Ag-CeO2 Based on Electrochemical Sensor for High-Efficient On-Site Detection of Nitrite in Aquaculture Water and Beverages.

Nitrite is one of the most common nitrogenous compounds, which is not only an important indicator of aquaculture water but also widely used as a food additive. Its potential toxicity poses a huge threat to aquatic products and human health. Therefore, it is important to develop a convenient and rapid sensor for the high-efficient onsite detection of nitrite. In this work, a novel electrochemical sensor was developed for the qualitative and quantitative analysis of nitrite. The developed nitrite electrochemical detection system is easily applied in onsite detection. The electrochemical working electrode was constructed based on the combination of Ag-CeO2 and conductive carbon paste (CPE) with excellent electrocatalysis activity and rapid electron transfer ability. By the application of the developed system and under the optimal conditions, the linear range was from 40.0 µM to 500.0 µM, and the detection limit was reduced to 4.3 µM. The recovery was between 92.1% and 108.1%, and the relative standard deviations (RSDs) were 0.49%~9.31%. The sensor exhibited superior reproducibility, high stability sensitivity, and anti-interference ability, confirming its effectiveness for nitrite analysis. Finally, the developed electrochemical sensor was successfully applied to detect nitrite in beverages and aquaculture water samples, indicating that this approach has great potential in onsite food testing and environmental monitoring.

Facile Recycling of Waste Biomass for Preparation of Hierarchical Porous Carbon with High-Performance Electromagnetic Wave Absorption.

Hierarchical-porous-structured materials have been widely used in the field of electromagnetic wave (EMW) absorption, playing a critical role in minimizing EMW interference and pollution. High-quality EMW absorbers, characterized by a lower thickness, lighter weight, wider absorption band, and stronger absorption capacity, have been instrumental in reducing damage and preventing malfunctions in the automotive and aviation industries. The utilization of discarded nut shells through recycling can not only alleviate environmental problems but relieve resource constraints. Herein, a facile method for the preparation of hierarchical porous biomass carbon derived from abandoned Xanthoceras Sorbifolium Bunge Shell (XSS) biomass was developed for high-performance EMW absorption. The porous structures of XSS biochar were studied by using different levels of the K2CO3 activator and simple carbonization. The effect of K2CO3 on the EMW parameters, including the complex permittivity, complex permeability, polarization relaxation, and impedance matching, was analyzed. The best EMW absorption performance of the XSS biochar was observed at a mass ratio of activator-to-biomass of 2:1. A minimum reflection loss (RLmin) of -38.9 dB was achieved at 9.12 GHz, and a maximum effective absorption bandwidth (EABmax) of up to 3.28 GHz (14.72~18.0 GHz) could be obtained at a 1.8 mm thickness. These results demonstrated that hierarchical porous XSS carbon was prepared successfully. Simultaneously, the prepared XSS biochar was confirmed as a potential and powerfully attractive EMW-absorbing material. The proposal also provided a simple strategy for the development of a green, low-cost, and sustainable biochar as a lightweight high-performance absorbing material.

Hierarchically Annular Mesoporous Carbon Derived from Phenolic Resin for Efficient Removal of Antibiotics in Wastewater.

Antibiotics have become a new type of environmental pollutant due to their extensive use. High-performance adsorbents are of paramount significance for a cost-effective and environmentally friendly strategy to remove antibiotics from water environments. Herein, we report a novel annular mesoporous carbon (MCN), prepared by phenolic resin and triblock copolymer F127, as a high-performance adsorbent to remove penicillin, streptomycin, and tetracycline hydrochloride from wastewater. The MCNs have high purity, rich annular mesoporosity, a high surface area (605.53 m2/g), and large pore volume (0.58 cm3/g), improving the adsorption capacity and facilitating the efficient removal of penicillin, streptomycin, and tetracycline hydrochloride from water. In the application of MCNs to treat these three kinds of residual antibiotics, the adsorption amounts of tetracycline hydrochloride were higher than penicillin and streptomycin, and the adsorption capacity was up to 880.6 mg/g. Moreover, high removal efficiency (99.6%) and excellent recyclability were achieved. The results demonstrate that MCN adsorbents have significant potential in the treatment of water contaminated with antibiotics.

Identification of super-enhancer-associated transcription factors regulating glucose metabolism in poorly differentiated thyroid carcinoma.

This study aimed to uncover transcription factors that regulate super-enhancers involved in glucose metabolism reprogramming in poorly differentiated thyroid carcinoma (PDTC). TCA cycle and pyruvate metabolism were significantly enriched in PDTC. Differentially expressed genes in PDTC vs. normal control tissues were located in key steps in TCA cycle and pyruvate metabolism. A total of 23 upregulated genes localized in TCA cycle and pyruvate metabolism were identified as super-enhancer-controlled genes. Transcription factor analysis of these 23 super-enhancer-controlled genes related to glucose metabolism was performed, and 20 transcription factors were obtained, of which KLF12, ZNF281 and RELA had a significant prognostic impact. Regulatory network of KLF12, ZNF281 and RELA controlled the expression of these four prognostic target genes (LDHA, ACLY, ME2 and IDH2). In vitro validation showed that silencing of KLF12, ZNF281 and RELA suppressed proliferation, glucose uptake, lactate production and ATP level, but increased ADP/ATP ratio in PDTC cells. In conclusion, KLF12, ZNF281 and RELA were identified as the key transcription factors that regulate super-enhancer-controlled genes related to glucose metabolism in PDTC. Our findings contribute to a deeper understanding of the regulatory mechanisms associated with glucose metabolism in PDTC, and advance the theoretical development of PDTC-targeted therapies.

Simultaneous Quantification of Ampicillin and Kanamycin in Water Samples Based on Lateral Flow Aptasensor Strip with an Internal Line.

In this work, a simple and rapid method based on the lateral flow assay (LFA) has been developed for the detection of dual antibiotics. To achieve the quantitative assay and to reduce the non-specific adsorption, an internal system has been developed. A non-specific DNA was exploited as an internal standard and could be recognized by the DNA marker that was coated at the internal line. Two different kinds of aptamers were applied to recognize ampicillin (AMP) and kanamycin (KAM), and the distance between the detection line and conjugate pad was then optimized. Under the optimum conditions, the quantitative assays of AMP (R2 = 0.984) and KAM (R2 = 0.990) were achieved with dynamic ranges of 0.50 to 500.0 ng/L, and of 0.50 to 1000.0 ng/L, respectively. The LOQs of AMP and KAM were 0.06 ng/L and 0.015 ng/L, respectively. Finally, the proposed method has been successfully applied to analyze aquaculture water, tap water, and lake water, and hospital wastewater, indicating the established method could be used to monitor the environment.

Self-Assembly of Functional Nucleic Acid-Based Colorimetric Competition Assay for the Detection of Immunoglobulin E.

In this work, we have developed a simple and rapid colorimetric assay for the detection of immunoglobulin E (IgE) using functional nucleic acids (FNAs) and a solid-phase competition enzyme-linked immunosorbent assay (ELISA). The FNAs including aptamer of recombinant IgE, G-quadruplex and its complementary fragments were immobilized on 96-well microplates to achieve recognition and detection of IgE in biological samples. The G-quadruplex DNAzyme catalyzed 2,2'-Azino-bis (3-ethylbenzothiazoline-6-sulfonic acid (ABTS)-hemin-H2O2 system was used to improve the sensitivity of colorimetric assay. In the presence of IgE, the hairpin structure and G-quadruplex would be destroyed, resulting in the inactivation of DNAzyme and subsequent reduction of its absorbance. This cost-effective approach detected IgE in the linear range from 5.0 pg/mL to 500 ng/mL, with the limit of detection (LOD) of 2.0 pg/mL, under optimal conditions. Moreover, the developed method was successfully applied to the rapid detection of IgE in human urine, indicating a great potentiality of this approach in clinical diagnosis and other biomedical applications.

Dual-Responsive Alginate Hydrogels for Controlled Release of Therapeutics.

In this work, with the drug oxytetracycline (OTC) released, cell cytotoxicity and antimicrobial studies of dual-responsive sodium alginate and N-Isopropylacrylamide hydrogels (SA/pNIPAAm) with enclosed OTC were investigated. The molecular OTC release was explored with different acid-base conditions and temperature conditions. In order to characterize cell cytotoxicity and antimicrobial efficacy, time-dependent OTC release analysis of different acid-base conditions was performed in SA/pNIPAAm hydrogels. OTC@SA/pNIPAAm hydrogels showed excellent time-dependent antimicrobial efficacy, in which the IC50 values were 50.11 µg mL-1, 34.27 µg mL-1, and 22.39 µg mL-1 among three consecutive days, respectively. Meanwhile, the human cells showed excellent viability at the IC50 dosage of OTC@SA/pNIPAAm (50.11 µg mL-1). OTC@SA/pNIPAAm performed in this study indicated that SA/pNIPAAm may serve as drug carriers for sustainable release at a specific concentration and for being employed as substrates for decreasing drug toxicity. Besides, pH-responsive and thermos-responsive SA/pNIPAAm may lead to the better selectivity of drug release in the ideal location or site. Finally, the results demonstrate that the designed, dual-responsive, biocompatible OTC@SA/pNIPAAm hydrogels showed excellent antimicrobial efficacy and may potentially be found to have enormous applicability in the field of pharmaceutics.

Reconstituting Glioma Perivascular Niches on a Chip for Insights into Chemoresistance of Glioma.

In this work, we report the direct diagnosing chemoresistance of glioma stem cells (GSCs) during chemotherapy on a biomimetric microsystem that reconstitutes glioma perivascular niches on a chip. Glioma stem cells and endothelial cells were specially cocultured onto the biomimetric system to precisely control stem cell coculture for the proof-of-principle studies. The expression levels of 6- O-methylguanine was confirmed by mass spectrometer, and Bmi-1 gene was also investigated to uncover the chemoresistance of GSCs. The results demonstrated that the formation of perivascular niches effectively maintains the glioma stem cells at a pluripotent status owing to their successful cellular interactions. A stronger chemoresistance of glioma stem cells was confirmed by the formation of the GSCs neurosphere, the expression levels of 6- O-methylguanine and Bmi-1 gene. The vital role of endothelial cells in chemoresistance was demonstrated. The chemoresistance reported in this work will contribute to glioma therapy.

Integrated Microfluidic Platform with Multiple Functions To Probe Tumor-Endothelial Cell Interaction.

Interaction between tumor and endothelial cells could affect tumor growth and progression and induce drug resistance during cancer therapy. Investigation of tumor-endothelial cell interaction involves cell coculture, protein detection, and analysis of drug metabolites, which are complicated and time-consuming. In this work, we present an integrated microfluidic device with three individual components (cell coculture component, protein detection component, and pretreatment component for drug metabolites) to probe the interaction between tumor and endothelial cells. Cocultured cervical carcinoma cells (CaSki cells) and human umbilical vein endothelial cells (HUVECs) show higher resistance to chemotherapeutic agents than single-cultured cells, indicated by higher cell viability, increased expression of angiogenic proteins, and elevated level of paclitaxel metabolites under coculture conditions. This integrated microfluidic platform with multiple functions facilitates understanding of the interaction between tumor and endothelial cells, and it may become a promising tool for drug screening within an engineered tumor microenvironment.

Online multi-channel microfluidic chip-mass spectrometry and its application for quantifying noncovalent protein-protein interactions.

To establish an automatic and online microfluidic chip-mass spectrometry (chip-MS) system, a device was designed and fabricated for microsampling by a hybrid capillary. The movement of the capillary was programmed by a computer to aspirate samples from different microfluidic channels in the form of microdroplets (typically tens of nanoliters in volume), which were separated by air plugs. The droplets were then directly analyzed by MS via paper spray ionization without any pretreatment. The feasibility and performance were demonstrated by a concentration gradient experiment. Furthermore, after eliminating the effect of nonuniform response factors by an internal standard method, determination of the association constant within a noncovalent protein-protein complex was successfully accomplished with the MS-based titration indicating the versatility and the potential of this novel platform for widespread applications.

A comparative study of three different nucleic acid amplification techniques combined with microchip electrophoresis for HPV16 E6/E7 mRNA detection.

Research towards nucleic acid amplification technologies for detection of human papillomavirus (HPV) 16 E6/E7 mRNA was carried out in combination with microchip electrophoresis (MCE). The approaches of nucleic acid sequence based amplification (NASBA), one-step RT-PCR and two-step RT-PCR were successfully developed. NASBA was a simple enzymatic reaction, which directly amplified HPV16 mRNA by isothermal amplification, leaving out the complex and tedious operation. One-step RT-PCR simplified the amplification step, while two-step RT-PCR was more sensitive and less vulnerable to the interference. Furthermore, instead of gel electrophoresis, microchip electrophoresis (MCE) for RNA assay was employed to realize high-throughput and rapid analysis. Finally, the results show that PCR-based or NASBA-based mRNA tests are valuable for HPV mRNA assay, which can be potentially applied for clinical diagnosis and prognosis of cervical and other anogenital carcinoma.

Interfacing microsampling droplets and mass spectrometry by paper spray ionization for online chemical monitoring of cell culture.

In this work, the establishment of a microdialysis-paper spray ionization-mass spectrometry (MS) system was described. A homemade microdialysis module was employed for sampling, and microdroplets were generated at the outlet of the capillary conducting the dialysate. Online MS analysis of each microdroplet was immediately accomplished, interfacing by paper spray ionization. Analytical performance of the method was investigated and improved through the introduction of thinner capillary tubes and the optimization of spray solvent and paper substrate. For microdroplets with concentrated salt at 50 nL, the limit of detection at 0.8 ppm (or 40 pg absolute) and a highest resolution at about 1.5 s were achieved. The integrated system was applied into the online monitoring of glucose concentration in cell culture mediums. A satisfactory linearity of the calibration curve between the relative MS intensity and the glucose concentration was observed. Furthermore, as a model, hormone regulation of the glucose concentration was investigated. This work demonstrated the potential application of the label-free, online "MS sensor" into studies on cellular metabolism.

High-throughput and automatic typing via human papillomavirus identification map for cervical cancer screening and prognosis.

A novel human papillomavirus (HPV) typing assay for cervical cancer screening and prognosis was developed by the combination of restriction fragment length polymorphism (RFLP) and microchip electrophoresis (MCE) to achieve higher levels of sensitivity and throughput. The detection limit of 2 × 10(2) copies, high sensitivity and typing accuracy on the account of PCR-RFLP-MCE method guarantee the successful diagnosis results of 4-fold higher infection rate over cytologic tests. From clinical samples, eleven kinds of HPV types were identified with a good compatibility degree of over 90%. The described method showed good reliability in clinical samples and provided a promising alternative for pathological studies at the molecular level.

Detection of BCR-ABL using one step reverse transcriptase- polymerase chain reaction and microchip electrophoresis.

One-step reverse transcriptase polymerase chain reaction (RT-PCR) coupled with microchip electrophoresis (MCE) was established to analyze BCR-ABL fusion gene. The use of one-step RT-PCR could simplify the RT-PCR procedure and thus reduced the risk of contamination and sample consumption. This method also enhanced the sensitivity for amplified target DNA and dramatically shorted the analysis time. Moreover, this assay can simultaneously identify b2a2 and b3a2. Orthogonal array design, which can investigated mutual effects of PCR parameters, was used to optimize the reaction system. This approach was highly effective, reproducible and sensitive, and would be suitable for the determination of BCR-ABL in clinic diagnosis.

A parallel G-quadruplex-selective luminescent probe for the detection of nanomolar calcium(II) ion.

A parallel G-quadruplex-selective iridium(III) complex has been synthesized and employed as a luminescent probe in a label-free G-quadruplex-based detection assay for Ca(2+) ions in aqueous solution. In this assay, a guanine-rich oligonucleotide (G4, 5'-G4T4G4-3') initially exists in an antiparallel G-quadruplex conformation, resulting in a low luminescence signal. Upon incubation with Ca(2+) ions, the antiparallel G-quadruplex is induced into a parallel G-quadruplex conformation, which greatly enhances the luminescence emission of the iridium(III) probe. This method was highly sensitive for Ca(2+) ions with a limit of detection in the nanomolar range, and was selective for Ca(2+) over other metal ions.

A simple integrated microfluidic platform for the research of hydrogels containing gradients in cell density induced breast cancer electrochemotherapy.

Cell density is important for tumour metastasis, treatment and prognosis. Characterizing changes in cell density for electrochemotherapy (ECT) can reveal sub-populations in pathological states, and adjust treatment program. In this work, a simple and convenient microfluidic platform was developed to study the effect cell density on ECT by integrating the improved cell gradient generator, cell culture chamber and indium tin oxide interdigital electrodes. Agarose, as extracellular matrix (ECM), was used to 3D cell culture to imitate in vivo microenvironment. The precision and reproducibility of cell density gradient with agarose solution were achieved because the hydrophobic modification of microchannels surface resulted in reducing cell adhesion and residue. ECT cytotoxicity assay with difference in cell densities was studied. The results showed that tumour cell density is one of the most factors for ECT treatment and ECT cytotoxicity has a certain of cell density-depended. But only electroporation on low cell density level, ECM would be one of the most key factors for ECT cytotoxicity, which would provide a new idea for chip-based cell assay in clinical diagnosis and drug screening in ordinary laboratories.

MiR-1286 inhibits lung cancer growth through aerobic glycolysis by targeting PKM2.

Introduction: This study aims to explore the effects of microRNA-1286 (miR-1286) on the development of non-small cell lung cancer (NSCLC) via the aerobic glycolysis pathway by targeting pyruvate kinase muscle isozyme M2 (PKM2). Material and methods: The mRNA levels of miR-1286 in NSCLC tissues and mouse tumor tissues were detected by q-PCR. MiR-1286 was knocked down and overexpressed separately in A549 cells. The effect of miR-1286 on cell proliferation was determined by CCK8 assay. Western blotting was used to measure the expression of PKM2 protein. Lactate production assay was used to detect the aerobic glycolysis in A549 cells. The effect of miR-1286 in vivo was determined by xenograft assay. Results: The mRNA level of miR-1286 decreased in NSCLC tissues compared with paired, tumor adjacent normal tissues. In addition, miR-1286 inhibited A549 cell proliferation in vitro. Moreover, knockdown of miR-1286 increased PKM2 expression and lactate production. Thus, miR-1286 expression negatively correlated with PKM2 in A549 cells. At the same time, in vivo experiments also showed that miR-1286 suppressed the growth of A549 cells and PKM2 was the target gene of miR-1286. Conclusions: These data show that miR-1286 inhibits lung cancer proliferation via aerobic glycolysis by targeting PKM2, which suggests that the functions of miR-1286 in NSCLC may play a key role in tumor progression and that miR-1286 can be a promising predictive biomarker and potential therapeutic target for NSCLC.

A Minireview for Recent Development of Nanomaterial-Based Detection of Antibiotics.

Antibiotics are considered a new type of organic pollutant. Antibiotic residues have become a global issue due to their harm to human health. As the use of antibiotics is increasing in human life, such as in medicine, crops, livestock, and even drinking water, the accurate analysis of antibiotics is very vital. In order to develop rapid and on-site approaches for the detection of antibiotics and the analysis of trace-level residual antibiotics, a high-sensitivity, simple, and portable solution is required. Meanwhile, the rapid nanotechnology development of a variety of nanomaterials has been achieved. In this review, nanomaterial-based techniques for antibiotic detection are discussed, and some reports that have employed combined nanomaterials with optical techniques or electrochemical techniques are highlighted.

Automated online pretreatment and cleanup recycle coupled with high-performance liquid chromatography-mass spectrometry for determination of deca-bromodiphenyl ether in human serum.

Automated online SPE-HPLC-MS was established for the determination of deca-bromodiphenyl ether in human serum. The online SPE with large volume injection was utilized to enhance the sensitivity. Online SPE with dilution line greatly decreased matrices effect, which enabled serum samples to be injected directly into pre-column. Washing line was designed for the system to solve the serious residual phenomenon and reduce the risk of sample wastage and contamination. Under the optimized conditions, the linear of the method was in the range 0.1-10 ng/mL with the LOD of 0.026 ng/mL. The recoveries of serum samples spiked with deca-bromodiphenyl ether at 0.5 ng/mL was in the range from 83.30 to 102.7% with RSD in interday less than 8.67%. The satisfactory results demonstrated that the method of online sample pretreatment and cleanup recycle were reliable for human serum analysis.

Inkjet printing-assisted single-cell microarray on a hydrophobic surface chip for real-time monitoring of enzyme kinetics at single-cell level.

A convenient, facile, and mask-free approach assay was developed for single-cell study by using a combination of inkjet printing technology and polydimethylsiloxane (PDMS) microchip-assisted processing. The inkjet printing technology resulted in 91% of the single-cell occupancy by individually spraying MCF-7 cells on a hydrophobic substrate and enabled the control over the number of cells with precision by strictly optimizing the printing parameters. Further, the microchip containing a cell chamber and straight channels was attached to the glass slide to explore the real-time performance of the cells. To address the performance attributes, the enzyme kinetics and various parameters of the post-printed MCF-7 cells, such as the levels of cell viability, reactive oxygen species (ROS), cell apoptosis, and proliferation, are monitored in real-time. Interestingly, high activity and proliferation, low level of ROS, and cell apoptosis demonstrated that the developed method provided a new way to the study of single-cell in-depth. Finally, ATP-induced cell proliferation of different cell number were analyzed, and the results would provide another perspective for the diagnosis and medical treatment.