Confined-Coordination Induced Intergrowth of Metal-Organic Frameworks into Precise Molecular Sieving Membranes.

Metal-organic framework (MOF) membranes with rich functionality and tunable pore system are promising for precise molecular separation; however, it remains a challenge to develop defect-free high-connectivity MOF membrane with high water stability owing to uncontrollable nucleation and growth rate during fabrication process. Herein, we report on a confined-coordination induced intergrowth strategy to fabricate lattice-defect-free Zr-MOF membrane towards precise molecular separation. The confined-coordination space properties (size and shape) and environment (water or DMF) were regulated to slow down the coordination reaction rate via controlling the counter-diffusion of MOF precursors (metal cluster and ligand), thereby inter-growing MOF crystals into integrated membrane. The resulting Zr-MOF membrane with angstrom-sized lattice apertures exhibits excellent separation performance both for gas separation and water desalination process. It was achieved H2 permeance of ~1200 GPU and H2/CO2 selectivity of ~67; water permeance of ~8 L ⋅ m-2 ⋅ h-1 ⋅ bar-1 and MgCl2 rejection of ~95 %, which are one to two orders of magnitude higher than those of state-of-the-art membranes. The molecular transport mechanism related to size-sieving effect and transition energy barrier differential of molecules and ions was revealed by density functional theory calculations. Our work provides a facile approach and fundamental insights towards developing precise molecular sieving membranes.

MnFe@N-CNTs Based Lactate Biomicrochips for Nonintrusive and Onsite Periodontitis Diagnosis.

In clinical settings, saliva has been established as a straightforward, noninvasive medium for diagnosing periodontitis. However, the precise diagnosis is often hampered by the absence of a specialized analyzer capable of detecting low concentrations of biomarkers typically found in saliva. In this study, we present a noninvasive, on-site screen-printed biomicrochip specifically engineered for the precise and sensitive quantification of lactate concentrations in saliva, a critical biomarker in the diagnosis of periodontitis. The microchip is constructed using a nanostructured ink formulation that includes MnFe@N-doped carbon nanotubes (MnFe@N-CNTs). These MnFe@N-CNTs exhibit a high degree of graphitization and low electrical resistance, significantly augmenting the electrocatalytic efficiency of the enzymatic reaction of lactate. This results in doubled sensitivity and a detection limit that surpasses those of the current advanced salivary assay methods. Remarkably, within just 30 s, the biomicrochip can quantitatively and precisely measure lactate concentrations in the saliva of 10 patients, which provides valuable insights into the severity of their periodontitis. This biosensor holds excellent potential for large-scale production and could broaden the scope of biomarker recognition, paving the way for the analysis of a wider range of oral diseases.

Nanomaterials-based electrochemical biosensors for diagnosis of COVID-19.

Since the outbreak of corona virus disease 2019 (COVID-19), this pandemic has caused severe death and infection worldwide. Owing to its strong infectivity, long incubation period, and nonspecific symptoms, the early diagnosis is essential to reduce risk of the severe illness. The electrochemical biosensor, as a fast and sensitive technique for quantitative analysis of body fluids, has been widely studied to diagnose different biomarkers caused at different infective stages of COVID-19 virus (SARS-CoV-2). Recently, many reports have proved that nanomaterials with special architectures and size effects can effectively promote the biosensing performance on the COVID-19 diagnosis, there are few comprehensive summary reports yet. Therefore, in this review, we will pay efforts on recent progress of advanced nanomaterials-facilitated electrochemical biosensors for the COVID-19 detections. The process of SARS-CoV-2 infection in humans will be briefly described, as well as summarizing the types of sensors that should be designed for different infection processes. Emphasis will be supplied to various functional nanomaterials which dominate the biosensing performance for comparison, expecting to provide a rational guidance on the material selection of biosensor construction for people. Finally, we will conclude the perspective on the design of superior nanomaterials-based biosensors facing the unknown virus in future.

Freestanding Nanofiber-Assembled Aptasensor for Precisely and Ultrafast Electrochemical Detection of Alzheimer's Disease Biomarkers.

Amyloid beta-protein (AßAß) is a main hallmark of Alzheimer's disease (AD), and a low amount of Aß protein accumulation appears to be a potential marker for AD. Here, an electrochemical DNA biosensor based on polyamide/polyaniline carbon nanotubes (PA/PANI-CNTs) is developed with the aim of diagnosing AD early using a simple, low-cost, and accessible method to rapidly detect Aß42 in human blood. Electrospun PA nanofibers served as the skeleton for the successive in situ deposition of PANI and CNTs, which contribute both high conductivity and abundant binding sites for the Aß42 aptamers. After the aptamers are immobilized, this aptasensor exhibits precise and specific detection of Aß42 in human blood within only 4 min with an extremely fast response rate, lower detection limit, and excellent linear detection range. These findings make a significant contribution to advancing the development of serum-based detection techniques for Aß42, thereby paving the way for improved diagnostic capabilities in the field of AD.

Facile construction of nanocubic Mn3[Fe(CN)6]2@Pt based electrochemical DNA sensors for ultrafast precise determination of SARS-CoV-2.

Owing to the high mortality and strong infection ability of COVID-19, the early rapid diagnosis is essential to reduce the risk of severe symptoms and the loss of lung function. In clinic, the commonly used detection methods, including the computed tomography (CT) and reverse transcription-polymerase chain reaction (RT-PCR), are often time-consuming with bulky instruments, which normally require more than one hour to report the results. To shorten the analytical period for testing the COVID-19 virus (SARS-CoV-2), we proposed an ultrafast and ultrasensitive DNA sensors to achieve an accurate determination of the DNA sequence by the RNA reverse transcription (rtDNA) of the SARS-CoV-2. A nanocubic architecture of the MnFe@Pt crystals was constructed to integrate both electrocatalysis and conductivity to greatly improve the biosensing performance. After the immobilization of a specific capture and report DNA on above nanocomposite, the rtDNA can be rapidly caught to the DNA sensor to form a double-helix structure, thus generating the current signal change. Within only 10 min, the as-prepared DNA sensors exhibited ultralow detection limit (1 × 10-20 M) and wide linear detection range, together with an outstanding selectivity among various interfering substances.

Homoporous polydimethylsiloxane membrane microfilter for ultrafast label-free isolation and recognition of circulating tumor cells in peripheral blood.

The detection of circulating tumor cells (CTCs) in peripheral blood is a novel and accurate technique for the early diagnosis of cancers. However, this method is challenging because of the need for high collection efficiency due to the ultralow content and similar size of CTCs compared with other blood cells. To address the aforementioned issue, we proposed a homoporous polydimethylsiloxane (PDMS) membrane and its microfilter device to perform the ultrafast isolation and identification of CTCs directly from peripheral blood without any labeling treatment. The membrane pores can be homogenously controlled at a size of 6.3 µm through the cross-linking time of PDMS during a filtration-coating strategy. Within only 10 s, the designed device achieved a retention rate greater than 70% for pancreatic cancer cells, and it exhibited excellent cell compatibility to support cell proliferation. The isolated CTCs on this membrane can be easily observed and identified using a fluorescence microscope.

Advances in nanostructured material-based non-enzymatic electrochemical glucose sensors.

Non-enzymatic electrochemical sensors that use functional materials to directly catalyze glucose have shown great promise in diabetes management, food control, and bioprocess inspection owing to the advantages of high sensitivity, long-term stability, and low cost. Recently, in order to produce enhanced electrochemical behavior, significant efforts have been devoted to the preparation of functional materials with regular nanostructure, as it provides high specific surface area and well-defined strong active sites for electrochemical sensing. However, the structure-performance correlation in this field has not been reviewed thoroughly in the literature. This review aims to present a comprehensive report on advanced zero- to three-dimensional nanostructures based on the geometric feature and to discuss in depth their structural effects on enzyme-free electrochemical detection of glucose. It starts by illustrating the sensing principles of nanostructured materials, followed by a detailed discussion on the structural effects related to the features of each dimension. The structure-performance correlation is explored by comparing the performance derived from diverse dimensional architectures, which is beneficial for the better design of regular nanostructure to achieve efficient enzyme-free sensing of glucose. Finally, future directions of non-enzymatic electrochemical glucose sensors to solve emerging challenges and further improve the sensing performance are also proposed.

Solid-solvent processing of ultrathin, highly loaded mixed-matrix membrane for gas separation.

Mixed-matrix membranes (MMMs) that combine processable polymer with more permeable and selective filler have potential for molecular separation, but it remains difficult to control their interfacial compatibility and achieve ultrathin selective layers during processing, particularly at high filler loading. We present a solid-solvent processing strategy to fabricate an ultrathin MMM (thickness less than 100 nanometers) with filler loading up to 80 volume %. We used polymer as a solid solvent to dissolve metal salts to form an ultrathin precursor layer, which immobilizes the metal salt and regulates its conversion to a metal-organic framework (MOF) and provides adhesion to the MOF in the matrix. The resultant membrane exhibits fast gas-sieving properties, with hydrogen permeance and/or hydrogen-carbon dioxide selectivity one to two orders of magnitude higher than that of state-of-the-art membranes.

Recent Progress on Nanomaterial-Facilitated Electrochemical Strategies for Cancer Diagnosis.

Cancer is a malignant disease that endangers human life, especially owing to its high fatality rate; therefore, rapid and accurate early screening is needed to effectively improve the survival rate. Compared with traditional cancer detection methods, electrochemical biosensors that recognize cancer biomarkers in blood have the advantages of low invasiveness, fast diagnosis, and low cost. However, there is always a trade-off between sensitivity and selectivity, which limits the detection of trace amounts of biomarkers produced in the early stages. To address this issue, an increasing number of nanomaterials with simultaneous improvements in both sensitivity and selectivity have recently been reported. In this review, different categories of state-of-the-art electrochemical biosensors and their operating principles are introduced, and their respective advantages and disadvantages are described. Furthermore, the review discusses the existing detection strategies and performance of nanomaterial-based cancer biosensors for biomarker recognition, providing overall guidance for the material selection of different biomarkers. Finally, the main challenges involving existing electrochemical cancer biosensors are evaluated to present the future development prospects of nanomaterials and detection strategies.

Scalable Printing of Prussian Blue Analogue@Au Edge-Rich Microcubes as Flexible Biosensing Microchips Performing Ultrasensitive Sucrose Fermentation Monitoring.

Sucrose is one of the most applied carbon sources in the fermentation process, and it directly determines the microbial metabolism with its concentration fluctuation. Meanwhile, sucrose also plays a key role of a protective agent in the production of biological vaccines, especially in the new mRNA vaccines for curing COVID-19. However, rapid and precise detection of sucrose is always desired but unrealized in industrial fermentation and synthetic biology research. In order to address the above issue, we proposed an ultrasensitive biosensor microchip achieving accurate sucrose recognition within only 12 s, relying on the construction of a Prussian blue analogue@Au edge-rich (PBA@AuER) microarchitecture. This special geometric structure was formed through exactly inducing the oriented PBA crystallization toward a certain plane to create more regular and continuous edge features. This composite was further transformed to a screen-printed ink to directly and large-scale fabricate an enzymatic biosensor microchip showing ultrahigh sensitivity, a wide detection range, and a low detection limit to the accurate sucrose recognition. As confirmed in a real alcohol fermentation reaction, the as-prepared microchip enabled us to accurately detect the sucrose and glucose concentrations with outstanding reusability (more than 300 times) during the whole process through proposing a novel analytical strategy for the binary mixture substrate system.

Nanomaterial-based electrochemical enzymatic biosensors for recognizing phenolic compounds in aqueous effluents.

With the rapid development of industrial society, phenolic pollutants already identified in water are severe threats to human health. Traditional detection techniques like chromatography are poor in the ability of cost-effectiveness and on-site detection. In recent years, electrochemical enzymatic biosensors have attracted increasing attention for use in the recognition of phenolic compounds, which is considered an effective strategy for the product transfer of portable analytical devices. Although electrochemical enzymatic biosensors provide a fast, accurate on-site detection technique, the difficulties of enzyme deactivation, poor stability and low sensitivity remain to be solved. Thus, effective immobilization methods of enzymes and nanomaterials with excellent properties have been extensively researched to obtain a high-sensitivity and high-stability biosensing platform. Simultaneous detection of multiple phenols may become the focus of further research. In this review, we provide an overview of recent progress toward electrochemical enzymatic biosensors for the detection of phenolic compounds, including enzyme immobilization approaches and advanced nanomaterials, especially nanocomposites with attractive properties such as good conductivity, high specific surface area, and porous structure. We will comprehensively discuss the features and mechanisms of the main enzymes adopted in the construction of different phenolic biosensors, as well as traditional methods (e.g., adsorption, covalent bonding, entrapment, encapsulation, cross-linking) of enzyme immobilization. The most effective method is based on the properties of enzymes, supports and application objective because there is no one-size-fits-all method of enzymatic immobilization. The emphasis will be given to various advanced nanomaterials, including their special nanostructures, preparation methods and performance. Finally, the main challenges in future research on electrochemical phenolic biosensors will be discussed to provide further perspectives for practical applications in dynamic and on-site monitoring. We believe this review will deliver an important inspiration for the construction of novel and high-performance electrochemical biosensors from enzyme selection to nanomaterial design for the detection of various hazardous materials. We believe this review will deliver an important inspiration on the construction of novel and high-performance electrochemical biosensors from the enzyme selection to the nanomaterial design for detections of various hazardous materials.

Membranes for the life sciences and their future roles in medicine.

Since the global outbreak of COVID-19, membrane technology for clinical treatments, including extracorporeal membrane oxygenation (ECMO) and protective masks and clothing, has attracted intense research attention for its irreplaceable abilities. Membrane research and applications are now playing an increasingly important role in various fields of life science. In addition to intrinsic properties such as size sieving, dissolution and diffusion, membranes are often endowed with additional functions as cell scaffolds, catalysts or sensors to satisfy the specific requirements of different clinical applications. In this review, we will introduce and discuss state-of-the-art membranes and their respective functions in four typical areas of life science: artificial organs, tissue engineering, in vitro blood diagnosis and medical support. Emphasis will be given to the description of certain specific functions required of membranes in each field to provide guidance for the selection and fabrication of the membrane material. The advantages and disadvantages of these membranes have been compared to indicate further development directions for different clinical applications. Finally, we propose challenges and outlooks for future development.

Screen-printing of core-shell Mn3O4@C nanocubes based sensing microchip performing ultrasensitive recognition of allura red.

Allura red (AR) is a member of azo dyes is commonly used as an additive in foods and soft drinks. However, due to the special harm of the azo structure to the human body, the dosage control of AR becomes particularly necessary. The present detection methods are time-consuming, expensive and complicated. In order to address the above issues, a core-shell nanocubes constructed sensor has been developed to determine the ultrawide detection range and selective recognition of AR with a long-term reusability. The core-shell architecture is composed of carbon material of 12.64 nm thickness covering 600 nm Mn3O4 nanocube. This nanocomposite combines the advantages of Mn3O4@C, possessing high electrocatalysis and chemical stability. As confirmed in using sports drinks as real samples, the as-prepared AR sensor exhibites excellent selectivity with an ultra-wide linear range from 0.1 to 1748.4 µM, and meanwhile, this sensor can also meet the requirements of remarkable anti-interference and reusability over 30 days.

In situ fabrication of urchin-like Cu@carbon nanoneedles based aptasensor for ultrasensitive recognition of trace mercury ion.

Mercury ion (Hg2+) is a strong toxic heavy ion that causes severe damages to the environment and readily accumulates in the food chain. However, it remains a major challenge to realize a sensitive and precise recognition of Hg2+ with a trace concentration for early identifying the pollution source. In this work, a novel electrochemical aptasensor was designed to achieve an ultrasensitive and quantitative detection of trace Hg2+, relying on an urchin-like architecture of Cu@carbon nanoneedles (Cu@CNNs) as the electroactive probe. This specific nanostructure was in-situ constructed through a controllable pyrolysis process, serving as a signal magnifier and DNA loading platform owing to its outstanding electrocatalysis and large specific surface areas. Meanwhile, an exonuclease III-assisted cycling amplification strategy was designed to efficiently amplify the signal strength of trace Hg2+via the consecutive release of report probes in nicking reaction. This as-prepared Hg2+ aptasensor exhibited an ultralow detection limit of 3.7 fM (7 × 10-6 ppm) and a wide linear range from 10 fM to 10 µM, together with the satisfactory stability and reusability for assay in real water samples. It is highly expected that this Cu@CNNs based aptasensor will have tremendous potentials in the early warning and efficient pollution monitoring of heavy metal ions.

A handheld testing device for the fast and ultrasensitive recognition of cardiac troponin I via an ion-sensitive field-effect transistor.

Cardiac troponin I (cTnI) is an efficient and specific biomarker for the accurate diagnosis of acute myocardial infarction (AMI), one of the diseases with the highest mortality worldwide. Due to the short course and high fatality of this disease, a rapid, accurate and portable device for quantitative detection is urgently needed for early diagnosis and treatment. In this work, we designed a handheld device based on a dual-gate ion-sensitive field-effect transistor (ISFET) for early and accurate warning of AMI through cTnI detection. A one-step enzyme-linked immunosorbent assay strategy was proposed for use in this device to recognize trace cTnI in serum, converting the cTnI concentration to a drain-source current generated by an ultrasensitive ISFET. This portable device exhibited an ultrahigh sensitivity of 132 pA pg-1·mL-1, a wide linear range from 1 to 1000 pg/mL that enabled coverage far exceeding the threshold level (280 pg/mL), and a low detection limit of 0.3 pg/mL for the cTnI assay, which was much lower than the current diagnostic cut-off for a healthy control level for AMI (40 pg/mL). In addition, this handheld device showed satisfactory selectivity and reliable results in the analysis of real serum within 20 min, indicating its potential applications in early screening and diagnosis for the clinical evaluation of AMI.

Clinical effectiveness of fish oil on arterial stiffness: A systematic review and meta-analysis of randomized controlled trials.

AIMS: The increase of arterial stiffness is an independent risk factor for cardiovascular diseases (CVD). Fish oil supplementation was shown to reduce the risk of CVD outcomes. However, the effects of fish oil on arterial stiffness remains controversial. This meta-analysis summarized existing randomized clinical trials (RCTs) to determine whether fish oil can affect arterial stiffness in adults. DATA SYNTHESIS: Systematic searches were performed using the PubMed/Medline, EMbase, Cochrane database, Clinical trials, and Web of Science. All RCTs assessed the effect of fish oil intervention on carotid to femoral-Pulse Wave Velocity (cf-PWV), brachial to ankle-PWV (ba-PWV), augmentation index (AIx) and AIx75 were considered. A fixed-effect model was used to calculate the pooled effect. A total of 14 RCTs were included. The pooled data analysis showed that fish oil significantly reduced PWV levels (SMD: -0.145, 95%CI: -0.265 to -0.033, P = 0.012) compared to the control group. In subgroup analyses, a significant decrease in PWV was found in trials that fish oil with low dosages (≤1.8 g/d), short time (<24 weeks), low DHA to EPA ratio (DHA/EPA<1) and among young participant (<50 years old). Besides, the effect of fish oil was more obvious in ba-PWV compared to cf-PWV. In contrast, the effect of fish oil supplementation on AIx (WMD: -0.588%, 95% CI: -2.745 to 1.568, P = 0.593) and AIx75 (WMD: 0.542%, 95% CI: -1.490 to 2.574, P = 0.601) was nonsignificant. CONCLUSIONS: The current study showed that fish oil supplementation had a beneficial effect on pulse wave velocity.

A Separation-Sensing Membrane Performing Precise Real-Time Serum Analysis During Blood Drawing.

Dynamic and on-site analysis of serum from human blood is crucial, however, state-of-the-art blood-assay methods can only collect single or discrete data of physiological analytes; thus, the online reports of the dynamic fluctuation of key analytes remains a great challenge. Here, we propose a novel separation-sensing membrane by constructing a heterogeneous-nanostructured architecture, wherein a surface nanoporous layer continuously extracts serum, while the biosensing nanochannels underneath dynamically recognise biotargets, thereby achieving a continuous testing of vital clinical indices as blood is drawn. By precisely controlling the pore structure and nanoshape of biosensing crystals, this membrane achieved accurate and online glucose and lactate monitoring in patients with a variety of medical conditions within 1 min, which is one order of magnitude faster than state-of-the-art techniques. Moreover, various kinds of bio-recognisers can be introduced into this membrane to accurately detect glutamate, transaminase, and cancer biomarkers.

In situ fabrication of aloe-like Au-ZnO micro/nanoarrays for ultrasensitive biosensing of catechol.

Currently, the large-scale and controllable fabrication of nanostructures on substrates remains a great challenge for further practical applications. In this work, a novel 3D aloe-like Au-ZnO nanocomposite was designed for in situ synthesis on an ITO substrate, achieving real-time detection of trace catechol (CC) in water. A seed-assisted hydrothermal approach was proposed to control the crystal distribution and growth direction to build a ZnO aloe-like architecture. To eliminate the natural weak conductivity of ZnO, Au nanoparticles were further deposited on all ZnO arrays to construct Au-ZnO micro/nanostructures. The synergetic effects derived from the aloe-like ZnO with a large specific area and Au nanoparticles with high conductivity resulted in both high electrocatalysis and fast electron transfer in enzymatic reactions. After laccase immobilization, the as-prepared biosensor exhibited specific recognition of catechol among other dihydroxybenzenes and phenol with an ultrahigh sensitivity of 131 µA mM-1, as well as an extremely wide linear range from 75 nM to 1100 µM and an ultralow detection limit of 25 nM. In addition, in the detection of real lake samples, this biosensor showed satisfactory anti-interference ability and provided reliable assay results.

Serum CTRP3 Levels In Obese Children: A Potential Protective Adipokine Of Obesity, Insulin Sensitivity And Pancreatic ß Cell Function.

PURPOSE: CTRP3 is a novel peptide that has recently emerged as an important regulatory adipokine of obesity and related metabolic disease. Little is known about its role in children. The current study aimed to investigate the potential role of CTRP3 in obese children and explore its relationships with insulin sensitivity, pancreatic ß cell function, and obesity-related markers. PATIENTS AND METHODS: We studied the levels of serum CTRP3 in 48 obese and 36 normal weight pre-puberty children. The levels of blood pressure, lipids, glucose, and insulin were measured, and the values of HOMA-IR, HOMA-ß and insulinogenic index were calculated. The correlations of these measurements with CTRP3 levels were analyzed. RESULTS: In this study, we found that CTRP3 serum levels significantly decreased in obese children compared to controls, and insulin resistant obese subjects have lower CTRP3 levels in contrast with the non-insulin resistant obese subjects. Moreover, serum CTRP3 concentrations significantly decreased, while glucose and insulin concentrations significantly increased after a 3 hrs oral glucose tolerance test in obese children. Furthermore, Serum CTRP3 levels correlated negatively and significantly with BMI, triglycerides, systolic blood pressure, fasting insulin, glucose, HOMA-IR, HOMA-ß and insulinogenic index in obese children. CONCLUSION: In summary, serum CTRP3 levels significantly decreased in obese children, and negatively correlated with insulin resistance and pancreatic ß cell function indicators. Therefore, CTRP3 may play a protective role in the glucose homeostasis and tightly related to ß cell function as well as obesity-related markers in obese children.

Circulating Spexin Decreased and Negatively Correlated with Systemic Insulin Sensitivity and Pancreatic ß Cell Function in Obese Children.

OBJECTIVES: Spexin (SPX) is a novel peptide that has recently emerged as an important regulatory adipokine of obesity and related metabolic disease. Little is known about its role in children. The aim of the current study was to determine the potential role of SPX in obese children and explore its relationships with obesity-related markers, insulin sensitivity and pancreatic ß cell function. METHOD: We studied the levels of serum SPX in 40 obese and 32 normal weight pre-puberty children (mean age was 8.59 ± 1.82 and 8.15 ± 2.03 years in obesity and control groups respectively). We investigated the levels of body mass index, blood pressure, lipids, glucose, insulin, Homeostasis model assessment for insulin-resistant (HOMA-IR, HOMA for ß-cell function [HOMA-ß]), insulinogenic index and C-peptide index and analyzed their correlations with SPX levels. RESULTS: SPX levels were significantly decreased in obese children compared to controls. Moreover, serum SPX levels were lower in IR obese subjects in contrast with the non-IR obese subjects. Serum SPX concentrations correlated negatively and significantly with triglycerides, systolic blood pressure, diastolic blood pressure, fasting insulin level, HOMA-IR, insulinogenic index, and HOMA-ß levels in obese children. CONCLUSIONS: In summary, serum SPX levels significantly decreased in obese children and negatively correlated with insulin resistance and pancreatic ß cell function indicators. Therefore, SPX may play a protective role in the process of glucose homeostasis and is closely related to ß cell function in obese children.