Development of label-free electrochemical OMP-DNA probe biosensor as a highly sensitive system to detect of citrus huanglongbing.

The fabrication of the first label-free electrochemical DNA probe biosensor for highly sensitive detection of Candidatus Liberibacter asiaticus (CLas), as the causal agent of citrus huanglongbing disease, is conducted here. An OMP probe was designed based on the hybridization with its target-specific sequence in the outer membrane protein (OMP) gene of CLas. The characterization of the steps of biosensor fabrication and hybridization process between the immobilized OMP-DNA probe and the target ssDNA oligonucleotides (OMP-complementary and three mismatches OMP or OMP-mutation) was monitored using cyclic voltammetry and electrochemical impedance spectroscopy based on increasing or decreasing in the electron transfer in [Fe (CN)6]3-/4- on the modified gold electrode surface. The biosensor sensitivity indicated that the peak currents were linear over ranges from 20 to 100 nM for OMP-complementary with the detection limit of 0.026 nM (S/N = 3). The absence of any cross-interference with other biological DNA sequences confirmed a high selectivity of fabricated biosensor. Likewise, it showed good specificity in discriminating the mutation oligonucleotides from complementary target DNAs. The functional performance of optimized biosensor was achieved via the hybridization of OMP-DNA probe with extracted DNA from citrus plant infected with CLas. Therefore, fabricated biosensor indicates promise for sensitivity and early detection of citrus huanglongbing disease.

Advancing chirality analysis through enhanced enantiomer characterization and quantification via fast Fourier transform capacitance voltammetry.

The exploration of the chiral configurations of enantiomers represents a highly intriguing realm of scientific inquiry due to the distinct roles played by each enantiomer (D and L) in chemical reactions and their practical utilities. This study introduces a pioneering analytical methodology, termed fast Fourier transform capacitance voltammetry (FFT-CPV), in conjunction with principal component analysis (PCA), for the identification and quantification of the chiral forms of tartaric acid (TA), serving as a representative model system for materials exhibiting pronounced chiral characteristics. The proposed methodology relies on the principle of chirality, wherein the capacitance signal generated by the adsorption of D-TA and L-TA onto the surface of a platinum electrode (Pt-electrode) in an acidic solution is harnessed. The capacitance voltammograms were meticulously recorded under optimized experimental conditions. To compile the final dataset for the analyte, the average of the FFT capacitance voltammograms of the acidic solution (without the presence of the analyte) was subtracted from those containing the analyte. A distinct arrangement was obtained by employing PCA as a linear data transformation method, representing D-TA and L-TA in a two/three-dimensional space. The outcomes of the study reveal the successful detection of the two chiral forms of TA with a considerable degree of precision and reproducibility. Moreover, the proposed method facilitated the establishment of two linear response ranges for the concentration values of each enantiomer, spanning from 1 to 20 µM, and 50 to 500 µM. The respective detection limits were also determined to be 0.4 µM for L-TA and 1.3 µM for D-TA. These findings underscore the satisfactory sensitivity and efficiency of the proposed method in both qualitative and quantitative assessments of the chiral forms of TA.

Simultaneous electrochemical determination of morphine and methadone by using CMK-5 mesoporous carbon and multivariate calibration.

For the first time, a sensitive electrochemical sensor using a glassy carbon electrode modified with CMK-5 Ordered mesoporous carbon was fabricated for simultaneous analysis of morphine and methadone. Modern electrochemical FFT-SWV techniques and partial least-squares as a multivariable analysis were used in this method. CMK-5 nanostructures were characterized by field emission scanning electron microscopy, transmission electron microscopy, X-ray diffraction analysis, and Raman spectroscopy. Variables such as accumulation time and pH for the proposed sensor were optimized before quantitative analysis. To train the proposed sensor, standard mixtures of morphine (MOR), and methadone (MET) were prepared in the established linear ranges of the analyzes. The results obtained from training samples were used for PLS modeling. The efficiency of the model was determined using test and real matrix samples. The root mean square error of prediction and the squared correlation coefficients (R2p) for MET and MOR were estimated to be 0.00772 and 0.00892 and 0.948 to 0.990, respectively. The recoveries in urine samples were reported to be 97.0 and 105.6% for both MOR and MET, respectively.

The global trend of exosome in diabetes research: A bibliometric approach.

BACKGROUND AND AIMS: Exosome as a novel biomarker reflecting cell behavior in normal and pathological conditions such as diabetes is being the center of academic attention. Therefore, we aimed to study the research output of exosome in diabetes globally. METHODS: We conducted a bibliometric approach to analyze publications on exosome and diabetes from the beginning to 2021 based on keyword search in the Scopus. Annual publications, citations, contributions, co-authorships, and co-occurrences were analyzed and plotted using VOSviewer and GraphPad Prism. RESULTS: 410 original articles and 149 reviews have published between 2009 and 2021. China and the USA were top countries in research output, sponsorship, and international collaborations. The top journals were Scientific Reports, Stem Cell Research and Therapy and Diabetes. The top institution was the University of Queensland in Australia. The top author was Chopp M. Co-occurrence analysis indicated that researchers focused on 1) extracellular vesicles in insulin resistance induced by metabolic disorders like obesity and diabetes mellitus; 2) diagnostic applicability of exosomal microRNAs as biomarkers for diabetic nephropathy; 3) therapeutic effect of exosome in wound healing and endothelial dysfunction during diabetes mellitus; and 4) The oxidative stress, autophagy, apoptosis, fibrosis, inflammation and angiogenesis mediated by exosomes during diabetes. CONCLUSION: The trend in research output has been increased in this field, and advanced countries are involved much more than other countries in terms of research, financial support, and international collaboration. The bibliometric results could be beneficial for further studies in better understanding of novel ideas in exosome and diabetes fields.

Review on oxidative stress relation on COVID-19: Biomolecular and bioanalytical approach.

COVID-19 disease has put life of people in stress worldwide from many aspects. Since the virus has mutated in absolutely short period of time the challenge to find a suitable vaccine has become harder. Infection to COVID-19, especially at severe life threatening states is highly dependent on the strength of the host immune system. This system is partially dependent on the balance between oxidative stress and antioxidant. Besides, this virus still has unknown mechanism of action companied by a probable commune period. From another hand, some reactive oxygen species (ROS) levels can be helpful on the state determination of the disease. Thus it could be possible to use modern bioanalytical techniques for their detection and determination, which could indicate the disease state at the golden time window since they have the potential to show whether specific DNA, RNA, enzymes and proteins are affected. This also could be used as a preclude study or a reliable pathway to define the best optimized time of cure beside effective medical actions. Herein, some ROS and their relation with SARS-CoV-2 virus have been considered. In addition, modern bioelectroanalytical techniques on this approach from quantitative and qualitative points of view have been reviewed.

High-Performance Voltammetric Aptasensing Platform for Ultrasensitive Detection of Bisphenol A as an Environmental Pollutant.

Bisphenol A (BPA) as a pervasive endocrine-disrupting compound (EDC) has been shown to cause multiple detrimental effects including cardiovascular disorders, pregnancy complications, obesity, glucose metabolism disorders, and reproductive toxicity even at a concentration as low as tolerable daily intake (TDI) (4 µg/kg/day). In the present study, a novel ultra-sensitive, electrochemical aptasensor was designed using a screen-printed carbon electrode (SPCE) modified by gold nanoparticles (Au NPs) conjugated to thiolated aptamers for accurate determination of BPA in biological, industrial and environmental samples. To characterize the electrochemical properties of the aptasensor, cyclic voltammetry (CV) and electrochemical impedance spectroscopy (EIS) were implemented. Detection of BPA was also performed through differential pulse voltammetry (DPV) in [Fe(CN)6]3-/4- electrolyte solution. Under optimum condition, the present electrochemical aptasensor demonstrated an outstanding linear response in the concentration range of 1 pM to 10 nM with a remarkably low limit of detection of 0.113 pM. Due to the superb affinity between anti-BPA aptamers and BPA molecules, the designed aptasensor did not show any significant interaction with other analytes in real samples. Also, fabricated biosensor remained perfectly stable in long-term storage. The analytical results of the fabricated aptasensor are well compatible with those obtained by the ELISA method, indicating the trustworthiness and reasonable accuracy of the application of aptasensor in real samples. Overall, the proposed aptasensor would be a credible and economical method of precise, reproducible, and highly selective detection of minimum levels of BPA in food containers and clinical samples. This would be a promising strategy to enhance the safety of food products and reduce the risk of BPA daily exposure.

A Sensitive Aptamer-Based Biosensor for Electrochemical Quantification of PSA as a Specific Diagnostic Marker of Prostate Cancer.

PURPOSE: The current project aimed to design a simple, highly sensitive, and economical label-free electrochemical aptasensor for determination of prostate-specific antigen (PSA), as the gold standard biomarker for prostate cancer diagnosis. The aptasensor was set up using a screen-printed carbon electrode (SPCE) modified by gold nanoparticles (Au NPs) conjugated to thiolated aptamers. METHODS: Cyclic voltammetry (CV) and electrochemical impedance spectroscopy (EIS) were implemented for electrochemical (EC) characterization of the aptasensor. The determination of PSA was also performed through differential pulse voltammetry (DPV) in [Fe (CN) 6]3-/4- electrolyte solution. RESULTS: The present aptasensor was shown an outstanding linear response in the concentration range of 1 pg/mL - 200 ng/mL with a remarkably lower limit of detection of 0.077 pg/mL. The optimum concentration for PSA separation and the optimum incubation time for antigen-aptamer binding were determined by observing and electing the highest electrochemical responses in a specified time or concentration. CONCLUSION: According to the results of the specificity tests, the designed aptasensor did not show any significant interactions with other analytes in real samples. Clinical functionality of the aptasensor was appraised in serum samples of healthy individuals and patients examining the PSA level through the fabricated aptasensor and the reference methods. Both methods are comparable in sensitivity. The present fabricated PSA aptasensor with substantial characteristics of ultra- sensitivity and cost-effectiveness can be conventionally built and used for the routine check-up of the men for prostate problems.

An Electrochemical Aptasensor Platform Based on Flower-Like Gold Microstructure-Modified Screen-Printed Carbon Electrode for Detection of Serpin A12 as a Type 2 Diabetes Biomarker.

PURPOSE: In the present study, a highly sensitive and simple electrochemical (EC) aptasensor for the detection of serpin A12 as a novel biomarker of diabetes was developed on a platform where flower-like gold microstructures (FLGMs) are electrodeposited onto a disposable screen-printed carbon electrode. Meanwhile, serpin A12-specific thiolated aptamer was covalently immobilized on the FLGMs. METHODS: The electrochemical activity of a fabricated aptasensor under various conditions were examined by cyclic voltammetry (CV) and electrochemical impedance spectroscopy (EIS). Aptamer concentration, deposition time, self-assembly time, and incubation time were optimized for assay of serpin A12. The differential pulse voltammetry (DPV) was implemented for quantitative detection of serpin A12 in K3 [Fe (CN) 6]/K4 [Fe (CN) 6] solution (redox probe). RESULTS: The label-free aptasensor revealed a linear range of serpin A12 concentration (0.039-10 ng/mL), detection limit of 0.020 ng/mL (S/N=3), and 0.031 ng/mL in solution buffer and plasma, respectively. CONCLUSION: The results indicate that this aptasensor has a high sensitivity, selectivity, stability, and acceptable reproducibility for detection of serpin A12 in diabetic patients.

Potential of Vetiver grass for the phytoremediation of a real multi-contaminated soil, assisted by electrokinetic.

Phytoremediation assisted by electrokinetic is a potential technology for remediation of contaminated soil, but little is known about its application on real contaminated soils. This study aims to evaluate the Vetiver grass application on the electro-phytoremediation of a real contaminated soil around a metal smelter factory. Different types of the electric field (AC-DC), voltage gradient (1-2V/cm), saturation and unsaturation condition, and Eh-pH variation were investigated for Vetiver electro-phytoremediation performance. Vetiver grass had been grown for 21 days. Then three different voltage gradients (1, 2DCV/cm and 2ACV/cm) were applied for 8 h/d across the soil domain for the next 21 days in comparison with a control cell without electric field (PR). The results showed that despite the AC current application which induced small changes, the application of DC current significantly changed the Eh-pH values. The maximum accumulation of extractable metals in Vetiver grass occurred in 2DCV/cm that shows approximately 50% increase in comparison with the AC and PR cells. The presence of contaminants poisons the Vetiver in all cells and all plants under 2DCV/cm dried out at the end of the experiment. Despite the significant reduction of heavy metals, there was no noticeable phytoextraction due to the application of DC current. Therefore, DC current can be used for phytoremediation through phytostabilization. However, the overall metals uptake in plants shoots under AC treatment with BCF>1 was much higher than the PR and DC treatment. Considering the translocation rate and plants health, if the AC current is applied in a long treatment time, it could have better results in electro-phytoremediation of the Vetiver grass through phytoextraction process. However, the maximum removal of heavy metals was in the cathode part of the cell under 2DCV/cm that shows 65% improvement in comparison with the PR cell.

Facile electrochemical preparation of overoxidizedpolypyrrole/RGO composite for ds-DNA immobilization: a novel signal amplified sensing platform for electrochemical determination of chlorpheniramine.

BACKGROUND: Chlorpheniramine (CPA), thanks to its relatively lower side effects, is a widely prescribed medicine for alleviating allergic symptoms as well as some medical emergencies. Owning to this extensive use, many efforts have been directed to measure chlorpheniramine both in vivo and in vitro. High performance liquid chromatography (HPLC), both normal and reverse phase, as well as spectrochemical and electrochemical methods are analytical approaches which have been extensively exploited for determination of CPA. Among them, electrochemical techniques have found elegant place for analysis of CPA due to simplicity, sensitivity and ease of instrumentation. METHODS: Herein, we have reported the preparation and characterization of a biosensor by immobilization of double-stranded DNA on the surface of overoxidizedpolypyrrole-reduced graphene oxide modified pencil graphite electrode (ds-DNA-PPyox/RGO/PGE) as well as its novel usability in measurement of chlorpheniramine (CPA). Scanning electron microscopy (SEM), electrochemical impedance spectroscopy (EIS), UV-Vis spectroscopy and differential pulse voltammetry (DPV) were exploited in order to characterize and evaluate the performance of the proposed biosensor. RESULTS: Final results showed that proposed strategy for modification of PGE introduces an ultra-sensitive biosensor for CPA which offers the best detection limitamong all previously reported electrochemical sensors for CPA. Taking advantage of this biosensor for determination of CPA, a wide linear dynamic range from 0.05 to 200 µM, and a low limit of detection 0.023 µM were obtained by using DPV method. Usability of this biosensor was also confirmed by determination of CPA in tablet and spiked urine samples. CONCLUSIONS: Overoxidized polypyrrole-reduced graphene oxide offered a suitable substrate for immobilization of ds-DNA by which a new biosensor for determination of CPA was fabricated. Proposed biosensor can successfully be used for determination of CPA in urine samples taking advantage of electroanalytical methods. Graphical abstract.

Layer-by-Layer Cathodic Deposition of Ni/Ni(OH)2 Particles on Steel Gauze Electrode for High-Performance Supercapacitor Application.

Layer-by-layer of Ni/Ni(OH)2 particles were deposited on Steel Gauze (SG) electrode via cathodic electrodeposition. The system with two electrodes was selected for electrodeposition in the galvanostatic condition. Electrodeposition of the first layer of Nickel was conducted in the electrochemical cell with an SG substrate as a cathode. This electrode was fixed between two parallel graphite anodes and electrodeposition was performed from a mixture of NiCl2, NH4Cl, NaCl solution. Electrodeposition of the second layer of Ni(OH)2 on the Ni layer which has been formed in the first step, was carried out in the same way from a solution containing Ni(NO3)2. TG, XRD and SEM techniques were used for the characterization of the prepared SG/Ni/Ni(OH)2 electrode. The prepared SG/Ni/Ni(OH)2 electrode was analyzed by electrochemical techniques such as Cyclic Voltammetry (CV), galvanostatic charge-discharge and Electrochemical Impedance Spectroscopy (EIS). The SG/Ni/Ni(OH)2 electrode demonstrated high specific capacity (1308 C g-1 at the scan rate of 5 mV s-1) and excellent cycling ability (8.9% capacity decay at the current density of 50 A g-1 after 1000 cycle).

Ultra-trace detection of methamphetamine in biological samples using FFT-square wave voltammetry and nano-sized imprinted polymer/MWCNTs -modified electrode.

An efficient voltammetric method for trace level monitoring of methamphetamine (MTM) stimulant drug in the human urine and serum samples is established. This method is based on fast fourier transform square wave voltammetric (FFT-SWV) determination of MTM at a molecularly imprinted polymer (MIP)/multi-walled carbon nanotube (MWCNTs)-modified carbon paste electrode. Voltammetric techniques development for electrochemical assay of MTM is a challenge, due to the weak electroactivity of this drug. Herein, MTM-imprinted nanopolymer was synthesized, using a simple precipitation polymerization method. The resulting polymer, along with MWCNT was then used to fabricate the modified carbon paste electrode which showed a well-defined anodic peak for MTM at about +1.0 V(vs. Ag/AgCl); whereas, the related blank electrode exhibited considerably lower signal at the same conditions. Utilizing the highly efficient MIP, MWCNTs (which increased the charge transfer phenomenon at the electrode surface) and the advanced electrochemical technique of FFT-SWV (which increased the created signal intensity) caused this method to be a high sensitive and selective approach for MTM measurement. In the optimum experimental conditions, the proposed sensor, exhibited linear response range of 1.0 × 10-8 -1.0 × 10-4 mol L-1 and the detection limit of 8.3 × 10-10 mol L-1 with acceptable relative standard deviations (RSD%) for real samples (1.0-3.5%). Herein, the first MIP-based voltammetric sensor for MTM which also exhibits the lowest detection limit, ever reported, is introduced. This approach seems to provide an effective way for rapid screening of MTM in human urine and serum samples.

Biochemical and molecular evidence on the role of vaspin in early detection of the insulin resistance in a rat model of high-fat diet and use of diazinon.

Vaspin, as a newly discovered adipocytokine, can modulate obesity with insulin-sensitizing effects. This study mainly focused on the plasma level of vaspin in insulin resistant rats, which received high-fat diet (HFD) and diazinon (DZN) (70 mg/kg). Upon 30-day experiment, related oxidative stress and inflammatory markers of plasma, the toxic effects of DZN and HFD on the histological structure of the liver, as well as the expression levels of potential genes associated with insulin resistance, phosphatase and tensin homolog (PTEN) and Forkhead box protein O1 (FoxO1) were evaluated. Metabolic parameters implicated to the glucose and insulin statues such as homeostatic model assessment of insulin resistance (HOMA-IR), oral glucose tolerance test (OGTT) and fasting blood glucose (FBG) were determined. DZN significantly inhibited almost 50% of the plasma cholinesterase (ChE) activity. A remarkable increase of MDA level was observed in groups that received DZN and DZN + HFD. Animals treated with DZN or DZN + HFD showed significant changes in reactive oxygen species (ROS) level. The level of plasma tumor Necrosis Factor alpha (TNF-α) was noticeably elevated in the exposed groups. The highest elevation in vaspin level was observed in HFD group followed by DZN treated animals. In all treated groups, insulin level significantly increased and also, the area under the curve (AUC0-180) values of plasma glucose heightened considerably. The histopathological micrographs of HFD + DZN treated group indicated a severe fatty change. The plasma concentration of DZN was significantly higher in the DZN-treated group in comparison to the DZN + HFD group. FoxO1 and PTEN mRNA levels were significantly overexpressed in the DZN and HFD exposed groups. In HFD treated group, PTEN expression significantly increased compared with the DZN and DZN + HFD groups. Consequently, in contrast to oxidative stress and inflammatory biomarkers, vaspin level would be a more reliable diagnostic factor when it comes to the insulin resistance.

Simple and effective label free electrochemical immunosensor for Fig mosaic virus detection.

Here, the construction and characterization of the first immunosensor for highly sensitive and label free detection of Fig mosaic virus (FMV) is reported. The specific antibody against nucleocapsid of the virus was raised and immobilized at the surface of 11-mercaptoundecanoic acid (MUA) and 3-mercapto propionic acid (MPA) modified gold electrode, via carbodiimide coupling reaction. The immunosensor fabrication steps were characterized using cyclic voltammetry (CV) and electrochemical impedance spectroscopy (EIS). The electrochemical detection of FMV was conducted using differential pulse voltammetry in ferri/ferrocyanide solution as a redox probe. The proposed immunosensor exhibited high selectivity, good reproducibility and high sensitivity for FMV detection in a range from 0.1 nM to 1 µM with a detection limit of 0.03 nM. Moreover, good results were obtained for determination of FMV in real samples, indicating the feasibility of the developed immunosensor for detection of fig mosaic disease, without the need for molecular (e.g. PCR) amplification.

Novel label-free electrochemical aptasensor for determination of Diazinon using gold nanoparticles-modified screen-printed gold electrode.

The present study aimed to develop a highly sensitive label-free electrochemical aptasensor for the detection of Diazinon (DZN), as one of the most widespread organophosphorus compounds. The aptasensor was assembled using screen-printed gold electrode modified by thiolated aptamers which were immobilized on gold nanoparticles (Au NPs). Optimum deposition time, in which the highest electrochemical response occurred, was found in 150 s. Electrochemical impedance spectroscopy and cyclic voltammetry were used to characterize electrochemical properties of the novel aptasensor. Electrochemical detection was carried out through differential pulse voltammetry in [Fe(CN)6]3-/4- solution. Fluctuation of the current was examined in the DZN concentration range of 0.1-1000 nM. According to the results, the designed aptasensor provided an extremely lower limit of detection (0.0169 nM) compared with HPLC and other colorimetric techniques for DZN detection. The present highly specific designed aptasensor doesn't interact with other analytes in the real sample. Consequently, the present aptasensor is easy to use and relatively inexpensive with a good sensitivity, stability, and reproducibility for this application. We are now evaluating all approaches to make a portable device for fast and sensitive quantification of DZN and related OPs.

Alteration of hepatocellular antioxidant gene expression pattern and biomarkers of oxidative damage in diazinon-induced acute toxicity in Wistar rat: A time-course mechanistic study.

In the present survey, the plasma level of diazinon after acute exposure was measured by HPLC method at a time-course manner. In addition, the impact of diazinon on the expression of the key genes responsible for hepatocellular antioxidative defense, including PON1, GPx and CAT were investigated. The increase in oxidative damages in treated rats was determined by measuring LPO, protein carbonyl content and total antioxidant power in plasma. After administration of 85 mg/kg diazinon in ten groups of male Wistar rats at different time points between 0-24 hours, the activity of AChE enzyme was inhibited to about 77.94 %. Significant increases in carbonyl groups and LPO after 0.75 and 1 hours were also observed while the plasma antioxidant power was significantly decreased. Despite the dramatic reduction of GPX and PON1 gene expression, CAT gene was significantly upregulated in mRNA level by 1.1 fold after 4 hours and 1.5-fold after 24 hours due to diazinon exposure, compared to control group. Furthermore, no significant changes in diazinon plasma levels were found after 4 hours in the treated rats. The limits of detection and quantification were 137.42 and 416.52 ng/mL, respectively. The average percentage recoveries from plasma were between 90.62 % and 95.72 %. In conclusion, acute exposure to diazinon increased oxidative stress markers in a time-dependent manner and the changes were consistent with effects on hepatic antioxidant gene expression pattern. The effect of diazinon even as a non-lethal dose was induced on the gene expression of antioxidant enzymes. The change in antioxidant defense system occurs prior to diazinon plasma peak time. These results provide biochemical and molecular evidence supporting potential acute toxicity of diazinon and is beneficial in the evaluation of acute toxicity of other organophosphorus pesticides as well.

Simultaneous extraction and determination of trace amounts of diclofenac from whole blood using supported liquid membrane microextraction and fast Fourier transform voltammetry.

A novel, simple, and inexpensive analytical technique based on flat sheet supported liquid membrane microextraction coupled with fast Fourier transform stripping cyclic voltammetry on a reduced graphene oxide carbon paste electrode was used for the extraction and online determination of diclofenac in whole blood. First, diclofenac was extracted from blood samples using a polytetrafluoroethylene membrane impregnated with 1-octanol and then into an acceptor solution, subsequently it was oxidized on a carbon paste electrode modified with reduced graphene oxide nanosheets. The optimal values of the key parameters influencing the method were as follows: scan rate, 6 V/s; stripping potential, 200 mV; stripping time, 5 s; pH of the sample solution, 5; pH of the acceptor solution,7; and extraction time, 240 min. The calibration curves were plotted for the whole blood samples and the method was found to have a good linearity within the range of 1-25 µg/mL with a determination coefficient of 0.99. The limits of detection and quantification were 0.1 and 1.0 µg/mL, respectively. Using this coupled method, the extraction and determination were merged into one step. Accordingly, the speed of detection for sensitive determination of diclofenac in complex samples, such as blood, increased considerably.

One-step cathodic electrodeposition of a cobalt hydroxide-graphene nanocomposite and its use as a high performance supercapacitor electrode material.

In this study, Co(OH)2-reduced graphene oxide has been synthesized using a simple and rapid one-step cathodic electrodeposition method in a two electrode system at a constant current density on a stainless steel plate, and then characterized as a supercapacitive material on Ni foam. The composites were characterized by FT-IR, X-ray diffraction, scanning electron microscopy, and cyclic voltammetry using a galvanostatic charge/discharge test. The feeding ratios of the initial components for electrodeposition had a significant effect on the structure and electrochemical performance of the Co(OH)2-reduced graphene oxide composite. The results show that the 1 : 4 (w/w) ratio of GO : CoCl2·6H2O was optimum and produced an intertwined composite structure with impressive supercapacitive behavior. The specific capacitance of the composite was measured to be 734 F g-1 at a current density of 1 A g-1. Its rate capability was ∼78% at 20 A g-1 and its capacitance retention was 95% after 1000 cycles of charge-discharge. Moreover, its average energy density and power density were calculated to be 60.6 W h kg-1 and 3208 W kg-1, respectively. This green synthesis method enables a rapid and low-cost route for the large scale production of Co(OH)2-reduced graphene oxide nanocomposite as an efficient supercapacitor material.

Recent advances in biosensor technology in assessment of early diabetes biomarkers.

Discovery of biosensors has acquired utmost importance in the field of healthcare. Recent advances in biological techniques and instrumentation involving nanomaterials, surface plasmon resonance, and aptasensors have developed innovative biosensors over classical methods. Integrated approaches provided a better perspective for developing specific and sensitive devices with wide potential applications. Type 2 diabetes mellitus is a complex disease affecting almost every tissue and organ system, with metabolic complications extending far beyond impaired glucose metabolism. Although there is no known cure for Type 2 diabetes, early diagnosis and interventions are critical to prevent this disease and can postpone or even prevent the serious complications that are associated with diabetes. Biomarkers for type 2 diabetes are useful for prediction and intervention of the disease at earlier stages. Proper selection of biomarkers that represent health and disease states is vital for disease diagnosis and treatment by detecting it before it manifests. In this respect, we provide an overview of different types of biosensors being used, ranging from electrochemical, fluorescence-based, nanomonitors, SPR-based, and field-effect transistor biosensors for early detection and management of diabetes with focus on prediabetes. In the future, novel non-invasive technologies combined with blood and tissue-based biomarkers will enable the detection, prevention, and treatment of diabetes and its complications long before overt disease develops.

Iron-Based Nanomaterials/Graphene Composites for Advanced Electrochemical Sensors.

Iron oxide nanostructures (IONs) in combination with graphene or its derivatives-e.g., graphene oxide and reduced graphene oxide-hold great promise toward engineering of efficient nanocomposites for enhancing the performance of advanced devices in many applicative fields. Due to the peculiar electrical and electrocatalytic properties displayed by composite structures in nanoscale dimensions, increasing efforts have been directed in recent years toward tailoring the properties of IONs-graphene based nanocomposites for developing more efficient electrochemical sensors. In the present feature paper, we first reviewed the various routes for synthesizing IONs-graphene nanostructures, highlighting advantages, disadvantages and the key synthesis parameters for each method. Then, a comprehensive discussion is presented in the case of application of IONs-graphene based composites in electrochemical sensors for the determination of various kinds of (bio)chemical substances.