Study on the preparation of molecular imprinted polymer for analysis of N-phenylglycine in human urine

N-phenylglycine (NPG) in human urine could be an important biomarker for predicting cancers, but its detection has difficulty due to its low abundance in urine. Herein, we report a molecular imprinted polymer (MIP) method to efficiently recognize NPG in urine. The MIP was prepared by precipitation polymerization, adopting NPG as the template, acrylamide (AM) as functional monomer, trimethylpropane triacrylate (TRIM) as crosslinking agent, and acetonitrile as porogen. The specificity and selectivity of MIP towards NPG in human urine were determined by comparing MIP's adsorption to the NPG and N-crotonylglycine (NTG) under the same conditions. The result β = Q_MIP-NPG/Q_MIP-NTG = 4.7 indicated the satisfactory specificity and selectivity. Parameters affecting the extraction efficiency were further optimized. Under the optimum conditions, the linear range, limit of detection, and limit of quantification of NPG were 0.5-100 mg∙L^-1, 1.6 × 10^-2 mg∙L^-1, and 5.5 × 10^-2 mg∙L^-1, respectively. Recoveries of NPG in human urine were in the range of 84.7-100.0% with RSD_S of 3.8-10.8%. The developed method demonstrated superior selectivity to the target analyte, which can be applied to separate and enrich the NPG from urine samples.

Multiplexed all-solid-state ion-sensitive light-addressable potentiometric sensor (ISLAPS) system based on silicone-rubber for physiological ions detection

Light-addressable potentiometric sensor (LAPS) has been widely used in biomedical applications since its advent. As a member of the potentiometric sensors, ion-sensitive LAPS (ISLAPS) can be obtained by modifying ion selective sensing membrane on the sensor surface. Compared with the conventional ion-selective electrodes (ISEs) with liquid contact, the all-solid-state ISEs have more advantages such as easy maintenance, more convenient for miniaturization and practical applications. However, the commonly used ion-sensitive membrane (ISM) matrix like PVC has many limitations such as poor adhesion to silicone-based sensor and easy overflow of the plasticizer from the membrane. In this work, LAPS was combined with a variety of ionophore-doped all-solid-state silicone-rubber ISMs for the first time, to establish a program-controlled multiplexed ISLAPS system for physiological ions (Na⁺, K⁺, Ca²⁺ and H⁺) detection. The silicone-rubber ISMs have better adhesion to silicon-based sensors without containing plasticizers, which can avoid the plasticizer pollution and improve the long-term stability. A layer of poly(3-octylthiophene-2,5-diyl) (P3OT) was pre-modified on the sensor surface to inhibit the formation of an aqueous layer and improve the sensor lifetime. With the aid of a translation stage, the light spot automatically illuminated the detection sites in sequence, and the response of the four ions could be obtained in one measurement within 1 min. The proposed multiplexed ISLAPS has good sensitivity with micromolar limit of detection (LOD), good selectivity and long-term stability (more than 3 months). The results of the real Dulbecco's Modified Eagle Medium (DMEM) sample detection proved that the ISLAPS system can be used for the physiological ions detection, and is promising to realize a multi-parameter microphysiometer.

[Interim follow-up of fetal cardiac intervention in five fetuses with pulmonary atresia with intact ventricular septum]

Objective: To summarize the interim outcome and right heart development of pulmonary atresia with intact ventricular septum (PA-IVS) in children after fetal cardiac intervention (FCI). Methods: The clinical data of 5 live births underwent FCI from October 2018 to April 2019 in Women and Children's Hospital, Qingdao University were analyzed retrospectively. The development of right ventricle (RV) and tricuspid valve (TV) in uterus after FCI, at birth, the age of 6 months, 1 year and 2 years, and the final outcome were assessed. Results: Five PA-IVS fetuses were included in this study. The first evaluation was performed at 24-26 weeks of gestational age, and the FCI was performed at 26-28 weeks of gestational age. During the follow-up of 6 weeks after FCI, the minimum diameter of tricuspid annulus increased from 0.85 cm to 0.92 cm, and the minimum Z-score of tricuspid annulus decreased from -0.03 to -1.62. The minimum values of TV/mitral valve annular diameter and RV/left ventricular length ratios of all fetuses increased from 0.57, 0.52 to 0.88, 0.82, respectively. The maximum tricuspid regurgitation velocity decreased from 4.60 m/s to 3.64 m/s. No severe hemodynamic change was found in any of the fetuses. All 5 fetuses were born alive. Three cases underwent percutaneous balloon pulmonary valvuloplasty (PBPV) and stent implantation for ductus arteriosus. Two cases received PBPV alone. At follow-up (26 to 32 months), obvious development of TV was observed 6 months to 1 year after birth in 5 cases with the growth rate ranging from 19.64% to 40.00%. Meanwhile, the RV development was relatively slow at 6 months with the growth rate ranging from 9.41% to 21.42%. There were individual differences in RV development at 2 years. The growth and development of all children were equal to healthy children of the same age with the body mass index less than 18.4 kg/m². At the last follow-up, all children had a transcutaneous oxygen saturation of greater than 0.95, three became biventricular circulation and two had circulation approximation to biventricular circulation with almost closed stent. Conclusions: The findings support the potential of development of right ventricular and tricuspid valve for fetuses with PA-IVS underwent FCI. All fetuses underwent FCI received intervention after birth, and biventricular circulation can be realized finally. The development of right ventricular and tricuspid valve is not proportional. In utero, the right ventricle develops rapidly, and the development of tricuspid valve is more advantageous after birth.

Spatial and Temporal Characteristics of PM2.5 Sources and Pollution Events in a Low Industrialized City

In recent years, cities in southern China have experienced severe air pollution, despite having few sources of pollutants. To study the pollution characteristics of PM2.5 in these “low industrialized” cities, a numerical method based on the HYSPLIT4 Model and Kriging Spatial Interpolation Technology was established. Simulation results showed that the PM2.5 pollution in Guilin was affected by both internal and external sources. The backward air mass trajectory from July 2017 to June 2018 was simulated using the HYSPLIT model. The cluster analysis results indicated that the direction of trajectory ? accounted for 63.09% of the air pollution in the city. The average concentration of PM2.5 pollution was 45.94 ?g.m-3. The pollutant originated from the “Xiang-Gui Corridor.” The location of the sources was collocated with high industry regions. The spatial characteristics of the four pollution processes in the winter of 2017 were analyzed using a spatial interpolation method. The results showed that the transport of air masses in the direction of trajectory ? was obstructed by a mountain system in the northeast. Therefore, two air pollution accumulation centers and a topographic weakening zone dominated by internal and external sources were formed. It can be inferred that the air pollution in Guilin is affected by both internal and external factors. These results provide important theoretical and technical support for regional air pollution control and environmental protection.

Electrochemical Nitric Oxide Reduction on Metal Surfaces

Electrocatalytic denitrification is a promising technology for removing NO_x species (NO₃ ^- , NO₂ ^- and NO). For NO_x electroreduction (NO_x RR), there is a desire for understanding the catalytic parameters that control the product distribution. Here, we elucidate selectivity and activity of catalyst for NO_x RR. At low potential we classify metals by the binding of *NO versus *H. Analogous to classifying CO₂ reduction by *CO vs. *H, Cu is able to bind *NO while not binding *H giving rise to a selective NH₃ formation. Besides being selective, Cu is active for the reaction found by an activity-volcano. For metals that does not bind NO the reaction stops at NO, similar to CO₂ -to-CO. At potential above 0.3 V vs. RHE, we speculate a low barrier for N coupling with NO causing N₂ O formation. The work provides a clear strategy for selectivity and aims to inspire future research on NO_x RR.

COPB2: a transport protein with multifaceted roles in cancer development and progression

The Coatomer protein complex subunit beta 2 (COPB2) is involved in the formation of the COPI coatomer protein complex and is responsible for the transport of vesicles between the Golgi apparatus and the endoplasmic reticulum. It plays an important role in maintaining the integrity of these cellular organelles, as well as in maintaining cell homeostasis. More importantly, COPB2 plays key roles in embryonic development and tumor progression. COPB2 is regarded as a vital oncogene in several cancer types and has been implicated in tumor cell proliferation, survival, invasion, and metastasis. Here, we summarize the current knowledge on the roles of COPB2 in cancer development and progression in the context of the hallmarks of cancer.

High-resolution DNA size enrichment using a magnetic nano-platform and application in non-invasive prenatal testing

Precise DNA sizing can boost sequencing efficiency, reduce cost, improve data quality, and even allow sequencing of low-input samples, while current pervasive DNA sizing approaches are incapable of differentiating DNA fragments under 200 bp with high resolution (<20 bp). In non-invasive prenatal testing (NIPT), the size distribution of cell-free fetal DNA in maternal plasma (main peak at 143 bp) is significantly different from that of maternal cell-free DNA (main peak at 166 bp). The current pervasive workflow of NIPT and DNA sizing is unable to take advantage of this 20 bp difference, resulting in sample rejection, test inaccuracy, and restricted clinical utility. Here we report a simple, automatable, high-resolution DNA size enrichment workflow, named MiniEnrich, on a magnetic nano-platform to exploit this 20 bp size difference and to enrich fetal DNA fragments from maternal blood. Two types of magnetic nanoparticles were developed, with one able to filter high-molecular-weight DNA with high resolution and the other able to recover the remaining DNA fragments under the size threshold of interest with >95% yield. Using this method, the average fetal fraction was increased from 13% to 20% after the enrichment, as measured by plasma DNA sequencing. This approach provides a new tool for high-resolution DNA size enrichment under 200 bp, which may improve NIPT accuracy by rescuing rejected non-reportable clinical samples, and enable NIPT earlier in pregnancy. It also has the potential to improve non-invasive screening for fetal monogenic disorders, differentiate tumor-related DNA in liquid biopsy and find more applications in autoimmune disease diagnosis.

Cardiomyocyte electrical-mechanical synchronized model for high-content, dose-quantitative and time-dependent drug assessment

Cardiovascular diseases have emerged as a significant threat to human health. However, drug development is a time-consuming and costly process, and few drugs pass the preclinical assessment of safety and efficacy. The existing patch-clamp, Ca2+ imaging, and microelectrode array technologies in cardiomyocyte models for drug preclinical screening have suffered from issues of low throughput, limited long-term assessment, or inability to synchronously and correlatively analyze electrical and mechanical signals. Here, we develop a high-content, dose-quantitative and time-dependent drug assessment platform based on an electrical-mechanical synchronized (EMS) biosensing system. This microfabricated EMS can record both firing potential (FP) and mechanical beating (MB) signals from cardiomyocytes and extract a variety of characteristic parameters from these two signals (FP-MB) for further analysis. This system was applied to test typical ion channel drugs (lidocaine and isradipine), and the dynamic responses of cardiomyocytes to the tested drugs were recorded and analyzed. The high-throughput characteristics of the system can facilitate simultaneous experiments on a large number of samples. Furthermore, a database of various cardiac drugs can be established by heat map analysis for rapid and effective screening of drugs. The EMS biosensing system is highly promising as a powerful tool for the preclinical development of new medicines.

A Robust PtNi Nanoframe/N-Doped Graphene Aerogel Electrocatalyst with Both High Activity and Stability

Insufficient catalytic activity and stability and high cost are the barriers for Pt-based electrocatalysts in wide practical applications. Herein, a hierarchically porous PtNi nanoframe/N-doped graphene aerogel (PtNiNF-NGA) electrocatalyst with outstanding performance toward methanol oxidation reaction (MOR) in acid electrolyte has been developed via facile tert-butanol-assisted structure reconfiguration. The ensemble of high-alloying-degree-modulated electronic structure and correspondingly the optimum MOR reaction pathway, the structure superiorities of hierarchical porosity, thin edges, Pt-rich corners, and the anchoring effect of the NGA, endow the PtNiNF-NGA with both prominent electrocatalytic activity and stability. The mass and specific activity (1647 mA mg_Pt ^-1 , 3.8 mA cm^-2 ) of the PtNiNF-NGA are 5.8 and 7.8 times higher than those of commercial Pt/C. It exhibits exceptional stability under a 5-hour chronoamperometry test and 2200-cycle cyclic voltammetry scanning.

Rationally Designed Multivalent Aptamers Targeting Cell Surface for Biomedical Applications

Specific interactions between ligands and receptors on cell surface play an important role in the cell biological process. Nucleic acid aptamers as commonly used ligands enable specific recognition and tight binding to membrane protein receptors for modulation of cell fate. Therefore, molecular probes with aptamers can be applied for cancer diagnosis and targeted therapy by targeting overexpression membrane proteins of cancer cells. However, because of their fast degradation and rapid glomerulus clearance in vivo, the applications of aptamers in physiological conditions remain challenged. Inspired by natural multivalent interactions, many approaches have been developed to construct multivalent aptamers to improve the performance of aptamers in complex matrices with higher binding affinity, more stability, and longer circulation time. In this review, we first introduce the aptamer generation from purified protein-based SELEX and whole cell-based SELEX for targeting the cell surface. We then highlight the approaches to fabricate multivalent aptamers and discuss their properties. By integrating different materials (including inorganic nanomaterials, diacyllipid, polymeric nanoparticles, and DNA nanostructures) as scaffolds with an interface modification technique, we have summarized four kinds of multivalent aptamers. After that, representative applications in biosensing and targeted therapy are illustrated to show the elevated performance of multivalent aptamers. In addition, we analyze the challenges and opportunities for the clinical practices of multivalent aptamers.

Recent advances in acoustic wave biosensors for the detection of disease-related biomarkers: A review

In the past several decades, acoustic wave biosensors, as an emerging kind of biosensors, have been developed and widely used for the detection of mass, viscosity, conductivity and density. Varieties of applications have been explored such as medical diagnosis, drug screening, environmental monitoring, food analysis and biochemical assay. Among them, the detection of disease-related biomarkers based on acoustic sensors has aroused great research interest all over the world. In this review, the classification and characteristics of acoustic wave biosensors are briefly introduced. Then, some classical studies and recent advances in disease-related biomarker detection utilizing these biosensors are summarized and detailed, respectively. Here, the disease-related biomarkers mainly include antigens, small molecular proteins, cancer cells, viruses and VOCs. Finally, challenges and future trends of these typical acoustic wave biosensors are discussed. Compared with other reviews of acoustic wave sensors, this review highlights the great potential of typical acoustic wave biosensors for early disease screening and diagnosis compared with widely-used medical imaging. Moreover, they are integrated with other technologies for the design of multi-analyte, multi-parameter and intelligent devices, collecting more comprehensive information from biomarkers. This review provides a new perspective on the applications and optimization of acoustic wave biosensors to develop more reliable platforms for disease-related biomarker detection and disease diagnosis.

Self-supported Pt-CoO networks combining high specific activity with high surface area for oxygen reduction

Several concepts for platinum-based catalysts for the oxygen reduction reaction (ORR) are presented that exceed the US Department of Energy targets for Pt-related ORR mass activity. Most concepts achieve their high ORR activity by increasing the Pt specific activity at the expense of a lower electrochemically active surface area (ECSA). In the potential region controlled by kinetics, such a lower ECSA is counterbalanced by the high specific activity. At higher overpotentials, however, which are often applied in real systems, a low ECSA leads to limitations in the reaction rate not by kinetics, but by mass transport. Here we report on self-supported platinum-cobalt oxide networks that combine a high specific activity with a high ECSA. The high ECSA is achieved by a platinum-cobalt oxide bone nanostructure that exhibits unprecedentedly high mass activity for self-supported ORR catalysts. This concept promises a stable fuel-cell operation at high temperature, high current density and low humidification.

c-FLIP regulates pyroptosis in retinal neurons following oxygen-glucose deprivation/recovery via a GSDMD-mediated pathway

Cellular FLICE-inhibitory protein (c-FLIP), an anti-apoptotic regulator, shows remarkable similarities to caspase-8, which plays a key role in the cleavage of gasdermin D (GSDMD). It has been reported that the oxygen-glucose deprivation/recovery (OGD/R) model and lipopolysaccharide (LPS)/adenosine triphosphate (ATP) treatment could induce inflammation and pyroptosis. However, the regulatory role of c-FLIP in the pyroptotic death of retinal neurons is unclear. In this study, we hypothesized that c-FLIP might regulate retinal neuronal pyroptosis by GSDMD cleavage. To investigate this hypothesis, we induced retinal neuronal damage in vitro (OGD/R and LPS/ATP) and in vivo (acute high intraocular pressure [aHIOP]). Our results demonstrated that the three injuries triggered the up-regulation of pyroptosis-related proteins, and c-FLIP could cleave GSDMD to generate a functional N-terminal (NT) domain of GSDMD, causing retinal neuronal pyroptosis. In addition, c-FLIP knockdown in vivo ameliorated the already established visual impairment mediated by acute IOP elevation. Taken together, these findings revealed that decreased c-FLIP expression protected against pyroptotic death of retinal neurons possibly by inhibiting GSDMD-NT generation. Therefore, c-FLIP might provide new insights into the pathogenesis of pyroptosis-related diseases and help to elucidate new therapeutic targets and potential treatment strategies.

Advances in Multidimensional Cardiac Biosensing Technologies: From Electrophysiology to Mechanical Motion and Contractile Force

Cardiovascular disease is currently a leading killer to human, while drug-induced cardiotoxicity remains the main cause of the withdrawal and attrition of drugs. Taking clinical correlation and throughput into account, cardiomyocyte is perfect as in vitro cardiac model for heart disease modeling, drug discovery, and cardiotoxicity assessment by accurately measuring the physiological multiparameters of cardiomyocytes. Remarkably, cardiomyocytes present both electrophysiological and biomechanical characteristics due to the unique excitation-contraction coupling, which plays a significant role in studying the cardiomyocytes. This review mainly focuses on the recent advances of biosensing technologies for the 2D and 3D cardiac models with three special properties: electrophysiology, mechanical motion, and contractile force. These high-performance multidimensional cardiac models are popular and effective to rebuild and mimic the heart in vitro. To help understand the high-quality and accurate physiologies, related detection techniques are highly demanded, from microtechnology to nanotechnology, from extracellular to intracellular recording, from multiple cells to single cell, and from planar to 3D models. Furthermore, the characteristics, advantages, limitations, and applications of these cardiac biosensing technologies, as well as the future development prospects should contribute to the systematization and expansion of knowledge.

High expression of NEK2 promotes gastric cancer progression via activating AKT signaling

Never in mitosis gene A-related kinase 2 (NEK2) has been recognized as an oncogene involved in the initiation and progression of various human cancers. However, our knowledge is still lacking in regard to the function of NEK2 in gastric cancer, the most common cancer in Eastern Asia associated with poor prognosis. Therefore, in the present study, we investigated the association of NEK2 with gastric cancer. We found that the development of gastric cancer is associated with NEK2 overexpression, particularly in patients with large tumor size and lymph node metastasis. We also provided evidence that NEK2 overexpression binds to and inhibits protein phosphatase 1 (PP1), which subsequently activates AKT and the downstream oncogenic pathways. As a result, via AKT/HIF1α axis, the glucose metabolism is reprogrammed towards aerobic glycolysis to provide rapid energy for the growth of gastric cancer cells. Moreover, the autophagic activity is suppressed via AKT/mTOR axis, leading to impaired response to cancer treatment and enhanced cell survival. In contrast, inactivating AKT by NEK2 silencing decreases aerobic glycolysis and promotes autophagic cell death, which eventually inhibits the growth of gastric cancer cell. All these results revealed that NEK2 promotes gastric cancer progression via activating AKT-mediated signaling pathways, which expanded our knowledge on gastric cancer pathogenesis and also provided novel target for clinical treatment.

Advanced electrocatalysts based on two-dimensional transition metal hydroxides and their composites for alkaline oxygen reduction reaction

The electrocatalytic oxygen reduction reaction (ORR) is a crucial part in developing high-efficiency fuel cells and metal-air batteries, which have been cherished as clean and sustainable energy conversion devices/systems to meet the ever-increasing energy demand. ORR electrocatalysts currently employed in the cathodes of fuel cells and metal-air batteries are mainly based on high-cost and scarce noble metal elements. It is thus of great importance to develop cheap and earth-abundant ORR electrocatalysts. In this aspect, redox-active transition metal hydroxides, a class of multifunctional inorganic layered materials, have been proposed as prospective candidates on account of their abundance and high ORR activities. In this article, the preparation and structural evolution of transition metal hydroxides, in particular their exfoliation into two-dimensional (2D) nanosheets, as well as compositing/integrating with catalytic active and/or conductive components to overcome the insulating nature of hydroxides in alkaline ORR, are summarized. Recent advances have demonstrated that 2D transition metal hydroxides with carefully tuned compositions and elaborately designed nanoarchitectures can achieve both high activity and high pathway selectivity, as well as excellent stability comparable to those of commercial Pt/C electrocatalysts. To realize the dream of renewable electrochemical energy conversion, new strategies and insights into rational designing of 2D hydroxide-based nanostructures with further enhanced electrocatalytic performance are still to be vigorously pursued.