Latest ArticlesNature consists of various soft tissues with well-ordered hierarchical anisotropic structures, which play essential roles in biological systems to exhibit particular functions. Mimicking bio-tissues, synthetic hydrogels with anisotropic structures have received considerable attention in recent years. However, existing approaches to fabricate anisotropic hydrogels often require complicated procedures, which are time-consuming and labor-demanding. Inspired by the dry-induced crystallization phenomenon, we report a simple yet effective prestretching-drying-swelling method to afford anisotropic crystalline polyvinyl alcohol hydrogels. Owing to the distinct anisotropic microstructure, the hydrogels demonstrate excellent mechanical properties with noticeable directional distinction. It is revealed that both the enhancing of pre-orientation strain and the extending of heating time make the hydrogels with better mechanical properties and more remarkable anisotropicity. Owing to the anisotropically aligned structure, the hydrogels exhibit remarkably differential ionic conductivity: the difference between the parallel and vertical conductivity of the same sample can reach as high as 6.6 times, making the materials possible candidates as nano-conductive materials. We anticipate that this simple yet effective approach may become highly useful for fabricating oriented hydrogels and endow the materials with more promising application prospects in the future.
Bladder cancer is the most common malignant tumours with high morbidity, mortality and recurrence. However, currently developed detection methods for bladder cancer-associated urine biomarkers are hindered by their extremely low abundance. Hence, the exploration of a highly sensitive and selective approach for the detection of trace bladder cancer-associated biomarkers in human urine is of vital importance for the diagnosis of bladder cancer. Herein, we developed a highly reliable indium gallium zinc oxide field effect transistor (IGZO FET) biosensor for the detection of bladder cancer-related biomarker microRNA. The single-stranded DNA-functionalized IGZO FET biosensors exhibit high sensing reproducibility and stability with an ultralow detection limit of 19.8 amol/L. The device could also be used for quantitative detection of trace microRNA in human urine samples and can effectively distinguish bladder cancer patients from healthy donors. The development of high performance IGZO FET biosensors presents new opportunities for the achievement of early-stage diagnosis of bladder cancer.
CO2 is a representative prototype model in energy and environmental fields. Many factors for CO2 capture and activation have been investigated extensively but the research on the influence of thermal conductivity is still absence. We herein have calculated many properties, including dipole moment, electric structure, and adsorption energies, on Pt doped graphene and 2D BC3N2 substrates and served the thermal conductivity as the bridge. Our results have demonstrated that the lower (higher) thermal conductivity for 2D BC3N2 (graphene) corresponds to larger (lower) dipole moment, which is beneficial for CO2 activation (capture) process. Our research have not only revealed the dominant role of heat conductivity for CO2 capture and activation, but also paved the way for further catalyst design of various areas.
In this study, natural mackinawite (FeS), a chalcophilic mineral, was utilized to prepare iron/copper bimetallic oxides (CuO@FexOy) by displacement plating and calcination process. Various characterization methods prove that Cu0 is successfully coated on the surface of FeS, which were further oxidized to CuO, Fe3O4 and/or Fe2O3 during calcination process, respectively. CuO@FexOy performed highly efficient capacity to activate PMS for the degradation of various emerging pollutants including sulfamethoxazole (SMX), carbamazepine (CBZ), bisphenol A (BPA), 2, 4-dichlorophenol (2, 4-DCP) and diclofenac (DCF) in aqueous solution. Complete removal of the above pollutants was observed after 8 min of CuO@FexOy/PMS treatment. Taking SMX as an example, the key parameters including CuO@FexOy dosage, PMS dosage and initial pH were optimized. The results show that the catalytic system can be worked in a wide pH range (3.0-9.0). The quenching experiments and electron spin resonance (ESR) test demonstrated that the main reactive oxygen species in CuO@FexOy/PMS system were hydroxyl radicals (•OH) and sulfate radicals (SO4•–), and SO4•– was the primary reactive species. Besides, the influence of coexisting anions (i.e., Cl–, NO3–, HCO3– and H2PO4–) for the degradation of SMX was explored. CuO@FexOy/PMS system can maintain good catalytic activity and reusability in different water bodies and long-term running. This work provided a green strategy to fabricate the efficient catalyst in PMS-based advanced oxidation processes.
The development of effective and low-energy-consumption catalysts for CO2 conversion into high-value-added products by constructing versatile active sites on the surface of heterogeneous compounds is an urgent and challenging task. In this study, a stable and well-defined heterogeneous cobalt hexacyanocobaltate (Co3[Co(CN)6]2), typical cobalt Prussian blue analogue (CoCo-PBA) modified with tetrabutylammonium bromide (TBAB), is proven to be the superior catalyst for CO2 and epoxide coupling to produce cyclic carbonates with > 99% yield under mild reaction conditions (1.0 MPa, 65 ℃). Based on a series of characterizations, it is revealed that the CoCo-PBA structure can maintain relatively high thermal and chemical stability. Recycling experiments exhibited that the CoCo-PBA system could retain 98% of the original activity after six reaction rounds. The CoCo-PBA/TBAB catalytic system was also highly active for coupling CO2 with other industrial-grade epoxides. These results show the CoCo-PBA catalytic system potential flexibility and the generality of the catalyst preparation strategy.
Macrophage is the key innate immune effector in first-line defense against the pathogens, and can be polarized into different phenotypes to regulate a variety of immunological functions. However, the plasticity of macrophage is extraordinarily recruited, activated, and polarized under pathological conditions, playing paramount roles in occurrence, development, and prognosis of various chronic diseases, such as rheumatoid arthritis (RA), atherosclerosis (AS), and cancer. To this end, macrophage has become an important therapeutic target for etiological treatment of these diseases. Meanwhile, with the development of nanotechnology, various nano-drug delivery systems have been explored to target macrophages for disease modulation, displaying unique advantages to address both pharmaceutic and biopharmaceutic limitations of various drugs. This review aims to summarize the recent progress of macrophage-targeted nanomedicine for chronic diseases immunotherapy. First, the origin, polarization and biological functions of macrophages have been introduced, in which macrophages can differentiate into different phenotypes in response to physiological stimuli to play various immunological roles. Then, the macrophage disorder has been reviewed in related with various chronic diseases, and several representative diseases, including AS, RA, obesity, and cancer, have been discussed in detail to elucidate the pathological contributions of macrophages for disease progress. Next, strategies to regulate macrophages for diseases immunotherapy, such as macrophages depletion, macrophage reprograming, inhibition of macrophage recruitment, are summarized, and particular attention has been paid on bio-functional nanomaterials to engineer macrophages via different mechanisms. Further, methods for macrophage-targeting delivery nanosystems are discussed based on both passive and active targeting approaches. Finally, the perspective is speculated for potential clinical translation, and there still has significant room for the development of novel macrophage-targeting nanomedicine for precise, effective, and biosafe therapy.
The drug resistance of chemotherapy is a major challenge to overcome for antineoplastic agents and the reverse of drug resistant is essential for cancer therapy. Herein, we developed a drug delivery system which can simultaneously detect/reverse the drug resistance and perform synergetic treatment of cancer. In this work, we integrated cyanine5 (Cy5) modified miRNA (let-7i) (Cy5-miRNA) and platinum onto nano-graphene oxide (NGO) (30-50 nm) platform to achieve simultaneously detection/reversion of drug resistance and synergetic treatment of cisplatin resistant SKOV3 cells (SKOV3DDP cells). The Cy5-miRNA adsorbed on NGO could selectively bind the drug resistance related mRNA follow by suppress the expression of drug resistance mRNA, and the binding simultaneously induced the release of Cy5-miRNA from the NGO, thus the fluorescence signal of Cy5 recovered and could be used for drug resistance monitoring. Moreover, the miRNA suppressed the Cyclin D1 protein expressions thus reversed the drug resistance. The loaded platinum(IV) (Pt(IV)) was converted to the therapeutic platinum(II) (Pt(II)) in both tumor acidic and reductive environment responsive behavior. NGO furtherly performed photothermal therapy under near infrared (NIR) laser irradiation and enhanced the therapeutic effect. All in all, this nanoplatform realized detection/reversion of the drug resistance as well as synergetic chemical-photothermal treatment of ovarian cancer cells, which holds great promise in the treatment of drug resistant cancer cells.
Efficient bifunctional OER/ORR catalysts are crucial for the further development of zinc-air battery. From a sustainable point of view, it is important that electrocatalysts are efficient, low cost, and composed of abundant resources instead of scarce metals. Due to their good conductivity, low cost, and strong durability, carbon-based materials are considered a promising alternative in the field of commercial zinc-air battery catalysts. Herein, we briefly introduce the zinc-air battery and then summarize recent progress in the development of carbon-based bifunctional catalysts by defect engineering, heteroatom doping and metal doping. Finally, we discuss the main challenges and prospects for the future development of carbon-based bifunctional oxygen catalysts.
Lysosomal polarity is considered a key indicator of lysosomal function due to its significant impact on membrane fluidity and enzymatic reactions in lysosomes. Monitoring lysosomal polarity can gain insight into the related physiological and pathological processes and develop new diagnostic methods. However, current fluorescent probes with lysosomal polarity response suffer from narrow linear range, photobleaching and complicated preparation. Herein, a ratiometric fluorescent probe (r-bCDs) for intracellular lysosomal polarity imaging is designed and constructed by amide bond assembly of polarity-sensitive red fluorescent carbon dots (rCDs) and referenced blue fluorescent carbon dots (bCDs). r-bCDs show a much wider linear range of polarity response (orientation polarizability Δf from 0.020 to 0.315) than other probes, and the interference of uneven distribution and instrument factors can be effectively eliminated by ratiometric fluorescent sensing. Imaging of intracellular lysosomal polarity with r-bCDs is implemented to observe the polarity variation caused by the change of cell state and the difference between cancer cells and normal cells. This work provides a promising tool for studying the related physiological and pathological processes and developing new diagnostic methods.
The development of amplification strategies is one of the central challenges for detection of low-abundance targets. One-to-many (1:M) amplification strategies in which one target lights many signal probes, has improved the detection sensitivity in bulk solution, but with discounted contrast in cell imaging, because the lighted probes are dissociative and dispersible. In this work, a one-to-large (1:L) signaling mechanism, in which the lighted probes were orderly connected to each other, was conceptually proposed to enhance the contrast in cell imaging by avoiding signal dispersion in amplification. Accordingly, target-triggered hairpin-free chain-branching assembly (HFCBA) holds great potential to implement the 1:L mechanism, but using it in cell imaging has yet to be demonstrated. As a proof of concept, a group of probes were first programmed to implement miRNA-21-triggered HFCBA. After transfection of probes, gradually-growing signal flares in cells were monitored along with the growth of DNA dendrimers; and the in situ fluorescence accumulation in HFCBA resulted in highly-enhanced contrast to the surrounding by avoiding signal dispersion in amplification. The contrast-enhanced imaging with signal amplification is significant for biological analysis and molecular medicine. We expect the 1:L mechanism will provide a new thought for high-performance imaging of biomarkers in cells.