Latest ArticlesDeveloping a new type of deep eutectic solvents (DESs) is indispensable for expanding their application in various fields. Here, we report a series of new highly basic DESs. FT-IR, quantitative 1H NMR, MD simulation and physical properties show that these basic liquids are made up of hydroxide acceptor of alkali metal hydroxides in which the hydrogen bonding interactions coordinate the donor. These DESs can be played three roles as new solvents, template and reactant for facile and ultra-fast preparation of transition metal oxide nanomaterials such as NiCo2O4, MnCo2O4, NiMn2O4, CoCu2O4 and Co3O4 under mild condition. This work shows one of the low energy-intensive methods for nanomaterial preparation. These initial findings of basic deep eutectic solvents provide a potential applicability around the systematic development of transition metal oxide nanosheets.
Bladder cancer is the most common malignant tumor in the urinary system, with high morbidity, mortality and recurrence after surgery. However, current bladder cancer urine diagnosis methods are limited by the low accuracy and specificity due to the low abundance of bladder cancer biomarkers in the urine with complex biological environments. Herein, we present a high stability indium gallium zinc oxide field effect transistor (IGZO-FET) biosensor for efficient identification of bladder cancer biomarkers from human urine samples. The recognition molecular functionalized IGZO-FET biosensor exhibits stable electronic and sensing performance due to the large-area fabrication of IGZO thin-film FET. Owing to the excellent electrical performance of IGZO-FET, the IGZO-FET biosensor exhibits high sensitivity and extremely low detection limit (2.7 amol/L) towards bladder cancer biomarkers. The IGZO-FET biosensor is also able to directly detect bladder tumor biomarker in human urine with high sensitivity and specificity, and could differentiate bladder cancer patients' urine samples from healthy donors effectively. These results indicate that our designed high-performance biosensor shows great potential in the application of portable digital bladder cancer diagnosis devices.
CuWO4, as an n-type oxide semiconductor with a bandgap of 2.2 eV, has stimulated enormous interest as a potential broad-spectrum-active photocatalyst for environmental pollution remediations. However, rapid charge recombination greatly hinders its practical applications. Herein, we present a cascaded electron transition pathway in a ternary heterostructure consisting of CdS quantum dots, carbon dots (CDs) and CuWO4 hollow spheres, which proves to greatly facilitate the photogenerated electron-hole separation, and eventually boosts the degradation efficiency of phenol and congo red by 100% and 46% compared to bare CuWO4. The enhanced performance of the CuWO4/CdS/CDs heterostructure mainly originates from the unidirectional electron migration from CdS to CuWO4 and then to the organics through CDs. This work elucidates the electron transfer kinetics in multi-phase system and provides a new design paradigm for optimizing the properties of CuWO4 based photocatalysts.
Graphene oxide (GO), an important chemical precursor of graphene, can stably disperse in aqueous surrounding and undergo aggregation as metal cations introduced. The usual instability of GO with ions is caused by the shielding effect of ions and crosslinking between GO and ions. However, the dynamic stability of GO under ions exchange still remains unclear. Here, we investigated the dynamic dispersion stability of GO with metal ions and observed a redispersion behavior in concentrated Fe3+ solution, other than permanent aggregation. The exchange with Fe3+ ions drives the reversion of zeta (ζ) potential and enables the redispersion to individual GO-Fe3+ complex sheets, following a dynamic electric double layer (EDL) mechanism. It is found that the specifically strong electrostatic shielding effect and coordination attraction between Fe3+ and functional oxygen groups allows the selective redispersion of GO in concentrated Fe3+ solution. The revealed dynamic dispersion stability complements our understanding on the dispersive stability of GO and can be utilized to fabricate graphene-metal hybrids for rich applications.
Exploring 3D hybrid nanocarbons encapsulated with metal nanoparticles (NPs) are recently considered as emerging catalysts for boosting CO2 electroreduction reaction (CRR) under practical and economic limits. Herein, we report a one-step pyrolysis strategy for fabricating N-doped carbon nanotube (CNT)-encapsulated Ni NPs assembled on the surface of graphene (N/NiNPs@CNT/G) to efficiently convert CO2 into CO. In such 3D hybrid, the particle size of Ni NPs that coated by five graphitic carbon layers is less than 100 nm, and the amount of N dopants introduced into graphene with countable CNTs is determined to 7.27 at%. Thanks to unique CNT-encapsulated Ni NPs structure and N dopants, the achieved N/NiNPs@CNT/G hybrid displays an exceptional CRR activity with a high Faradaic efficiency of 97.7% and large CO partial current density of 7.9 mA/cm2 at -0.7 V, which outperforms those reported metallic NPs loaded carbon based CRR electrocatalysts. Further, a low Tafel slope of 134 mV/dec, a turnover frequency of 387.3 CO/h at -0.9 V, and tiny performance losses during long-term CRR operation are observed on N/NiNPs@CNT/G. Experimental observations illustrate that the Ni NPs encapsulated by carbon layers along with N dopants are of great importance in the conversion of CO2 into CO with high current density.
Cancer is one of the diseases that have the highest mortality, which threatens the human health. Chemotherapy functions as the most widely used strategy in clinic to treat cancer, still exists urgent problems, like lacking selectivity and causing severe side effects. According to detailed researches on the metabolism, functions and histology of cancer tissues, many different features of cancer are uncovered, like lower pH in microenvironment, abnormal redox level in intracellular compartments and elevated expression level of several enzymes and receptors. Recently, the development of smart nanoparticles that response to tumor specific microenvironment has lighted up hope for selective cancer therapy. Herein, this review mainly focuses on pH-sensitive nanoscale materials for anti-cancer drug delivery. We summarized the formation progress of acidic tumor microenvironment, the mechanism of pH-responsive drug delivery system and nanomaterials that responsive to acidic pH in tumor microenvironment.
Commercial carbon clothes have the potential to be utilized as supercapacitor electrodes due to their low cost and high conductivity. However, the negligible surface area of the carbon clothes serves as a serious impediment to their utilization. Herein, we report a facile calcination activation method for carbon cloths to realize remarkable comprehensive electrochemical performance. The activated carbon cloths deliver a high areal capacitance (1700 mF/cm2), good rate capability, and stable cycling performance up to 20, 000 cycles. Owing to the stability in the wide potential window, a designed symmetric capacitor can function in a cell voltage of 2.0 V and delivers high volumetric and gravimetric energy densities of 7.62 mWh/cm3 and 18.2 Wh/kg, respectively. The remarkable electrochemical performance is attributed to rich microporosity with high surface area, superior electrolyte wettability, and stability in wide potential window.
We developed a merocyanine-based fluorescent probe, NEPB, for tracing hydrazine (N2H4) in a ratiometric manner with large Stokes shifts and long emission wavelength. The fluorescence color of probe NEPB changed from green to yellow upon addition of hydrazine. Probe NEPB displayed high selectivity and sensitivity to hydrazine in solution, and could ratiometrically monitor N2H4 in living cells and zebrafish with low cytotoxicity.
Metalloenzymes which employ metal species and organic ligands as central active sites play significant roles in various biological activities. Development of artificial metalloenzymes can help to understand the related physiological mechanism and promote the applications of metalloenzymes in biosynthesis, energy conversion and biosensing. In this work, inspired by the active sites of ferriporphyrin-based metalloenzymes, Fe-MOFs by using ferric as the metal center and a porphyrin analog as the organic ligand were developed as an artificial metalloenzyme. The Fe-MOFs exhibit high peroxidase-like catalytic activity with excellent long-term stability. Moreover, highly sensitive biosensors were built to detect H2O2 and glucose based on the Fe-MOFs. Such MOFs-based artificial metalloenzyme offers an efficient strategy for the development of highly stable and efficient metalloenzymes, showing great potential in catalysis, energy transfer, biosensing and medical diagnosis.
Effective detection of cellular microenvironments and understanding of physiological activities in living cells remain a considerable challenge. In recent years, fluorescence (or Förster) resonance energy transfer (FRET) technology has emerged as a valuable method for real-time imaging of intracellular environment with high sensitivity, specificity and spatial resolution. Particularly, polymer-based imaging systems show enhanced stability, improved biodistribution, increased dye payloads, and amplified signal/noise ratio compared with small molecular sensors. This review summarizes the recent progress in FRET-based polymeric systems for probing the physiological environments in cells.