Micropattern Fabricated by Acropetal Migration Controlled through Sequential Photo and Thermal Polymerization.

Bottom-up patterning technology plays a significant role in both nature and synthetic materials, owing to its inherent advantages such as ease of implementation, spontaneity, and noncontact attributes, etc. However, constrained by the uncontrollability of molecular movement, energy interaction, and stress, obtained micropatterns tend to exhibit an inevitable arched outline, resulting in the limitation of applicability. Herein, inspired by auxin's action mode in apical dominance, a versatile strategy is proposed for fabricating precision self-organizing micropatterns with impressive height based on polymerization-induced acropetal migration. The copolymer containing fluorocarbon chains (low surface energy) and tertiary amine (coinitiator) is designed to self-assemble on the surface of the photo-curing system. The selective exposure under a photomask establishes a photocuring boundary and the radicals would be generated on the surface, which is pivotal in generating a vertical concentration difference of monomer. Subsequent heating treatment activates the material continuously transfers from the unexposed area to the exposed area and is accompanied by the obviously vertical upward mass transfer, resulting in the manufacture of a rectilinear profile micropattern. This strategy significantly broadens the applicability of self-organizing patterns, offering the potential to mitigate the complexity and time-consuming limitations associated with top-down methods.

Effect of ionic groups on the morphology and transport properties in a novel perfluorinated ionomer containing sulfonic and phosphonic acid groups: a molecular dynamics study.

Combining the phosphonic acid group with the sulfonic acid group in PEMs has been shown to be an effective strategy for improving the fuel cell performance. However, the interplay of two different ionic groups and the resulting effect on the membrane properties have not been fully elucidated. Here, we used classical molecular dynamics simulation to investigate the morphologies, transport properties and effects of ionic groups in a novel perfluorinated PEM containing two ionic groups (PFSA-PFPA) in comparison to the corresponding homopolymers. Phase separations between hydrophilic and hydrophobic domains are confirmed in these PEMs and result from the evolution of water clusters formed around the ionic groups. The combination of both ionic groups brings a complicated morphological feature in PFSA-PFPA, with near-cylindrical aqueous domains of large length scales interconnected by tortuous domains of small sizes. And we found that the self-diffusion coefficients of water molecules are strongly related to morphologies, with the water transport in PFSA-PFPA lying between two analogous homopolymers. At the molecular level, we found that the sulfonic and phosphonic acid groups have distinct effects on the coordination behaviors and the dynamics of water molecules and hydronium ions. Strong electrostatic interactions lead to compact coordination structures and sluggish dynamics of hydronium ions around phosphonic acid groups, which determine the morphological evolution and transport properties in PFSA-PFPA. Our study affords insights into the relationship between molecular characteristics and transport properties bridged by phase-separated morphologies in a novel PEM containing both sulfonic acid and phosphonic acid groups, which deepens the understanding of the interplay between two ionic groups and may inspire the rational design of high-performance PEMs.

Light-driven dynamic surface wrinkles for adaptive visible camouflage.

Camouflage is widespread in nature, engineering, and the military. Dynamic surface wrinkles enable a material the on-demand control of the reflected optical signal and may provide an alternative to achieve adaptive camouflage. Here, we demonstrate a feasible strategy for adaptive visible camouflage based on light-driven dynamic surface wrinkles using a bilayer system comprising an anthracene-containing copolymer (PAN) and pigment-containing poly (dimethylsiloxane) (pigment-PDMS). In this system, the photothermal effect-induced thermal expansion of pigment-PDMS could eliminate the wrinkles. The multiwavelength light-driven dynamic surface wrinkles could tune the scattering of light and the visibility of the PAN film interference color. Consequently, the color captured by the observer could switch between the exposure state that is distinguished from the background and the camouflage state that is similar to the surroundings. The bilayer wrinkling system toward adaptive visible camouflage is simple to configure, easy to operate, versatile, and exhibits in situ dynamic characteristics without any external sensors and extra stimuli.

Facile Synthesis of 2D SiOx -3D Si Hybrid Anode Materials by Ca Modification Effect for Enhanced Lithium Storage Performance.

Al-Si dealloying method is widely used to prepare Si anode for alleviating the issues caused by a drastic volume change of Si-based anode. However, this method suffers from the problems of low Si powder yield (<20 wt.% Si) and complicated cooling equipment due to the hindrance of large-size primary Si particles. Here, a new modification strategy to convert primary Si to 2D SiOx nanosheets by introducing a Ca modifier into Al-Si alloy melt is presented. The thermodynamics calculation shows that the primary Si is preferentially converted to CaAl2 Si2 intermetallic compound in Al-Si-Ca alloy system. After the dealloying process, the CaAl2 Si2 is further converted to 2D SiOx nanosheets, and eutectic Si is converted to 3D Si, thus obtaining the 2D SiOx -3D Si hybrid Si-based materials (HSiBM). Benefiting from the modification effect, the HSiBM anode shows a significantly improved electrochemical performance, which delivers a capacity retention of over 90% after 100 cycles and keeps 98.94% capacity after the rate test. This work exhibits an innovative approach to produce stable Si-based anode through Al-Si dealloying method with a high Si yield and without complicated rapid cooling techniques, which has a certain significance for the scalable production of Si-based anodes.

Closed-Loop Recycling of Vinylogous Urethane Vitrimers.

Devising energy-efficient strategies for the depolymerization of plastics and the recovery of their structural components in high yield and purity is key to a circular plastics economy. Here, we report a case study in which we demonstrate that vinylogous urethane (VU) vitrimers synthesized from bis-polyethylene glycol acetoacetates (aPEG) and tris(2-aminoethyl)amine can be degraded by water at moderate temperature with almost quantitative recovery (≈98 %) of aPEG. The rate of depolymerization can be controlled by the temperature, amount of water, molecular weight of aPEG, and composition of the starting material. These last two parameters also allow one to tailor the mechanical properties of the final materials, and this was used to access soft, tough, and brittle vitrimers, respectively. The straightforward preparation and depolymerization of the aPEG-based VU vitrimers are interesting elements for the design of polymer materials with enhanced closed-loop recycling characteristics.

Chemical Upcycling of Conventional Polyureas into Dynamic Covalent Poly(aminoketoenamide)s.

The chemical upcycling of polymers is an emerging strategy to transform post-consumer waste into higher-value chemicals and materials. However, on account of the high stability of the chemical bonds that constitute their main chains, the chemical modification of many polymers proves to be difficult. Here, we report a versatile approach for the upcycling of linear and cross-linked polyureas, which are widely used because of their high chemical stability. The treatment of these polymers or their composites with acetylacetone affords di-vinylogous amide-terminated compounds in good yield. These products can be reacted with aromatic isocyanates, and the resulting aminoketoenamide bonds are highly dynamic at elevated temperatures. We show here that this conversion scheme can be exploited for the preparation of dynamic covalent poly(aminoketoenamide) networks, which are healable and reprocessable through thermal treatment without any catalyst.

Anode-Free Lithium Metal Batteries Based on an Ultrathin and Respirable Interphase Layer.

Anode-free lithium (Li) metal batteries are desirable candidates in pursuit of high-energy-density batteries. However, their poor cycling performances originated from the unsatisfactory reversibility of Li plating/stripping remains a grand challenge. Here we show a facile and scalable approach to produce high-performing anode-free Li metal batteries using a bioinspired and ultrathin (250 nm) interphase layer comprised of triethylamine germanate. The derived tertiary amine and Lix Ge alloy showed enhanced adsorption energy that significantly promoted Li-ion adsorption, nucleation and deposition, contributing to a reversible expansion/shrinkage process upon Li plating/stripping. Impressive Li plating/stripping Coulombic efficiencies (CEs) of ≈99.3 % were achieved for 250 cycles in Li/Cu cells. In addition, the anode-free LiFePO4 full batteries demonstrated maximal energy and power densities of 527 Wh kg-1 and 1554 W kg-1 , respectively, and remarkable cycling stability (over 250 cycles with an average CE of 99.4 %) at a practical areal capacity of ≈3 mAh cm-2 , the highest among state-of-the-art anode-free LiFePO4 batteries. Our ultrathin and respirable interphase layer presents a promising way to fully unlock large-scale production of anode-free batteries.

Wavelength-Selective Photo-Cycloadditions of Styryl-Anthracene.

Light-tunable covalent chemistry is highly urgent in the fields of chemistry, biology, and materials science, especially for the smart materials and surface, due to the spatiotemporal control and feasible operation. Here, a new type of wavelength-selective photo-cycloaddition of styryl-anthracene carboxylic acid (SACA) is reported. Upon the irradiation of 450 nm visible light or 365 nm UV light, SACA can undergo [2+2] or [2+4] photocycloaddition, respectively. Furthermore, the [2+2] photocycloaddition induced by vis-light of 450 nm is reversible and can be disrupted by 365 nm UV light to form dimer-24 which cannot be photo-cleavable. Owing to the feasibility and spatiotemporal characteristics of UV-vis light-controlled photocycloaddition, the SACA possesses potential applications in various areas such as self-assembly, dynamic wrinkles, and fluorescence patterns, which are also explored and exhibited in this work.

DEM Study of the Motion Characteristics of Rice Particles in the Indented Cylinder Separator.

The precise separation of rice particles is an important step in rice processing. In this paper, discrete element simulations of the motion of rice particles of different integrity in an indented cylinder separator were carried out using numerical simulation methods. The effects of single factors (cylinder rotation rate, cylinder axial inclination angle, and collection trough inclination angle) on the motion trajectories of particles are investigated and the probability distribution functions of particles are obtained. The statistical method of Kullback-Leibler divergence is used to quantitatively evaluate the differences in the probability distribution functions of the escape angles of particles of different degrees of integrity. The purpose of this paper is to determine the optimum parameters for an indent cylinder separator by understanding the material cylinder separating process from particle scale and to provide a basis for the numerical design of a grain particle cylinder separators.

Maturity Stage Discrimination of Camellia oleifera Fruit Using Visible and Near-Infrared Hyperspectral Imaging.

The maturity of Camellia oleifera fruit is one of the most important indicators to optimize the harvest day, which, in turn, results in a high yield and good quality of the produced Camellia oil. A hyperspectral imaging (HSI) system in the range of visible and near-infrared (400-1000 nm) was employed to assess the maturity stages of Camellia oleifera fruit. Hyperspectral images of 1000 samples, which were collected at five different maturity stages, were acquired. The spectrum of each sample was extracted from the identified region of interest (ROI) in each hyperspectral image. Spectral principal component analysis (PCA) revealed that the first three PCs showed potential for discriminating samples at different maturity stages. Two classification models, including partial least-squares discriminant analysis (PLS-DA) and principal component analysis discriminant analysis (PCA-DA), based on the raw or pre-processed full spectra, were developed, and performances were compared. Using a PLS-DA model, based on second-order (2nd) derivative pre-processed spectra, achieved the highest results of correct classification rates (CCRs) of 99.2%, 98.4%, and 97.6% in the calibration, cross-validation, and prediction sets, respectively. Key wavelengths selected by PC loadings, two-dimensional correlation spectroscopy (2D-COS), and the uninformative variable elimination and successive projections algorithm (UVE+SPA) were applied as inputs of the PLS-DA model, while UVE-SPA-PLS-DA built the optimal model with the highest CCR of 81.2% in terms of the prediction set. In a confusion matrix of the optimal simplified model, satisfactory sensitivity, specificity, and precision were acquired. Misclassification was likely to occur between samples at maturity stages two, three, and four. Overall, an HSI with effective selected variables, coupled with PLS-DA, could provide an accurate method and a reference simple system by which to rapidly discriminate the maturity stages of Camellia oleifera fruit samples.

Photo-Oxidation-Controlled Surface Pattern with Responsive Wrinkled Topography and Fluorescence.

Wrinkles and photo-oxidation reactions are widely found in soft materials, which are intimately associated with the failure of materials and structures. It is expected that the photo-oxidation process could also have a positive effect on the material and its surface. Here, we report the photo-oxidation of 2-(4-dietheylaminophenyl)-4,5-bis(4-methoxyphenyl) imidazole (DEA-TAI) into a wrinkled bilayer system to control surface wrinkle and fluorescent patterns, in which a supramolecular polymer network composed of carboxylic acid-containing copolymer (PS-BA-AA; PS=poly(styrene), BA=butyl acrylate; AA=acrylic acid) and DEA-TAI were used as the skin layer. Ultraviolet (UV) irradiation can induce photo-oxidation of the imidazole ring of DEA-TAI to weaken the intermolecular hydrogen bonding between PS-BA-AA and DEA-TAI, resulting in the release of stress in the bilayer system. The wrinkled morphology and fluorescence of the surface can be simultaneously regulated by photo-oxidation of DEA-TAI under UV light, and the resulting wrinkles are extremely sensitive to the pH value, which can be quickly and reversibly erased by NH3 gas. Smart surfaces with specific hierarchical wrinkles and fluorescence can be achieved by selective irradiation with photomasks, which may find potential applications in smart displays and multi-code information storage.

Effects of a 4-year intervention on hand hygiene compliance and incidence of healthcare associated infections: a longitudinal study.

PURPOSE: Studies have demonstrated improvements in hand hygiene (HH) compliance through interventions, noting the negative association of HH and healthcare associated infections (HAIs), but how to sustain long-term improvement is still unknown in the Chinese population. This study sought to determine the extent of change in HH compliance after multimodal HH interventions, and to evaluate the relationship between that change and HAI incidence. METHODS: We conducted a longitudinal study in a general teaching hospital in China from 2017 to 2020. Trained investigators observed HH practices based on the World Health Organization's 5 moments for HH. We identified the incidence of HAIs using semi-automated constant surveillance software. We used the Cochran-Mantel-Haenszel test to assess the secular trend of HH compliance and HAIs. The Spearman correlation coefficient (rs) was used to evaluate the relationship between the incidence of HAIs and compliance with HH. RESULTS: The study made 480,943 observations, where HH was occurring between 2017 and 2020. HH compliance increased from 68.90 to 91.76% during that period (Ptrend < 0.01), while the incidence of HAIs decreased from 1.10 to 0.91%. Compliance also increased for each moment type and for each healthcare worker (Ptrend < 0.01). Lower HH compliance was observed in before-patient contact and after contact with patient surroundings, and among interns and cleaners. We also observed a weak but statistically significant negative correlation between the monthly HH compliance and incidence of HAIs (rs = - 0.27; P = 0.037). CONCLUSIONS: The multimodal HH implementation delivered sustained improvement in HH compliance, and this change was associated with a decline in the incidence of HAIs.

Aminoesterenamide Achieved by Three-Component Reaction Heading toward Tailoring Covalent Adaptable Network with Great Freedom.

Covalent adaptable networks (CANs) have recently received extensive interests due to their reprocessability and repairability. Rethinking the libraries of the published CANs, most of them are fabricated by one/two-component reactions and few cases utilize multi-component reactions to construct CANs while multi-component reactions are conductive to tailoring the properties of polymers due to their structural designability and flexible choice of raw materials. A novel kind of dynamic covalent bond named aminoesterenamide is presented through three-component reaction between acetoacetyl, amine and isocyanate. Aminoesterenamide exhibits thermal reversibility through dissociating into vinylogous urethane and isocyanate. When it is used to prepare CANs, the synthesized polymer networks can be reprocessed many times via the exchange reaction between aminoesterenamides. Moreover, the forming of aminoesterenamide involving three starting components imparts CANs with great freedom to tailor their properties. Therefore, the authors believe this method that utilizes three-component reaction to fabricate CANs would bring new stories and perspectives to the exploration of new types of CANs.

Smart Patterned Surface with Dynamic Wrinkles.

Patterned surfaces are fundamentally important to physics, chemistry, materials, and biology science, endowing significant functions and thus bearing broad and fantastic applications whether in natural or man-made events. Among the various methods for patterning surfaces, wrinkling or buckling offers a powerful alternative to prepare surface patterns because of its spontaneous nature, versatility, easy preparation in large-scale, and capability to be responsive to various stimuli. In particular, patterned surfaces with dynamic wrinkles can tailor the encoded surface properties on demand and can provide a promising alternative for smart surfaces, which has potential for wide applications in enhanced and tunable optical or photoelectric devices, responsive microstructures, switchable wettability, smart adhesion and friction, and so on. The concept of smart patterned surfaces based on dynamic wrinkles is fundamental and versatile, and it is expected that there will be extensive future work based on this concept in generalizing this work to other smart materials and systems, and in using dynamic pattern systems to tune not only morphology but also functional properties encoded in the system's topography. In this Account, we present recent progress on smart surfaces with dynamic wrinkle patterns, including their design, preparation, and potential applications. First, we provide a brief introduction of a basic concept for mechanical instability induced wrinkle patterns and outline the general strategies and mechanics for dynamic wrinkles. Then, we discuss how the wrinkling and dewrinkling processes of a rigid skin bound to a soft substrate in bilayers or gradient layer systems occur by controlling the mechanical properties and geometric characteristics of the top and bulk layers, thereby paving the way for a smart patterned surface using chemical and physical approaches. Next, we discuss various chemical and physical stimuli, including light, temperature, pH, and chemicals, which can be harnessed into an extensive library of complex dynamic wrinkles. We highlight recent advances in preparing multiresponsive dynamic wrinkling patterns by adjusting the intrinsic properties of the skin layers (i.e., Young's modulus and cross-linking density) via dynamic chemistry, such as the Diels-Alder reaction, photodimerization, and supramolecular chemistry. Then, we outline how functional inclusions, such as photothermic or photoelectric additives and magnetic nanoparticles, can enable the composite elastic substrate as a dynamic platform for various functional top-layers to fabricate a smart surface for a desired function. In particular, photothermally reconfigurable wrinkle systems were investigated, where the carbon nanotube (CNT) served to efficiently convert its absorbed light energy into heat, hence actuating a real-time response of a near-infrared light (NIR)-sensitive wrinkle pattern and providing access to the development of advanced optoelectronic devices. In addition, based on their unique characteristics, applications of dynamic wrinkle patterns for smart displays, memory, flexible electronics, dynamic gratings, tunable adhesion, friction, and wettability are presented. Finally, we conclude by offering our perspective on future developments of this rapidly evolving field.

miR-32 promotes esophageal squamous cell carcinoma metastasis by targeting CXXC5.

MicroRNA-32 (miR-32) functioned as a tumor oncogene in some cancer, which control genes involved in important biological and pathological functions and facilitate the tumor growth and metastasis. However, the role of miR-32 modulates esophageal squamous cell carcinoma (ESCC) malignant transformation has not been clarified. Here, we focused on the function and the underlying molecular mechanism of miR-32 in ESCC. Results discovered a significant increased expression of miR-32 in ESCC tissues and cells. Downregulation of miR-32 inhibited the migration, invasion, adhesion of ESCC cell lines (EC9706 and KYSE450), and the levels of EMT protein in vitro. In vivo, miR-32 inhibitors decrease tumor size, tumor weight, and the number of metastatic nodules. Hematoxylin and eosin (H&E) results revealed that inhibition of miR-32 attenuate lung metastasis. Immunohistochemistry and immunofluorescence assay showed increased level of E-cadherin and decreased level of N-cadherin and Vimentin with treatment of miR-32 inhibitors. Furthermore, miR-32 targeted the 3'-untranslated region (3'-UTR) of CXXC5, and inhibited the level of mRNA and protein of CXXC5. There is a negative correlation between the expressions of CXXC5 and miR-32. Then, after EC9706 and KYSE450 cells cotransfected with si-CXXC5 and miR-32 inhibitors, the ability of cell migration, invasion, and adhesion was significantly reduced. In addition, the protein expression of EMT and TGF-ß signaling was also depressed. Collectively, these data supply an insight into the positive role of miR-32 in ESCC progression and metastasis, and its biological effects may attribute the inhibition of TGF-ß signaling mediated by CXXC5.

Tumor-suppressive microRNA-10a inhibits cell proliferation and metastasis by targeting Tiam1 in esophageal squamous cell carcinoma.

Aberrant microRNAs (miRNAs) expressions could contribute to the progression of numerous cancers, including esophageal squamous cell carcinoma, while miR-10a participates in multiple biological processes on cancers. However, the molecular mechanism of miR-10a in esophageal squamous cell carcinoma (ESCC) has not been investigated. Herein, miR-10a was significantly reduced in ESCC clinical tissues and ESCC cell lines (EC109 and TE-3). In addition, immunohistochemistry indicated that the expressions of α-SMA, Ki-67, and PCNA in tumor tissues were higher than that of controls. In vitro, overexpression of miR-10a dramatically suppressed cell proliferation and enhanced cell apoptosis, while the decrease of miR-10a expressed the opposite outcome. Specially, overexpression of miR-10a caused a G0/G1 peak accumulation. Moreover, miR-10a also negatively regulated ESCC cell migration and invasion. Furthermore, targetscan bioinformatics predictions and the dual-luciferase assay confirmed that Tiam1 was a direct target gene of miR-10a. The statistical analysis showed Tiam1 was negatively in correlation with miR-10a in ESCC patient samples. And silencing Tiam1 could lead to a decline on cell growth, invasion, and migration in ESCC cell lines, while it could enhance cell apoptosis and cause a G0/G1 peak accumulation. In vivo, it revealed that miR-10a notably decreased the tumor growth and metastasis in xenograft model and pulmonary metastasis model. And it showed a lower expressions of Tiam1 in the miR-10a mimics group by immunohistochemistry. Taken together the results, they indicated that miR-10a might function as a novel tumor suppressor in vitro and in vivo via targeting Tiam1, suggesting miR-10a to be a candidate biomarker for the ESCC therapy.

Multifunctional Polymer Sponge with Molecule Recognition: Facile Mechanic Induced Separation.

Polymer sponges with molecular recognition provide a facile approach to water purification and industrial separation with easy operation, but its fabrication is still challenging because some critical issues of selective adsorption, high mechanical strength, and easy collection/re-use are difficult to be achieved in one material. Here, inspired by natural sponges, novel multifunctional polymer sponges were developed which were fabricated by ice-templating with multifunctional amine polyethylenimine and diepoxide cross-linker poly(ethylene glycol) diglycidyl ether for highly efficient harvesting of dyes and simultaneous pure water recovery both in mechanic pressing and filtration processes. The as-prepared sponge (SP-1) was further modified by poly(caffeic acid) through a simple dipping-cross-linking process to obtain the hybrid polymer sponge (SP-2), which showed higher compressive strength than SP-1. These sponges possessed a cross-linked three-dimensional macroporous structure with quick water absorbing properties over ten times of their own weight within 20 s directed by capillary. The adsorption behavior of the obtained polymer sponges to 11 hydrophilic dyes was studied in detail by mechanic induced separation. All these polymer sponges exhibited a high selective adsorption to hydrophilic dyes in water. For example, SP-1 has high adsorption capacity over 150 µmol/g to erythrosin B, which is 20 times higher than that of calcein. With the modified poly(caffeic acid) layer, SP-2 exhibited different adsorption properties for methylene blue (180 µmol/g) to SP-1 (∼0 µmol/g), indicating that the tailorable structures of the sponge can regulate their selectivity to guest molecules. Based on the unique recognition to guest molecules, the methodology of dynamic separation of the dye's mixture in water was demonstrated by using these sponges through mechanical pressing or fast filtration, which provides a facile alternative with easy operation for water purification.

Polymeric nanofiber coating with tunable combinatorial antibiotic delivery prevents biofilm-associated infection in vivo.

Bacterial biofilm formation is a major complication of implantable medical devices that results in therapeutically challenging chronic infections, especially in cases involving antibiotic-resistant bacteria. As an approach to prevent these infections, an electrospun composite coating comprised of poly(lactic-coglycolic acid) (PLGA) nanofibers embedded in a poly(ε-caprolactone) (PCL) film was developed to locally codeliver combinatorial antibiotics from the implant surface. The release of each antibiotic could be adjusted by loading each drug into the different polymers or by varying PLGA:PCL polymer ratios. In a mouse model of biofilm-associated orthopedic-implant infection, three different combinations of antibiotic-loaded coatings were highly effective in preventing infection of the bone/joint tissue and implant biofilm formation and were biocompatible with enhanced osseointegration. This nanofiber composite-coating technology could be used to tailor the delivery of combinatorial antimicrobial agents from various metallic implantable devices or prostheses to effectively decrease biofilm-associated infections in patients.

Interfacial Activity of Amine-Functionalized Polyhedral Oligomeric Silsesquioxanes (POSS): A Simple Strategy To Structure Liquids.

Amine-functionalized polyhedral oligomeric silsesquioxane (POSS), the smallest, monodisperse cage-shaped silica cubic nanoparticle, is exceptionally interfacially active and can form assemblies that jam the toluene/water interface, locking in non-equilibrium shapes of one liquid phase in another. The packing density of the amine-functionalized POSS assembly at the water/toluene interface can be tuned by varying the concentration, the pH value, and the degree of POSS functionalization. Functionalized POSS gives a higher interface coverage, and hence a lower interfacial tension, than nanoparticle surfactants formed by interactions between functionalized nanoparticles and polymeric ligands. Hydrogen-bonded POSS surfactants are more stable at the interface, offering some unique advantages for generating Pickering emulsions over typical micron-sized colloidal particles and ligand-stabilized nanoparticle surfactants.

miR-184 Inhibits Tumor Invasion, Migration and Metastasis in Nasopharyngeal Carcinoma by Targeting Notch2.

BACKGROUND/AIMS: A recent study found that dysregulated microRNA-184 (miR-184) is involved in the proliferation and survival of nasopharyngeal carcinoma (NPC). This study aimed to evaluate the detailed mechanisms of invasion, migration and metastasis of NPC cells. METHODS: Quantitative reverse-transcription PCR (qRT-PCR) and Western blot were used to confirm the expression levels of miR-184 and Notch2. NPC cell invasion and migration were subsequently examined using in vitro cell invasion and wound-healing assays, respectively. MicroRNA (miRNA) target gene prediction databases and dual-luciferase reporter assay were adopted to validate the target genes of miR-184. RESULTS: MiR-184 was downregulated in the NPC cell lines. The miR-184 inhibitor increased the number of invading NPC cells, whereas miR-184 mimics inhibited the invasive ability of such cells. The protein level of E-cadherin decreased, whereas those of N-cadherin and vimentin increased in the anti-miR-184 group. This result showed that miR-184 inhibited NPC cell invasion and metastasis by regulating EMT progression. MiRNA target gene prediction databases indicated the potential of Notch2 as a direct target gene of miR-184. Such a notion was then validated by results of dual-luciferase reporter assay. Notably, shRNANotch2 restrained the EMT and partially abrogated the inhibitory effects of miR-184 on EMT progression in NPC cells. CONCLUSION: MiR-184 functions as a tumour-suppressive miRNA targeting Notch2 and inhibits the invasion, migration and metastasis of NPC.