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The establishment of rapid and efficient contamination detection methods in agricultural fields is of great significance for safeguarding agricultural production and human health, and for ensuring the healthy development of agricultural industries. As a booming analytical method, photoelectrochemical (PEC) sensors, which combine the advantages of electrochemical analysis and optical analysis, have received increasing research attention. Due to the complete separation of the excitation source (light) and the detection signal (current), the background signal of PEC sensors is greatly decreased, and their sensitivity is high. This review aims to cover the advances in PEC sensors for contamination analysis in agricultural fields over the past 5 years, including the analysis of heavy metals, antibiotics, pesticides, and toxins. The future prospects in this field are also discussed.

Organic manure and biochar amendments have been used in agriculture to improve soil fertility and enhance crop productivity. Plant roots play an important role in the functionality of individual plants, and although the addition of organic manure and biochar reportedly affect roots, it remains unclear how root morphology and physiology respond. We conducted a field experiment to test the hypothesis that organic manure combined with biochar amendment could also enhance the productivity of continuous cropping systems in Xinjiang cotton plantations. Different levels of organic manure and biochar were applied. Organic manure and biochar significantly affected root morphology and physiology by improving soil nutrients. In the absence of biochar, organic manure amendment increased Root TTC reducing capacity, glutamine synthetase and nitrate reductase activity. Furthermore, morphological and physiological parameters peaked with 6% organic manure combined with 1% biochar. A significant increase in root physiology was recognized with an increase in soil nutrient content at the bud stage and a negative relationship between root physiology and soil total K content at the harvesting stage. Thus, our results indicate that organic manure combined with biochar positively influenced cotton roots, and therefore should be used to improve root health in continuous cropping systems.

Mesenchymal stem cells (MSCs) are multipotent adult stem cells and can be isolated from many tissues of the body. Due to their potentials to treat various diseases and be applied in animal breeding, MSCs have been isolated and identified regarding their biological properties. Common hippos (Hippopotamus amphibius) are a vulnerable species and yet the cryopreservation of their genetic materials is scare. In this study, we successfully established two MSC lines (UC-MSCs and AT-MSCs) from the umbilical cord and adipose tissue of a neonatal common hippo and comparatively described their features. Both UC-MSCs and AT-MSCs showed fibroblastoid morphology and could be continuously passaged for over 17 passages without dramatic signs of senescence. The cell cultures had normal chromosome composition, say, 17 pairs of autosomes and 1 pair of X chromosomes. UC-MSCs and AT-MSCs displayed similar gene expression profiles. They were positive for CD45, CD73, CD90 and CD105 and negative for HLA-DR. They demonstrated stemness maintenance by expression of classical stem cell markers. UC-MSCs and AT-MSCs manifested different differentiation potentials into other cell lineages. In summary, these two cell lines demonstrated the essential properties of mesenchymal stem cells and might play a role in the future research.

Silicon effectively alleviates the damage caused by salt stress in plants and can improve plant salt tolerance. However, the details of the mechanism by which silicon improves salt tolerance of liquorice are limited, and the effects of foliar application of silicon on different liquorice species under salt stress are not known. Here, the effects of foliar spray of silicon on the growth, physiological and biochemical characteristics, and ion balance of Glycyrrhiza uralensis Fisch. and Glycyrrhiza inflata Bat. were investigated. High salt stress resulted in the accumulation of a large amount of Na+, decreased photosynthetic pigment content, perturbed ion homeostasis, and eventually inhibited the both liquorice species growth. These effects were more pronounced in G. uralensis, as G. inflata is more salt tolerant than G. uralensis. Foliar spraying of silicon effectively reduced the decomposition of photosynthetic pigments, improved gas exchange parameters, and promoted photosynthesis. It also effectively inhibited lipid peroxidation and electrolyte leakage and enhanced osmotic adjustment of plants. Further, silicon application increased the K+ concentration, reduced Na+ absorption, transport and accumulation in the plants. The protective effects of silicon were more pronounced in G. uralensis than those in G. inflata. In conclusion, silicon reduces Na+ absorption, improves ion balance, and alleviates the negative effects of salt stress in the two liquorice species studied, but the effect is liquorice species-dependent. These findings may inform novel strategies for protecting liquorice plants against salt stress and also provide a theoretical basis for the evaluation of salt tolerance and the scientific cultivation of liquorice.

Silicon (Si) effectively alleviates the effects of salt stress in plants and can enhance salt tolerance in liquorice. However, the mechanisms by which Si improved salt tolerance in liquorice and the effects of foliar application of Si on different liquorice species under salt stress are not fully understood. We investigated the effects of foliar application of Si on the growth, physiological and biochemical characteristics, and ion balance of two liquorice species, Glycyrrhiza uralensis and G. inflata. High salt stress resulted in the accumulation of a large amount of Na

Dopamine (DA) and uric acid (UA) have similar peak potentials in vivo, and it is difficult to distinguish them by general electrode material. Here, we used a magnetron sputtering method to sputter the ZnO seed layer on carbon fiber and prepare ultra-long ZnO nanofibers/carbon fibers (ZnO NF/CF) electrode by in situ hydrothermal method. As a free-standing electrode, not only electrochemical detection of DA and UA but also a separation of oxidation potential peaks of DA and UA can be achieved. In addition, in the case of high concentration UA (0.1 mM), ZnO NF/CF shows high sensitivity and selectivity and shows a wide linear range for DA (4–20 µM). Meanwhile, we proposed the electrochemical mechanism and process of DA and UA on the surface of ZnO, which helps us to understand the simultaneous detection of DA and UA by such electrochemical electrodes.

Metal nanoparticle assisted photoelectrochemical (PEC) biosensing has attracted attention for point-of-care testing due to its fast and low background noise signal. However the interfacial charge transfer of plasmonic-enhanced biosensing is not yet fully understood. Herein, a plasmonic-enhanced PEC platform has been demonstrated for glutathione (GSH) detection based on a hybrid structure of a well-oriented zinc oxide nanorod array (ZnO NR) with gold nanoparticles (Au NPs) as photoanode. In the PEC system, the self-powered bioanalysis is carried out at 0 V versus Ag/AgCl under simulated sunlight. In detail, the optical experiments (e.g. photoluminescence, PL) and theoretical analysis (e.g. finite-difference time-domain, FDTD) illustrate the photoresponse enhancement mechanism of the Au NPs–ZnO NRs and reaction process of GSH. The GSH oxidization and the effect of pH on the photocurrent response are demonstrated and investigated. The as-prepared surface plasmon resonance (SPR) based PEC sensor could be considered for GSH detection for early diagnosis of tumors.

Mesenchymal stem cells (MSCs) are multipotent adult stem cells and can be isolated from many tissues of the body. Due to their potentials to treat various diseases and be applied in animal breeding, MSCs have been isolated and identified regarding their biological properties. Common hippos (Hippopotamus amphibius) are a vulnerable species and yet the cryopreservation of their genetic materials is scare. In this study, we successfully established two MSC cultures (UC-MSCs and AT-MSCs) from the umbilical cord and adipose tissue of a neonatal common hippo and comparatively described their features. Both UC-MSCs and AT-MSCs showed fibroblastoid morphology and could be continuously passaged for over 17 passages without dramatic signs of senescence. The cell cultures had normal chromosome composition, say, 17 pairs of autosomes and 1 pair of X chromosomes. UC-MSCs and AT-MSCs displayed similar gene expression profiles. They were positive for CD34, CD45, CD73, CD90 and CD105 and negative for HLA-DR. They demonstrated stemness maintenance by expression of classical stem cell markers. UC-MSCs and AT-MSCs manifested different differentiation potentials into other cell lineages. In summary, these two cell cultures demonstrated the essential properties of mesenchymal stem cells and might play a role in the future research.

The application of combinational therapy breaks the limitation of monotherapy and achieves better clinical benefit for tumor therapy. Herein, a hyaluronic acid/Pluronic F68-based copolymer-mixed micelle was constructed for targeted delivery of chemotherapeutical agent docetaxel (PHDM) in combination with programmed cell death ligand-1(PD-L1) antibody. When PHDM+anti-PDL1 was injected into the blood system, PHDM could accumulate into tumor sites and target tumor cells via CD44-mediated endocytosis and possess tumor chemotherapy. While anti-PDL1 could target PD-L1 protein expressed on surface of tumor cells to the immune checkpoint blockade characteristic for tumor immunotherapy. This strategy could not only directly kill tumor cells but also improve CD8+ T cell level and facilitate effector cytokines release. In conclusion, the rational-designed PHDM+anti-PDL1 therapy strategy creates a new way for tumor immune-chemotherapy.

CH3NH3PbBr3 single crystal, one of organometal halide perovskites, as novel optoelectronic and photovoltaic materials could be easily precipitated using an antisolvent method. Understanding of the growth mechanism will significantly improve reproducibility, quality, and controllability of the single crystals. However, it is difficult to capture the growth process due to the super solubility of CH3NH3PbBr3 crystals in N,N-dimethylformamide solution. Here, filter paper was used to separate the intermediate states of CH3NH3PbBr3 crystals out of N,N-dimethylformamide solution in the growth process. The developed fabrication approach can monitor the morphology evolution of CH3NH3PbBr3 single crystals as a whole. Meanwhile, the precursor solution’s properties and degradation of CH3NH3PbBr3 single crystals were also investigated systematically. It indicates that the CH3NH3PbBr3 single crystal growth process is similar to sodium chloride crystals grown from solution in the presence of nitrilotriacetamide. The res...

A reduced graphene oxide@zeolitic imidazolate framework-8 (rGO@ZIF-8) based electrochemical sensor was developed and used for dopamine detection. ZIF-8 was rapidly prepared by zinc hydroxide nitrate (Zn-HDS, Zn5(OH)8(NO3)2·2H2O) as precursor. Subsequently, rGO was introduced to enhance the performance of ZIF-8 (e.g., high carrier mobility, favorable stability), and a label-free electrochemical dopamine sensor based on the composite material was obtained with high specific surface area and better conductivity verified by Brunauer–Emmett–Teller surface analysis and electrochemical impedance spectroscopy, respectively. Consequently, rGO@ZIF-8 complex exhibited an admirable electrochemical catalytic performance. For determination of dopamine, the sensor behaves wide linear range from 2.0 × 10−6 to 1.4 × 10−4 mol l−1 and lower detection limit of 2.0 × 10−8 mol l−1 (S/N = 3). It also showed sufficient repeatability and durability due to the coordinated amplification effect of rGO and ZIF-8.

Graphene quantum dots (GQDs) offer new opportunities for the applications of electrochemical sensing because of their intrinsic peroxidase-like activity. To develop a sensitive electrochemical sensor with better stability and reproducibility, polydopamine (PDA) has been employed as an adhesive agent to integrate the GQDs and gold nanoparticles (Au NPs) tightly through a green, facile and rapid method. The synergistic effect of Au-PDA-GQD nanocomposite presented an excellent electrocatalytic activity towards the reduction of hydrogen peroxide (H 2 O 2 ). Hence, the H 2 O 2 biosensor based on Au-PDA-GQD exhibited better sensing performances, such as wide linear range (0.1–40 μM and 40–20,000 μM), low detection limit (5.8 nM) and fast response time ( 2 O 2 biosensors.

Iron depletion is an efficient strategy for the development of anticancer agents. In an effort to develop efficient chelators, two new 3-hydroxy-4-pyridinone based polyazamacrocycles 1e and 2e were designed and synthesized. A preliminary study of the ligands was carried out to investigate their iron chelating capability and anti-tumor activity. Chelating kinetics revealed that the ligands exhibited excellent iron depletion capacity in neutral and acidic NH4OAc buffer solutions. Moreover, MTT assay showed that the new ligands displayed potent inhibitory activity in the proliferation of HepG2 cells. The attachment of hydroxypyridione units on the polyazamacrocycles promoted iron chelating capability and improved the anti-tumor activity by offering additional chelating sites and lipophilicity. These results indicate that two novel compounds may possess the therapeutic potential in the treatment of cancer through depleting cellular iron.

A simple and “green” radio frequency (RF) magnetron sputtering-assisted hydrothermal method was utilized to synthesize carbon fibers/ZnO coaxial nanocable with sharp control. The X-ray powder diffraction (XRD) and scanning electron microscopy (SEM) were used to characterize the crystal phase and morphology of the obtained material. Based on the electrocatalytical activity of the material towards ascorbic acid (AA), the material was used to develop a biosensor which make the diagnosis easy and convenient. The property of the electrode was investigated by cyclic voltammetry (CV). Differential pulse voltammograms (DPV) was used to sensing AA with wide range detection capabilities. This work provides a portable and green route to construct biomedical sensor, which is promising for clinical diagnosis.