Polydopamine-Coated Copper-Doped Co3O4 Nanosheets Rich in Oxygen Vacancy on Titanium and Multimodal Synergistic Antibacterial Study.

Medical titanium-based (Ti-based) implants in the human body are prone to infection by pathogenic bacteria, leading to implantation failure. Constructing antibacterial nanocoatings on Ti-based implants is one of the most effective strategies to solve bacterial contamination. However, single antibacterial function was not sufficient to efficiently kill bacteria, and it is necessary to develop multifunctional antibacterial methods. This study modifies medical Ti foils with Cu-doped Co3O4 rich in oxygen vacancies, and improves their biocompatibility by polydopamine (PDA/Cu-Ov-Co3O4). Under near-infrared (NIR) irradiation, nanocoatings can generate •OH and 1O2 due to Cu+ Fenton-like activity and a photodynamic effect of Cu-Ov-Co3O4, and the total reactive oxygen species (ROS) content inside bacteria significantly increases, causing oxidative stress of bacteria. Further experiments prove that the photothermal process enhances the bacterial membrane permeability, allowing the invasion of ROS and metal ions, as well as the protein leakage. Moreover, PDA/Cu-Ov-Co3O4 can downregulate ATP levels and further reduce bacterial metabolic activity after irradiation. This coating exhibits sterilization ability against both Escherichia coli and Staphylococcus aureus with an antibacterial rate of ca. 100%, significantly higher than that of bare medical Ti foils (ca. 0%). Therefore, multifunctional synergistic antibacterial nanocoating will be a promising strategy for preventing bacterial contamination on medical Ti-based implants.

Ni─Co─O─S Derived Catalysts on Hierarchical N-doped Carbon Supports with Strong Interfacial Interactions for Improved Hybrid Water Splitting Performance.

Simultaneously improving electrochemical activity and stability is a long-term goal for water splitting. Herein, hierarchical N-doped carbon nanotubes on carbon nanowires derived from PPy are grown on carbon cloth, serving as a support for NiCo oxides/sulfides. The hierarchical electrodes annealed in N2 or H2/N2 display improved intrinsic activity and stability for hydrogen evolution reaction (HER) and glucose oxidation reaction. Compared with Pt/C||Ir/C in alkaline media, the glucose electrolysis assembled with electrodes exhibits a cell voltage of 1.38 V at 10 mA cm-2, durability for >12 h at 50 mA cm-2, and resistance to glucose/gluconic acid poisoning. In addition, electrocatalysts can also be applied in ethanol oxidation reactions. Systematic characterizations reveal the strong interactions between NiCo and N-doped carbon support-induced partial charge transfer at the interface and regulate the local electronic structure of active sites. Density functional theory calculations demonstrate that the synergistic effect between N-doped carbon supports, metallic NiCo, and NiCo oxides/sulfides optimize the adsorption energy of H2O and the H* free energy for HER. The energy barrier of the dehydrogenation of glucose effectively decreased. This work will attract attention to the role of metal-support interactions in enhancing the intrinsic activity and stability of electrocatalysts.

Conductive and capacitive network for enriching the exoelectrogens and enhancing the extracellular electron transfer in microbial fuel cells.

Although lots of nanomaterials modified anodes have been reported to improve the bacterial attachment and extracellular electron transfer (EET) in microbial fuel cells (MFCs), the lack of a three dimensional (3D) conductive and capacitive network severely limited MFCs performance. In this work, 3D conductive networks derived from mucor mycelia were grown on carbon cloth (CC), and capacitive FeMn phosphides/oxides were further anchored on these 3D networks by electrochemical deposition (denoted as FeMn/CMM@CC) to simultaneously address the above challenges. As a result, the multivalent metal active sites were evenly distributed on 3D conductive network, which favored the enrichment of exoelectrogens, mass transport and EET. Consequently, the as-prepared FeMn/CMM@CC anode displayed accumulated charge of 131.4C/m2, higher than bare CC. Meanwhile, FeMn/CMM@CC anode substantially promoted flavin excretion and the amounts of nano conduits. The abundance of Geobacter was 63 % on bare CC, and greatly increased to 83 % on FeMn/CMM@CC. MFCs equipped by FeMn/CMM@CC anode presented the power density of 3.06 W/m2 and coulombic efficiency (29.9 %), evidently higher than bare CC (1.29 W/m2, 7.3 %), and the daily chemical oxygen demand (COD) removal amount also increased to 92.6 mg/L/d. This work developed a facile method to optimize the abiotic-biotic interface by introducing 3D conductive and capacitive network, which was proved to be a promising strategy to modify macro-porous electrodes.

Efficacy and safety of stem cell therapy for Crohn's disease: a meta-analysis of randomized controlled trials.

PURPOSE: Small-scale clinical trials have provided evidence suggesting the effectiveness of stem-cell therapy (SCT) for patients diagnosed with Crohn's disease (CD). The objective of the research was to systematically assess the effectiveness and safety of SCT for individuals diagnosed with CD through a comprehensive review and meta-analysis. METHODS: A search was conducted in Medline (PubMed), CENTER (Cochrane Library), and Embase (Ovid) to find randomized controlled trials (RCTs) that assessed the impact of SCT on the occurrence of clinical remission (CR) and severe adverse events (SAE) among patients diagnosed with CD. The Cochrane Q test and estimation of I2 were used to assess heterogeneity among studies. After incorporating heterogeneity, a random-effects model was employed for data pooling. RESULTS: Overall, 12 RCTs involving 632 adult patients with medically refractory CD or CD-related fistula were included. In comparison with placebo or no treatment, SCT showed a greater likelihood of CR (odds ratio [OR] 2.08, 95% CI 1.39-3.12, p < 0.001) without any notable heterogeneity (I2 = 0%). Consistent results were observed in subgroup analyses based on study design, patient diagnosis, source and type of stem cells, and follow-up durations, with all p-values for subgroup analyses being greater than 0.05. The occurrence of SAE was similar among patients assigned to SCT and the placebo/no treatment cohorts (OR 0.70, 95% CI 0.37-1.33, p = 0.28; I2 = 0%). CONCLUSIONS: For patients with medically refractory CD or CD-related fistula, SCT may be an alternatively effective and safe treatment.

A Synergistic Antibacterial Study of Copper-Doped Polydopamine on Ti3C2Tx Nanosheets with Enhanced Photothermal and Fenton-like Activities.

In response to the trend of drug-resistant and super bacteria, the existing single antibacterial methods are not sufficient to kill bacteria, and the development of multifunctional antibacterial nanomaterials is urgent. Our study aims to construct copper-doped polydopamine-coated Ti3C2Tx (CuPDA@Ti3C2Tx) with an enhanced photothermal property and Fenton-like activity. The nanocomposite hydrogel consisting of CuPDA@Ti3C2Tx and alginate can improve the antioxidant activity of two-dimensional MXene nanosheets by coating them with a thin layer of PDA nanofilm. Meanwhile, Cu ions are adsorbed through the coordination of PDA-rich oxygen-containing functional groups and amino groups. Calcium ions were further used to crosslink sodium alginate to obtain antibacterial hydrogel materials with combined chemotherapy and photothermal therapy properties. The photothermal conversion efficiency of CuPDA@Ti3C2Tx is as high as 57.7% and the antibacterial rate of Escherichia coli reaches 96.12%. The photothermal effect leads to oxidative stress in bacteria, increases cell membrane permeability, and a high amount of ROS and copper ions enter the interior of the bacteria, causing protein denaturation and DNA damage, synergistically leading to bacterial death. Our study involves a multifunctional synergistic antibacterial nanodrug platform, which is conducive to the development of high-performance antibacterial agents and provides important research ideas for solving the problem of drug-resistant bacteria.

Semi-Supervised Crowd Counting via Multiple Representation Learning.

There has been a growing interest in counting crowds through computer vision and machine learning techniques in recent years. Despite that significant progress has been made, most existing methods heavily rely on fully-supervised learning and require a lot of labeled data. To alleviate the reliance, we focus on the semi-supervised learning paradigm. Usually, crowd counting is converted to a density estimation problem. The model is trained to predict a density map and obtains the total count by accumulating densities over all the locations. In particular, we find that there could be multiple density map representations for a given image in a way that they differ in probability distribution forms but reach a consensus on their total counts. Therefore, we propose multiple representation learning to train several models. Each model focuses on a specific density representation and utilizes the count consistency between models to supervise unlabeled data. To bypass the explicit density regression problem, which makes a strong parametric assumption on the underlying density distribution, we propose an implicit density representation method based on the kernel mean embedding. Extensive experiments demonstrate that our approach outperforms state-of-the-art semi-supervised methods significantly.

Enhanced microorganism attachment and flavin excretion in microbial fuel cells via an N,S-codoped carbon microflower anode.

Commonly used dense arrays of nanomaterials on carbon cloth (CC) are not suitable to accommodate microorganisms in microbial fuel cells (MFCs) due to their unmatched size. To simultaneously enrich exoelectrogens and accelerate the extracellular electron transfer (EET) process, SnS2 nanosheets were selected as sacrificial templates to prepare binder-free N,S-codoped carbon microflowers (N,S-CMF@CC) by polymer coating and pyrolysis. N,S-CMF@CC showed a cumulative total charge of 125.70C/m2, approximately 2.11 times higher than that of CC, indicating its better electricity storage capacity. Moreover, the interface transfer resistance and diffusion coefficient in bioanodes were 42.68 Ω and 9.27 × 10-10 cm2/s, respectively, superior to CC (141.3 Ω and 1.06 × 10-11 cm2/s). Remarkably, N,S-codoped carbon microflowers excreted more flavin than CC, as confirmed by continuous fluorescence monitoring. Biofilm and 16S rRNA gene sequence analysis revealed that exoelectrogens were enriched, and nanoconduits were generated on the N,S-CMF@CC anode. In particular, flavin excretion was also promoted on our hierarchical electrode, effectively driving the EET process. MFCs equipped with the N,S-CMF@CC anode could deliver a power density of 2.50 W/m2, coulombic efficiency of 22.77 %, and chemical oxygen demand (COD) removal amount of 90.72 mg/L/d, higher than that of bare CC. These findings not only demonstrate that our anode is capable of solving the cell enrichment issue, but it may also increase EET rates by bound flavin with outer membrane c-type cytochromes (OMCs) to simultaneously boost the power generation and wastewater treatment performance of MFCs.

The polyoxometalates mediated preparation of phosphate-modified NiMoO4-x with abundant O-vacancies for H2 production via urea electrolysis.

It is urgent to develop non-noble metal electrocatalysts with both excellent activity and durable stability for H2 production via water electrolysis. Electric energy is mainly consumed by the sluggish anodic oxygen evolution reaction (OER). The electrocatalytic urea oxidation reaction (UOR) has been regarded as a promising reaction to replace OER because of its small thermodynamic oxidation potential. However, developing a facile and large-scale preparation method for bifunctional hydrogen evolution reaction (HER) and UOR electrocatalysts is still challenging. Herein, phosphate-modified (4.46 atomic%) NiMoO4-x net-like nanostructures are formed on Ni foam (NF) via H3PMo12O40 etching strategy at room temperature (denoted as NF/P-NiMoO4-x). The etched NF can directly serve as HER electrode, and delivers overpotential of 116 mV at current density of 10 mA/cm2 with Tafel slope of 77.5 mV/dec. Furthermore, it displays excellent UOR activity with potential of 1.359 V at current density of 10 mA/cm2 and Tafel slope of 19.3 mV/dec. The apparent activation energy of NF/P-NiMoO4-x is 20.6 kJ/mol, lower than that of NF (37.7 kJ/mol), indicating smaller apparent barrier for CN bond cleavage in urea. The cell voltage of urea electrolysis is around 1.48 V for H2 production to deliver current density of 10 mA/cm2, and better long-term stability for 50 h than that of Ir/C||Pt/C. The etching solution can be recycled for five times by addition of H2O2, turning heteropoly blue into its original state. This work develops a facile and large-scale method to prepare bifunctional HER and UOR electrocatalysts for H2 production in a less-energy saving way via urea electrolysis.

N-Doped Carbon Nanowire-Modified Macroporous Carbon Foam Microbial Fuel Cell Anode: Enrichment of Exoelectrogens and Enhancement of Extracellular Electron Transfer.

Microbial fuel cell (MFC) performance is affected by the metabolic activity of bacteria and the extracellular electron transfer (EET) process. The deficiency of nanostructures on macroporous anode obstructs the enrichment of exoelectrogens and the EET. Herein, a N-doped carbon nanowire-modified macroporous carbon foam was prepared and served as an anode in MFCs. The anode has a hierarchical porous structure, which can solve the problem of biofilm blockage, ensure mass transport, favor exoelectrogen enrichment, and enhance the metabolic activity of bacteria. The microscopic morphology, spectroscopy, and electrochemical characterization of the anode confirm that carbon nanowires can penetrate biofilm, decrease charge resistance, and enhance long-distance electron transfer efficiency. In addition, pyrrolic N can effectively reduce the binding energy and electron transfer distance of bacterial outer membrane hemin. With this hierarchical anode, a maximum power density of 5.32 W/m3 was obtained, about 2.5-fold that of bare carbon cloth. The one-dimensional nanomaterial-modified macroporous anodes in this study are a promising strategy to improve the exoelectrogen enrichment and EET for MFCs.

3D Hierarchical Co8FeS8-FeCo2O4/N-CNTs@CF with an Enhanced Microorganisms-Anode Interface for Improving Microbial Fuel Cell Performance.

Microbial fuel cells (MFCs) are promising ecofriendly techniques for harvesting bioenergy from organic and inorganic matter. Currently, it is challenging to design MFC anodes with favorable microorganism attachment and fast extracellular electron transfer (EET) rate for high MFC performance. Here we prepared N-doped carbon nanotubes (NCNTs) on carbon felt (CF) and used it as a support for growing hierarchical Co8FeS8-FeCo2O4/NCNTs core-shell nanostructures (FeCo/NCNTs@CF). We observed improved wettability, specific areal capacitance, and diffusion coefficient, as well as small charge transfer resistance compared with bare CF. MFCs equipped with FeCo/NCNTs@CF displayed a power density of 3.04 W/m2 and COD removal amount of 221.0 mg/L/d, about 47.6 and 290.1% improvements compared with that of CF. Biofilm morphology and 16s rRNA gene sequence analysis proved that our anode facilitated the enrichment growth of exoelectrogens. Flavin secretion was also promoted on our hierarchical elelctrode, effectively driving the EET process. This work disclosed that hierarchical nanomaterials modified electrode with tailored physicochemical properties is a promising platform to simultaneously enhance exoelectrogen attachment and EET efficiency for MFCs.

Bixin Prevents Colorectal Cancer Development through AMPK-Activated Endoplasmic Reticulum Stress.

Chemicals isolated from natural products have been broadly applied in the treatment of colorectal cancer (CRC). Bixin, an apocarotenoid from the seeds of Bixa orellana, exerts multiple pharmacological properties, including neuroprotective, anti-inflammatory, cardioprotective, and antitumor effects; yet, the therapeutic effects of Bixin on CRC are still unknown. Here, we described that Bixin treatment significantly inhibited the proliferation and motility of two CRC cell lines (CaCO2 and SW480) in vitro and in vivo. In addition, Bixin administration has sensitized CRC cells to TNF-related apoptosis-inducing ligand- (TRAIL-) induced cell apoptosis. Moreover, we showed that Bixin treatment initiated the activation of PERK/eIF-2α signal in CaCO2 and SW480 cells, leading to endoplasmic reticulum stress-associated apoptosis. Pharmacological inhibition of AMP-activated protein kinase (AMPK) abrogated the Bixin-induced activation of protein kinase RNA-like endoplasmic reticulum kinase (PERK)/eukaryotic initiation factor 2 alpha (eIF-2α) pathway, as well as reversed the inhibitory effects of Bixin on CRC development. In conclusion, this study indicated that Bixin treatment inhibits the progression of CRC through activating the AMPK/PERK/eIF-2α pathway, providing a novel potential strategy for clinical prevention of CRC.

MiR-495 regulates cell proliferation and apoptosis in H2O2 stimulated rat spinal cord neurons through targeting signal transducer and activator of transcription 3 (STAT3).

BACKGROUND: MicroRNA-495 (miR-495) is a post-translational modulator that performs several functions, and it is involved in several disease states. On the other hand, the physiological functions of miR-495 in H2O2 stimulated mouse spinal cord neuronal dysfunction have not yet been fully understood. METHODS: In this study, we speculated that miR-495 may regulate the expression of STAT3 in the processes of neuronal proliferation and apoptosis following spinal cord injury (SCI). Cell viability was assessed with methyl thiazolyl tetrazolium (MTT) assay. Caspase-3 activity was assayed with ELISA. Cellular apoptotic changes were measured with TUNEL assay. Intracellular ROS production was determined by measuring uptake of dichlorodihydrofluorescein diacetate (DCFH-DA; PCR was used to assay the mRNA expression of STAT3 gene bearing predicted targeting positions for miR-495, while qRT-PCR was used to measure miR-495 mRNA. RESULTS: The results demonstrated that treatment of SCNs with H2O2 led to a significant decrease in cell survival, while it enhanced apoptosis. The H2O2 treatment induced cell membrane dysfunction, and increased ROS levels and DNA damage. Interestingly, the expression of miR-495 was markedly suppressed when SCNs were exposed to H2O2. However, miR-495 overexpression reversed H2O2-induced cytotoxicity and apoptosis in SCNs. Moreover, H2O2 exposure elevated protein and mRNA concentrations of STAT3 in SCNs. Bioinformatics analysis showed likely binding domains of miR-495 in the 3'-untranslated regions of STAT3 in SCNs. MiR-495 loss-of-function and gain-of-function significantly up-regulated and down-regulated both STAT3 mRNA and protein expressions, respectively, in SCNs. CONCLUSIONS: miR-495 overexpression inhibited H2O2-induced SCN dysfunction. This mechanism was mediated through the down-regulation of STAT3 expression.

Coaxial Ni-S@N-Doped Carbon Nanofibers Derived Hierarchical Electrodes for Efficient H2 Production via Urea Electrolysis.

Electrochemical water splitting into hydrogen is a promising strategy for hydrogen production powered by solar energy. However, the cell voltage of an electrolyzer is still too high for practical application, which is mainly limited by the sluggish oxygen evolution reaction process. To this end, hybrid water electrolyzers have drawn tremendous attention. Herein, coaxial Ni/Ni3S2@N-doped nanofibers are directly grown on nickel foam (NF), which is highly active for hydrogen evolution reaction. Meanwhile, the Ni3S2@N-doped nanofibers on NF prepared in an Ar atmosphere display superior urea oxidation reaction performance to previously reported catalysts. The cell voltage is about 1.50 V in urea electrolysis to deliver a current density of 20 mA cm-2, lower than that of a traditional water electrolyzer (1.82 V). The current density is around 77% relative to its initial value of 20 mA cm-2 after 20 h, superior to Pt/C|Ir/C-based urea electrolysis (14%). It is found that the synergistic effect between metallic Ni and Ni3S2, as well as the interfacial effect between metal centers and N-doped carbon, favors the initial dissociation of H2O and the adsorption/desorption of H* with thermal neutral Gibbs free energy. Meanwhile, the in-situ generated NiOOH on the outer surface of Ni3S2 possessed lower electrochemical activation energy for urea decomposition. Meanwhile, the abundant oxygen vacancies in electrodes could expose more active sites for the adsorption of intermediates, including H* and OOH*. It is also found that the hierarchical nanostructure of densely packed nanowires provides ideal electronic and ionic transport paths for fast electrocatalytic kinetics. The present work indicated that the modulation of compositions and hierarchical nanostructure is effective to prepare efficient catalysts for H2 production via urea electrolysis.

Oxygen Vacancy-rich Ni/NiO@NC Nanosheets with Schottky Heterointerface for Efficient Urea Oxidation Reaction.

H2 production via electrocatalytic water splitting is greatly hindered by the sluggish oxygen evolution reaction (OER). The urea oxidation reaction (UOR) draws specific attention not only because of its lower theoretical voltage of 0.37 V compared with OER (1.23 V), but also for treating sewage water. Herein, Ni/NiO nanosheets with an ultrathin N-doped C layer containing a Schottky Ni and NiO heterointerface is constructed. Because of the self-driven charge redistribution at the heterointerface, janus charge domains are successfully created to drive the cleavage of urea molecules. Meanwhile, the synergistic effect between N-doped C and Ni/NiO restrains the deactivation of active sites in alkaline solution. The catalyst displays 1.35 V for UOR at 10 mA/cm2 , 0.27 V lower than that of OER. The final potential increase is only 2 mV after long-term stability test of 12 h for UOR, much smaller than the uncoated sample (38 mV). The present work shows that C-coated transition metal nanomaterials with oxygen vacancies and a Schottky heterointerface are promising candidates for simultaneously boosting UOR with both high activity and long-term stability.

Electronic coupling between molybdenum disulfide and gold nanoparticles to enhance the peroxidase activity for the colorimetric immunoassays of hydrogen peroxide and cancer cells.

Peroxidase nanoenzymes exhibit a specific affinity toward substrates, thereby demonstrating application potential for realizing the colorimetric immunoassays of hydrogen peroxide (H2O2), which can be further used as a probe for imaging cancer cells. To enhance the intrinsic peroxidase activity of molybdenum sulfide (MoS2) nanomaterials, gold (Au) nanoparticles with an average diameter of approximately 2.1 nm were modified on a MoS2/carbon surface (denoted as MoS2/C-Au600) via ascorbic acid reduction. MoS2/C-Au600 can oxidize 3,3',5,5'-tetramethylbenzidine (TMB) to generate a blue oxidation product in the presence of H2O2; this product exhibits peroxidase-like activities, superior to those of most existing MoS2-based nanoenzymes. Furthermore, MoS2/C-Au600 exhibits a high detection capability for H2O2 in the range of 1 × 10-5 to 2 × 10-4 mol/L (R2 = 0.99), and the lowest detection limit is 1.82 µmol/L in a sodium acetate and acetic acid buffer solution. Steady state kinetics studies indicate that the catalytic mechanism is consistent with the ping-pong mechanism. Given its strong absorption peak at 652 nm in the visible region, MoS2/C-Au600 can be used to image cancer cells due to the enhanced permeability and retention effect. Our findings demonstrate that the synergistic electronic coupling between multiple components can enhance the peroxidase activity, which can facilitate the development of an effective, facile, and reliable method to perform colorimetric immunoassays of H2O2 and cancer cells.

Enhanced Piezoelectric Effect Derived from Grain Boundary in MoS2 Monolayers.

Recent discovery of piezoelectricity that existed in two-dimensional (2D) layered materials represents a key milestone for flexible electronics and miniaturized and wearable devices. However, so far the reported piezoelectricity in these 2D layered materials is too weak to be used for any practical applications. In this work, we discovered that grain boundaries (GBs) in monolayer MoS2 can significantly enhance its piezoelectric property. The output power of piezoelectric devices made of the butterfly-shaped monolayer MoS2 was improved about 50% by the GB-induced piezoelectric effect. The enhanced piezoelectricity is attributed to the additional piezoelectric effect induced by the existence of deformable GBs which can promote polarization and generates spontaneous polarization with different piezoelectric coefficients along various directions. We further made a flexible piezoelectric device based on the 2D MoS2 with the GBs and demonstrated its potential application in self-powered precision sensors for in situ detecting pressure changes in human blood for health monitoring.

Two-Dimensional van der Waals Materials with Aligned In-Plane Polarization and Large Piezoelectric Effect for Self-Powered Piezoelectric Sensors.

Piezoelectric two-dimensional (2D) van der Waals (vdWs) materials are highly desirable for applications in miniaturized and flexible/wearable devices. However, the reverse-polarization between adjacent layers in current 2D layered materials results in decreasing their in-plane piezoelectric coefficients with layer number, which limits their practical applications. Here, we report a class of 2D layered materials with an identical orientation of in-plane polarization. Their piezoelectric coefficients (e22) increase with layer number, thereby allowing for the fabrication of flexible piezotronic devices with large piezoelectric responsivity and excellent mechanical durability. The piezoelectric outputs can reach up to 0.363 V for a 7-layer α-In2Se3 device, with a current responsivity of 598.1 pA for 1% strain, which is 1 order of magnitude higher than the values of the reported 2D piezoelectrics. The self-powered piezoelectric sensors made of these newly developed 2D layered materials have been successfully used for real-time health monitoring, proving their suitability for the fabrication of flexible piezotronic devices due to their large piezoelectric responses and excellent mechanical durability.

Asymmetrically synchronous reduction and assembly of graphene oxide film on metal foil for moisture responsive actuator.

Graphene has drawn tremendous attention for the fabrication of actuators because of its unique chemical and structural features. Traditional graphene actuators need integration with polymers or other responsive components for shape-changeable behaviour. Searching for a sole material with asymmetric properties is difficult and challenging for actuators that are responsive to external stimulus. Herein, asymmetrically synchronous reduction and assembly of a graphene oxide (GO) film with oxygen-containing group gradients was prepared on various metal foils. Such film possessed asymmetric surface chemical components on both sides, which showed reversible deformation via alternating moisture. Importantly, we can detect the moisture change via recording the voltage pulse during self-deformation on the basis of spontaneous H3O+ ions diffusion across the GO film without the need of power input. Finally, a smart gripper was developed using a moisture responsive GO film. Present work opens a new avenue for developing smart actuator using a sole material and simultaneously realizing the detection of deformation in self-powered mode.

MiRNA-204-5p and oxaliplatin-loaded silica nanoparticles for enhanced tumor suppression effect in CD44-overexpressed colon adenocarcinoma.

Main purpose of present study was to enhance the therapeutic efficacy in the treatment of colon adenocarcinoma by combining the benefits of chemotherapy and gene therapy. In this study, we have successfully formulated oxaliplatin (OXL) and miRNA-204-5p loaded polyethyleneimine (PEI)/hyaluronic acid (HA)-assembled mesoporous silica nanoparticles (OXmi-HSMN). Our study, for the first time, proved that miRNA-204-5p can generate a synergistic anticancer effect with OXL with HMSN, and thus improve the effects of therapeutic efficacy in colon cancers. In vitro targeting studies showed that OXmi-HSMN exhibited higher uptake efficiency in CD44 receptor over-expressed HT-29 cells via CD44 receptor-mediated endocytosis. OXmi-HMSN exhibited a higher cell cytotoxicity compared to any other formulations indicating that internalization via CD44 receptor-mediated endocytosis increased the anticancer effect. The OXmi-HMSN showed significantly higher pre-apoptotic cells (43.9%) with significant apoptosis fractions (upper right quadrant - 20%) indicating the superior anticancer efficacy in terms of apoptosis inducing potentials. Importantly, OXmi-HMSN caused conspicuous inhibition of tumor growth and was significantly greater than that of either OXL or OXL-MSN (p < 0.0001). OXmi-HMSN showed 30% of TUNEL positive cells compared to 8% TUNEL positive cells for free OXL and 6% for free miRNA-204-5p treated group indicating the wide spread apoptosis of cells throughout the tissue section. Current study provides a delivery platform for dual therapeutics for enhanced therapeutic efficacy in the management of colon cancer.

Graphene nanoparticle strain sensors with modulated sensitivity through tunneling types transition.

Highly sensitive strain sensors show great potential for use in wearable health monitoring, autonomous intelligent robots and biomimetic prosthetics. The current resistive strain sensors mainly work through piezoresistors. Here, the robust tunneling mechanism based nanoscale strain sensors with high sensitivity are reported. The strain sensors are fabricated from graphene nanoparticle film. The sensitivity of graphene nanoparticle strain sensors could be tunable through the modulation of tunneling type, suggesting a theoretical support in performance optimization of tunneling strain sensors. The output characterization indicates the direct tunneling (DT) and Fowler-Nordheim tunneling (FNT) are dominant for charge carrier transport in the low voltage and high voltage regions, respectively. It is found that gauge factors are ∼79 at low voltage of 0-4 V, and ∼110 at high voltage of 20-40 V, showing profound dependence on DT and FNT types. The strain sensor bearing 0.3% strain shows a great stability over 100 cycles at bias voltage of 1 V and 40 V, respectively. An integrated strain sensor array with 5 × 5 patterned graphene nanoparticle film on a polyethylene terephthalate substrate is fabricated and demonstrates great spatial strain distribution, guiding the design for flexible and transparent strain sensor e-skins.