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This communication describes the development of polyvinyl chloride electrochemical system in which a paper layer loaded with reagents is inserted into the device, demonstrating a new concept of a paper card-like pad for a reagent-free and easy measurement of the target analyte in solution. This device detects glucose in artificial tears in the range of 0.2–2 mM with a detection limit of 50 μM by simply adding the artificial tears to the paper card-like pad. The novel configuration goes beyond the state of the art, widening the application range of paper in the design of smart analytical devices. [ABSTRACT FROM AUTHOR]

We created novel Pd/CB-Ni@rGO nanomaterials for glucose detection. The as-synthesized nanomaterials were dropped on the electrode surface using the drop casting technique. The prepared electrode was then attached to a paper-based device containing the sample zone and the reaction zone, enabling plasma isolation and an enzymatic reaction for glucose detection in whole blood. The nanomaterials and surfaces of electrodes were characterized by FTIR, TEM, and SEM. The proposed approach is a disposable glucose detection method that is unaffected by protein fouling on the electrode, and it requires only one drop of human blood. Therefore, there is no need for extensive sample preparation, and there is less sample consumption. Under optimal conditions, Pd/CB-Ni@rGO can accurately measure blood glucose levels with a linear range of 7 to 7140 μM (R2 = 0.9986) and a low detection limit of 0.82 μM. Besides, the developed sensor shows excellent anti-interference capacity, stability, and satisfactory reproducibility and repeatability. Importantly, Pd/CB-Ni@rGO was successfully applied for glucose in whole blood from 4 volunteers, with results that correlated well with those obtained using an Accucheck glucometer at a 95% confidence level. Given its low cost, high accuracy, and ease of use, the blood glucose sensor holds significant potential for clinical use and broadens the area of future noninvasive sensor development. [ABSTRACT FROM AUTHOR]

The monosaccharide 1,5-anhydroglucitol (1,5-AG) is a known indicator of glucose levels. Conventional 1,5-AG quantification methods with enzyme-based sensors using pyranose oxidase (PROD) require elimination of interference from the sample (a laborious and time-consuming process), as PROD cannot distinguish 1,5-AG from other sugars. We developed a one-step paper-based sensor for detecting 1,5-AG using glucose oxidase, catalase, and mutarotase that eliminates excess glucose, which interferes with 1,5-AG detection. This sensor consists of two compartments for the quantification of glucose and 1,5-AG and reflects the concentration of these targets after reaction with water or spiked human urine. The limit of detection of the sensor was 0.9 mg dL−1 for glucose and 3.2 μg mL−1 for 1,5-AG. [ABSTRACT FROM AUTHOR]

Sensitive detection of glucose is important for public health, but non-enzymatic glucose biosensors still face significant challenges. In this paper, a novel and sensitive non-enzymatic glucose sensor was developed by in situ preparation of CuO nanorod-supported NiCo LDH nanosheet arrays on copper foam (CuO@NiCo LDH NSAs/CF). Because the hierarchical core–shell nanostructure provides more active sites and increases the exposed surface area of the catalyst, the catalytic activity of the electrode was significantly increased. As a working electrode, the CuO@NiCo LDH NSAs/CF catalyst showed good glucose sensing performance in a linear range of 0.6 μM–3 mM and a detection limit of 0.16 μM (S/N = 3). The sensor also showed repeatable responses over a month with negligible interference, and satisfactory recoveries with real human serum samples. [ABSTRACT FROM AUTHOR]

In this paper we describe the synthesis, characterization, and use of a glucose-assisted magnetic aluminum oxyhydroxide@carbon (γ-AlOOH/Fe3O4@C) nanocomposite as a novel sorbent for the extraction and pre-concentration of deferasirox (DFX) present in plasma and urine samples using the ultrasonic-assisted dispersive solid-phase microextraction (UA-DSPME) method prior to HPLC-UV measurement. The sorption process was systemically optimized by experimental design and statistical analysis to maximize the extraction efficiency of DFX. The proposed method could be successfully employed for DFX determination in double-distilled water, plasma, and urine samples (real and spiked samples), with recovery range of 96.1–105%. Also, a good linear range from 10 to 3500 ng mL−1 was found with a correlation value of 0.9938, and relative recoveries between 2.09 and 5.22% were achieved adequately. Furthermore, the limit of quantification (LOQ) and the limit of detection (LOD) were found to be 5.421 and 0.163 ng mL−1 (based on a signal-to-noise ratio of 3) which were acceptable values compared to those of other reports. [ABSTRACT FROM AUTHOR]

The introduction of halogen atoms into the skeleton to regulate the intrinsic properties or improve task-specific performance of metal–organic frameworks (MOFs) has developed rapidly in recent years. Herein, a series of halogen-engineered MOFs were designed and prepared for electrochemical glucose sensing. Three isomorphic Ni-MOFs were constructed by using tetra-halogenated-phthalic acids as the organic ligand and incorporating 4,4′-bipyridine as an auxiliary ligand. Halogen atoms can enhance the stability of Ni-MOFs through their hydrophobicity and interlayer halogen bonds (X–X or X–π, X = F, Cl, Br). Combined experimental and theoretical results show that the hydrogen bond between halogen atoms and glucose improves the reaction thermodynamics, enabling the wide linear range of 0.01–5.0 mM, high sensitivity of 4709.9 μA mM−1 cm−2 and low detection limit of 0.043 μM. This work provides practical guidance for the rational design of halogenated MOFs and promotes their applications in electrochemical sensing. [ABSTRACT FROM AUTHOR]

An ultrasensitive fluorescent biosensor is reported for glucose detection based on a Fenton-like reaction triggered chemical redox-cycling signal amplification strategy. In this amplified strategy, Cu2+ oxidizes chemically o-phenylenediamine (OPD) to generate photosensitive 2,3-diaminophenazine (DAP) and Cu+/Cu0. On the one hand, the generated Cu0 catalyzes the oxidation of OPD. On the other hand, H2O2 reacts with Cu+ to produce hydroxyl radicals (˙OH) and Cu2+ through a Cu+-mediated Fenton-like reaction. The generated ˙OH and recycled Cu2+ ions take turns oxidizing OPD to produce more photoactive DAP, triggering a self-sustaining chemical redox-cycling reaction and a remarkable fluorescent enhancement. It is worth mentioning that the cascade reaction did not stop until OPD molecules were completely consumed. Benefiting from H2O2-triggered chemical redox-cycling signal amplification, the strategy was exploited for the development of an ultrasensitive fluorescent biosensor for glucose determination. Glucose content monitoring was realized with a linear range from 1 nM to 1 μM and a limit of detection of 0.3 nM. This study validates the practicability of the chemical redox-cycling signal amplification on the fluorescent bioanalysis of glucose in human serum samples. It is expected that the method offers new opportunities to develop ultrasensitive fluorescent analysis strategy. [ABSTRACT FROM AUTHOR]

This paper reports a two-step seed-mediated synthesis of gold core@silver shell nanoparticles (Au@Ag NPs). The plasmonic properties of Au@Ag NPs were controlled through the etching effect of H2O2 generated from the oxidation of glucose. Therefore, we used Au@Ag NPs as surface-enhanced Raman scattering (SERS) substrates and 4-mercaptobenzoic acid (4-MBA) as the Raman tag to detect glucose concentration. This method exhibits a rapid detection process (5 min), a determination range from 10−1 M to 10−6 M and a detection limit of 10−6 M, which indicate that Au@Ag NPs can serve as sensitive SERS sensors for clinical detection of blood sugar. [ABSTRACT FROM AUTHOR]

A novel light-driven non-enzymatic glucose sensor based on AuNi nanodendrites has been successfully constructed and applied in glucose detection. The AuNi nanodendrites were fabricated through a one-step underpotential electrodeposition approach, in which porous anodic aluminum was introduced as the template. This nanodendritic structure with a large surface area provides abundant active sites and good electron transfer for the oxidation of glucose. Considering the plasmonic effect of Au, such a hierarchical hybrid structure displayed remarkable photoelectrocatalytic activity for glucose under the visible light illumination. As a result, the light-driven glucose sensor based on AuNi nanodendrites reveals a high sensitivity of ∼183 μA cm−2 mM−1 (0.1–18 mM) and a relative low detection limit (0.01 mM), without applying an external electrical power supply. The current work is promising in the design of novel hybrid materials for glucose sensors under visible light illumination without electrical power consumption. [ABSTRACT FROM AUTHOR]

With the rapid development of glucose sensor devices in recent years, it is critical to obtain a highly sensitive and low-cost sensing material by a facile method. In this study, 0D/1D heterostructured Au@Cu2O/CuO/Cu(OH)2 with multivalent Cu(I)/Cu(II) was prepared as an efficient electrocatalyst for glucose sensing by using a simple one-pot wet chemical method. Au@Cu2O/CuO/Cu(OH)2 exhibited a sensitivity of 1024.6 μA mM−1 cm−2 and a detection limit of 0.26 μM toward glucose sensing, which was 1.57 times higher than that of pure Au@Cu2O NPs and 123.2 times higher than that of pure Au/Cu(OH)2. The excellent performance of Au@Cu2O/CuO/Cu(OH)2 can be attributed to the synergistic effect of excellent charge transport brought by the Cu(OH)2 nanowire and the rapid mass transfer capability resulting from the multivalent Cu-based oxides during the glucose sensing process. In addition, the obtained Au@Cu2O/CuO/Cu(OH)2 exhibited excellent stability and bending stability toward glucose sensing, revealing its great potential for practical applications in the field of wearable sensors. [ABSTRACT FROM AUTHOR]

A novel highly sensitive and selective non-enzymatic electrochemical sensor of glucose has been achieved based on a macroporous bird's nest-like CoFePBA nanomaterial, namely HN-CoFePBA. Its pore size is about 750 nm. It is the first time that a hollow PBA material with such a big hole has been successfully obtained based on a two-step design strategy. Herein, ZIF-67 is selected as a sacrificial template and in situ converted and fabricated into the target PBA. More remarkably, the as-synthesized HN-CoFePBA as an electrochemical sensor realizes high-performance detection of glucose including a wide linear range of 5 μM–0.57 mM, a high sensitivity of 564.6 μA mM−1 cm−2, a low limit of detection (LOD), remarkable stability and good selectivity. The related sensing mechanism for the enhanced glucose performance is also discussed in detail. In a word, this work has developed a new avenue for the construction of macroporous PBA materials with excellent sensing performance. [ABSTRACT FROM AUTHOR]

A glucose sensor with high sensitivity and low detection limit is vital for human beings' health. Herein, a CoO nanoneedle array with an unique electronic structure was successfully constructed by a hydrothermal and subsequent high-temperature calcination process. The optimized CoO-400 nanoneedles exhibit a larger electrochemical active surface area, beneficial electronic structure, favorable lattice distortion, and abundant active sites, which effectively promote electrochemical properties toward glucose sensing. The glucose sensor constructed by CoO-400 nanoneedles shows a high sensitivity of 84.23 mA cm−2 mM−1 and low detection limit of 4.4 × 10−7 M, superior to the results from most previous reports. Moreover, outstanding anti-interference ability, superior long-term stability, good repeatability, and satisfactory reproducibility in glucose detection for CoO-400 nanoneedles are also demonstrated. [ABSTRACT FROM AUTHOR]

Developing carbon-based materials with high catalytic performance and sensitivity has significance in low-cost and highly efficient nanozymes. Herein, for the first time, Cu,N-codoped hollow carbon nanospheres (CuNHCNs) with highly active Cu-Nx sites were successfully assembled through a template-free strategy, in which Cu2+-poly(m-phenylenediamine) (Cu-PmPD) nanospheres were utilized as the source of Cu, N and C. Benefiting from the synergistic effect of the hollow spherical structure and optimized composition, the CuNHCN exhibits high affinity for 3,3′,5,5′-tetramethylbenzidine and H2O2 with 0.0655 mM and 0.918 mM, respectively, which are superior to those of HRP and most metal-based nanozymes. Moreover, by employing glucose and ascorbic acid (AA) as biomolecule models, a CuNHCN-based colorimetric detection platform is developed. The CuNHCN exhibits superior peroxidase mimicking activity and sensitivity in detecting glucose and AA with a detection limit of 0.187 μM and 68.9 nM (S/N = 3), respectively. Also, the colorimetric detection based on the CuNHCN towards glucose and AA in human serum presents superior practicability and accuracy. The assay provides a new avenue for designing and fabricating low-cost peroxidase nanozymes with high performance in bioassays. [ABSTRACT FROM AUTHOR]

This work reports on the effect of the morphology of ZIF-67 on its performance as a non-enzymatic electrochemical uric acid sensor. Three different structures were prepared using a simple co-precipitation method with different solvents. The characterization studies on ZIF-67 were carried out by several techniques including X-Ray Diffraction (XRD) and Scanning Electron Microscopy (SEM). The characterization results showed that ZIF-67 which was prepared using methanol, water, and a mixture of methanol and water displayed dodecahedral, microplate, and irregular shapes, respectively. The three different structures are denoted as Me-ZIF-67, W-ZIF-67, and M-ZIF-67, respectively. The uric acid sensor performances were evaluated by conducting Cyclic Voltammetry (CV) and Differential Pulse Voltammetry (DPV) measurements in PBS solution with a pH of 7.4 containing uric acid. The test results show that W-ZIF-67 has the highest electrocatalytic activity compared to the other two materials possessing the highest current and the lowest overpotential. As a uric acid sensor, W-ZIF-67 has a sensitivity of 0.0377 μA μM−1 cm−2 with a relatively wide linear detection range of 20–1000 μM, and a detection limit of 3.04 μM. W-ZIF-67 also has good reproducibility and is stable against interfering species such as urea, glucose, ascorbic acid, and NaCl. [ABSTRACT FROM AUTHOR]

In this research, dual-strategy biosensing of glucose was proposed based on multifunctional CuWO4 nanoparticles (CuWO4 NPs), which were prepared for the application of electrochemical and colorimetric sensing of glucose. CuWO4 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 CuWO4 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/CuWO4 cascade nanozyme, which shows a linear range of 0.05–1.0 mM with excellent selectivity. CuWO4 NPs as a promising matrix open up a dual-strategy biosensor for sensitive and selective detection of glucose. [ABSTRACT FROM AUTHOR]

Developing novel electrocatalysts is of great importance for the practical application of non-enzymatic glucose sensors. One-dimensional (1D) carbon fiber-supported copper–cobalt bimetallic electrocatalysts (CuCo-P350) are successfully prepared via electrospinning technology and pyrolysis treatment. The morphology and structure of the composites are analyzed by XRD, SEM, TEM, and XPS. The CuCo-P350 is utilized as the electrocatalyst for non-enzymatic glucose sensors. Its 1D nano-structure provides highly exposed active sites and rapid charge transfer channels. Moreover, the surface phosphorization enhances its electrocatalytic activity. The CuCo-P350 delivers a superior sensitivity of 2272 μA mM−1 cm−2 in the range of 100–500 μM. In a large linear range of 5–825 μM, it exhibits an excellent sensitivity of 1100 μA mM−1 cm−2 with a low detection limit of 2.92 μM. The CuCo-P350 exhibits acceptable anti-interference ability, good reproducibility, and stability. The sensor can be used in human serum detection. Our results provide a reference for the structure design and fabrication of novel electrocatalysts for non-enzymatic glucose sensors. [ABSTRACT FROM AUTHOR]

The colorimetric detection of glucose using hybrid nanostructures is a rapidly growing research hotspot. In this work, we established a simple route for the synthesis of a class of multi-metal hybrid nanostructure materials and investigated their peroxidase-like performance for the colorimetric detection of glucose. The hybrid nanomaterial (Fe3O4@Au–Pt) incorporated ferrosoferric oxide nanoparticles (Fe3O4 NPs) and heterodimers composed of gold (Au) and platinum (Pt), which presents excellent morphology and structure. On the basis of our research, we constructed an easy and sensitive colorimetric sensor for the detection of glucose and hydrogen peroxide (H2O2), and the results indicated that the Fe3O4@Au–Pt hybrid nanomaterial possessed preferable peroxidase-like activity in comparison with other nanozyme materials and showing prominent selectivity for glucose detection. For H2O2, the sensor has a linear range of 0.05–120 μM and a relatively low limit of detection (LOD) of 0.018 μM. For glucose, the linear range is 0.05–140 μM with an LOD of 0.025 μM. It is envisioned that these hydrophilic hybrid nanostructures will be widely applied in sensing target analytes, biomedical diagnosis, and therapeutic applications in the future by taking advantage of their specific structure and excellent catalytic performance. [ABSTRACT FROM AUTHOR]

One-pot synthesis of Mn3O4 nanorods is reported for the first time by the oxidation of manganese metal resulting from reducing Mn2+ by NaBH4 at room temperature. The resultant Mn3O4 nanorods were 10–70 nm in width and up to hundreds of nanometers in length, and were very stable in aqueous solution. The Mn3O4 nanorods can oxidize H2O2 under acidic conditions quickly accompanying their decomposition. Using 3,3′,5,5′-tetramethylbenzidine (TMB) as a competitive chromogenic substance, colorimetric methods were developed for the sensitive detection of H2O2 and glucose. The methods exhibited a linear range of 2–100 μM with a limit of detection (LOD) of 1.7 μM for detecting H2O2, and a linear range of 5–200 μM with a LOD of 4.4 μM for detecting glucose. The application in analyzing glucose in human serum samples demonstrates its practicability. [ABSTRACT FROM AUTHOR]

Metal–organic frameworks (MOFs) as a peroxidase mimic have been integrated with glucose oxidase (GOx) to achieve one-step glucose detection. However, limited by the loading amount of GOx, the performances of the developed glucose sensing assays still remain to be further improved to meet sensing requirements in diverse biological samples. Herein, with Fe3+ as the metal ion and 2-amino-benzenedicarboxylic acid as a ligand, a fluorescent Fe-based organic framework (NH2-MIL-101) with peroxidase-like activity was synthesized. Due to the large specific surface area (791.75 m2 g−1), 68 μg mg−1 GOx could be immobilized through the amidation coupling reaction, and the product was designated GOx@NH2-MIL-101. With OPD as the substrate, Gox@NH2-MIL-101 achieved highly efficient biomimetic cascade catalysis for one-step glucose detection through an inner filter effect: upon reacting with glucose, GOx@NH2-MIL-101 catalytically oxidized glucose using dissolved O2, and the produced H2O2 concurrently oxidized o-phenylenediamine (OPD) to oxidized OPD (oxOPD), accompanied by the fluorescence of GOx@NH2-MIL-101 at 456 nm being quenched and that of oxOPD at 565 nm being enhanced. With the fluorescent ratio F565/F456 used as a readout signal, a wide linear range of 0.1–600 μM was obtained, and the detection limit was 0.0428 μM. Based on the excellent selectivity and high stability of GOx@NH2-MIL-101, the developed assay was successfully applied to glucose detection in human serum and saliva, presenting potential applications in diverse biological samples and even medical diagnosis. [ABSTRACT FROM AUTHOR]

Bienzymatic systems are often used with electrochemical affinity biosensors to achieve high signal levels and/or low background levels. It is important to select two enzymes whose reactions do not exhibit mutual interference but have similar optimal conditions. Here, we report a sensitive electrochemical immunosensor based on a bienzymatic system consisting of β-galactosidase (Gal, a hydrolase enzyme) and flavin adenine dinucleotide-dependent glucose dehydrogenase (FAD-GDH, a redox enzyme). Both enzymes showed high activities at neutral pH, the reactions catalyzed by them did not exhibit mutual interference, and the electrochemical-enzymatic redox cycling based on FAD-GDH coupled with enzymatic amplification by Gal enabled high signal amplification. Among the three amino-hydroxy-naphthalenes and 4-aminophenol (potential Gal products), 4-amino-1-naphthol showed the highest signal amplification. Glucose, as an electro-inactive, stable reducing agent for redox cycling, helped in achieving low background levels. Our bienzymatic system could detect parathyroid hormone at a detection limit of ∼0.2 pg mL−1, implying that it can be used for highly sensitive electrochemical detection of parathyroid hormone and other biomarkers in human serum. [ABSTRACT FROM AUTHOR]

In this study, ultrafine and uniform cuprous oxide (Cu2O) nanocubes with different sizes and rough surfaces were prepared via a seed-mediated process. The Cu2O nanocubes were formed by the self-assembly of the subsequently generated Cu2O crystallites on the surface of the introduced seed medium. The obtained samples were used for non-enzymatic glucose detection and exhibited good capabilities. The Cu2O nanocubes obtained from a beaker 3 modified electrode showed the best performance, such as high sensitivity (3213 μA mM−1 cm−2), low limit of detection (LOD, 0.14 μM), acceptable linear range (0.05 to 5.15 mM) and fast electrocatalytic response (<1 s). In addition, the acceptable selectivity and long-term stability prove that Cu2O nanocube modified non-enzyme glucose biosensors are promising for practical applications. [ABSTRACT FROM AUTHOR]

The combination of an electrocatalyst with a semiconductor light absorber is of great importance to increase the efficiency of photoelectrochemical (PEC) glucose detection. Here, in situ and synchronous fabrication of a Ni-based electrocatalyst (NiEC) and CdS semiconductor in laser-induced graphene (LIG) on indium–tin oxide glass is demonstrated via a one-step laser-induced solid phase transition. A series of component and structural characterization experiments suggest that the laser-induced NiEC uniformly disperses in the hybrid nanocomposite and exists mainly in the Ni0 and NiO states. Moreover, both electrochemical and PEC investigations confirm that the as-prepared hybrid photoelectrode exhibits excellent photoelectrocatalytic ability towards glucose, which is not only attributed to the strong synergistic interaction between CdS and NiEC, but also benefited from the high conductivity as well as 3D macroporous configuration of the simultaneously formed LIG, providing the key factor to achieve sensitive non-enzymatic PEC glucose sensors. Therefore, the laser-induced hybrid photoelectrode is then applied to the PEC detection of glucose, and a low detection limit of 0.4 μM is obtained with good stability, reproducibility, and selectivity. This study provides a promising paradigm for the facile and binder-free fabrication of an electrocatalyst–semiconductor–graphene hybrid photoelectrode, which will find potential applications in sensitive PEC biosensing for a broad range of analytes. [ABSTRACT FROM AUTHOR]

A new chemiluminescence (CL) system, indigo carmine/glucose/hemin/H2O2, has been found and developed for non-enzymatic detection of indigo carmine (IC) and glucose. The CL response increases linearly with IC concentrations from 3.2 μM to 10 mM and glucose concentrations from 0.06 μM to 3.5 mM. The detection limits are 1.45 μM and 15.0 nM for IC and glucose, respectively. This method allows the determination of glucose in blood and urine after simple dilution. The recoveries for the determination of glucose are between 98.5% and 101.0% in blood and between 98.5% and 101.3% in urine. This method shows good sensitivity, selectivity, simplicity, and is low cost, suggesting its promising broad applications. [ABSTRACT FROM AUTHOR]

Porous Co3O4 nanoplates constructed by loosely interconnected nanoparticles were synthesized via an L -lysine assisted hydrothermal treatment and subsequent thermal annealing. The hydrothermal conditions of reaction time, reaction temperature and reactant concentrations were investigated in detail. The results suggested that the high affinity of L -lysine could effectively control the redissolution–recrystallization and even restrict the dehydration–condensation reaction of the Co(OH)2 precursor, and thus played the key role for the preparation of the resulting porous Co3O4 nanoplates. Cyclic voltammetry and amperometric methods were used to evaluate the electrochemical performance of the resulting porous Co3O4 nanoplates toward glucose sensing in an alkaline medium. The sensors constructed by the porous Co3O4 nanoplates exhibited a fast response time (within 5 s), a detection limit of 2.7 μM, a sensitivity of 212.92 μA cm−2 mM−1, a linear range from 0.05 mM to 3.2 mM and good stability at a low applied potential (0.38 V vs. Ag/AgCl), suggesting its high performance towards non-enzymatic glucose sensing. [ABSTRACT FROM AUTHOR]

In this study hybrid nanostructures of Au–graphene oxide (Au–GO) were synthesized via a two-step process and used to modify the glassy carbon electrode (GCE) for electrochemical measurements of glucose. The modified electrode exhibits a fast response less than 4 s, a low detection limit of 0.025 μM and a high signal-to-noise ratio (S/N) of 3.5. The fabricated sensor shows a linear response in a large concentration range from 0.0025 mM to 15 mM with a reproducible sensitivity of 84.53 μA cm−2 mM−1, which is much higher than that of the individual Au, GO and previously reported GO/rGO based sensors. In addition, the biosensor shows excellent results for human serum which agree well with those obtained using a laboratory glucometer. Moreover, the glucose amount in selective commercially available food samples and fresh juices was also successfully measured. The biosensor exhibits excellent selectivity, thermal stability and reproducibility. The enhanced and efficient sensitivity of the developed Au–GO based biosensor may be due to the synergic effects of the plasmonic Au-nanoparticles and GO. The performance of the biosensor suggests that the reported Au–GO hybrid nanostructures can provide a novel platform for developing non-enzymatic biosensors for biomedical and industrial applications. [ABSTRACT FROM AUTHOR]

The development of noble ultra-small biocompatible Pt nanoclusters (Pt NCs) for glucose detection has been drawing great attention. Herein, ultra-small biocompatible jujube polysaccharide (JP) stabilized platinum nanoclusters (Ptn-JP NCs) are prepared using natural JP as a reducing and solubilizing agent. Ptn-JP NCs were studied for the colorimetric detection of glucose. Ptn-JP NCs (n = 50, 200 and 400) had an average particle diameter of 1–2 nm. Particularly, the measurements of hydrodynamic sizes of Ptn-JP NCs indicated that they maintained good stability in solution for one week. Pt200-JP NCs showed good biocompatibility, and were not toxic against HeLa cells at a high concentration of 400 μg mL−1. Furthermore, Pt200-JP NCs catalyzed the oxidation of 3,3′,5,5′-tetramethylbenzidine (TMB) with H2O2 to produce blue oxidized TMB (oxTMB). This reaction followed typical Michaelis–Menten kinetics. More importantly, the glucose concentration could be sensitively detected by the color change, and this process was not interfered by other sugars. The linear range for glucose concentration was from 0.01 to 1 mM with a detection limit of 5.47 μM. The glucose concentrations of real samples of serum using Pt200-JP NCs were 9.2, 4.9 and 6.5 mM, respectively. The prepared Ptn-JP NCs have great potential in various biomedical detection methods. [ABSTRACT FROM AUTHOR]

In this communication, for the first time, an easy preparation method of nickel–iron (Ni–Fe) hybrid nanocubes for glucose oxidation, which is highly efficient in alkaline media, is described. As an impressive redox probe for glucose, the Ni–Fe hybrid nanocubes exhibit many remarkable sensing performances, for example, low-response time (7 s), broad detection range (from 10 μM to 20.5 mM), and low detection limit (0.64 μM, S/N = 3). The selectivity, reliability and stability of the Ni–Fe hybrid nanocubes for glucose oxidation are also investigated. The glucose sensor based on Ni–Fe hybrid nanocubes shows a superior sensing performance to that of Ni-based or Fe-based electrochemical sensors. Furthermore, the Ni–Fe hybrid nanocubes were used to detect glucose in real samples of human blood serum. All the findings demonstrate that the glucose sensor based on Ni–Fe hybrid nanocubes is successful for glucose detection and shows promise for future applications in medical diagnostics, the food industry and biological processes. [ABSTRACT FROM AUTHOR]

The development of ultra-small platinum nanoparticles is very important for the sensitive detection of glucose in complex medium without protein interference. Zwitterionic dendrimer-encapsulated platinum nanoparticles (Ptn-G5MC NPs) have been developed and studied for the highly sensitive and selective colorimetric detection of glucose. Firstly, zwitterionic dendrimer (G5MC) was obtained by surface modification of generation 5 poly(amidoamine) dendrimer with maleic anhydride and cysteamine. The calculated average diameters of Pt nanoparticles (Pt NPs) for Ptn-G5MC (n = 55, 110, and 165) were 1.64 ± 0.22, 2.09 ± 0.24, and 2.98 ± 0.29 nm, respectively. Ptn-G5MC NPs not only had high stability in various pH solutions and fibrinogen solutions, but also showed no noticeable cytotoxicity against HUVEC cells and HeLa cells. In addition, Ptn-G5MC NPs catalyzed oxidation of 3,3′,5,5′-tetramethylbenzidine (TMB) with H2O2 to generate blue oxidized TMB (oxTMB), indicating their peroxidase-like property. This peroxidase-like reaction followed a typical Michaelis–Menten kinetics. Furthermore, this colorimetric reaction was used for glucose detection with high sensitivity and selectivity. The linear range of glucose concentration with absorbance at 652 nm was from 7 to 1380 μM, and the detection limit was 2.8 μM. More importantly, the relative activity of Ptn-G5MC NPs was not affected by proteins. These enhanced properties are attributed to the ultra-small size of Pt NPs and high stability of Pt55-G5MC NPs in complex medium. The glucose concentration in saliva as a real sample was found to be 0.18 mM. The proposed glucose sensor could have promising applications for glucose detection in biocatalysis and bioassays in the future. [ABSTRACT FROM AUTHOR]

Creatinine is a kidney dysfunction biomarker, and its sensing properties have become an important tool in the diagnosis of abnormal kidney function. In the present study, a new enzyme-less creatinine sensor was developed by the bulk modification of carbon paste with the as-prepared inulin-based bio-nanocomposite. The electrochemical sensing of creatinine was conducted using the a sensor that exhibited two linear working ranges of 0.2 μM to 1 μM and 0.05 mM to 12 mM with the corresponding limits of detections of 60 nM and 90 μM. The sensitivity (204 mA mM cm−2), selectivity (in presence of other interferences like glucose, urea, ascorbic acid and uric acid) and stability (240 days) were also established. The sensitivity of the fabricated electrode was further validated by the determination of creatinine in urine samples spiked with various concentrations of creatinine. The analytical performance of the electrode was compared with that of the standard spectrophotometric method. This implied the better sensitivity of the fabricated sensor with nM-level sensing, which is a million times higher than that obtained using the spectrophotometric method. [ABSTRACT FROM AUTHOR]

In this study, Ni nanoparticles were grown on a silver-coated nylon yarn (SCNY) surface by electrochemical deposition to prepare SCNY@Ni. The hierarchical Ni–Ag nanostructure promoted their synergistic effect, which enhanced the electrocatalytic behavior of glucose oxidation. The test result of SCNY@Ni showed its high sensitivity (115.26 μA mM−1 cm−2 and 67.37 μA mM−1 cm−2) with a wide linear response (from 2 μM to 1 mM and from 1 mM to 22 mM) of glucose con-centration range, a low detection limit (LOD) of 2 μM, fast response time (3 s), and good selectivity for glucose determination in the presence of sucrose (SU), aceta-mino phenol (AP), D -fructose (D -Fru), ascorbic acid (AA), dopamine (DA), hydro-quinone (HQ) and uric acid (UA) as potential interference species. Also, SCNY@Ni exhibited excellent stability, repeatability, reproducibility and flexibility. It has good prospects for large-scale production. [ABSTRACT FROM AUTHOR]

Precisely detecting the concentration of glucose in the human body is an attractive way to prevent or treat diabetes. Portable glucose sensors with non-enzymatic catalytic materials have received great attention in recent years. Herein, a facile strategy for fabricating a high-performance electrochemical sensor is proposed. A non-enzymatic three-electrode integrated glucose sensor device based on CuO nano-coral arrays/nanoporous Cu (NCA/NPC) is designed and fabricated. The portable NCA/NPC glucose sensor device exhibits high catalytic activity for glucose. The great performance of the NCA/NPC glucose sensor device derives from the excellent conductivity of the NPC substrate and the high electrocatalytic activity of CuO nano-coral arrays. This device exhibits a high sensitivity of 1621 μA mM−1 cm−2 in the linear range of 0.0005–5.0 mM, low detection limit of 200 nM (S/N = 3), fast response time of 3 s, good anti-interference performance, excellent repeatability and considerable stability for glucose detection. This work will certainly provide an efficient structure and proper catalytic material choices for future non-enzymatic glucose sensors. [ABSTRACT FROM AUTHOR]