Highly sensitive and selective photoelectrochemical detection of bis(2-ethylhexyl)phthalate on broad-spectrum responsive and interfacial electronic interaction induced p-n BiOI/ZnO nanoarrays heterojunction.

Bis(2-ethylhexyl)phthalate (DEHP), an endocrine disruptor, shows carcinogenic, teratogenic, mutagenic and estrogenic effects. It is easy to release from plastic materials and migrate to soil environment, causing serious pollution and posing a great threat to human health. In our work, a photoelectrochemical (PEC) sensing platform for DEHP detection was constructed using BiOI/ZnO nanoarrays (NRs) as the transducer species and the DEHP aptamers as the biological recognition elements. ZnO NRs with three-dimensional and large diameter area were prepared by hydrothermal method to increase the light absorption capacity. Coupling BiOI in a narrow band gap with ZnO NRs strengthened visible-light absorption, while promoting charge carrier separation and transportation. This was attributed to the generation of an internal electric field between BiOI and ZnO NRs, exhibiting obvious photocurrent response. The as-developed PEC sensing platform demonstrated great sensing performance for detection of DEHP. Furthermore, the photocurrent varied and the logarithm of DEHP concentration showed a linear relationship from 1.0 × 10-11 to 5.0 × 10-7 mol/L, and the limit of detection was estimated to be 3.8 × 10-12 mol/L. In the meantime, while evaluating its usage in real soil samples, satisfying outcomes were realized. Thus, the as-proposed PEC sensing platform provided a potential device to monitor DEHP in the environment.

Electrochemical sensor based on Bi/Bi2O3 doped porous carbon composite derived from Bi-MOFs for Pb2+ sensitive detection.

It is of great significance to develop electrochemical sensors based on novel functional nanomaterials for heavy metal ions detection. In this work, a novel Bi/Bi2O3 co-doped porous carbon composite (Bi/Bi2O3@C) was prepared by simple carbonization of bismuth-based metal-organic frameworks (Bi-MOFs). The micromorphology, internal structure, crystal and elemental composition, specific surface area and porous structure of the composite were characterized by SEM, TEM, XRD, XPS, and BET. Further, a sensitive electrochemical sensor for Pb2+ detection was constructed by modifying Bi/Bi2O3@C on the surface of the glassy carbon electrode (GCE) based on the square wave anodic stripping voltammetric (SWASV). The different factors affecting the analytical performance were optimized systematically, such as material modification concentration, deposition time, deposition potential, and pH value. Under optimized conditions, the proposed sensor exhibited a wide linear range from 37.5 nM to 2.0 µM with a low detection limit of 6.3 nM. Meanwhile, the proposed sensor showed good stability, acceptable reproducibility, and satisfactory selectivity. The reliability of the as-proposed sensor was confirmed by the ICP-MS method for Pb2+ detection in different samples.

Effects of silicon application on leaf structure and physiological characteristics of Glycyrrhiza uralensis Fisch. and Glycyrrhiza inflata Bat. under salt treatment.

BACKGROUND: Soil salinization leads to a significant decline in crop yield and quality, including licorice, an important medicinal cash crop. Studies have proofed that the application of exogenous silicon can significantly improve the ability of licorice to resist salt stress, however, few studies concentrated on the effects of foliar silicon application on the morphology, physiological characteristics, and anatomical structure of licorice leaves under salt stress. In this study, the effects of Si (K2SiO3) on the structural and physiological characteristics of Glycyrrhiza uralensis Fisch. and G. inflata Bat. leaves under different salt concentrations (medium- and high-salt) were studied. RESULTS: Compared with the control (without salt), the plant height, total dry weight, leaf area, leaf number, relative water content, xylem area, phloem area, ratio of palisade to spongy tissue, gas exchange parameters, and photosynthetic pigment content of both licorice varieties were significantly reduced under high-salt (12S) conditions. However, the thickness of the leaf, palisade tissue, and spongy tissue increased significantly. Applying Si to the leaf surface increased the area of the vascular bundle, xylem, and parenchyma of the leaf's main vein, promoted water transportation, enhanced the relative leaf water content, and reduced the decomposition of photosynthetic pigments. These changes extended the area of photosynthesis and promoted the production and transportation of organic matter. G. uralensis had a better response to Si application than did G. inflata. CONCLUSIONS: In conclusion, foliar application of Si can improve water absorption, enhance photosynthesis, improve photosynthetic capacity and transpiration efficiency, promote growth and yield, and alleviate the adverse effects of salt stress on the leaf structure of the two kinds of licorice investigated.

Biological characteristics of two mesenchymal stem cell cultures isolated from the umbilical cord and adipose tissue of a neonatal common hippo (Hippopotamus amphibius).

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.

Research progress on photoelectrochemical sensors for contamination analysis in agricultural fields.

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.

Silicon improves ion homeostasis and growth of liquorice under salt stress by reducing plant Na+ uptake.

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+, decreased photosynthetic pigment concentrations, perturbed ion homeostasis, and eventually inhibited both liquorice species growth. These effects were more pronounced in G. uralensis, as G. inflata is more salt tolerant than G. uralensis. Foliar application of Si effectively reduced the decomposition of photosynthetic pigments and improved gas exchange parameters, thereby promoting photosynthesis. It also effectively inhibited lipid peroxidation and leaf electrolyte leakage and enhanced osmotic adjustment of the plants. Furthermore, Si application increased the K+ concentration and reduced Na+ absorption, transport, and accumulation in the plants. The protective effects of Si were more pronounced in G. uralensis than in G. inflata. In conclusion, Si reduces Na+ absorption, improves ion balance, and alleviates the negative effects of salt stress in the two liquorice species studied, but the effect is species dependent. These findings may help to develop novel strategies for protecting liquorice plants against salt stress and provide a theoretical basis for the evaluation of salt tolerance and the scientific cultivation of liquorice.

Soil properties, root morphology and physiological responses to cotton stalk biochar addition in two continuous cropping cotton field soils from Xinjiang, China.

Long-term and widespread cotton production in Xinjiang, China, has resulted in significant soil degradation, thereby leading to continuous cropping obstacles; cotton stalk biochar (CSB) addition may be an effective countermeasure to this issue, with effects that are felt immediately by root systems in direct contact with the soil. In this study, we assess the effects of different CSB application rates on soil nutrient contents, root morphology, and root physiology in two soil types commonly used for cotton production in the region. Compared with CK (no CSB addition), a 1% CSB addition increased total nitrogen (TN), available phosphorus (AP), and organic matter (OM) by 13.3%, 7.2%, and 50% in grey desert soil, respectively , and 36.5%, 19.9%, and 176.4%, respectively, in aeolian sandy soil. A 3% CSB addition increased TN, AP, and OM by 38.8%, 23.8%, and 208.1%, respectively, in grey desert soil, and 36%, 13%, and 183.2%, respectively, in aeolian sandy soil. Compared with the aeolian sandy soil, a 1% CSB addition increased TN, OM, and AP by 95%, 94.8%, and 33.3%, respectively, in the grey desert soil , while in the same soil 3% CSB addition increased TN, OM, and AP by 108%, 21.1%, and 73.9%, respectively. In the grey desert soil, compared with CK, a 1% CSB application increased the root length (RL) (34%), specific root length (SRL) (27.9%), and root volume (RV) (32.6%) during the bud stage, increased glutamine synthetase (GS) (13.9%) and nitrate reductase (NR) activities (237%), decreased the RV (34%) and average root diameter (ARD) (36.2%) during the harvesting stage. A 3% CSB addition increased the RL (44%), SRL (20%), and RV (41.2%) during the bud stage and decreased the RV (29%) and ARD (27%) during the harvesting stage. In the aeolian sandy soil, 1% CSB increased the RL (38.3%), SRL (73.7%), and RV (17%), while a 3% caused a greater increase in the RL (55%), SRL (89%), RV (28%), soluble sugar content (128%), and underground biomass (33.8%). Compared with the grey desert soil, a 1% CSB addition increased the RL (48.6%), SRL (58%), and RV (18.6%) in the aeolian sandy soil, while a 3% further increased the RL (54.8%), SRL (84.2%), RV (21.9%), and soluble sugar content (233%). The mechanisms by which CSB addition improves the two soils differ: root morphology changed from coarse and short to fine and long in the grey desert soil, and from fine and long to longer in the aeolian sandy soil. Overall, a 3% CSB addition may be a promising and sustainable strategy for maintaining cotton productivity in aeolian sandy soil in the Xinjiang region.

Silk Fibroin Coated Magnesium Oxide Nanospheres: A Biocompatible and Biodegradable Tool for Noninvasive Bioimaging Applications.

Fluorescent nanoparticles (NPs) have been increasingly studied as contrast agents for better understanding of biological processes at the cellular and molecular level. However, their use as bioimaging tools is strongly dependent on their optical emission as well as their biocompatibility. This work reports the fabrication and characterization of silk fibroin (SF) coated magnesium oxide (MgO) nanospheres, containing oxygen, Cr3+ and V2+ related optical defects, as a nontoxic and biodegradable hybrid platform for bioimaging applications. The MgO-SF spheres demonstrated enhanced emission efficiency compared to noncoated MgO NPs. Furthermore, SF sphere coating was found to overcome agglomeration limitations of the MgO NPs. The hybrid nanospheres were investigated as an in vitro bioimaging tool by recording their cellular uptake, trajectories, and mobility in human skin keratinocytes cells (HaCaT), human glioma cells (U87MG) and breast cancer cells (MCF7). Enhanced cellular uptake and improved intracellular mobilities of MgO-SF spheres compared to MgO NPs was demonstrated in three different cell lines. Validated infrared and bright emission of MgO-SF NP indicate their prospects for in vivo imaging. The results identify the potential of the hybrid MgO-SF nanospheres for bioimaging. This study may also open new avenues to optimize drug delivery through biodegradable silk and provide noninvasive functional imaging feedback on the therapeutic processes through fluorescent MgO.

Rational Design of Hyaluronic Acid-Based Copolymer-Mixed Micelle in Combination PD-L1 Immune Checkpoint Blockade for Enhanced Chemo-Immunotherapy of Melanoma.

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.

Benefits of organic manure combined with biochar amendments to cotton root growth and yield under continuous cropping systems in Xinjiang, China.

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.

New polyazamacrocyclic 3-hydroxy-4-pyridinone based ligands for iron depletion antitumor activity.

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.

CdS quantum dots/Au nanoparticles/ZnO nanowire array for self-powered photoelectrochemical detection of Escherichia coli O157:H7.

In this paper, the hydrothermally grown ZnO nanowire array (NWs) was modified by Au nanoparticles (NPs) and CdS quantum dots (QDs) to construct a high-performance photoelectrochemical (PEC) electrode. The aligned ZnO NWs, which decorated Au NPs and CdS QDs have the effective light absorption range from UV to visible region. This hybrid structure provided a self-powered PEC electrode with a favorable energy-band configuration for fast charge separation and transportation. Meanwhile, the Au NPs and CdS QDs also made increase of the surface area to improve the immobilization of the analytes. After assembling aptamer as recognition element, this composite nanoarray was further developed as a self-powered PEC biosensor by synergizing above multiple enhancement factors. The PEC aptasensor exhibited a rapid response in a wide linear range of 10-107 CFU/mL with the detection limit as low as 1.125 CFU/mL to Escherichia coli O157:H7 (E. coli O157:H7). This approach would offer an alternative PEC transduction for fast environment monitoring and clinical diagnosis related to pathogenic bacteria.

Acanthoic acid modulates lipogenesis in nonalcoholic fatty liver disease via FXR/LXRs-dependent manner.

Acanthoic acid (AA) is a pimaradiene diterpene isolated from Acanthopanax koreanum Nakai (Araliaceae), with anti-inflammatory and hepatic-protective effects. The present study intended to reveal the effect and mechanism of AA on nonalcoholic fatty liver disease (NAFLD) associated with lipid accumulation by activating Farnesoid X receptor (FXR) and liver X receptors (LXRs) signaling. C57BL/6 mice were received a modified Lieber-DeCarli diet with 71% high-fat (L-D) and treated with AA (20 and 40 mg/kg) or equal volume of saline for 12 weeks. The regulation of AA on lipid accumulation was also detected in pro-steatotic stimulated AML12 cells with palmitic acid (PA). When L-D diet-fed mice were treated with AA, loss in body weight, liver index, and liver lipid droplet were observed along with reduced triglyceride (TG) and serum transaminase. Furthermore, AA decreased sterol regulatory element binding protein 1 (SREBP-1) and target genes expression, regulated PPARα and PPARγ expressions, ameliorated hepatic fibrosis markers, enhanced hepatic FXR and LXR, and regulated AMPK-LKB1 and SIRT1 signaling pathway. Moreover, AA attenuated lipid accumulation via FXR and LXR activation in steatotic AML-12 cells, which was confirmed by guggulsterones (FXR antagonist) or GW3965 (LXR agonist). Activation of FXR and LXR signaling caused by AA might increase AMPK-SIRT1 signaling and then contribute to modulating lipid accumulation and fatty acid synthesis, which suggested that activated FXR-LXR axis by AA represented an effective strategy for relieving NAFLD.

Ultrasensitive immunosensor for acrylamide based on chitosan/SnO2-SiC hollow sphere nanochains/gold nanomaterial as signal amplification.

An electrochemical immunosensor for ultrasensitive detection of acrylamide (AA) in water and food samples was developed. SnO2-SiC hollow sphere nanochains with high surface area and gold nanoparticles with good electroconductivity were fabricated onto the surface of a glassy carbon electrode pre-coated with chitosan. The coating antigen (AA-4-mercaptophenylacetic acid-ovalbumin conjugate, AA-4-MPA-OVA) was immobilized on the electrode. Polyclonal antibody specific for AA-4-MPA was conjugated to gold nanorod (AuNR) as primary antibody (AuNR-Ab1). Horseradish peroxidase labelled anti-rabbit antibody produced in goat was conjugated to AuNR as secondary antibody (HRP-AuNR-Ab2). For detection, the analyte (AA-4-MPA) in sample competed with coating antigen for binding with AuNR-Ab1. After washing, HRP-AuNR-Ab2 was added to capture the AuNR-Ab1, and the electrical signal was obtained by addition of hydroquinone and H2O2. After investigation of the binding ability on nanomaterials and optimization of competitive immunoassay conditions, the proposed immunosensor exhibited a sensitive response to AA with a detection limit of 45.9 ±â€¯2.7 ng kg-1, and working range of 187 ±â€¯12.3 ng kg-1 to 104 ±â€¯8.2 µg kg-1 for drinking water samples. Recoveries of AA from spiked samples were ranged from 86.0% to 115.0%. The specificity, repeatability and stability of the immunosensor were also proved to be acceptable, indicating its potential application in AA monitoring.

Portable amperometric immunosensor for histamine detection using Prussian blue-chitosan-gold nanoparticle nanocomposite films.

Histamine (HA) is a biogenic amine that can accumulate to high concentration levels in food as a result of microbial activity and can cause toxic effects in consumers. In this work, a portable electrochemical immunosensor capable of detecting HA with high sensitivity and selectivity was developed. Prussian blue-chitosan-gold nanoparticle (PB-CS-AuNP) nanocomposite films with excellent biocompatibility were synthesized and characterized by scanning electron microscopy and energy dispersive X-ray analysis. The PB-CS-AuNP were coated onto a screen-printed electrode by one-step electrodeposition and used to conjugate the HA ovalbumin conjugate (HA-Ag). HA was determined by a competition between the coating HA-Ag and the HRP labeled HA antibody (HRP-HA-Ab). After careful optimization of assay conditions and Box-Behnken analysis, the developed immunosensor showed a linear range from 0.01 to 100µg/mL for HA in fish samples. The average recoveries from spiked samples ranged from 97.25% to 105%. The biosensor also showed good specificity, reproducibility, and stability, indicating its potential application in monitoring HA in a simple and low cost manner.

Development of a progesterone immunosensor based on thionine-graphene oxide composites platforms: Improvement by biotin-streptavidin-amplified system.

Progesterone (P4) is a kind of hormone that can cause neuropathic disturbances in humans when the concentration overpasses a certain degree. In this work, an electrochemical immunosensor capable of detecting P4 sensitively and selectively was developed. Thionine-graphene oxide (Thi-GO) composites with excellent biocompatibility were synthesized and coated to a clear glassy carbon electrode. P4 coating antigen (P4-OVA) was immobilized to the electrode, then sample as well as biotinylated antibody (biotin-P4 Ab) were added. The free P4 can compete with P4-OVA for binding to biotin-P4 Ab. After the further addition of streptavidin-HRP, H2O2 was introduced to develop electrical signal for quantitative determination of P4. After careful optimization of assay conditions, the proposed immunosensor showed a linear range from 0.02 to 20ngmL-1 for P4 in milk samples. The averaged recoveries from spiked samples ranged from 84.0% to 102.0%, which correlated well with standard HPLC-MS/MS. The biosensor also showed good specificity, reproducibility and stability, indicating its potential application in monitoring of P4 in a simple and low cost manner.