and a higher recombination resistance than those of two-step sintering. Therefore, the perovskite solar cell with the TiO2 compact film prepared by thermal oxidation has a higher short-circuit current density and a higher fill factor.

The treatment of bacterial infection is one of the most challenging tasks in the biomedical field. Antibiotics were developed over 70 years and are regarded as the most efficient type of drug to treat bacterial infection. However, there is a concern that the overuse of antibiotics can lead to a growing number of multidrug-resistant bacteria. The development of antibiotic delivery systems to improve the biodistribution and bioavailability of antibiotics is a practical strategy for reducing the generation of antibiotic resistance and increasing the lifespan of newly developed antibiotics. Here we present an antibiotic delivery system (Van⊂SGNPs@RBC) based on core-shell supramolecular gelatin nanoparticles (SGNPs) for adaptive and "on-demand" antibiotic delivery. The core composed of cross-linked SGNPs allows for bacterial infection-microenvironment responsive release of antibiotics. The shell coated with uniform red blood cell membranes executes the function of disguise for reducing the clearance by the immune system during the antibiotic delivery, as well as absorbs the bacterial exotoxin to relieve symptoms caused by bacterial infection. This approach demonstrates an innovative and biomimetic antibiotic delivery system for the treatment of bacterial infection with a minimum dose of antibiotics.

Nickel sulfide (NiS) nanowall networks have been prepared by a novel one-step hydrothermal method on a nickel (Ni) foam substrate. The Ni foam has a high conductivity and porous structure. To our knowledge, the Ni foam is used as a conductive substrate for the dye-sensitized solar cell (DSSC) for the first time. The Ni foam is used as not only the conductive substrate but also the Ni sources of the reaction. The Ni foam supported NiS prepared by this simple hydrothermal method shows high catalytic activity for reduction of triiodide ions. The DSSC with a transparent conductive oxide (TCO)-free NiS counter electrode (CE) was herein developed and showed a higher power conversion efficiency of 8.55% than that with a TCO supported NiS CE (7.47%) and a TCO supported platinum CE (7.99%).

We report on fabrication of 4-terminal all-perovskite tandem solar cells with power conversion efficiencies exceeding 23% by mechanically stacking semitransparent 1.75 eV wide-bandgap FA0.8Cs0.2Pb(I0.7Br0.3)3 perovskite top cells with 1.25 eV low-bandgap (FASnI3)0.6(MAPbI3)0.4 bottom cells. The top cells use MoOx/ITO transparent electrodes and achieve transmittance up to 70% beyond 700 nm.

The construction of nanoporous conductive polymer membranes has potential applications in catalysts and energy-conversion devices. In this letter, we present a facile method to prepare free-standing polypyrrole (PPy) nanotube films by simply heating pulp-like homogeneous suspensions at a low temperature, which can be employed as a novel counter electrode (CE) to substitute for the expensive fluorine-doped tin oxide (FTO) glass and Pt used in dye-sensitized solar cells (DSSCs). The DSSCs assembled with these paper-like PPy membranes show an impressive conversion efficiency of 5.27%, which is about 84% of the cell with a conventional Pt/FTO CE (6.25%).

An out-of-plane elastic vibration test method is developed to directly study the elastic stability of elastic Ti foil-supported porous carbon nanocomposite (CNC) counter electrode (CE) of dye sensitized solar cells (DSSCs). The stability of CE, estimated by that of power conversion efficiency (PCE) of the CE-based DSSC device, is studied from the views of CNC morphology, equivalent resistances, exchange current density and contact model of CE. The results suggest thinner thickness and bigger interbundling degree of CNC layer is beneficial to the total internal impedance value of CE, and then beneficial to the CE stability. With optimal CNC structure, even if the CE is springed 1000 times with max amplification about 10 mm, the PCE of CE-based DSSC can remain 80% of the initial value. The test method is interesting and the results may have a potential use for elastic stability study of general elastic devices.

A facile in situ carbonization method was demonstrated to prepare the highly transparent carbon counter electrode (CE) with good mechanical stability for bifacial dye-sensitized solar cells (DSCs). The optical and electrochemical properties of carbon CEs were dramatically affected by the composition and concentration of the precursor. The well-optimized carbon CE exhibited high transparency and sufficient catalytic activity for I3(-) reduction. The bifacial DSC with obtained carbon CE achieved a high power conversion efficiency (PCE) of 5.04% under rear-side illumination, which approaches 85% that of front-side illumination (6.07%). Moreover, the device shows excellent stability as confirmed by the aging test. These promising results reveal the enormous potential of this transparent carbon CE in scaling up and commercialization of low cost and effective bifacial DSCs.

Bis(imidazolium) iodides (bis-Im(+)I(-)s) are synthesized with different substituents and used as electrolytes in dye-sensitized solar cells (DSSCs). Three kinds of low-volatility electrolytes are prepared by using 1,1'-methylene bis(3-imidazolium) diiodide (MIDI), 1,1'-methylene bis(3-n-methylimidazolium) diiodide (MMIDI), and 1,1'-methylene-bis(3-n-ethylimidazolium) diiodide (MEIDI) as the iodide sources. The effects of these substituents on the photovoltaic performance of the cells are investigated. It is found that the device shows a lower short-circuit photocurrent (Jsc), higher open-voltage (Voc) and fill factor (FF) with the increased cation size in electrolyte. These results are explained by electrostatic interactions between the solvated Im(+) and the negatively charged species. Meanwhile, the explanation is supported by electrochemical impedance spectroscopy (EIS), cyclic voltammetry (CV), open circuit voltage decay (OCVD), and dark current measurements.

Submicrometer-sized monodispersed TiO2 spheres were synthesized by a controlled hydrolysis of titanium tetraisopropoxide (TTIP) and subsequent solvothermal treatment. The X-ray diffraction (XRD), scanning electron microscopy (SEM), and UV–visible spectroscopy analyses revealed that aqueous ammonia concentration and calcining temperature significantly influence the morphology, crystallization, dye loading, and light scattering capacity of TiO2 microspheres. And it was found that the TiO2 microspheres prepared by this method showed a good thermal stability of phase. Bilayered dye-sensitized solar cells (DSSCs) composed of TiO2 microspheres as the scattering cover layers and TiO2 nanocrystallines as the underlayer exhibited a remarkable improvement in the power conversion efficiency (8.25%) compared with the nanocrystalline TiO2 DSSC (6.38%), owing to high light scattering efficiency and the dye-loading capacity of the microsphere cover layer. In addition, electrochemical impedance spectra (EIS) and open-cir...

Novel selectively edge grown ZnO–carbon nanotube (CNT) heterostructure field emission (FE) arrays have been fabricated by a facile and repeatable two-step process. First, with the combined effect from a ZnO seed layer and a passivation layer for nanorod growth, ZnO nanorods could only grow on the edge of a 4 μm diameter circle. Meanwhile, the local morphology such as ZnO nanorod density, uniformity, and growth direction can be modulated by the thickness of ZnO seed layer. With this adjustment, the FE performance of the ZnO nanorod ring pattern arrays is significantly improved. Then CNTs were radically grown on the surface of the ZnO nanorod ring pattern arrays. As a consequence of all these optimizations, the lowest turn-on field of 2.1 V/μm, threshold field of 3.19 V/μm, and a current density of 7 mA/cm2 at a field of 4.95 V/μm were ultimately obtained. Via calculating the electrostatic field distribution, it was found that this giant enhancement of FE performance is due to the typical morphology which c...

Highly uniform and transparent polyaniline (PANI) electrodes that can be used as counter electrodes in dye-sensitized solar cells (DSSCs) were prepared by a facile in situ polymerization method. They were used to fabricate a novel bifacially active transparent DSSC, which showed conversion efficiencies of 6.54 and 4.26% corresponding to front- and rear-side illumination, respectively. Meanwhile, the efficiency of the same photoanode employing a Pt counter electrode was 6.69%. Compared to conventional Pt-based DSSCs, the design of the bifacial DSSC fabricated in this work would help to bring down the cost of energy production due to the lower cost of the materials and the higher power-generating efficiency of such devices for their capabilities of utilizing the light from both sides. These promising results highlight the potential application of PANI in cost-effective, transparent DSSCs.

Solvent, dispersant, and surfactant play different roles in forming porous films of dye-sensitized solar cells (DSSCs) when they are added into the paste. We investigate the influence of ethanol, acetylacetone, and Triton-X100 on the photoelectrode of DSSCs with orthogonal array design experiments. Stereoscopic morphologies of photoelectrodes scanned with atomic force microscopy (AFM) show that decreasing the amount of ethanol in TiO2 paste results in forming a more compact structure of the photoelectrode for DSSCs. The TiO2 photoeletrode made with 2.5 g of TiO2 nanoparticle powder dissolved in 20 mL of ethanol presents lower root-mean-square (rms) roughness calculated from AFM, and its corresponding performance in DSSCs shows higher photoelectric conversion efficiency, while the effects of acetylacetone and Triton-X100 on the performance of DSSCs are not very apparent. Optimized photoelectrode dyed with N719 shows increased light absorption. This may result from adsorbing more amount of dye on a larger i...

Novel strain sensor based on ZnO bridging nanorods has been fabricated on Kapton substrate by a single-step hydrothermal reaction, and fully packaged by a polydimethylsioxane layer. Via introducing a metastable contact that can be controlled by strain, flexible strain sensors with high sensitivity and a strain driving transistor with an ultrahigh 107 scale “on”−“off” ratio have been demonstrated. However, high performance devices only come from the samples fabricated with lower nutrient solution concentration and are only sensitive to tensile strain. We found out that the response behavior strongly depends on the device structure. The I−V characteristic is highly sensitive to strain due to the change in Schottky barrier height, as well as the change of contact area between ZnO bridging nanorods induced by the metastable morphology under strain.

Nanoparticles are regarded as promising transfection reagents for effective and safe delivery of nucleic acids into a specific type of cells or tissues providing an alternative manipulation/therapy strategy to viral gene delivery. However, the current process of searching novel delivery materials is limited due to conventional low-throughput and time-consuming multistep synthetic approaches. Additionally, conventional approaches are frequently accompanied with unpredictability and continual optimization refinements, impeding flexible generation of material diversity creating a major obstacle to achieving high transfection performance. Here we have demonstrated a rapid developmental pathway toward highly efficient gene delivery systems by leveraging the powers of a supramolecular synthetic approach and a custom-designed digital microreactor. Using the digital microreactor, broad structural/functional diversity can be programmed into a library of DNA-encapsulated supramolecular nanoparticles (DNA⊂SNPs) by systematically altering the mixing ratios of molecular building blocks and a DNA plasmid. In vitro transfection studies with DNA⊂SNPs library identified the DNA⊂SNPs with the highest gene transfection efficiency, which can be attributed to cooperative effects of structures and surface chemistry of DNA⊂SNPs. We envision such a rapid developmental pathway can be adopted for generating nanoparticle-based vectors for delivery of a variety of loads.

Lateral zinc oxide (ZnO) nanorod metal-semiconductor-metal ultraviolet detectors with different metal contact were fabricated on glass substrate by a single-step hydrothermal reaction. With the combined effect from a ZnO seed layer and an inactive layer for nanorod growth, ZnO nanorods could grow laterally and aligned between the interdigitated electrodes. When the growth process is terminated, the integration of ZnO nanorods into a function device can be achieved in the meantime. The structure can be modeled as being composed of two same Schottky barriers connected back to back, in series with a resistance of R. The devices are visible-blind and have great response even in mid ultraviolet region. The photodetectors with Ni electrode show better performance both in the aspect of photocurrent and response time, owing to the larger Schottky barrier at the Ni/ZnO interface. By surface coating with polymethyl methacrylate, the response has been further improved. Our approach provides a simple and effective wa...

Novel lateral field emission devices composed of ZnO nanorods have been fabricated by a single-step hydrothermal approach on glass substrate. With the combined effect from a ZnO seed layer and a passivation layer for nanorod growth, ZnO nanorods could grow laterally and aligned between two electrodes. In this way, the conventional “pick and place” method and pattern grown on single crystal of nanorod integration are avoided. All the Fowler−Nordheim (FN) curves are straight lines and in excellent agreement with FN theory, which indicates that the electron emission of the as-grown samples is a tunneling and cold electron emission process. Measurement results also show that the samples with larger separation distance exhibit better field emission characteristics. By calculating the electrostatic field distribution, it was found that the electric field near the surface of the emitter is strongly dependent on the vacuum separation distance.

By using different types of ZnO thin films as seed layers, we systematically investigated the effects of seed layers on the morphologies and growth behaviors of ZnO nanorods by the vapor-phase transport method. It was found that ZnO nanorods can be grown on a variety of polycrystalline ZnO seed layers. The formation of a network wetting layer facilitates the uniform growth of an aligned ZnO nanorod. However, once a continuous ZnO network layer is formed, the alignment will be independent of seed layer thickness and surface roughness. Our results indicate that a ZnO seed layer with a high c-axis orientation, good crystallinity, and less lattice stress leads to the growth of well-aligned ZnO nanorod arrays with uniform diameters and narrow density distributions.

Generating droplets via microfluidic chips is a promising technology in microanalysis and microsynthesis. To realize room-temperature ionic liquid (IL)-water two-phase studies in microscale, a water-immiscible IL was employed as the continuous phase for the first time to wrap water droplets (either plugs or spheres) on flow-focusing microfluidic chips. The IL, 1-butyl-3-methylimidazolium hexafluorophosphate ([BMIM][PF6]), could wet both hydrophilic and hydrophobic channel surfaces because of its dual role of hydrophilicity/hydrophobicity and extremely high viscosity, thus offering the possibility of wrapping water droplets in totally hydrophilic (THI), moderately hydrophilic (MHI), and hydrophobic (HO) channels. The droplet shape could be tuned from plug to sphere, with the volume from 6.3 nL to 65 pL, by adding an orifice in the focusing region, rendering the hydrophilic channel surface hydrophobic, and suppressing the Uw/UIL ratio below 1.0. Three different breakup processes were defined and clarified, in which the sub-steady breakup and steady breakup were essential for the formation of plugs and spheric droplets, respectively. The influences of channel hydrophilicity/hydrophobicity on droplet formation were carefully studied by evaluating the wetting abilities of water and IL on different surfaces. The superiority of IL over water in wetting hydrophobic surface led to the tendency of forming small, spheric aqueous droplets in the hydrophobic channel. This IL-favored droplet-based system represented a high efficiency in water/IL extraction, in which rhodamine 6G was extracted from aqueous droplets to [BMIM][PF6] in the hydrophobic orifice-included (HO-OI) channel in 0.51 s.

The self-assembled growth of vertically well-aligned ZnO nanorod arrays with uniform length and diameter on Si substrate has been demonstrated via thermal evaporation and vapor-phase transport. The structural, photoluminescence (PL), and field emission properties of the as-prepared nanorod arrays were investigated. The PL spectrum at 10 K shows a strong and sharp near-band gap emission (NBE) peak ( full width at half-maximum (FWHM) = 4.7 meV) and a weak neglectable deep-level emission (DL) peak (I-NBE/I-DL= 220), which implies its good crystallinity and high optical quality. The room-temperature NBE peak was deduced to the composition of free exciton and its first-order replicas emissions by temperature-dependent PL spectra. The field emission measurements indicate that, with a vacuum gap of 400 Am, the turn-on field and threshold field is as low as 2.3 and 4.2 V/mu m. The field enhancement factor beta and vacuum gap d follows a universal equation.

Microscale wide and millimeters long comblike ZnO single crystals with well-aligned cuboid nanobranches were fabricated using a double-tube simple thermal evaporation method without the presence of...