Nanospheres Research Articles

Fabrication of a tailorable polystyrene nanoscale mesh of honeycomb morphology using nano sphere lithography

Surface morphology of a substrate is altered to achieve adhesion-, thermal-, electrical-, electrochemical- and optical-enhancements in many applications in the field of interfacial engineering. This study presented an approach based on nanosphere lithography (NSL) to produce a tailorable polystyrene (PS) nanoscale mesh with ‘honeycomb’ morphology. First, silica nanoparticles of uniform-size, ranging from 100 to 1500 nm, were synthesized using Stober method. These silica nanoparticles were made to self-assemble on a silicon wafer to form a 2-D hexagonal-packed array through spin coating. The process parameters were optimized at every fabrication step to ensure the monolayer formation of silica nanospheres on a silicon wafer. The inter-particle space in the monolayer was filled with PS without covering the silica nanospheres using dewetting. The etching of silica nanospheres in the subsequent step resulted in the fabrication of PS honeycomb nano-mesh. Such PS honeycomb mesh can be used as a mask or etch-resist layer for selective surface treatments (physical or chemical) in many applications to create a periodic and controllable surface topography. As the NSL is highly inexpensive and the PS for the purpose of etch mask can be obtained directly from waste materials, the PS honeycomb mesh can be produced at very low-cost.

Facile electrodeposition of Ni3(BO3)2 nanospheres on Ti mesh for high-performance asymmetric supercapacitors

The construction of cost-effective, efficient, and sustainable energy storage systems is extremely important for future fuels globally. Nickel borates display important characteristics in electrochemical catalytic applications, whereas few reports have focused on their energy storage properties in supercapacitors. Herein, Ni3(BO3)2 nanospheres (NSs) are fabricated on titanium (Ti) mesh to afford Ni3(BO3)2NSs@Ti using a simple and scalable electrodeposition technique, whose electrochemical performance is carefully studied. The Ni3(BO3)2NSs@Ti obtained at 1.2 V (Ni3(BO3)2 NSs-1.2V) exhibits a higher specific capacitance of 663 F g−1 with a current density of 0.5 A g−1. Furthermore, by directly employing Ni3(BO3)2 NSs-1.2V as the positive electrode and activated carbon as the negative electrode, an asymmetric supercapacitor (ASC) device can be fabricated and displays the energy density up to 30.6 Wh kg−1 at the power density of 400 W kg−1. Hence, the facile electrodeposited Ni3(BO3)2 NSs can be a potential platform for energy storage applications.

Chitosan/Cyclodextrin Nanospheres for Potential Nose-to-Brain Targeting of Idebenone.

Idebenone (IDE) is a powerful antioxidant that is potentially active towards cerebral diseases, but its low water solubility and fast first pass metabolism reduce its accumulation in the brain, making it ineffective. In this work, we developed cyclodextrin-based chitosan nanospheres (CS NPs) as potential carriers for nose-to-brain targeting of IDE. Sulfobutylether-β-cyclodextrin (SBE-β-CD) was used as a polyanion for chitosan (CS) and as a complexing agent for IDE, permitting its encapsulation into nanospheres (NPs) produced in an aqueous solution. Overloading NPs were obtained by adding the soluble IDE/hydroxypropyl-β-CD (IDE/HP-β-CD) inclusion complex into the CS or SBE-β-CD solutions. We obtained homogeneous CS NPs with a hydrodynamic radius of about 140 nm, positive zeta potential (about +28 mV), and good encapsulation efficiency and drug loading, particularly for overloaded NPs. A biphasic release of IDE, finished within 48 h, was observed from overloaded NPs, whilst non-overloaded CS NPs produced a prolonged release, without a burst effect. In vitro biological studies showed the ability of CS NPs to preserve the antioxidant activity of IDE on U373 culture cells. Furthermore, Fourier transform infrared spectroscopy (FT-IR) demonstrated the ability of CS NPs to interact with the excised bovine nasal mucosa, improving the permeation of the drug and potentially favoring its accumulation in the brain.

Biomolecules adsorption to trigger the self-assembly of nanospheres and nanorods

HypothesisThe self-assembly (SA) of nanostructures triggered by the adsorption of biomolecules (BSA) is investigated as a platform to develop diagnostics and functional applications. Mixing nanostructures of different morphologies; SiO2 nanospheres (NS) to a cellulose nanorod crystals (CNC) leads to the formation of short range ordered domains in the dried film. Adding biomolecules-treated SiO2 NS into the CNC develop the long range ordered assembly in the composite film. ExperimentsThe CNC-SiO2 composite films were prepared by mixing CNC suspension (3 wt%) with the SiO2 NS of different concentration (0.5–5 mg/mL) followed by drying at the ambient conditions. The CNC-SiO2 @BSA films are prepared by first mixing the BSA (1 mg/mL) with the SiO2 suspension of different concentrations. Later the SiO2 @BSA suspension was mixed with the CNC and left for drying at the ambient conditions. The self-assembly mechanisms of CNC, SiO2 and BSA are studied by combining SEM, DLS, UV-Vis, QCM-D and SAXS analysis. FindingsThe SA mechanism of aqueous suspensions of CNC blended with SiO2 NS pre-treated with BSA (by adsorption) is studied by a combination of small angle X-ray scattering (SAXS), scanning electron microscopy (SEM), UV-Vis spectroscopy (UV-Vis), dynamic light scattering (DLS) and quartz crystal microbalance with dissipation (QCM-D). Both CNC and SiO2 NS are negatively charged and have demonstrated self-assembly ability driven from a combination of long- and short- range order arrangement. Adding SiO2 NS to a CNC suspension disrupts the original SA of both CNC and SiO2, which leads to the formation of small, short- range ordered domains of large polydispersity. Surprisingly, adding BSA-treated SiO2 NS into the CNC network enhances the arrangement of CNC and NS towards a new system with long range ordered assembly. The SA mechanisms of cellulose-SiO2 composites result from the balance of electrostatic repulsion and van der Waal attraction in the structure factor, radial distance distribution and potential of mean force. Understanding the effect of biomolecule adsorption on the self-assembling mechanisms of CNC nanorods with SiO2 nanospheres enables the efficient engineering of catalysis, biosensors and diagnostics.

Unveiling charge dynamics of Co3S4 nanowalls/CdS nanospheres n-n heterojunction for efficient photoelectrochemical Cr(VI) detoxification and N2 fixation

Photoelectrochemical (PEC) conversion of solar energy is a sustainable and ecological approach as it offers green energy carriers, renewable fuels as well as environmental remediation. Herein, a polyaniline-coated anodized stainless-steel mesh (PANI-ASSM) was supported n-n heterojunction of CdS nanosphere (NSs)-Co3S4 nanowalls (NWs) by a simple step by step electrochemical deposition method. The PEC performance of the developed photoanode was then assessed toward Cr(VI) detoxification and N2 fixation. The PL, UV-Vis, electrochemical impedance spectroscopy (EIS), intensity-modulated photocurrent spectroscopy (IMPS), cyclic voltammetry (CV), transient photocurrent (TPC), chronopotentiometry, and Bode phase tests also proved the excellent PEC performance and significant stability of this catalyst. UV–vis, Urbach energy (UE), Mott-Schottky (M-S), and linear sweep voltammetry (LSV) results coupled to the Robert Mulliken method confirmed the formation of robust n-n CdS-NSs-Co3S4-NWs heterojunction with viable band edge potential for Cr(VI) detoxification and N2 fixation; while PANI only acted as a powerful bridge to transfer the photo-generated electrons to ASSM support. The possible mechanism was investigated by experimental and electrochemical analysis which suggested a 3-electron-coupled Cr(VI) and 6-electron-coupled N2 reduction pathway. Such a PEC exhibited considerable electrocatalytic performance due to effective electron-hole separation with an ammonia yield and Cr(VI) reduction of 12.33 µg/mol.h NH3 and 90.61%, respectively. This work presented a new paradigm for the illustrative design of promising photoanodes for renewable fuel production and detoxification performance.

Dendritic Cu2+-Doped Ca2SiO4 Nanosphere for Cancer Therapy via Double Ion Interference

Ion interference therapy (IIT) is a promising cancer treatment strategy that can reverse ion distribution via bioactive nanomaterials so as to interfere with or hinder the physiological processes such as metabolism and proliferation of tumor cells. In this study, a dendritic Cu2+-doped calcium silicate nanosphere (Ca2SiO4) loaded with ruthenium red (RuR) and disulfiram (DSF) (RD-CCP) was constructed for self-enhanced chemodynamic therapy and IIT of tumors through the combination of Cu and Ca. Under the slightly acidic environment of the tumor, dendritic RD-CCP nanospheres (NPs) rapidly collapsed, and a toxic dithiocarbamate–Cu complex was generated in situ through the chelation reaction between DSF and the co-released Cu2+ ions. ROS accumulation was promoted by Fenton-like reaction between the Cu+ ions and the high level of H2O2 and glutathione. In addition, Ca2+-overload was promoted by the combination of the input of exogenous Ca2+ and the participation of RuR, which can inhibit the Ca2+ transport channel (MCU and SERCA), therefore promoting mitochondrial damage and enhancing oxidative stress in tumor cells. Furthermore, calcium transport channel imbalance caused by oxidative stress can promote tumor calcification and necrosis. In conclusion, dendritic RD-CCP NPs can simultaneously induce a Fenton-like response and a calcium-related signal imbalance at the tumor site through the double interference of Cu2+ and Ca2+, eventually leading to rapid tumor apoptosis, which has great application potential in the clinical application of tumor therapy.

Morphologically tailored facet dependent silver nanoparticles supported α-Al2O3 catalysts for chemoselective reduction of aromatic nitro compounds

The nanoparticles surface area, intrinsic sites, exposed microcrystal shapes and lattice planes are some of the key factors in nanocatalysis. The influence of nanoparticles shape dependent had been profound effect on its catalytic activity. This study is focused on the synthesis of morphologically shape-controlled silver (Ag) nanoparticles supported on α-Al2O3 catalysts were performed. The correlation of Ag NPs with varied facets and lattice planes on the catalytic activities in chemoselective reduction of nitro compounds was investigated. Engineering the silver nanoparticles with different shapes and facets i.e., nanocubes (AgNCs), nanowires (AgNWs) and nano spheres (AgNSPs) were synthesized by using modified polyol method. It is demonstrated that there is a significant difference in their activities with respect to the shape and nanocrystal facets. The evolution of nanoshapes and the structural properties of Ag nanoparticles were analysed by SEM, TEM, HR-TEM and P-XRD techniques. From XRD, Ag nanocubes exhibited high percentage of low index (100) facets which are favourable active centers than (111) plane in nitro reduction. We observed that the silver nanocubes selectively exposed (100) facets, which are highly favorable for the enhanced catalytic activity in nitro reduction. The reaction rate of nitro phenol to amino phenol over different Ag nanoshapes are 35.01 × 10−3 min−1 (AgNCs/Al2O3), 8.28 × 10−3 min−1 (AgNWs/Al2O3), 0.65 × 10−3 min−1 (AgNSPs/Al2O3), respectively. The calculated thermodynamic parameters of the Ea values 23.6, 28.6 and 29.4 for the AgNC, AgNWs and AgNSP respectively.

Shape-controlled and undercoordinated site-abundant Ru nanocrystals for low-temperature and additive-free benzene semi-hydrogenation

Shape manipulation of Ru nanocrystals (NCs) may afford the prominent enhancement in the catalytic performances and a well-defined catalytic model for mechanistic investigation in benzene semi-hydrogenation (BSH) by remolding the surface-atom arrangements. Herein, the Ru NCs with tailored shapes including irregular assemblies (IASs), nanospheres (NSPs), ultrathin triangle nanoplates (TNPs), and ultrathin irregular nanoplates (INPs) were fabricated, which were recognized to determine both the types and numbers of active sites. Ru IASs exposed few undercoordinated (unc) sites including atomic edges, vertexes, and defects as well as few coordinately saturated (csa) sites such as atomic terraces, while Ru NSPs primarily exposed csa sites, and Ru TNPs and Ru INPs exposed dominant and increased unc sites. Such difference contributed to a decreased order of turnover frequency (TOF) of benzene in Ru IASs > Ru INPs > Ru TNPs > Ru NSPs but an increased sequence of cyclohexene selectivity in Ru IASs < Ru NSPs < Ru TNPs < Ru INPs via manipulating the coordination configuration of benzene and so the net formation rate of cyclohexene. The initial selectivity toward cyclohexene (S0) attained to 90.6% on Ru INPs exposed most unc sites under green conditions, evidencing its high catalytic efficiency in BSH.

Regulating electronic environment on alkali metal-doped Cu@NS-SiO2 for selective anisole hydrodeoxygenation

Lignin utilization is a potential approach for replacing fossil energy and releasing the environment pressure. Herein, we synthesized a series of novel Cu-based catalysts, Cu@NS-SiO2 (NS = nano sphere) and alkali metals (Na, K, Rb, and Cs) doped Cu@NS-SiO2, and applied them in hydrodeoxygenation reaction of anisole. High Cu dispersion was presented on all catalysts. The modification of alkali metals on Cu@NS-SiO2 significantly enhanced the electron density of Cu sites in the following order: Cs > Rb > K > Na, among which Cs decreased the Cu 2p3/2 binding energy most (by 0.7 eV). Moreover, the modification did not substantially affect the geometric structure of Cu species. This regulable electronic environment of Cu sites was crucial for selective deoxygenation and inhibiting the hydrogenation of aromatic rings in anisole, and thus promoted the selectivity of benzene. Compared with Cu@NS-SiO2 (∼59%), the highest benzene selectivity was obtained on Cs/10Cu@NS-SiO2 at ∼83%.

Plasmonic enhancement of exciton and trion photoluminescence in 2D MoS2 decorated with Au nanorods: Impact of nonspherical shape

Two-dimensional (2D) MoS2 is emerging as a promising candidate for novel optoelectronics and flexible devices, but the photoluminescence (PL) efficiency is still limited for actual photonic applications. Plasmonic enhancement is the best way to increase the PL emission of 2D materials. In this study, the PL enhancement of 2D MoS2 decorated with Au nanorods (NRs) and nanospheres (NSs) at room temperature is investigated, focusing in particular on the effect of the nonspherical shape of NRs. To have a proper comparison, both nanoparticles have very similar diameters of 13–14 nm, while the NR average length is 81 nm. After decorating with Au NRs and NSs, the average PL enhancement of few-layer MoS2 is about 4.3 and 2 times, respectively. The Raman spectra are similarly enhanced, 3.8 and 2.4 times (A1g mode), respectively. The maximal enhancement is observed for the samples with Au NRs: this feature can be related to highly localized plasmonic hot spots in vicinity of the NR tips. A strong electric field within the hot spots causes the generation of additional free electron-hole pairs and, in turn, the enhancement of exciton excitation and the increase of the PL intensity. Simultaneously, the injection of hot electrons from the metal increases the probability of trions generation, thus contributing to the PL enhancement.

Dermal Toxicity Influence of Gold Nanomaterials after Embedment in Cosmetics.

Gold nanomaterials (Au NMs) have been widely used in cosmetic products for improving the brightening, and reducing the wrinkling of, skin, etc.; however, the dermal safety of Au NMs is rarely concerned. A previous study found that cosmetics could enhance the toxicity of Au nanosheets, but different physicochemical properties of Au NMs will induce different interaction modes with ingredients of cosmetics, potentially leading to different toxicity profiles. In the present study, spherical and rodlike Au NMs were first found in commercial cosmetics, and then Au nanospheres (NSs) with different sizes and Au nanorods (NRs) with different aspect ratios were prepared to simulate these Au NMs in cosmetics and further investigate their toxicity before and after embedment in cosmetics. It was found that the primary sizes, morphologies, and optical absorptions of these Au NSs and NRs before and after embedment were similar; however, their hydrodynamic sizes and zeta potentials were noticeably different. Then, these Au NSs and NRs presented weak or no cytotoxicity against HaCaT keratinocytes, while cosmetic cream could alleviate their cytotoxicity. Moreover, the cream could enhance the accumulation of Au NSs and NRs in the skin of hairless mice, but it also alleviated the toxicological responses of Au NSs and NRs in terms of superoxide dismutase (SOD) elevation and malondialdehyde (MDA) reduction. Therefore, the embedment of Au NSs and NRs into cosmetics can alleviate the in vitro and in vivo dermal toxicities of Au NSs and NRs.

Bonding of single-layered Cu2O nanospheres on Cu substrates in irradiating near-infrared femtosecond laser pulses

We investigated the bonding mechanism of single-layered Cu2O nanospheres (NSs) on Cu thin films. When near-infrared femtosecond laser pulses were focused and irradiated on the Cu2O NS films containing the NSs and reducing agents on Cu thin film-coated Si substrates, single-layered NSs were bonded just above the substrates after rinsing the non-bonded NSs. The minimum pulse energy for the single bonding on the Cu thin film-coated Si substrates was smaller than that on Si substrates. The electromagnetic enhancement was calculated between the Cu2O NSs and Cu thin films by simulating the finite element method. The enhancement was estimated using a transverse mode of the linear polarization of the incident femtosecond laser pulses. The experimental and simulation results indicated that the single-layered NSs were bonded on the Cu thin films by femtosecond laser pulse-induced local heating and melting due to the localized plasmon enhancement between the Cu2O NSs and substrates.

Hollow Double-Shell CuCo2O4@Cu2O Heterostructures as a Highly Efficient Coreaction Accelerator for Amplifying NIR Electrochemiluminescence of Gold Nanoclusters in Immunoassay.

The evolution of electrochemiluminescence (ECL) emission amplified by coreaction accelerator in near-infrared (NIR) area has been overwhelmingly anticipated for ultrasensitive detection of disease biomarkers. Herein, the hollow double-shell CuCo2O4@Cu2O (HDS-CuCo2O4@Cu2O) heterostructures were conveniently prepared and utilized as an attractive coreaction accelerator to improve the NIR ECL performance of gold nanoclusters (AuNCs) for the first time. Benefiting from perfect-matched lattice spacing, unique Cu2O nanoparticles (NPs) were formed in situ on the layered-hollow CuCo2O4 nanospheres (NSs) to obtain HDS-CuCo2O4@Cu2O heterostructures. The formed heterojunctions supplied shorter charge transfer distance and better interfacial charge transfer efficiency as well as more effective separation performance. Consequently, HDS-CuCo2O4@Cu2O heterostructures as an admirable electroactive substrate could significantly promote the formation of sufficient coreactant intermediate radicals to react with AuNCs cationic radicals, realizing about 3-folds stronger NIR ECL response than that of individual AuNCs. In addition, the AuNCs templated by l-methionine (l-Met) exhibited NIR ECL emission around 830 nm, which could decrease the photochemical damage to even realize a nondestructive detection with improved susceptibility and circumambient adaptability. Subsequently, a well site-oriented fixation strategy utilizing HWRGWVC heptapeptide as the specific antibody immobilizer was introduced to further preserve the bioactivity of antibody on the HDS-CuCo2O4@Cu2O and AuNCs surface along with enhancing the incubation performance markedly. In view of the progressive sensing mechanism, a NIR immunosensor was obtained for the ultrasensitive analysis of CYFRA21-1, which achieved a broad linear ranging from 2 fg/mL to 50 ng/mL and a low limit of detection (LOD) of 0.67 fg/mL (S/N = 3).

Temperature and Tumor Microenvironment Dual Responsive Mesoporous Magnetic Nanospheres for Magnetothermal Effect-Induced Cancer Theranostics

Temperature and Tumor Microenvironment Dual Responsive Mesoporous Magnetic Nanospheres for Magnetothermal Effect-Induced Cancer Theranostics

Control of the morphologies of molybdenum disulfide for hydrogen evolution reaction

In this study, different morphologies of molybdenum disulfide (MoS2), including MoS2 nanoparticle (NP), MoS2 nanoflower (NF), MoS2 nanosphere (NS), MoS2 nanohollow (NH), and MoS2/MoO2 composite, are successfully synthesized via a facile-route hydrothermal process employing different solutions. The structure and chemical bonding of the different morphologies of MoS2 are investigated via X-ray diffraction (XRD), Raman spectroscopy, scanning electron microscopy (SEM), and X-ray photoelectron spectroscopy (XPS). Thereafter, the synthesized materials are applied to the hydrogen evolution reaction (HER) employing a three-electrode system in a standard acidic medium (0.5 M H2SO4). The MoS2 NH exhibits higher performance: an overpotential of −230 mV at −10 mAcm−2, a Tafel slope of 64 mVdec−1, a high double-layer capacitance (Cdl) of 11.98 mFcm−2 and larger BET surface area (22.59 m2/g), as well as super stability after stability tests, representing the best catalytic behavior among the synthesized materials. The results indicate that the electrocatalytic efficiencies of materials depend on their morphologies which is highly related to the surface area of catalysts. The results avail a novel avenue for synthesizing the various morphologies of MoS2, as well as the new morphology of MoS2 (MoS2 NH). It can be a promising material for electrocatalytic and energy-storage applications.

Facile fabrication of wafer-scale flexible SERS substrate via cryo-transferring SiO2 nanosphere multilayer into waterborne polyurethane (WPU) film

Preparing flexible Surface-Enhanced Raman Scattering (SERS) substrates with close-packed nanosphere monolayer has attracted considerable interest. Regrettably, although nanosphere (NS) multilayer can be much more easily assembled at a large area than monolayer, it has not yet been employed in the SERS field. Herein, we report the facile fabrication of wafer-scale flexible SERS substrate with NS multilayer for the first time. In detail, we cryo-transferred SiO2 NS multilayer which was easily spin-coated on host Si substrate completely into waterborne polyurethane (WPU) film, followed by air plasma etching to remove part of WPU to make only one layer of embedded SiO2 NS exposed. Cauliflower-like Au nanostructure with abundant “hot spots” was formed on NS crowns by e-beam evaporation, finally enabling the 2-inch flexible SERS substrate with a rhodamine 6G (R6G) detection limit of 10-9 M and the corresponding enhancement factor (EF) of ∼108.

Electronic and Potential Synergistic Effects of Surface-Doped P-O Species on Uniform Pd Nanospheres: Breaking the Linear Scaling Relationship toward Electrochemical Oxygen Reduction.

Developing efficient oxygen reduction reaction (ORR) electrocatalysts is critical to fuel cells and metal-oxygen batteries, but also greatly hindered by the limited Pt resources and the long-standing linear scaling relationship (LSR). In this study, ∼6 nm and highly uniform Pd nanospheres (NSs) having surface-doped (SD) P-O species are synthesized and evenly anchored onto carbon blacks, which are further simply heat-treated (HT). Under alkaline conditions, Pd/SDP-O NSs/C-HT exhibits respective 8.7 (4.3)- and 5.0 (5.5)-fold enhancements in noble-metal-mass- and area-specific activity (NM-MSA and ASA) compared with the commercial Pd/C (Pt/C). It also possesses an improved electrochemical stability. Besides, its acidic ASA and NM-MSA are 2.9 and 5.1 times those of the commercial Pd/C, respectively, and reach 65.4 and 51.5% of those of the commercial Pt/C. Moreover, it also shows nearly ideal 4-electron ORR pathways under both alkaline and acidic conditions. The detailed experimental and theoretical analyses reveal the following: (1) The electronic effect induced by the P-O species can downshift the surface d-band center to weaken the intermediate adsorptions, thus preserving more surface active sites. (2) More importantly, the potential hydrogen bond between the O atom in the P-O species and the H atom in the hydrogen-containing intermediates can in turn stabilize their adsorptions, thus breaking the ORR LSR toward more efficient ORRs and 4-electron pathways. This study develops a low-cost and high-performance ORR electrocatalyst and proposes a promising strategy for breaking the ORR LSR, which may be further applied in other electrocatalysis.

Efficient Radiative Enhancement in Perovskite Light-Emitting Devices through Involving a Novel Sandwich Localized Surface Plasmon Structure.

In recent years, CsPbX3 (X = Cl, Br, I) perovskite quantum dots (QDs) have been considered as the most promising materials for light-emitting diodes (LEDs). However, the advances of CsPbX3 quantum dot-based light emitting diodes (QLEDs) still lagged behind inorganic III-V LEDs and other organic LEDs. Herein, a strategy to improve the performances of perovskite QLEDs is reported by utilizing the localized surface plasmon resonance (LSPR) effects of Au nanospheres (NSs). It is accomplished by introducing a Au NS layer into the electron transport layer of Ca2+ -CsPbBr3 QLEDs, where the diameter and spacing of Au NSs and the interaction distance between the Ca2+ -CsPbBr3 QD and Au NS layers are modulated, according to the theoretical simulation of Finite-difference time-domain. As a result, the photoluminescence quantum yield of Ca2+ -CsPbBr3 QD layer is improved from 31.5% to 73.3%. Finally, the luminance of Ca2+ -CsPbBr3 QLEDs is improved from 16824 to 63931cd m-2 and external quantum efficiency (EQE) is improved from 4.2% to 10.5%. The radiative transition rate can be remarkably modulated from 0.7 × 107 to 6.6 × 107 s-1 . The enhancement in luminance and EQE are the best values in the LSPR modified perovskite QLEDs and the strategy offered in this work fits with other LEDs and optoelectrical devices.

Effective Combination of Isoniazid and Core-Shell Magnetic Nanoradiotherapy Against Gastrointestinal Tumor Cell Types.

IntroductionRadiotherapy is a conventional treatment for gastrointestinal tumors. However, its therapeutic effect might not be satisfactory because of factors such as radio-resistance of tumor cells and dose reduction applied to avoid damage to normal tissues. We developed a novel combination therapy involving the use of isoniazid (INH) and core-shell magnetic nanospheres (NPs) to enhance the efficacy of radiotherapy.MethodsMagnetic core-shell NPs were synthesized. The shell manganese dioxide (MnO2) reacted with intracellular glutathione to produce Mn2+, which decomposed hydrogen peroxide (H2O2) to hydroxyl radicals (·OH) in the presence of INH to produce sufficient amount of reactive oxygen species. In addition to this chemodynamic therapy, MnO2 catalyzed H2O2 to O2, which alleviated hypoxia in tumors and thus enhanced the effect of radiotherapy. In addition, iron oxide (Fe3O4) and reduced Mn2+ were potential candidates for T1–T2 dual-mode magnetic resonance imaging (MRI) with remarkable magnetic targeting ability.ResultsNPs exhibited efficient tumor targeting performance under the magnetic field and improved T1/T2 dual-mode MRI, which elevated oxygen levels without toxicity to the mice to achieve remarkable therapeutic outcomes, reaching a tumor inhibition rate of 93.2%. Moreover, chemodynamic therapy mediated by INH and NPs enhanced the therapeutic effect of radiotherapy both in vivo and in vitro.ConclusionThe results demonstrated that the combination of INH and NPs could be a novel strategy for radiosensitization with clinical potential.

Self-assembled DNA/RNA nanospheres with cascade signal amplification for intracellular MicroRNA imaging

In situ visual detection of microRNAs (miRNAs) is of great significance for early diagnosis of miRNA-related diseases. In this study, we designed a rolling circle replication-driven self-assembled nucleic acid nanosphere (NS) for imaging miRNAs in living cells, which was loaded with four functional oligonucleotides (THp, H1, H2, H3) through hybridization. The DNA/RNA NS showed excellent biocompatibility, stability and RNase H-responsiveness, enabling on-demand delivery of sensing components and live-cell applications. In the presence of the target miRNA, the cascade amplification of catalytic hairpin assembly (CHA) and hybridization chain reaction (HCR) would be triggered to generate a strong fluorescence signal. Taking miRNA 155 as a model, the developed DNA/RNA NS achieved sensitive detection of the target in vitro and in tumor cells, demonstrating the potential of miRNA-based tumor screening.