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A novel self-powered and flexible enzymatic biofuel cell (EBFC)-based aptasensor was developed for the sensitive and selective detection of 17 β-estradiol (E2). A flexible polyvinyl alcohol (PVA)-tannic acid‑carbon nanotube/reduced graphene oxide (PTCR) substrate was modified with gold nanoparticles (AuNPs) and thiolated aptamer 1 (Apt1) to yield Apt1@AuNPs/PTCR. A copper-based metal-organic framework (Cu-MOF) with peroxidase mimicking activity was employed to anchor glucose oxidase (GOD) and Apt2, forming the Cu-MOF@GOD/Apt2 tag. When E2 was recognized by Apt1, the anchored E2 quantitatively recognized Cu-MOF@GOD/Apt2 to create a Cu-MOF@GOD/Apt2-E2-Apt1 sandwich structure for glucose oxidation to generate electrical power. Increased E2 concentrations enhanced Cu-MOF@GOD/Apt2 capture and amplified the electrical signal. The electrical power increased linearly as the E2 concentration increased from 1.0 pM to 1.0 nM. The sensor was successfully applied to various food samples and blood serum detection. This work promoted the application of novel self-powered biosensors for food safety analysis., Competing Interests: Declaration of competing interest The authors declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper., (Copyright © 2024 Elsevier Ltd. All rights reserved.)

Rapid and highly sensitive detection of tumor marker (TM) is critical for the early diagnosis and treatment of cancers. Herein, utilizing highly bright and water-stable CsPbBr 3 perovskite nanocrystals (NCs) capped with amphiphilic polymer ligand of octylamine-modified polyacrylic acid (OPA) and gold nanoparticles (AuNPs) as reporters, a lateral flow immunoassay (LFIA) strip is developed for fluorescence and colorimetric dual-mode detection of carcinoembryonic antigen (CEA). The prepared CsPbBr 3 NCs capped by an amphiphilic polymeric of OPA ligand showed high stability and bright fluorescence. Moreover, the AuNPs immunoprobes were captured with CEA antigen and quench the green fluorescence of CsPbBr 3 /OPA NCs on the T line due to the inner filter effect (IFE). Therefore, CEA could be quantitative analyzed by the dual-readout of fluorescence and colorimetric signal. The detection limits of CEA can reach as low as 0.023 ng/mL and 0.027 ng/mL for the fluorescence and colorimetric mode, respectively. Good specificity and reproducibility were also demonstrated for this method. Finally, the CsPbBr3/OPA NCs-based LFIA showed good accuracy in detection of CEA level from clinical serum samples. This work firstly enables the application of CsPbBr 3 perovskite NCs in a LFIA, displaying great potential in point-of-care clinical diagnosis., Competing Interests: Declaration of competing interest The authors declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper., (Copyright © 2023 Elsevier B.V. All rights reserved.)

CsPbX 3 perovskite nanocrystal (NC) is considered as an excellent optical material and is widely applied in optoelectronics. However, its poor water stability impedes its study in enzyme-like activity, and further inhibits its application in biomimetic cascade catalysis. Herein, for the first time, the oxidase-like and ascorbate oxidase-like activities of an amphiphilic polymer capped CsPbX 3 are demonstrated, and its catalytic mechanism is further explored. Furthermore, an all-nanozyme cascade system (multifunctional CsPbBr 3 @Zr-metal organic framework (Zr-MOF) and Prussian blue as oxidase-like and peroxidase-like nanozyme) is constructed with a portable paper-based device for realizing the dual-mode (ratiometric fluorescence and colorimetric) detection of ascorbic acid in a point-of-care (POC) fashion. This is the first report on the utilization of all-inorganic CsPbX 3 perovskite NC in biomimetic cascade catalysis, which opens a new avenue for POC clinical disease diagnosis., (© 2023 The Authors. Advanced Science published by Wiley-VCH GmbH.)

Non-invasive wearable sweat glucose sensors are expected to be highly desirable for personalized diabetes management. Therefore, developing facile, convenient, and scalable manufacturing method of such wearable sensors is urgently needed. Herein, we report a simple and low-cost stamping-vacuum filtration dry transfer (SVFDT) method for construction of a wearable sweat glucose electrochemical sensor. In this patch, a three-electrode array template was made by using a polyvinyl chloride (PVC) stamp, followed by the preparation of multiwalled carbon nanotubes (MWCNTs)/polydimethylsiloxane (PDMS) (MP) film electrode using the vacuum-filtration dry transfer method. In addition, for further enhancing the conductivity of the electrode, another similar stamp with a raised surface dipping carbon nanotubes (CNTs) conductive coating was stamped on the surface of the MP electrode to obtain CNTs/MWCNTs/PDMS (CMP) electrode. CMP electrode was modified with the enzyme-like Ni-Co metal-organic framework (MOF) material which showed good electro-catalytic activity and achieved high sensitivity for glucose detection with a low detection limit of 6.78 μM and a wide linear range of 20 μM - 1.1 mM. More importantly, the Ni-Co MOF modified CMP (NCMP) electrode also displayed high stability under stretching and bending conditions. Finally, the sweat absorbent cloth was combined with the NCMP film electrode to form a wearable flexible electrochemical sensor patch, which could adhere to the skin to enrich sweat and realize real-time detection of sweat glucose with high accuracy. This SVFDT method can also be applied to the fabrication of other electronic devices., Competing Interests: Declaration of competing interest The authors declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper., (Copyright © 2023 Elsevier B.V. All rights reserved.)

Although nanozymes with intrinsic enzyme-like characteristics have aroused great interest in the biosensing field, the challenge is to keep high enzyme-like activity of the nanozyme after the modification of biomolecules onto nanozymes. Herein, a functional zonation strategy of a heterodimer nanozyme was proposed to tackle the challenge and further construct a multiple chemiluminescence (CL) imaging immunoassay. Here Fe 3 O 4 -Au as a heterodimer nanozyme model was divided into two zones, in which Fe 3 O 4 nanoparticles (NPs) were regarded as a nanozyme zone and AuNPs were defined as an antibody immobilization zone. A signal amplification probe (Fe 3 O 4 -Au-Ab 2 ) was prepared by modifying the secondary antibody (Ab 2 ) on AuNPs of the Fe 3 O 4 -Au heterodimer owing to the Au-S bond. The exposed Fe 3 O 4 of the Fe 3 O 4 -Au-Ab 2 probe shows very high peroxidase-like activity and can efficiently catalyze H 2 O 2 -luminol to produce strong CL imaging signals for multiple antigens detection. Using chicken interleukin-4 (ChIL-4) and chicken gamma interferon (ChIFN-γ) as models, the proposed CL imaging immunoassay shows wide linear ranges (0.005-0.10 ng/mL for both ChIL-4 and ChIFN-γ) and low detection limits (0.58 pg/mL for ChIL-4, 0.47 pg/mL for ChIFN-γ) with the characteristics of high sensitivity, high specificity, and good stability. This work provides a promising functional zonation concept for nanozymes to construct new types of nanozyme probes for immunoassay of multiple biomolecules.

In spite of organic-inorganic perovskite emerging as a novel efficient light-harvesting material owing to their superior optical properties, excitonic properties, and electrical conductivity, the related applications are severely limited for their poor stability and selectivity. Herein, we introduced hollow carbon spheres (HCSs) and 2-(perfluorohexyl) ethyl methacrylate (PFEM) based molecularly imprinted polymers (MIPs) to dual-functionalize CH 3 NH 3 PbI 3 . HCSs can provide perovskite load conditions, passivate perovskite defects, increase carrier transport and effectively improve its hydrophobicity. The perfluorinated organic compound based MIPs film can not only enhance the water and oxygen stability of perovskite, but also endow it specific selectivity. Moreover, it can reduce the photoexcited electron-hole pair recombination and prolong the electron lifetime. Benefiting from the synergistic sensitization of HCSs and MIPs, an ultrasensitive photoelectrochemical platform (MIPs@CH 3 NH 3 PbI 3 @HCSs/ITO) for cholesterol sensing was acquired with a very wide linear range of 5.0 × 10 -14 -5.0 × 10 -8  mol/L and an extremely low detection limit of 2.39 × 10 -15  mol/L. The designed PEC sensor exhibited good selectivity and stability, as well as practicality for real sample analysis. The present work extended the development of the high-performance perovskite and showed its broad application prospect for advanced PEC construction., Competing Interests: Declaration of competing interest We declare that we have no financial and personal relationships with other people or organizations that can inappropriately influence our work, there is no professional or other personal interest of any nature or kind in any product, service and/or company that could be construed as influencing the position presented in, or the review of the manuscript entitled, “Molecularly imprinted ultrasensitive cholesterol photoelectrochemical sensor based on perfluorinated organics functionalization and hollow carbon spheres anchored organic-inorganic perovskite”., (Copyright © 2023 Elsevier B.V. All rights reserved.)

NLRC4 gain-of-function variants are known to cause various autoinflammatory phenotypes, including familial cold autoinflammatory syndrome (FCAS4) and NLRC4 macrophage activation syndrome (NLRC4-MAS). However, to date, no study has linked NLRC4 gain-of-function variants to systemic lupus erythematosus (SLE). In this study, we identified a novel NLRC4 W655S variant in an SLE patient and her son, who had neonatal lupus complicated with macrophage activation syndrome. Our in vitro experiments demonstrated that the W655S NLRC4 increased ASC speck formation and mature IL-1β secretion compared to the wild-type NLRC4. In addition, the patient had elevated levels of IL-1β and IL-18 in both serum and PBMCs. RNA sequencing showed that NF-κB and interferon signaling pathways were significantly activated in the patient compared to healthy controls. Furthermore, gene set enrichment analysis revealed upregulation of NLRC4-related pathways in patient PBMCs. In conclusion, our study identified the NLRC4 W655S variant in a patient with SLE. This is the first report linking inflammasomopathy to monogenic SLE. Our findings suggest that inflammasome activation may be a critical driver in the pathogenicity of lupus, and autoinflammatory pathways may play important roles in the development of the disease., Competing Interests: Declaration of Competing Interest Authors declare that they have no competing interests., (Copyright © 2023 Elsevier Inc. All rights reserved.)

Metal-organic frameworks (MOFs) show excellent catalytic activity and have been widely applied in diagnosis of diseases and tumors. However, current assay methods usually involve cumbersome configurations and complicated procedures, which inhibit their practical applications. Hence, a Cu-Ni MOF/carbon printed electrode (CPE)-based integrated electrochemical immunosensor was constructed for highly sensitive and efficient determination of carcinoembryonic antigen (CEA). First, highly conductive carbon ink was screen-printed onto a polyethylene terephthalate substrate to manufacture a CPE. Afterward, an aminated Cu-Ni MOF was prepared by a typical solvothermal strategy and modified on the CPE. Owing to its excellent peroxidase activity, the Cu-Ni MOF can catalytically oxidize hydroquinone using hydrogen peroxide, which greatly amplifies the peak current signal. Then the formation of an immune complex inhibited the catalytic activity of the MOF, thus enabling the quantitative determination of CEA content with a wide linear range of 0.5 pg mL -1 -500 ng mL -1 and a low detection limit of 0.16 pg mL -1 . Furthermore, the Cu-Ni MOF/CPE-based integrated portable electrochemical immunosensor also showed satisfactory performance in the detection of CEA in clinical serum samples with excellent accuracy, showing great potential for application in point-of-care disease diagnosis.

Monitoring cortisol, a hormone released by the adrenal cortex in response to stress, is essential to evaluate the endocrine response to stress stimuli. While the current cortisol sensing methods require large laboratory settings, complex assay, and professional personnel. Herein, a novel flexible and wearable electrochemical aptasensor based on a Ni-Co metal-organic frameworks (MOF) nanosheet-decorated carbon nanotubes (CNTs)/polyurethane (PU) film is developed for rapid and reliable detection of cortisol in sweat. First, the CNTs/PU (CP) film was prepared by a modified wet spinning technology, and the CNTs/polyvinyl alcohol (PVA) solution was thermally deposited on the surface of CP film to form the highly flexible CNTs/PVA/CP (CCP) film with excellent conductivity. Then aminated Ni-Co MOF nanosheet prepared by a facile solvothermal method was conjugated with streptavidin and modified on the CCP film. Biofunctional MOF can effectively capture cortisol aptamer due to its excellent specific surface area. In addition, the MOF with peroxidase activity can catalytic oxidization of hydroquinone (HQ) by hydrogen peroxide (H 2 O 2 ), which could amplify the peak current signal. The catalytic activity of Ni-Co MOF was substantially suppressed in the HQ/H 2 O 2 system due to the formation of the aptamer-cortisol complex, which reduced the current signal, thereby realizing highly sensitive and selective detection of cortisol. The sensor has a linear range of 0.1-100 ng/mL and a detection limit of 0.032 ng/mL. Meanwhile, the sensor showed high accuracy for cortisol detection under mechanical deformation conditions. More importantly, the prepared MOF/CCP film based three-electrode was assembled with the polydimethylsiloxane (PDMS) substrate, and the sweat-cloth was used as the sweat collection channel to fabricate a wearable sensor patch for monitoring of cortisol in volunteers' sweat in the morning and evening. This flexible and non-invasive sweat cortisol aptasensor shows great potential for quantitative stress monitoring and management., Competing Interests: Declaration of competing interest The authors declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper., (Copyright © 2023 Elsevier B.V. All rights reserved.)

Ultrasensitive determination of tumor marker (TM) is of great significance in cancer prevention and diagnosis. Traditional TM detection methods involve large instrumentation and professional manipulation, which complicate the assay procedures and increase the cost of investment. To resolve these problems, an integrated electrochemical immunosensor based on the flexible polydimethylsiloxane/gold (PDMS/Au) film with Fe-Co metal-organic framework (Fe-Co MOF) as a signal amplifier was fabricated for ultrasensitive determination of alpha fetoprotein (AFP). First, gold layer was deposited on the hydrophilic PDMS film to form the flexible three-electrode system, and then the thiolated aptamer for AFP was immobilized. Afterward, the aminated Fe-Co MOF possessing high peroxidase-like activity and large specific surface area was prepared by a facile solvothermal method, and subsequently the biofunctionalized MOF could effectively capture biotin antibody (Ab) to form MOF-Ab as a signal probe and amplify the electrochemical signal remarkably, thereby realizing highly sensitive detection of AFP with a wide linear range of 0.01-300 ng/mL and a low detection limit of 0.71 pg/mL. In addition, the PDMS based-immunosensor showed good accuracy for assaying of AFP in clinical serum samples. The integrated and flexible electrochemical immunosensor based on the Fe-Co MOF as a signal amplifier demonstrates great potential for application in the personalized point-of-care (POC) clinical diagnosis., Competing Interests: Declaration of competing interest The authors declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper., (Copyright © 2023 Elsevier B.V. All rights reserved.)

This study developed an electrochemical sensor for the determination of Mn 2+ in Chinese liquor by modifying a glass carbon electrode with TiO 2 -NH 2 @COF DPTB , which was synthesized via the controllable growth of COF DPTB onto the surface of TiO 2 -NH 2 using the Schiff-base condensation reaction between 2,5-dimethoxyterephthalaldehyde and 1,3,5-tris(4-aminophenyl)benzene. The morphological and structural characterization studies of the proposed TiO 2 -NH 2 @COF DPTB were carried out by SEM, TEM, HRTEM, EDX, BET, XRD and FTIR techniques. Owing to the excellent properties and the synergism between TiO 2 and COF DPTB , the introduction of TiO 2 -NH 2 @COF DPTB improved the electrochemical response significantly. By optimizing the experimental parameters, the sensor exhibited good linearity in the range of 0.1-1.0 nM and 0.08-10 μM with a detection limit of 2.83 × 10 -11 M and 9.50 × 10 -9 M, respectively, showing competitive performance for Mn 2+ determination. Besides, the proposed sensor was successfully applied to Mn 2+ detection in liquor samples, suggesting its practical application performance.

MicroRNAs (miRNAs) in tumor-derived extracellular vesicles (tEVs) are important cancer biomarkers for cancer screening and early diagnosis. Multiplex detection of miRNAs in tEVs facilitates accurate diagnosis but remains a challenge. Herein, we propose an encoded fusion strategy to profile the miRNA signature in tEVs for pancreatic cancer diagnosis. A panel of encoded-targeted-fusion beads was fabricated for the selective recognition and fusion of tEVs, with the turn-on fluorescence signals of molecule beacons for miRNA quantification and barcode signals for miRNA identification using readily accessible flow cytometers. Using this strategy, six types of pancreatic-cancer-associated miRNAs can be profiled in tEVs from 2 μL plasma samples ( n = 36) in an isolation-free and lysis-free manner with only 2 h of processing, offering a high accuracy (98%) to discriminate pancreatic cancer, pancreatitis, and healthy donors. This encoded fusion strategy exhibits great potential for multiplex profiling of miRNA in tEVs, offering new avenues for cancer diagnosis and screening.

Pyroptosis is widely involved in many diseases, including periodontitis. Nonetheless, the functions of pyroptosis-related genes (PRGs) in periodontitis are still not fully elucidated. Therefore, we aimed to investigate the role of PRGs in periodontitis. Three datasets (GSE10334, GSE16134, and GSE173078) from the Gene Expression Omnibus (GEO) were selected to analyze the differences in expression values of the PRGs between nonperiodontitis and periodontitis tissue samples using difference analysis. Following this, five hub PRGs (charged multivesicular body protein 2B, granzyme B, Z-DNA-binding protein 1, interleukin-1 β , and interferon regulatory factor 1) predicting periodontitis susceptibility were screened by establishing a random forest model, and a predictive nomogram model was constructed on the basis of these genes. Decision curve analysis suggested that the PRG-based predictive nomogram model could provide clinical benefits to patients. Three distinct PRG patterns (cluster A, cluster B, and cluster C) in the periodontitis samples were revealed according to the 48 significant PRGs, and the difference in the immune cell infiltration among the three patterns was explored. We observed that all infiltrating immune cells, except type 2 T helper cells, differ significantly among the three patterns. To quantify the PRG patterns, the PRG score was calculated by principal component analysis. According to the results, cluster B had the highest PRG score, followed by cluster A and cluster C. In conclusion, PRGs significantly contribute to the development of periodontitis. Our study of PRG patterns might open up a new avenue to guide individualized treatment plans for patients with periodontitis., Competing Interests: The authors declare that they have no conflicts of interest., (Copyright © 2023 Xiaofan Cheng et al.)

The extension application of perovskites in aqueous media such as bioassays requires the development of a water-stable perovskite with a simple preparation process and low cost. However, the degradation of perovskites in aqueous solution is still a thorny problem. Here, we develop a methylimidazole-assisted two-step synthesis protocol to prepare CsPbBr 3 @PbBrOH nanorods with superior water stability and remarkable optical properties at room temperature. The synergy of 2-methylimidazole (2-MIM), an N-donor ligand, with water can not only facilitate CsPbBr 3 formation and suppress CsPb 2 Br 5 or Cs 4 PbBr 6 formation, but also promote the formation of a PbBrOH shell capping CsPbBr 3 . 2-MIM is ionized into 2-MIM - in DMF and 2-MIM + in water. They passivated the surface defects and changed the crystallization environment, leading to water-stable CsPbBr 3 @PbBrOH. The obtained CsPbBr 3 @PbBrOH nanorods can still maintain 91% PL intensity after being stored in water for more than 2 months. Furthermore, the CsPbBr 3 @PbBrOH nanorods show excellent stability in polar solvents, water, and phosphate buffer solution in a wide pH range, as well as better thermal and irradiation stability. In addition, the CsPbBr 3 @PbBrOH nanorods are further functionalized with polydopamine (PDA) for biomolecular immobilization and immunoassay studies. The resulting assay shows a detection limit of 0.003 ng mL -1 for IgG detection, illustrating important progress towards expanding fluorescence labeling application of perovskite nanomaterials for immunoassays.

Background: As one of the fundamental problems in bioinformatics, the double digest problem (DDP) focuses on reordering genetic fragments in a proper sequence. Although many algorithms for dealing with the DDP problem were proposed during the past decades, it is believed that solving DDP is still very time-consuming work due to the strongly NP-completeness of DDP. However, none of these algorithms consider the privacy issue of the DDP data that contains critical business interests and is collected with days or even months of gel-electrophoresis experiments. Thus, the DDP data owners are reluctant to deploy the task of solving DDP over cloud., Results: Our main motivation in this paper is to design a secure outsourcing computation framework for solving the DDP problem. We at first propose a privacy-preserving outsourcing framework for handling the DDP problem by using a cloud server; Then, to enable the cloud server to solve the DDP instances over ciphertexts, an order-preserving homomorphic index scheme (OPHI) is tailored from an order-preserving encryption scheme published at CCS 2012; And finally, our previous work on solving DDP problem, a quantum inspired genetic algorithm (QIGA), is merged into our outsourcing framework, with the supporting of the proposed OPHI scheme. Moreover, after the execution of QIGA at the cloud server side, the optimal solution, i.e. two mapping sequences, would be transferred publicly to the data owner. Security analysis shows that from these sequences, none can learn any information about the original DDP data. Performance analysis shows that the communication cost and the computational workload for both the client side and the server side are reasonable. In particular, our experiments show that PP-DDP can find optional solutions with a high success rate towards typical test DDP instances and random DDP instances, and PP-DDP takes less running time than DDmap, SK05 and GM12, while keeping the privacy of the original DDP data., Conclusion: The proposed outsourcing framework, PP-DDP, is secure and effective for solving the DDP problem., (© 2023. The Author(s).)

Background and Purpose: White blood cell count to mean platelet volume ratio (WMR) is increasingly recognized as a promising biomarker. However, its predictive capability for acute ischemic stroke (AIS) patients is relatively less researched. The primary aim of this study is to explore its prognostic value in AIS patients after reperfusion regarding 3-month poor functional outcome., Methods: A total of 549 AIS patients who had undergone vascular reperfusion procedure with complete 3-month follow-up were retrospectively recruited in this study. White blood cell count, mean platelet volume at 24 h of admission were recorded. Stroke severity had been estimated using the National Institutes of Health Stroke Scale (NIHSS) and poor outcome was defined as modified Rankin Scale (mRS) 3-6 at 3 months., Results: AIS patients with poor functional outcome at 3 months displayed higher WMR. A positive correlation between WMR and NIHSS score was found (r = 0.334, p < 0.001). After adjusting potential confounders, WMR was still an independent risk factor for poor prognosis at 3 months (OR = 2.257, 95% CI [1.117-4.564], p = 0.023) in multivariate logistic regression model. Subgroup analyses further suggested a significant association between WMR and poor outcome in high baseline NIHSS (per 0.1-point increase: OR = 1.153, 95% CI [1.014-1.312], p = 0.030) group. Receiver operating characteristic (ROC) curves analysis was utilized to assess the predictive ability of WMR, indicating a cut-off value of 0.86. A nomogram that includes age, sex, NIHSS on admission, high WMR for predicting 1-year all-cause survival was also developed (C-index = 0.628)., Conclusions: WMR is significantly correlated with stroke severity on admission and is proved to be an important prognostic indicator for AIS outcomes, especially in high NIHSS on admission group. Additionally, the developed nomogram that includes high WMR for predicting 1-year survival provides us with an effective visualization tool., Competing Interests: The authors declare that the research was conducted in the absence of any commercial or financial relationships that could be construed as a potential conflict of interest., (Copyright © 2022 Weng, Gao, Zhao, Zeng, Huang, Xie, Huang, Chen, Hu, Xu, Zhu, Lin, Ke, Li and Zhang.)

In this research, dual-strategy biosensing of glucose was proposed based on multifunctional CuWO 4 nanoparticles (CuWO 4 NPs), which were prepared for the application of electrochemical and colorimetric sensing of glucose. CuWO 4 NPs show large specific surface area and good conductivity as well as excellent peroxidase-like activity. A sensitive and selective electrochemical glucose biosensor was fabricated with the immobilization of glucose oxidase (GOx) on a CuWO 4 NP modified electrode for enhancing the direct electron transfer behavior. A wide linear range of 0.005-1.8 mM with a low detection limit of 1.5 μM and a high sensitivity of 28.02 mA M -1 cm -2 were achieved by using the electrochemical biosensor. Meanwhile, a colorimetric and visual glucose biosensor was constructed based on the GOx/CuWO 4 cascade nanozyme, which shows a linear range of 0.05-1.0 mM with excellent selectivity. CuWO 4 NPs as a promising matrix open up a dual-strategy biosensor for sensitive and selective detection of glucose.

The flexible electrochemical sensor is a key component of the health monitoring system which can continuously track the physiological signals of the human body, while there is no obvious discomfort and invasiveness. Therefore, it has great potential in personalized medical testing. However, the development of flexible electrochemical sensors currently faces many difficulties, such as the limitations of conductive material properties and manufacturing methods, and the disadvantages of commonly used flexible substrates that are not resistant to high temperatures. In this work, inorganic nanomaterials commonly used to make flexible electrochemical sensors were classified to zero-dimensional (0D) nanomaterials, one-dimensional (1D) nanomaterials, two-dimensional (2D) nanomaterials, and hybrid nanomaterials according to their morphology. The fabrication method of the nanomaterials-based flexible electrochemical sensors was also introduced. Furthermore, the application of flexible electrochemical sensors for chemical and biological sensing and their detection performance were summarized. The detection targets were classified to ion, small molecule, biomacromolecule, and bacteria, respectively., (Copyright © 2022 Elsevier B.V. All rights reserved.)

Activated alumina (Al 2 O 3 ) has been widely used to remove aqueous anionic pollutants such as phosphate for preventing the eutrophication phenomenon. While Al 2 O 3 , as a fine powder material, cannot be stably packed into continuous flow treatment, which limits its practical applications. Herein, we proposed a new strategy in which Al 2 O 3 was encapsulated by calcium alginate (CA) to fabricate Al 2 O 3 /CA composite, which has relatively large particle size and can be suitable for application in columns. The BET surface area of Al 2 O 3 /CA increased to 51.73 m 2 /g compared with 37.31 m 2 /g of Al 2 O 3 . The maximum adsorption capacity of phosphate on Al 2 O 3 /CA was estimated at 1.92-fold compared with that of pure Al 2 O 3 by Langmuir fitting. The main mechanism of phosphate adsorption was the formation of aluminum phosphate precipitation. Moreover, the column studies showed that the adsorption of phosphate on Al 2 O 3 /CA was affected by the amount of outer calcium alginate, bed height, influent flow rates and phosphate concentration. This study demonstrated that Al 2 O 3 /CA composite has better adsorption capacity and can be used in the dynamic adsorption system as a promising approach for phosphate removal from water.

In-situ growth of CsPbBr 3 nanocrystal into Eu-BTC was realized for synthesis of dual-emission CsPbBr 3 @Eu-BTC by a facile solvothermal method, and a novel ratiometric fluorescence sensor based on the CsPbBr 3 @Eu-BTC was prepared for rapid, sensitive and visual detection of Hg 2+ in aqueous solution. The transmission electron microscopy (TEM), X-ray diffraction pattern (XRD), X-ray photoelectron spectroscopy (XPS) and Brunauer-Emmett-Teller (BET) analysis were used to verify the successful incorporation of CsPbBr 3 into the Eu-BTC. Meanwhile, the CsPbBr 3 @Eu-BTC nanocomposite maintained high fluorescence performance and stability in aqueous solution. After adding Hg 2+ , the green fluorescence of CsPbBr 3 was quenched and the red fluorescence of Eu 3+ remained unchanged, while the color changed from green to red obviously. The occurrence of dynamic quenching and electron transfer were verified by fluorescence lifetime, Stern-Volmer quenching constant and XPS analysis. The ratiometric fluorescence sensor shows high analytical performance for Hg 2+ detection with a wide linear range of 0-1 μM and a low detection limit of 0.116 nM. In addition, it also shows high selectivity for the detection of Hg 2+ and can be successfully applied to detect Hg 2+ in environmental water samples. More importantly, a novel paper-based sensor based on the CsPbBr 3 @Eu-BTC ratiometric probe was successfully manufactured for the visual detection of Hg 2+ by naked eyes. This new type of ratiometric fluorescent sensor shows great potential for applications in point-of-care diagnostics., (Copyright © 2022 Elsevier B.V. All rights reserved.)

The weak interfacial binding affinities of the inorganic perovskite core with ligands and high density of surface defect states induce the facile detachment of surface ligands from nanocrystals (NCs), resulting in their poor colloidal stability and fluorescence in aqueous. In this work, a powerful ligand engineering strategy was proposed for eliminating the surface defects and aggregation of the NCs. Using an amphiphilic polymer octylamine-modified polyacrylic acid (OPA) as a capping ligand, the as-synthesized CsPbBr 3 NCs retain high photoluminescence intensity and stability by the modified ligand-assisted reprecipitation method. The increase in the fluorescence lifetime and NC size could also be observed, and how the NC particle size influences fluorescence lifetime was further studied. In addition, the water stability, photostability, and thermal stability were significantly improved, and the fluorescence of NCs can maintain 80.13% of the original value in water for 15 d. We further validated that the strong binding affinity of OPA and oleylamine ligands with CsPbBr 3 NCs leads to a reduction in surface trap states, and a large amount of carboxyl groups of the OPA made the NCs preserve good water solubility. In addition, the OPA has the ability of adjusting the particle size of NCs. Furthermore, a wavelength-shifted colorimetric sensor based on these NCs was constructed for detection of Cl - in sweat, which enables the rapid and visual detection of Cl - with high accuracy and stability. Overall, these CsPbBr 3 NCs synthesized by the ligand engineering strategy validated their wide applications in biomedical sensing fields.

The development of flexible substrate materials and nanomaterials with high electrochemical performance is of great significance for constructing efficient wearable electrochemical sensors for real-time health monitoring. Herein, a wearable electrochemical sweat sensor based on a Ni-Co MOF nanosheet coated Au/polydimethylsiloxane (PDMS) film was prepared for continuous monitoring of the glucose level in sweat with high sensitivity. First, a stretchable Au/PDMS film based three-electrode system was prepared by chemical deposition of a gold layer on the hydrophilic treated PDMS. Then, Ni-Co MOF nanosheets with high electrocatalytic activity were synthesized by a facile solvothermal method and modified on the Au/PDMS electrode. The electrocatalytic activity of the Ni-Co MOF nanosheets synthesized under different Ni : Co ratios was investigated. The Ni-Co MOF/Au/PDMS (NCAP) film electrode showed excellent electrochemical performance for glucose detection with a wide linear range of 20 μM to 790 μM and a high sensitivity of 205.1 μA mM -1 cm -2 . In addition, the flexible sensor shows high stability and a good electrochemical response to glucose when stretched and bent to different levels. Moreover, it maintained long-term stability and high selectivity for glucose monitoring. Lastly, a sweat-absorbent cloth was used to cover the working area of the sensor and was fixed with a needle and thread to form a wearable sweat glucose sensor. The sensor can be attached to the skin for stable, accurate and continuous monitoring of glucose levels in human sweat for one day. This work validates the potential of our high-performance wearable sensor for out-of-clinic health monitoring.

The porous polyvinyl alcohol (PVA)/Al 2 O 3 composite by supporting activated alumina on the cross-linked network of PVA has been successfully prepared and its property for the removal of phosphate in aqueous solution was also evaluated. The structure of the PVA/Al 2 O 3 was examined by scanning electron microscopy. It showed that the activated alumina particles with an average size of 1 μm were evenly dispersed and fixed in the cross-linked network structure of PVA. The effects of adsorption time, solution temperature, pH, initial concentration of phosphate, Al 2 O 3 loading rate, dosage and coexisting ions on the phosphate removal were further studied. The results showed that the highest removal phosphate efficiency of 95% can be obtained with the Al 2 O 3 loading rate of PVA/Al 2 O 3 being 60 wt.% at pH of 4 at 30 °C. The maximum adsorption capacities of PO 4 3 - by PVA/Al 2 O 3 suggested by the Langmuir isothermal model was 10.12 mg/g. The adsorption process of phosphate can be fit well with a pseudo-second-order model ( R 2  = 0.9900). The PVA/Al 2 O 3 composite exhibited a high selective adsorption of phosphate in the presence of commonly coexisting anions except the obvious effect of CO 3 2 - in water. Meanwhile, the PVA/Al 2 O 3 composite can be easily separated and recovered due to the granulation of adsorbent. PVA/Al 2 O 3 composite also shows the excellent properties of regeneration and recycling use with the removal efficiency of phosphate was 88.93%, 88.38% and 94.34% after three cycles, respectively. It can be proposed that the PVA/Al 2 O 3 composite is a promising recyclable adsorbent for removing phosphate at low concentration from aqueous solution.

A noninvasive fiber material-based wearable electrochemical sensor to continuously monitor the glucose level in sweat is highly desirable for smart fabrics for personal diabetes management. To achieve it, the key challenge is to construct fibers with high stretchability and excellent electrochemical performance. Herein, a highly stretchable Ni-Co metal-organic framework/Ag/reduced graphene oxide/polyurethane (Ni-Co MOF/Ag/rGO/PU) fiber-based wearable electrochemical sensor is fabricated for monitoring the glucose level in sweat continuously with high sensitivity and accuracy. The rGO/PU fiber was simply produced by an improved wet spinning technology, and the Ni-Co MOF nanosheet was coated on its surface to prepare the Ni-Co MOF/Ag/rGO/PU (NCGP) fiber electrode. The Ni-Co MOF has a large specific surface area and high catalytic activity, which enables the fiber sensors with good electrochemical performance with a high sensitivity of 425.9 μA·mM -1 ·cm -2 and a wide linear range of 10 μM-0.66 mM. More importantly, the NCGP fiber electrode also shows extremely high stretching and bending stability under mechanical deformation. Also, the NCGP fiber electrode has high selectivity and long-time storage stability. Moreover, the NCGP fiber-based three-electrode system was sewn with an absorbent fabric and fixed on a stretchable polydimethylsiloxane film substrate to form a nonenzymatic sweat glucose wearable sensor, which realized real-time monitoring of glucose in human sweat with high accuracy. This indicates that our designed NCGP fiber can be used as a wearable electrochemical sensor for the bio-diagnostics of body sweat.

The poor stability and aqueous-quenching of fluorescence of perovskite nanocrystals (NCs) hinder their application in bio-detection and bio-imaging. Herein, through the synergistic effects of polymer surface ligand and silica encapsulation, highly stable and enhanced aqueous fluorescent CsPbBr 3 -mPEG@SiO 2 NCs were synthesized and used as a novel "on-off-on" fluorescent probe for highly sensitive and selective detection of mercury ions (Hg 2+ ) and glutathione (GSH) in aqueous solutions. The effects of the methoxypolyethylene glycol amine (mPEG-NH 2 ) ligand and silica encapsulation on the stability and aqueous fluorescence of the CsPbBr 3 NCs were studied. It indicated that the aqueous fluorescence of perovskite NCs was increased by 2.59 times. The water stability was also greatly improved, with the NCs maintaining 73% of their original fluorescence after storage for 30 days in water. X-ray diffraction (XRD), transmission electron microscopy (TEM) and Fourier transform infrared spectroscopy (FT-IR) analyses further demonstrated that the NCs were successfully passivated by mPEG-NH 2 and silica. The fluorescence of the CsPbBr 3 -mPEG@SiO 2 nanocrystals was effectively quenched by Hg 2+ which is attributed to the electron transfer process between NCs and Hg 2+ . Then, through the interaction between Hg 2+ and GSH, the restoration of fluorescence for CsPbBr 3 -mPEG@SiO 2 was realized. The "on-off-on" fluorescent probe can be used for the detection of Hg 2+ and GSH with a low detection limit of 0.08 nM and 0.19 μM, respectively. It also shows a fast response time and high accuracy for practical sample detection. The simple and sensitive fluorescent probe of CsPbBr 3 -mPEG@SiO 2 shows great potential in environmental and biological sensing.

Using two-dimensional (2D) nickel-based metal organic framework (Ni-MOF) nanosheets as a matrix, Eu 3+ and Ag + were incorporated to synthesize Ag/Eu@Ni-MOF with double luminescence centers of Eu 3+ ion (615 nm) and organic ligand (524 nm). And a ratiometric luminescence sensor is constructed based on Ag/Eu@Ni-MOF for sensitive detection of biothiols in aqueous solutions. The dual-emissive fluorescence properties can be tuned by changing the amounts of Ag + ions doping. The results of temperature and pH effects on the fluorescence of Ag/Eu@Ni-MOF indicates that the Ag/Eu@Ni-MOF is a temperature-sensitive material and the fluorescence of Ag/Eu@Ni-MOF can keep stable over a wide pH range. Due to the binding of -SH in cysteine (Cys) and glutathione (GSH) with Ag + , the ligand luminescence was significantly inhibited by weakening the Ag + influence on the energy transfer process in the MOFs. Therefore, ratiometric fluorescent sensing of biomolecular thiols was realized based on the dual-emission Ag/Eu@Ni-MOF. More importantly, the fluorescence color change can be observed with naked eyes to realize visual detection. The ratiometric fluorescent sensor exhibits high performance for Cys and GSH detection with a wide linear range of 5-250 µM and a relatively low detection limit of 0.20 µM and 0.17 µM, respectively. Furthermore, the biothiols content in human serum was determined with satisfactory results. It proves the Ni-MOF nanosheets can be used as a stable matrix for construction luminescent MOFs for the first time, and validate the great potential of Ag/Eu@Ni-MOF as a ratiometric fluorescent probe for point-of-care testing (POCT) in disease diagnosis., (© 2021. The Author(s), under exclusive licence to Springer Science+Business Media, LLC, part of Springer Nature.)

A covalent organic framework (COF) is a promising type of porous material with customizable surface characteristics. Confining multiple catalytic units within a mesoporous COF can generate abundant active sites and improve the catalytic performance. In this work, a COF with both metalloporphyrin and a metal nanoparticle complex denoted as hemin/TAPB-DMTP-COF/AuNPs (TAPB: 1,3,5-tris(4-amino-phenyl)benzene, DMTP: 2,5-dimethoxyterephaldehyde, AuNPs: Au nanoparticles) has been successfully fabricated through a hierarchical encapsulation method. The as-synthesized composite was then employed to construct an electrochemical sensing platform for the efficient detection of bisphenol A (BPA). Under the optimal conditions, the hemin/TAPB-DMTP-COF/AuNP sensor presented a linear range of 0.01-3 μmol L -1 and a low detection limit of 3.5 nmol L -1 . The satisfactory signal amplification is based on a triple-signaling amplification strategy due to the abundant Fe 3+ sites of Fe-porphyrin, high conductivity of AuNPs and a large specific surface area of the TAPB-DMTP-COF. The proposed method was used to measure the content of BPA in different water samples with a satisfactory recovery from 95.5 to 104.0%, suggesting the great potential of the sensor in practical applications.

It is very important to develop a rapid, simple, low cost point-of-care (POC) method for the early diagnosis of pathogens. In this work, a flexible paper-based electrode based on nickel metal-organic framework (Ni-MOF) composite/Au nanoparticles/carbon nanotubes/polyvinyl alcohol (Ni-Au composite/CNT/PVA) was constructed to detect target human immunodeficiency virus (HIV) DNA by DNA hybridization using methylene blue (MB) as a redox indicator. The CNT/PVA and Ni-Au composite were deposited on the cellulose membrane by vacuum filtration and drop-coating method in turn to obtain Ni-Au composite/CNT/PVA (CCP) film electrode. Compared to the CNT/PVA film electrode, CCP film electrode makes a higher loading of the probe DNA for its large specific surface area and conjugated π-electron system that can provide hydrogen bond sources to achieve interactions between MOF and single-stranded DNA, which improves the sensitivity for detecting target DNA. The variation of peak current for MB molecules adsorbed onto DNA before and after hybridization with HIV DNA was monitored. Electrochemical results proved that the CCP film maintained stable electrochemical property even after bending 200 times or stretching under different strains from 0% to 20%. The flexible paper electrode showed excellent sensing performance with a linear range of 10 nM-1 μM and a low detection limit of 0.13 nM. The target HIV DNA was successfully detected even in complex serum samples using the flexible CCP film electrode. Therefore, the simple and inexpensive flexible paper-based MOF composite film electrode can also be utilized for other pathogens POC diagnosis., (Copyright © 2021. Published by Elsevier B.V.)

Metal-organic frameworks (MOFs), which are a class of coordination polymers constructed by metal ions or clusters with organic ligands, have emerged as exciting inorganic-organic hybrid materials with the superiorities of inherent crystallinity, adjustable pore size, clear structure, and high degree of functionalization. The MOFs have attracted much attention to develop good luminescent functional materials due to their inherent luminescent centers of both inorganic and organic photonic units. Furthermore, the pores within MOFs can also be used to encapsulate a large number of luminescent guest species, which provides a broader luminescent property for MOF materials. MOFs possess the incomparable multifunctional advantages of inorganic and organic luminescent materials. A large number of luminescent MOFs (LMOFs) have been synthesized for applications in sensing, white-light-emitting diodes (LED), photocatalysis, biomedicine, etc. This paper reviews the encapsulation of various luminescent guests such as lanthanide ions, dyes, quantum dots, and luminescent complexes in metal-organic frameworks to construct luminous sensors with single- or double-emission centers, as well as the research progress of these sensors in chemical sensing. Finally, the challenges in these fields were outlined and the prospects for future development were put forward.

Near-infrared (NIR) emitting Ag 2 S quantum dots (QDs) are excellent fluorescent nanoprobes for bioassays with low toxicity. A novel fluorescent sensing platform which employing NIR fluorescent Ag 2 S QDs and MnO 2 2D nanosheets as NIR emitters and quenchers is designed for rapid and selective determination of glutathione (GSH). A facile and efficient approach was demonstrated for the synthesis of NIR fluorescent Ag 2 S QDs with the emission of 845 nm. Then the NIR fluorescent nanoprobe of Ag 2 S QDs-MnO 2 nanosheets is obtained by adsorbing Ag 2 S QDs onto the surface of MnO 2 nanosheets which have atomically thick two-dimensional structure and high specific surface area. And the NIR fluorescence of Ag 2 S QDs is quenched by the MnO 2 nanosheets. The presence of GSH could reduce MnO 2 to Mn 2+ that results in the restoration of NIR fluorescence for Ag 2 S QDs. The NIR fluorescent nanoprobe could be used for highly selective detection of GSH. Also a low detection limit of 60 μmol/L was obtained. Because NIR fluorescence of the Ag 2 S QDs can efficiently reduce the interferences from background scattering and autofluorescence. The NIR fluorescent nanoprobe was directly applied to monitor the GSH level in human serum sample with high accuracy and precision., (Copyright © 2020 Elsevier B.V. All rights reserved.)

Existing electrochemical biosensing platforms, using traditional rigid and unstretchable electrodes, cannot monitor the biological signaling molecules released by cells in a mechanically deformed state in real time. Here, a stretchable and flexible electrochemical sensor was developed based on nickel metal-organic framework composite/Au nanoparticle-coated carbon nanotubes (Ni-MOF composite/AuNPs/CNTs) for sensitive detection of dopamine (DA) released by C6 living cells in real time. A Ni-MOF composite was obtained by introducing Ni, NiO, and a carbon frame onto the surface of two-dimensional (2D) Ni-MOF nanosheets using an efficient one-step calcination method. The hybrid of Ni-MOF composite/AuNPs/CNTs that deposited on the poly(dimethylsiloxane) (PDMS) film endowed the sensor with excellent electrochemical performance with a wide linear range of 50 nM to 15 μM and a high sensitivity of 1250 mA/(cm 2 M) and also provided the sensor with desirable stability against mechanical deformation. Furthermore, the stretchable electrode also displayed good cellular compatibility while C6 living cells can be cultured and proliferated on it with strong adhesion. Then, the DA released by C6 living cells with chemical induction in both natural and stretched states was monitored using our stretchable and flexible electrochemical sensor in real time. This indicates that our new design of flexible Ni-MOF composite/AuNPs/CNTs/PDMS (NACP) film electrodes provides more opportunities for the detection of chemical signals released from cells and soft living organisms even under mechanically deformed states.

With the development of credit businesses, privacy data leakage and data accuracy in loan transactions among different banks tend to be worrisome issues hindering the prosperity of the industry. To address the problem, we propose a blockchain-based cross-bank over-loan prevention (CBOL-ring) mechanism, which ensures that, on the one hand, the plaintext of loan transactions cannot be access to neither participants on the nodes except the bank that handles loan/repayment requests, so as to prevent the borrower from loaning without revealing their privacy data; on the other hand, the other participants are able to prove the effectiveness of the plaintexts through checking the ciphertexts on the blockchain. In addition, we propose a blockchain-based cross-bank over-loan prevention mechanism with low communication volume (CBOL-bullet), which reduces the size of the range proof generated by the BBCBOLP mechanism, thereby reducing the size of the communication volume and saving resources during the data transmission process. Finally, we analyze the security and performance of the two mechanisms, and compare the communication volume of the two mechanisms.

In this research, a novel manganese dioxide nanorod-anchored graphene oxide (MnO 2 NRs/GO) composite was synthesized by a simple hydrothermal method for electrochemical sensing application. A highly sensitive electrochemical sensor for dopamine (DA) was constructed by modifying glassy carbon electrode (GCE) with MnO 2 NRs/GO. The morphology and performance of the composite material and modified GCEs were investigated by using scanning electron microscopy (SEM), X-ray diffraction (XRD) and cyclic voltammetry (CV), respectively. The resultant MnO 2 NRs/GO composite has a large electroactive area and shows excellent electrochemical activity toward DA. Under the optimal conditions, the DA sensor shows a linear response in the DA concentration ranges of 0.1 μM-0.08 mM and 0.08-0.41 mM with a low detection limit of 0.027 μM and a high sensitivity of 602.4 μA·mM -1 ·cm -2 . The MnO 2 NRs/GO composite provides a promising platform for the construction of a highly sensitive and selective sensor of DA.

The fabrication of chemically stable metal-organic frameworks for electrochemical sensors is essential to broaden their applications. In this study, the integration of a Zr-based metal-organic framework (UiO-66-NH2) with multi-walled carbon nanotubes (MWCNTs) was achieved by a one-pot solvothermal reaction. This composite was then characterized by scanning electron microscopy, transmission electron microscopy, powder X-ray diffraction, Fourier transform infrared spectroscopy, and contact angle measurements. The porous structure and unreacted amine groups provided by UiO-66-NH2 frameworks accompanied by the excellent conductivity of MWCNTs have made this composite an ideal electrode material for lead detection. After the optimization of MWCNT content and the detection conditions, the oxidation peak currents were proportional to lead concentrations in the range of 0.001-0.8 μmol L-1 with a low detection limit of 0.5 nmol L-1 (S/N = 3). More importantly, the well-preserved crystallinity of MWCNTs@UiO-66-NH2 after 80 cycles and after being soaked in different pH aqueous solutions indicates the promising application of this sensor for real samples. Satisfactory recoveries were achieved when this sensor was used to detect lead in real samples. Furthermore, the excellent stability of this composite makes it possible to be employed in other fields, including extreme acidic media.

Herein, we report the synthesis of novel nanosized reduced graphene oxide@polystyrene nanospheres (rGO@PS NSs) through an electrostatic interaction method, and further their exploitation for highly sensitive label-free electrochemical immunoassay applications. These rGO@PS NSs provide a universal and promising carrier platform to develop excellent biosensors for clinical screening and diagnostic applications.

Multiwalled carbon nanotubes coated with cobalt(II) sulfide nanoparticles were prepared and used for immobilization of glucose oxidase (GOx) to obtain an electrochemical glucose biosensor. The nanocomposite was synthesized through an in-situ hydrothermal method and characterized by X-ray diffraction, scanning electron microscopy, transmission electron microscopy, and electrochemical impedance spectroscopy. The results show that the nanocomposite possesses a large specific surface area and apparently enhances the direct electron transfer between GOx and the surface of the electrode, best at a potential near -0.43 V (vs. SCE). The immobilized GOx retains its good bioactivity even at a high surface coverage of 30 pmol cm -2 . Under the optimum conditions. The biosensor exhibits a wide linear range (from 8 μM to 1.5 mM), a high sensitivity (15 mA M -1  cm -2 ), and a 5 μM detection limit (at S/N = 3). The sensor is selective, acceptably repeatable, specific and stable. Graphical abstractMultiwalled carbon nanotubes coated with cobalt(II) sulfide nanoparticles (CoS-MWCNTs) were synthesized through in situ hydrothermal method for the construction of a sensitive electrochemical glucose biosensor.

Porphyrinic Metal-Organic Frameworks (porph-MOFs) are attracting attention due to the redox activity in the porphyrin subunit. Herein, we report the design of a novel core-shell structure hybrid material with a sea-cucumber morphology, namely PMeTh, containing the poly(3-methythiophene) conducting polymer coated on the surface of iron-based porph-MOFs PCN-222(Fe) via in-situ oxidative chemical polymerization. The porous PCN-222(Fe) serves as the electrocatalytic sites, while the poly(3-methythiophene) conducting polymer functions as the charge collector to facilitate the charge transport to the redox active sites. The resulting PMeTh composite demonstrates an excellent electrochemical response towards the levodopa detection. The sensitivity towards the L-dopa detection is estimated to be 1.868 μA ⋅ μM -1 ⋅ cm -2 in the linear concentration of 0.05-7.0 μmol ⋅ L -1 and 0.778 μA ⋅ μM -1 ⋅ cm -2 in the linear concentration of 7.00-100 μmol ⋅ L -1 , respectively. Additionally, the levodopa sensor exhibits a low detection limit of 2 nmol L -1 as well as excellent stability after 120 cycles in 10 μmol L -1 levodopa. The feasibility of this novel L-dopa sensor was evaluated in human urine samples by standard addition. The satisfactory recoveries were in the range of 97.0-104.5% with the R.S.D. value lower than 4.4%. The method of intergrating porph-MOFs and conducting polymers can efficiently expand the porph-MOFs based composites in bioanalysis., (Copyright © 2019 Elsevier B.V. All rights reserved.)

In this work, a water stable zirconium metal-organic framework functionalized with thiol groups was synthesized by a solvent-assisted ligand incorporation technique. The composites were characterized by powder X-ray diffraction, X-ray photoelectron spectroscopy, specific surface area measurement and field emission scanning electron microscopy. The prepared material was then used as a novel adsorbent for Cu(ii) removal from water. The experimental parameters associated with adsorption capability, such as the initial solution pH, contact time, and the presence of competing cations were investigated in detail. Under the optimal conditions, the adsorption follows a pseudo-second-order kinetics, and the equilibration time for the adsorption is 15 min. The Langmuir adsorption model was in better correlation with the isothermal adsorption data than the Freundlich model. The maximum Cu(ii) adsorption capacity reached up to 42.70 mg g -1 . Quantitative recovery of Cu(ii) was achieved by using 0.1 mol L -1 HCl. The prepared adsorbent has fast adsorption efficiency, high adsorption capacity, and exceptional stability up to 50 adsorption/desorption cycles. It can be used as a promising candidate material for heavy metal ion removal and water treatment.

A photoelectrochemical (PEC) sensor was constructed for the detection of non-electroactive malathion. It is based on the use of a hierarchical CuO material derived from a Cu-BTC metal-organic framework (where BTC stands for benzene-1,3,5-tricarboxylic acid). The modified CuO was obtained by calcination of Cu-BTC at a high temperature (300 °C) and possesses a high photocurrent conversion efficiency. Under irradiation with visible light and in the presence of malathion, the formation of the CuO-malathion complex on the CuO gave rise to an increase in steric hindrance. This results in a decrease in photocurrent. This novel PEC detection method has a lower detection limit of 8.6 × 10 -11  mol L -1 and a wide linear range (1.0 × 10 -10 ~ 1.0 × 10 -5  mol L -1 ). Graphical abstract Schematic presentation of the Cu-BTC MOF derived photoelectrochemical sensor for non-electroactive malathion detection.

A novel NH 4 + voltammetric electrochemical biosensor was constructed by immobilizing glutamate dehydrogenase (GLDH)/Fe 3 O 4 /graphene (GR)/chitosan (CS) nanobiocomposite onto a glassy carbon electrode (GCE). On the GLDH/Fe 3 O 4 /GR/CS/GCE, GLDH catalyzed the reversible reaction, i.e., the reductive amination of α-ketoglutaric acid and the oxidative deamination of L-glutamate. The electrons produced in the enzymatic reactions were transferred to the surface of the electrode via the [Fe(CN) 6 ] 3-/4- couple, which helped for the amplification of the electrochemical signal. The electrochemical detection of NH 4 + was based on the fact that the enhanced response current was proportional to the NH 4 + concentration. Owing to the combination of the advantages of the synergistic effects of Fe 3 O 4 nanospheres, GR and CS, a promising platform for NH 4 + sensing was provided. Under optimum conditions, the introduced biosensor had a linear range of 0.4-2.0 μM for NH 4 + with the detection and quantification limits of 0.08 and 0.27 μM, respectively. Moreover, the biosensor exhibited good sensitivity and excellent reproducibility. It could retain 91.8% of its original response after two weeks of storage at 4 °C, suggesting satisfactory stability. Additionally, the proposed biosensor was successfully applied to detect NH 4 + levels in PM 2.5 samples, indicating its feasibility for application in NH 4 + monitoring in the environmental fields., (Copyright © 2019 Elsevier B.V. All rights reserved.)

Quantitative detection of multiple chicken cytokines is a good evaluation of cell-mediated immunity in chickens after disease infection or vaccination. However, current assay methods for chicken cytokines cannot meet the needs of clinical diagnosis due to unsatisfactory sensitivity and low assay throughput. Herein, a sensitive chemiluminescence (CL) imaging immunosensor array has been developed for high-throughput detection of multiple chicken cytokines. The chicken cytokines immunosensor array was prepared by assembling different cytokine capture antibodies onto a disposable silanized glass chip, where horseradish peroxidase and antibody-conjugated gold nanoparticles were used as multienzymatic amplification probe for CL imaging signal amplification. By using a sandwich assay mode, the amplified CL signals from each sensing array cell were collected for quantitation. Using chicken interleukin-4 and chicken interferon-γ as model cytokines, this novel multiplexed and amplified method demonstrated simultaneous measurement of the two chicken cytokines in the linear ranges of 0.008-0.12 ng/mL and 0.005-0.20 ng/mL, respectively, which yields limits of detection down to 2 pg/mL and 3 pg/mL. The CL imaging array method reported here also demonstrated high specificity, good repeatability, and high stability and accuracy, providing a novel multiplex immunoassay strategy for highly sensitive and high-throughput detection of chicken cytokines and further disease diagnosis in poultry., (Copyright © 2018 Elsevier B.V. All rights reserved.)

We report a new concept of a chemiluminescence imaging nanozyme immunoassay (CINIA), in which nanozymes are exploited as catalytic tags for simultaneous multiplex detection of cytokines. The CINIA provides a novel and universal nanozyme-labeled multiplex immunoassay strategy for high-throughput detection of relevant biomarkers and further disease diagnosis.

This work investigated the feasibility and efficiency of a heterogeneous photo-Fenton catalyst, Fe/Si codoped TiO 2 , for the degradation of metronidazole (MNZ) under visible light irradiation. The Fe/Si codoped TiO 2 was prepared via a facile and simple sol-gel solvothermal process followed by annealing at 480 °C for 4 hours. High resolution transmission electron microscopy (HRTEM) and X-ray photoelectron spectroscopy (XPS) measurements revealed that the photo-Fenton process did not change the structure, textural and surface morphologies of this catalyst. Elemental mapping results indicated the good dispersion of Fe and Si ions in TiO 2 . Nitrogen adsorption and desorption measurements indicated that Si doping increased the surface area of the catalysts. The Fe and Si doping narrowed the band gap of TiO 2 . They also facilitated the transfer of photo-generated electrons from TiO 2 to Fe(iii). Under visible light irradiation and the optimum operating conditions, MNZ could be completely degraded in 50 min by this catalyst within a wide pH range. Hydroxyl radicals and holes were verified to be responsible for degrading MNZ. The leaching of iron ions was less than 0.047 ppm even after illuminating the catalyst for 6 hours, indicating the good stability of the Fe/Si codoped TiO 2 . The as-prepared catalysts with excellent catalytic activity, and remarkable reusability and stability could provide a new insight into the preparation of photocatalysts and have wide applications for antibiotics removal., Competing Interests: There are no conflicts to declare., (This journal is © The Royal Society of Chemistry.)

Titanium dioxide (TiO₂) nanomaterials have caused a widespread concern in the past several decades for their bulk characteristics and potential applications in many different areas. Lately, the combination between molecularly imprinted polymers (MIPs) and TiO₂ nanomaterials have been proven to improve the relative adsorption capacity, selectivity and accelerate the rate of mass transfer of analyte which is not possible using TiO₂ alone. Considering the unique performance of the MIPs modified TiO₂ nanomaterials, this review intends to give an overview of the recent progresses in the development of MIPs modified TiO₂ nanomaterials, the potential applications of their tailor-made characteristics. The limitations and challenges in this practically promising nanomaterials have also been raised and summarized. By means of the points raised in this article, we would like to provide some assistance for further development of preparation methodologies and the expansion of some potential applications in the field of MIPs modified TiO₂ nanomaterials.

A two-dimensional (2D) Ni based metal-organic framework (MOF) nanosheets were synthesized using a one-step solvent-thermal method. The as-prepared nanosheets were characterized by transmission electron microscopy (TEM), scanning electron microscopy (SEM), powder X-ray diffraction (XRD) and energy disperse spectroscopy (EDS) mapping. Ni-MOF nanosheet was first time found to used as a peroxidase mimetic with catalytic activities and could catalyze the oxidation of the substrate 3,3,5,5-tetramethylbenzidine (TMB) in the presence of hydrogen peroxide (H 2 O 2 ). Catalytic mechanism analysis suggested the enzymatic kinetics of Ni-MOF nanosheets followed typical Michaelis-Menten theory and Ni-MOF nanosheets possess a higher affinity for two substrates (TMB and H 2 O 2 ) than horseradish peroxidase (HRP). Furthermore, Ni-MOF nanosheet was applied to establish an H 2 O 2 colorimetric sensor which deserves a wide linear range of 0.04 ~ 160 μM and a low detection limit of 8 nM. Also the application of this sensor for H 2 O 2 detection in human serum and disinfectant was demonstrated and satisfactory results were obtained. Thus, the simple and sensitive Ni-MOF/TMB/H 2 O 2 colorimetric system has great promising applications in clinical medicine and food environment analysis., (Copyright © 2018. Published by Elsevier B.V.)

In this work, an ultrasensitive electrochemiluminescence (ECL) method was established for the detection of trace amount of Ag ions (Ag + ). In sulfuric acid medium, Ag(II), the electro-oxidized product of Ag(I), oxidizes manganese ions (Mn 2+ ) to produce permanganate (MnO 4 - ) by using a pair of graphite catheters as electrodes. While permanganate and luminol can produce strong chemiluminescence, based on the catalytic effect of Ag(II) on Mn 2+ oxidation, there is a good linear relationship between the concentration of Ag + and luminescence intensity. Under optimized conditions, the linear range of this method for Ag + is from 0.2 to 150 nM with a detection limit of 0.06 nM. The method was applied for determination of Ag + in various water samples with satisfactory results., (Copyright © 2018 Elsevier B.V. All rights reserved.)

A nonenzymatic glucose electrochemical sensor was constructed based on Au nanoparticles (AuNPs) decorated Ni metal-organic-framework (MOF)/Ni/NiO nanocomposite. Ni-MOF/Ni/NiO nanocomposite was synthesized by one-step calcination of Ni-MOF. Then AuNPs were loaded onto the Ni-based nanocomposites' surface through electrostatic adsorption. Through characterization by transmission electron microscopy (TEM), high resolution TEM (HRTEM) and energy disperse spectroscopy (EDS) mapping, it is found that the AuNPs were well distributed on the surface of Ni-based nanocomposite. Cyclic voltammetric (CV) study showed the electrocatalytic activity of Au-Ni nanocomposite was highly improved after loading AuNPs onto it. Amperometric study demonstrated that the Au-Ni nanocomposites modified glassy carbon electrode (GCE) exhibited a high sensitivity of 2133.5 mA M -1 cm -2 and a wide linear range (0.4-900 μM) toward the oxidation of glucose with a detection limit as low as 0.1 μM. Moreover, the reproducibility, selectivity and stability of the sensor all exhibited outstanding performance. We applied the as-fabricated high performance sensor to measure the glucose levels in human serum and obtained satisfactory results. It is believed that AuNPs decorated Ni MOF/Ni/NiO nanocomposite provides a new platform for developing highly performance electrochemical sensors in practical applications., (Copyright © 2018 Elsevier B.V. All rights reserved.)

Dual-functional cupric oxide nanorods (CuONRs) as peroxidase mimics are proposed for the development of a flow-through, label-free chemiluminescent (CL) immunosensor. Forming the basis of this cost-efficient, label-free immunoassay, CuONRs, synthesized using a simple hydrothermal method, were deposited onto epoxy-activated standard glass slides, followed by immobilization of biotinylated capture antibodies through a streptavidin bridge. The CuONRs possess excellent catalytic activity, along with high stability as a solid support. Antigens could then be introduced to the sensing system, forming large immunocomplexes that prevent CL substrate access to the surface, thereby reducing the CL signal in a concentration dependent fashion. Using carcinoembryonic antigen (CEA) as a model analyte, the proposed label-free immunosensor was able to rapidly determine CEA with a wide linear range of 0.1-60ngmL -1 and a low detection limit of 0.05ngmL -1 . This nanozyme-based immunosensor is simple, sensitive, cost-efficient, and has the potential to be a very promising platform for fast and efficient biosensing applications., (Copyright © 2017 Elsevier B.V. All rights reserved.)

In this work, a novel molecularly imprinted electrochemical sensor based on the amino-functionalized silica nanoparticles was built for the sensitive and selective detection of 2,4-dichlorophenoxyacetic acid (2,4-D). The hierarchical porous dendrimer-like silica nanoparticles (HPSNs-NH 2 ) were synthesized by an ethyl ether emulsion method. The selective molecularly imprinted polymers (MIP) was prepared on the HPSNs-NH 2 modified electrode via electropolymerization by using 2,4-D as the template and o-phenylenediamine (OPD) as the monomer. The porous structure of HPSNs-NH 2 reduced the diffusion limitations of the analytes, enhanced the accessibility and increased the surface area of the sensor, while the MIP layer offered the ability to recognize and quantify target 2,4-D by using ferro/ferricyanide as probes. Several significant experimental parameters on the analytical performance of the MIP/HPSNs-NH 2 sensor were explored and optimized. Under the optimized condition, the sensor displayed an appreciable selectivity over structurally related compounds and good sensitivity toward 2,4-D. The linear range of 2,4-D detection was from 1.00 × 10 -10 to 2.50 × 10 -8 M and the detection limit was down to 1.17 × 10 -11 M according to the 3S a /b criteria. This method has been applied to detect 2,4-D in bean sprout samples with satisfying results., (Copyright © 2017. Published by Elsevier B.V.)