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The Alborz Mountains are among the areas exhibiting high tectonic and seismic activity in northern Iran. Studying key parameters of tectonic structures, including quantitative analysis and observational studies, in such active regions is essential to identify potential active faults and assess the consequent seismic hazards. This study focuses on seismicity and seismotectonics by analyzing seismic parameters, including b-value, mean seismic activity rate, earthquake recurrence time, seismic moment, and fractal dimension derived from micro and teleseismic data. The b-values vary between 0.6 and 1.1 in the tectonically active parts of the study area, corresponding with the reverse/thrust and strike-slip active faults. Large earthquakes might be prone to occur at 10–25 km depth because both catalogues show low b-values (b < 1.0) concentrations at this depth range. The high fractal dimension (> 1.5), high seismic activity rate, large seismic moment parameters, and its continuously increasing trend. Short recurrence periods (20–50 years) of M 6.5 events also emphasize the high seismic activity and high seismic hazard. On the other hand, the prevalence of low b-values is notably observed in areas encompassing densely populated cities such as Rasht, Lahijan, Amol, Babol, Sari, Behshahr, Gorgan, and the megacity of Tehran. Furthermore, we have identified asperities where the Gorgan Plain, the Khazar, and the Alamutrud Fault Zones are located. These findings emphasize the seismic hazard potential in the identified areas and urban centers within the study area. Therefore, particular attention should be directed towards areas exhibiting low b-values when assessing and mitigating seismic hazards. It underscores the necessity for additional focus on seismic hazard assessment and implementation of mitigation strategies in the Alborz region. [ABSTRACT FROM AUTHOR]

Complex geology and tectonics of the NW Iran, the Caucasus region, and Eastern Turkey, are responsible for the present‐day landscapes of the region. The Aras drainage basin located in Iran, Azerbaijan and Armenia borders, provides an appropriate geographical environment for systematically studying the landforms produced or modified by active tectonic processes. Several morphometric indices were calculated for 114 sub‐basins to assess relative tectonic activity levels. Results were evaluated using two different methods; Index of Active Tectonics (IAT) and Analytical Hierarchy Process (AHP) methods. IAT results show that 2% of the sub‐basins belong to very high, 25% to high, 46% to moderate and 27% to low tectonic activity classes. AHP results, display that 12% of the sub‐basins belong to very high, 25% to high, 43% to moderate, and 20% to low tectonic activity classes. Results of both methods show approximate consistency and indicate that the tectonic activity along the Aras drainage basin is moderate to high and decreases from southwest to the northwest which is probably due to terminating fault branches in young unconsolidated deposits or strain partitioning processes. The major fault zones (e.g., Aras, Pambak–Sevan–Sunik, Akera, and Moghan fault zones) include areas with very high and high tectonic activity classes. Accordingly, the uplift rates have been estimated as >0.5 mm/yr for central and western parts, whereas the uplift rates are relatively less in the eastern part (<0.5 mm/yr). The Aras fault zone includes five active structural segments that the main Aras and Horadiz segments of them show relatively higher tectonic activity. [ABSTRACT FROM AUTHOR]

NW Iran is among the most interesting and complex areas within Arabian-Eurasia collision zone. Historical and instrumental earthquake records in this region indicate that active faults have the potential to produce serious seismic hazards in the future. The North Bozgush Fault Zone, an anastomosing fault zone, consists of several parallel and sub-parallel faults which have developed in a right lateral strike-slip system with a reverse component. Our structural analysis shows that faulting occurs along a strong dominant compressional strike-slip regime and is predominantly related to NW-SE shortening along the zone. This paper represents an analysis of the morphometric indices to depict the tectonic activity of the northern part of the Bozgush Mountains, an area with a typical tectono-morphology. The result of the morphometric analysis shows that relative tectonic activity along the North Bozgush Fault Zone decreases significantly from west to east. Measured uplift rates show that the uplift rate is higher than 0.5 mm/yr in the western and central parts and decreases in the eastern part to between 0.5 and 0.05 mm/yr. The structural and morphometric data are indicative of the relation between the North Bozgush Fault Zone and the Tabriz Fault Zone during Quaternary time. [ABSTRACT FROM AUTHOR]

As one of the most well-known metal nanoparticles, gold nanoparticles (AuNPs) have attracted much attention for the biological applications. This great interest in AuNPs can be attributed to their outstanding physical and chemical properties, such as special optical and electrochemical characteristics, high X-ray attenuation ability, strong X-ray absorption, photothermal effect, stability and biocompatibility. In addition, due to the ease of synthesis and modification of the surface of AuNPs, it is possible to control their shape, size and surface characteristics. All these features suggest that AuNPs can be used for biosensing strategies, drug delivery, photothermal therapy, nanobrachytherapy, enhanced radiotherapy and CT imaging. In addition, they can be used as antibacterial and antifungal agents. This minireview focuses on the key principles, research achievements and new opportunities in the synthesis of AuNPs as well as their biological applications. In fact, the growing progress in the use of AuNPs for the diagnostic and therapeutic applications is described in this survey. Overall, a better understanding of the key aspects of the synthesis methodologies will lead to the development of new protocols that can provide ideas for more cost-effective and reliable approaches to the production of AuNPs. [ABSTRACT FROM AUTHOR]

A highly sensitive impedimetric immunosensor based on a gold nanoparticles/multiwall carbon nanotube-ionic liquid electrode (AuNPs/MW-CILE) was developed for the determination of human epidermal growth factor receptor 2 (HER2). Gold nanoparticles were used to enhance the extent of immobilization and to retain the immunoactivity of the antibody Herceptin on the electrode. Cyclic voltammetry and electrochemical impedance spectroscopy were employed for characterization of various layers coated onto the AuNPs/MW-CILE. The impedance measurements at different steps were based on the charge transfer kinetics of the [Fe(CN) 6 ] 3−/4− redox pair. The immobilization of antibody and the corresponding antigen–antibody interaction at the electrode surface altered the interfacial electron transfer. The interactions of antibody with various concentrations of antigen were also monitored via the change of impedance response. The results showed that the charge transfer resistance increases linearly with increasing concentrations of HER2 antigen. The linear range and limit of detection were found as 10–110 ng mL −1 and 7.4 ng mL −1 , respectively. The sensitivity and specificity of the immunosensor were validated. The results showed that the prepared immunosensor is a useful tool for screening of trace amounts of HER2 in serum samples of breast cancer patients. [ABSTRACT FROM AUTHOR]

The purpose of this work was to investigate the performance of electrodes synthesized with Polyacrylonitrile-based carbon nanofibers (PAN-based CNFs). The homogenous PAN solutions with different concentrations were prepared and electrospun to acquire PAN nanofibers and then CNFs were fabricated by heat treatment. The effective parameters for the production of electrospun CNF electrode were investigated. Scanning electron microscopy (SEM) was used to characterize electrospun nanofibers. Cyclic voltammetry was applied to investigate the changes of behavior of electrospun CNF electrodes with different diameters. The structure of CNFs was also evaluated via X-ray diffraction (XRD) and Raman spectroscopy. The results exhibited that diameter of nanofibers reduced with decreasing polymer concentration and applied voltage and increasing tip-to-collector distance, while feeding rate did not have significant effect on nanofiber diameter. The investigations of electrochemical behavior also demonstrated that cyclic voltammetric response improved as diameter of CNFs electrode decreased. [ABSTRACT FROM AUTHOR]

Hyperthermia, the mild elevation of temperature to 40–45 °C, can induce cancer cell death and enhance the effects of radiotherapy and chemotherapy. Due to the nature of hyperthermia, especially their ability to combine nanotechnology, hyperthermia possesses the potential to open a novel paradigm for the therapeutic strategies. However, achievement of its full potential as a clinically relevant treatment modality has been restricted by its inability to effectively and preferentially heat malignant cells. The main challenge of current hyperthermia treatment is to adequately heat whole volumes of deep-seated tumors without overheating surrounding healthy tissues. So, hyperthermia is under clinical trials (research study with people) and is not widely available. In this Review, we summarize a basic knowledge of hyperthermia before focusing on their applications to the cancer therapy and synthesis. We try to give a comprehensive view of the role of nanomaterials in the designing of hyperthermia-based therapeutic protocols and compare the studies in this field with the purpose of providing a source of helpful information for planning forthcoming hyperthermia researches. However, establishing comparisons between hyperthermia studies is a challenge due to the widely different conditions used by different authors, which, in some cases, is aggravated by the lack of crucial information concerning a certain aspect of the procedure. [Display omitted] • Different types of hyperthermia and their applications in the thermotherapy and synthesis were reviewed. • A comprehensive view of the role of nanomaterials in the designing of hyperthermia-based therapeutic protocols was provided. • A source of helpful information for planning forthcoming hyperthermia researches was provided. [ABSTRACT FROM AUTHOR]

Highlights: [•] Design of a novel impedimetric immunosensor for detection of HSA in biological fluids. [•] Use of a multiwall carbon nanotube-ionic liquid electrode (MW-CILE) modified with AuNPs as a base. [•] Immobilization of activated anti-HAS on AuNPs/MW-CILE using 1,6-hexanedithiol as a cross linker. [•] Achieving linear dynamic range and limit of detection of 0.1–100μgmL−1 and 15.4ngmL−1, respectively. [•] Method development and validation for selective assay of HSA in biological fluids. [ABSTRACT FROM AUTHOR]

The application of rod‐shaped gold nanoparticles as probes and carriers in biological systems have recently attracted great interest. UV–vis spectroscopy, circular dichroism, Fourier transform infrared spectroscopy, scanning electron microscopy and atomic force microscopy were used to study optical and structural properties of rod‐shaped gold nanoparticles when interacting with DNA oligomers in phosphate sodium salt buffer. The morphological transformation process of rod‐shaped gold nanoparticles resulting from the interaction with single‐stranded DNA (ssDNA) showed the role of hexadecyltrimethylammonium bromide (CTAB) in nanostructures as the main interacting agent. The obtained results confirmed that the CTAB coat of rod‐shaped gold nanoparticles have powerful positive charges for conjugations with surface negative charges of phosphate groups on ssDNA oligomers. The CTAB also inhibit the formation of covalent sulphide bonds between the gold core of rod‐shaped nanoparticles and alkanethiol oligonucleotides. The authors found that when the nanorods were exposed to ssDNA oligonucleotides, the gold nanorods changed their shapes and sizes, and exposed some microscopic malformations which could be used in the development of colorimetric assays of nucleic acids. [ABSTRACT FROM AUTHOR]

cysteamine (CysAm) nanostructure was generated to act as an intermediate layer between gold electrode and carbon nanotubes. A bare gold electrode was placed in a solution of CysAm to create a self-assembled monolayer on its surface. The modified electrode was then incubated with a solution of multi-walled carbon nanotubes. Cyclic voltammetry and atomic force microscopy were used to characterize the modified electrode. The results indicated that the number of functionalized MWCNTs on the surface of the electrodes increased by enhancing incubation time. [Figure not available: see fulltext.] [ABSTRACT FROM AUTHOR]

The aim of this study is to develop a nucleic acid sensor based on piezoelectric crystal microbalance system (QCM) for following hybridization. Piezoelectric quartz crystal surfaces were first treated in a glow–discharge apparatus with ethylene diamine (EDA) plasma at 15 W (discharge power), 2.5 min (incubation time) and 35 ml/min (monomer flow rate) to create amino groups on the crystal surfaces. The thickness of the EDA–plasma film formed was about 43±24 A˚. Then, the amino groups on the crystal surfaces were converted to aldehyde groups by reacting the amino groups with glutaraldehyde (GA) at different conditions. A GA concentration of 2.5% and an incubation time of 2 h were selected as optimal values at this step, corresponding to a GA surface concentration of about 270 ng/cm2. A double strand Oligonucleotides, having one extra base on 5′-end of one of the complementary strands, were immobilized through the amino groups of this base onto the GA-modified crystals. Optimal immobilization conditions were as follows: oligonucleotide concentration: 1 μg/ml; time: 3 h; pH: 9.2 carbonate buffer; ionic strength: 0.1; and temperature: 20 °C. The QCM sensor carrying the covalently bound strand was used in the hybridization experiments, which showed that equilibrium is achieved in about 5 min, and the frequency shift measured is related to the concentration of the target strand to be measured within the medium. [Copyright &y& Elsevier]

The aim of this study is to investigate complexation of metallothionein (MT) with cadmium and zinc ions. An oligopeptide (i.e. Lys-Cys-Thr-Cys-Cys-Ala), a fragment of MT was covalently immobilized onto piezoelectric crystals, which were first treated with ethylene diamine plasma in a glow-discharge apparatus, and then were chemically reacted with glutaraldehyde. Complexation of the immobilized MT with Zn(II) and Cd(II) ions in aqueous media was followed by recording the changes of the frequency shifts of the piezoelectric quartz crystals. The amount of Cd(II) ions interacted with the immobilized MT molecules was the highest at pH 7.4, and decreased with an increase in the pH of the medium, in parallel to the decrease in the amount of immobilized MT. The number of Zn(II) ions interacted with the immobilized MT molecules was higher than the number of Cd(II) ions when the adsorption was from solutions containing a single-metal ion with the same ion concentrations. In consecutive adsorption studies, we observed that the type of metal ions used in the first interaction is important. These experiments showed also that there is an exchange between the metal ions, and competition provokes adsorption of both ions due to synergistic–antagonistic effects. [Copyright &y& Elsevier]

The aim of this study is to develop an immunoaffinity sensor based on piezoelectric crystals for human serum albumin (HSA) detection in aqueous media. Quartz crystals were treated with ethylene diamine (EDA) plasma in a glow-discharge apparatus in order to substitute amino groups on their surfaces. Then anti-HSA antibodies were immobilized via these amino groups by using glutaraldehyde (GA) as cross-linker. Immobilization of the antibody on the quartz crystal was examined for different pH, antibody concentration and treatment time. The optimum conditions for anti-HSA immobilization were evaluated by the measurements of the activity of the surface against HSA. The optimum values of pH, antibody concentration and treatment time were found 6.2, 0.15 mg/ml and 2 h, respectively. For detection of HSA into the solution, two methods were used. In the first (dip and dry) method, the frequency shifts were measured in air after the 1 h interaction of the anti-HSA immobilized crystals with HSA solution. In the other (direct) method, the frequency shifts were followed continuously for 60 min. while the probe was immersed in the HSA solution. An increase for the frequency shifts was observed with increasing of HSA concentration of 16–128 μg/ml. Both the immobilization and antibody-interaction conditions were found important on the extend of these specific interaction. The relations between the HSA concentrations and frequency shifts were exponential in both methods. [Copyright &y& Elsevier]

The outbreak rate of human coronaviruses (CoVs) especially highly pathogenic CoVs is increasing alarmingly. Early detection of these viruses allows treatment interventions to be provided more quickly to people at higher risk, as well as helping to identify asymptomatic carriers and isolate them as quickly as possible, thus preventing the disease transmission chain. The current diagnostic methods such as RT-PCR are not ideal due to high cost, low accuracy, low speed, and probability of false results. Therefore, a reliable and accurate method for the detection of CoVs in biofluids can become a front-line tool in order to deal with the spread of these deadly viruses. Currently, the nanomaterial-based sensing devices for detection of human coronaviruses from laboratory diagnosis to point-of-care (PoC) diagnosis are progressing rapidly. Gold nanoparticles (AuNPs) have revolutionized the field of biosensors because of the outstanding optical and electrochemical properties. In this review paper, a detailed overview of AuNP-based biosensing strategies with the varied transducers (electrochemical, optical, etc.) and also different biomarkers (protein antigens and nucleic acids) was presented for the detection of human coronaviruses including SARS-CoV-2, SARS-CoV-1, and MERS-CoV and lowly pathogenic CoVs. The present review highlights the newest trends in the SARS-CoV-2 nanobiosensors from the beginning of the COVID-19 epidemic until 2022. We hope that the presented examples in this review paper convince readers that AuNPs are a suitable platform for the designing of biosensors. [ABSTRACT FROM AUTHOR]

• NE-striking Aras Fault Zone (AFZ) bounds the Talesh and Lesser Caucasus blocks. • The AFZ is characterized by well-developed geological and geomorphological features. • Paleostress results along the AFZ indicate a similar tectonic regime since Pliocene. • The transpressive tectonic regime controls the structural evolution of the AFZ. • Transpressive tectonic regime leads to strain partitioning along the AFZ. Aras Fault Zone (AFZ) is one of the most important intra-plate fault zones within the Turkish-Iranian Plateau. The AFZ is divided into five fault branches based on geometrical and structural properties called the Aras Main, Horadiz, Khodafarin, Asadkandi, and Aslanduz fault branches. Our geometric and kinematic analysis indicates that these faults exhibit compressional left-lateral strike-slip fault characteristics with general directions of NE-SW and dipping to SE. Structural mapping has revealed that the NE section of the AFZ shows typical horsetail fault geometry. Few meters to approximately 17 km of left-lateral displacements were observed along the AFZ, indicating the occurrence of numerous historical earthquake events. Paleostress analysis of fault slip data reveals that the AFZ has developed in the dominant NNE-SSW and NE-SW oriented compressional stress regime. Evaluating the Ratio of Principal Stress Differences (R), Stress Regime Index (R'), and principal stress directions show that the zone is under the transpressional tectonic regime. Paleostress orientations are consistent with orientations of the GPS velocity vectors, which indicates that the region, including the AFZ, is under the effect of the same tectonic regime, at least since Pliocene. The amounts of strike-slip partitioning on discrete strike-slip faults are determined as 33–41%, which means at least 41% of total wrench components in the region have been accommodated by discrete strike-slip faulting along the AFZ. Results indicate that the simple shear component of total stress applied to the area is consistent with the GPS slip velocities. [ABSTRACT FROM AUTHOR]

The effect of surface modification on enhancing the magnetic heating behavior of magnetic nano fluids were investigated, for this purpose Fe3O4 nanoparticles were synthesized using co-precipitation method and surface modification was done using citric acid, ascorbic acid, tetraethyl orthosilicate (TEOS), polyvinyl alcohol (PVA) and polyethylene glycol (PEG). Experimental heating tests using AC magnetic field were done in the frequency of 100 kHz and different magnetic field (H) intensities. Theoretically the specific absorption rate (SAR) in magnetic nano fluids is independent of nanoparticles concentration but the experimental results showed different behavior. The theoretical SAR value @ H = 12kA.m–1 for Nano fluids containing bare Fe3O4 nanoparticles was 11.5 W/g but in experimental tests the obtained value was 9.72 W/g for nano fluid containing 20,000 ppm of dispersed nanoparticles. The experimental SAR calculation was repeated for sample containing 10,000 ppm of nanoparticles and the results showed increase in experimental SAR that is an evidence of nanoparticles agglomeration in higher concentrations. The surface modification has improved the dispersion ability of the nanoparticles. The Ratio of SAR, experimental, 20000ppm to SAR, experimental, 10000ppm was 0.85 for bare Fe3O4 nanoparticles dispersion but in case of surface modified nanoparticles this ratio has increased up to 0.98 that shows lower agglomeration of nanoparticles as a result of surface modification, although on the other hand the surface modification agents were magnetically passive and so it is expected that in constant concentration the SAR for bare Fe3O4 nanoparticles to be higher than this variable for surface modified nanoparticles. At lower concentrations the dispersions containing bare Fe3O4 nanoparticles showed higher SAR values but at higher concentrations the surface modified Fe3O4 nanoparticles showed better results although the active agent amount was lower at them. Finally, it should be noted that the nanoparticles that were surface modified using polymeric agents showed the highest decrease in experimental SAR amounts comparing theoretical results that was because of the large molecules of polymers comparing other implemented surface modification agents. [ABSTRACT FROM AUTHOR]

The 1944 earthquake segment of the North Anatolian Fault Zone contains paleoseismological signatures of major earthquake events. The segment consists of three active main faults and secondary faults showing anastomosing fault pattern. Stratigraphic and structural relationships and radiocarbon ages from trench excavation reveal that the main active fault located at the northernmost part of the region has produced four major earthquakes events up to now. These events, from north to south, correspond to 1944, 1668, 967, and 300 AD earthquakes on the segment. Our findings suggest that earthquake recurrence interval on the segment range from 276 ± 30 to ~700 years. The amount of displacement caused by surface faulting and earthquake recurrence interval indicates that the slip rate along the 1944 earthquake segment is 17–21 mm/yr in the late Holocene. [ABSTRACT FROM AUTHOR]

Abstract In this work, a novel simple and sensitive electrochemical immunosensor was developed based on lactate oxidase as a single electrochemical probe for the detection of carcinoma antigen 125 (CA125). Chitosan-gold nanoparticle/multiwall carbon nanotube/graphene oxide (CS-AuNP/MWCNT/GO) was used as the electrode substrate to increase the electrode specific surface area and improve the protein immobilization and the electrochemical performance of the electrode in terms of oxidation of H 2 O 2. Due to the peroxidase-like function of CS-AuNP, the oxidation peak of H 2 O 2 was observed at a very low potential (0.034 V). The lactate oxidase is used, for the first time, as the single-enzyme label in a sandwich type immunosensor. In the optimum condition, the designed immunosensor exhibited two linear ranges (0.01–0.5 U/mL and 0.5–100 U/mL) by chronoamperometry (CHA). The limit of detection (LOD) was estimated to be 0.002 U/mL. The immunosensor displayed excellent reproducibility and stability with remarkable selectivity in terms of the detection of CA125 even in the human serum samples as compared to the ELISA. In conclusion, the engineered immunosensor is proposed as an ultra-sensitive tool for the detection and monitoring of CA125 in the human serum. Graphical abstract fx1 Highlights • A novel sandwich immunosensor based on lactate oxidase as a single-enzyme label was developed for the detection of CA125. • Gold nanoparticles were synthesized using chitosan as the reducing and capping agent. • The potential of hydrogen peroxide oxidation was reduced to 0.034 V by the chitosan-Au nanoparticles. • CA125 was detected with a low limit of detection of 0.002 U/mL and a linear range of 0.01–100 U/mL. [ABSTRACT FROM AUTHOR]

Herein, aptamer-modified self-propelled nanomotors were used for transportation of human promyelocytic leukemia cells (HL-60) from a human serum sample. For this purpose, the fabricated manganese oxide nanosheets-polyethyleneimine decorated with nickel/gold nanoparticles (MnO 2 -PEI/Ni/Au) as nanomotors were added to a vial containing thiolated aptamer KH1C12 solution as a capture aptamer to attach to the gold nanoparticles on the surface of nanomotors covalently. The aptamer-modified self-propelled nanomotors (aptamer KH1C12 /nanomotors) were then separated by placing the vial in a magnetic stand. The aptamer-modified self-propelled nanomotors were rinsed three times with water to remove the non-attached aptamers. Then, the resulting aptamer KH1C12 /nanomotors were applied for the on-the-fly” transporting of HL-60 cancer cell from a human serum sample. To release of the captured HL-60 cancer cells, the complementary nucleotide sequences of KH1C12 aptamer solution (releasing aptamer) that has a with capture aptamer was added to phosphate buffer solution (1 M, pH 7.4) containing HL-60/aptamer KH1C12 /nanomotors. Because of the high affinity of capture aptamer to complementary nucleotide sequences of aptamer KH1C12 , the HL-60 cancer cells released on the surface of aptamer KH1C12 /nanomotors into the solution. The second goal of the present work was determining the concentration of HL-60 cancer cell in the human serum samples. The electrochemical impedance spectroscopy technique (EIS) was used for the determination of HL-60 cancer cell. The concentration of separated cancer cell was determined by aptamer/gold nanoparticles-poly(3,4-ethylene dioxythiophene) modified GC electrode (GC/PEDOT-Au nano /aptamer KH1C12 ). The proposed aptasensor exhibited a good response to the concentration of HL-60 cancer cells in the range of 2.5 × 10 1 to 5 × 10 5 cells mL -1 with a low limit of detection of 250 cells mL -1 . [ABSTRACT FROM AUTHOR]

The authors describe an electrochemical method for aptamer-based determination of insulin at femtomolar concentrations. The surface of a screen printed electrode was modified with ordered mesoporous carbon that was chemically modified with 1,3,6,8-pyrenetetrasulfonate (TPS). The amino-terminated aptamer was then covalently linked to TPS via reactive sulfonyl chloride groups. Subsequently, the redox probe Methylene Blue (MB) was interacted into the aptamer. The MB-modified binds to insulin and this results in the release of MB and a decreased signal as obtained by differential pulse voltammetry, best at a working voltage of -0.3 V (versus silver pseudo-reference electrode). Insulin can be quantified by this method in the 1.0 fM to 10.0 pM concentration range, with a 0.18 fM limit of detection (at 3σ/slope). The assay was applied to the determination of insulin in spiked human serum samples. The method is highly sensitive, selective, stable, and has a wide analytical range. [ABSTRACT FROM AUTHOR]

Herein, for the first time a visible-light-driven photoelectrochemical (PEC) aptasensor for shrimp tropomyosin determination was fabricated by using graphitic carbon nitride (g-C 3 N 4 ) and titanium dioxide (TiO 2 ) as photoactive nanomaterials, ascorbic acid (AA) as electron donor and ruthenium (III) hexaammine (Ru(NH 3 ) 6 3+ ) as signal enhancer. The surface of an ITO electrode was first modified with g-C 3 N 4 , TiO 2 , and polyethyleneimine (PEI) and then the amine terminal aptamer TROP probe was attached to PEI by the use of glutaraldehyde (GA) as cross-linker. After that, Ru(NH 3 ) 6 3+ was adsorbed on aptamer to enhance the photocurrent signal. The principle of proposed PEC aptasensor is based on the formation of a selective complex between tropomyosin and immobilized aptamer TROP probe on the surface of ITO/g-C 3 N 4 -TiO 2 /PEI/aptamer TROP -Ru(NH3) 6 +3 . After the incubation of tropomyosin with TROP aptamer probe, the photocurrent signal decreased due to releasing adsorbed Ru(NH 3 ) 6 3+ on aptamer and preventing AA from scavenging photogenerated holes to the photoactive modified electrode. Under the optimized conditions, the fabricated PEC aptasensor was used for the determination of shrimp tropomyosin in the concentration range of 1–400 ng mL −1 with a limit of detection of 0.23 ng mL −1 . The proposed PEC aptasensor exhibited high selectivity, sensitivity, and good stability. [ABSTRACT FROM AUTHOR]

In this research, we demonstrated a flow injection amperometric sandwich-type aptasensor for the determination of human leukemic lymphoblasts (CCRF-CEM) based on poly(3,4-ethylenedioxythiophene) decorated with gold nanoparticles (PEDOT-Au nano ) as a nano platform to immobilize thiolated sgc8c aptamer and multiwall carbon nanotubes decorated with palladium nanoparticles/3,4,9,10-perylene tetracarboxylic acid (MWCNTs-Pd nano /PTCA) to fabricate catalytic labeled aptamer. In the proposed sensing strategy, the CCRF-CEM cancer cells were sandwiched between immobilized sgc8c aptamer on PEDOT-Au nano modified surface electrode and catalytic labeled sgc8c aptamer (MWCNTs-Pd nano /PTCA/aptamer). After that, the concentration of CCRF-CEM cancer cells was determined in presence of 0.1 mM hydrogen peroxide (H 2 O 2 ) as an electroactive component. The attached MWCNTs-Pd nano nanocomposites to CCRF-CEM cancer cells amplified the electrocatalytic reduction of H 2 O 2 and improved the sensitivity of the sensor to CCRF-CEM cancer cells. The MWCNT-Pd nano nanocomposite was characterized with transmission electron microscopy (TEM) and energy dispersive X-ray (EDX). The electrochemical impedance spectroscopy (EIS) and cyclic voltammetry (CV) were used to confirm the stepwise changes in the electrochemical surface properties of the electrode. The proposed sandwich-type electrochemical aptasensor exhibited an excellent analytical performance for the detection of CCRF-CEM cancer cells ranging from 1.0 × 10 1 to 5.0 × 10 5 cells mL −1 . The limit of detection was 8 cells mL −1 . The proposed aptasensor showed high selectivity toward CCRF-CEM cancer cells. The proposed aptasensor was also applied to the determination of CCRF-CEM cancer cells in human serum samples. [ABSTRACT FROM AUTHOR]

Herein, a flow injection amperometric aptasensor was developed for the determination of adenocarcinoma gastric cell (AGS) cancer cells in presence of hydrogen peroxide (H 2 O 2 ). For this purpose, the aptamer/gold-core and silver-shell (Au@Ag) nanoparticles were synthesized as the secondary labeled aptamers using thiolated cytosine-rich aptamer. First, the thiolated aptamer was self-assembled to the gold nanoparticles (AuNPs) surface through S-AuNPs bonds. Then, this cytosine-rich aptamer/AuNPs were added to the Ag + solution to form (C-Ag + -C) n complexes. The adsorbed Ag + ions on the aptamer were then reduced to Ag shell on the surface of AuNPs core by thyme leaves extract as a green reducing agent. The surface of screen printed electrode (SPE) was also modified with multiwall carbon nanotube decorated with gold nanoparticles (MWCNT-Au nano ) as a nano-platform to increase the surface area to immobilize primary thiolated non-cytosine-rich aptamer and improve electron transfer property of electrode. The MWCNT-Au nano , AuNPs and aptamer AGS -Au@Ag nanoparticles were characterized using transmission electron microscopy (TEM) and energy dispersive X-ray (EDX). Cyclic voltammetry and electrochemical impedance spectroscopy (EIS) were used to confirm the stepwise changes in the electrochemical surface properties of the electrode. The determination processes were performed in a flow injection microchannel device under the optimized conditions. The selective interactions between primary aptamer/AGS/secondary aptamer-Au@Ag nanoparticles led to increase in the response of aptasensor to AGS cancer cell in presence of 0.1 mM H 2 O 2 because of the electrocatalytic activity of Au@Ag nanoparticles toward the reduction of H 2 O 2 . The proposed sandwich-type electrochemical aptasensor exhibited a good response to the logarithmic value of AGS cancer cells in the range of 1 × 10 1 to 5 × 10 5 cells mL −1 with a low limit of detection of 6 cells mL −1 in the flow injection amperometric determination process. The target-aptamer dissociation constant (k d ) was also calculated based on the change in current to be 104 cells mL −1 . The fabricated sandwich-type electrochemical aptasensor was applied for the determination of AGS cancer cell in the human serum sample. The proposed sandwich-type aptasensor exhibited good linear range responsibility, selectivity, and stability. [ABSTRACT FROM AUTHOR]

Biosensors combine the sensitivity of detection technology with the specificity of a designated biological entity. Owing to their specificity and sensitivity, biosensors are applied for sensing and monitoring of different diseases. Simultaneous sensing of myriad of biomarkers in different diseases at the early stages is swiftly finding its way towards disease's hallmarks, even though the biological contexts are complex matrices with possible cross-reactivity of restrained biomolecules. Electrochemical biosensors are considered as simple and cost-effective methods, which make the concurrent detection of multiple biomarkers plausible for ultimate diagnosis of diseases in clinic. Simultaneous sensing of multiple biomarkers by electrochemical techniques can be achieved through either multi-label or multi-electrode approaches, which can be implemented as miniaturized screen-printed or even lab-on-a-chip systems. Here, we reviewed literature (2000–2016) and provided a comprehensive insight on various biosensing platforms, articulating the most recent advancements in each type of biosensors applied for the detection of biomolecules. [ABSTRACT FROM AUTHOR]

Here in, a high sensitive sandwich-type electrochemical immunosensor for the determination of SKBR-3 breast cancer cell has been fabricated using of green synthesized reduced graphene oxide as a platform to the immobilization of primary Herceptin antibody (Anti-HCT). The various reduced graphene oxide-tetrasodium 1, 3, 6, 8-pyrenetetrasulfonic acid/metal hexacyanoferrates (rGO-TPA/MHCF nano ) nanocomposites included rGO-TPA/FeHCF, rGO-TPA/CoHCF, rGO-TPA/NiHCF and rGO-TPA/CuHCF were used as electrochemical labels of secondary Herceptine antibody. The obtained result showed that the sensitivity of proposed sandwich-type electrochemical immunosensor for the determination of SKBR-3 breast cancer cells (30,000 cells mL −1 ) using rGO-TPA/FeHCF nano labeled secondary Herceptine antibody was higher than the other rGO-TPA/MHCF nano -labeled secondary Herceptine antibodies. The differential pulse voltammetry (DPV) technique was used for the determination of SKBR-3 breast cancer cell in the concentration range of 500–30,000 cells mL −1 with the limit of detection of 21 cells mL −1 . The proposed sandwich-type electrochemical immunosensor exhibited high selectivity, liner range responsibility and good stability. [ABSTRACT FROM AUTHOR]

Herein, a novel electrochemical bi-aptasensor using green synthesized reduced graphene-poly(amidoamine)/gold nanocomposite (rGO-PAMAM/Au nano ) as supporting matrix for covalent immobilization of flavin adenine dinucleotide (FAD) and thionine (Th) on the first (W 1 ) and second (W 2 ) surfaces of dual working electrode screen printed electrode has proposed. FAD and Th probes were immobilized by glutaraldehyde linker based on a reaction between primary amines (–NH 2 ) of FAD and Th with –NH 2 of rGO-PAMAM/Au nano modified dual working electrode for simultaneous determination of cytochrome c (CYC) and vascular endothelial growth factor (VEGF 165 ) tumor markers. The principle response of proposed bi-aptasensor was based on the selective interaction of CYC with W 1 /rGO-PAMAM-FAD/Au nano /Anti-ptamer CYC and VEGF 165 with W 2 /rGO-PAMAM-Th/Au nano /Anti-ptamer VEGF165 , respectively. This selective interaction, leads to decrease of response currents of immobilized electrochemical probes of FAD and Th that have different formal potential (E 0 ′). Electrochemical behavior of bi-aptasensor was studied by cyclic voltammetry (CV) and differential pulse voltammetry (DPV). The liner calibration curve for tumor markers determination was 2.5–320.0 pM. The limit of detections (LOD) for CYC was 1.0 pM and for VEGF 165 was 0.7 pM (3σ/S). The biomarker-aptamer dissociation constant (k d ) was calculated based on the change in current to be 63.9 pM for CYC/Anti-aptamer CYC and 38.4 pM for VEGF 165 /Anti-aptamer VEGF165 , respectively. This bi-aptasensor was used for the determination of VEGF 165 and CYC in the human serum sample. [ABSTRACT FROM AUTHOR]

[Display omitted] • Developing a graphite nanocrystals (GNCs)/paper electrode using ion beam sputtering deposition method. • An electrochemical genosensor using the cDNA-functionalized Au@CD core/shell NPs for the SARS-CoV-2 RdRP detection. • Engineering a signal-on mechanism based on the intercalation of toluidine blue into the large grooves of cDNA-RdRP duplex. Currently, the development of biosensors is an urgent need due to the rapid spread of SARS-CoV-2 and the limitations of current standard methods for the diagnosis of COVID-19. Hence, many researchers have focused on the design of high-performance biosensors for measuring coronavirus genes. In this study, a voltammetric genosensor was developed for the determination of SARS-CoV-2 RdRP gene based on the format of cDNA probe/Au@CD core–shell NPs/graphite nanocrystals (GNCs)/paper electrode. For the first time, graphite nanocrystals were used in the electrochemical biosensor design. This genosensor was exposed to different concentrations of virus gene and then the hybridization between cDNA probe and RdRP gene was monitored by redox-active toluidine blue (TB). With increasing the RdRP concentration, the reduction peak current of TB enhanced in a linear range of 0.50 pM-12.00 nM according to the regression equation of I (μA) = 7.60 log C RdRP (pM) + 25.78. The repeatability with a RSD of 2.2% clearly exhibited that the response of modified electrode is stable because of the high adhesion of GNC layer on the paper substrate and the high stability of cDNA-Au@CD bioconjugates. The spike-and-recovery studies showed the acceptable recoveries for the sputum samples (>95%). [ABSTRACT FROM AUTHOR]

Recently, there has been a growing demand to develop portable devices for the fast detection of contaminants in food safety, healthcare, and environmental fields. Herein, two biosensing methods were designed by the use of nicotinamide adenine dinucleotide phosphate (NAD(P)H)-dependent TetX2 enzyme activity and thionine as an excellent electrochemical and colorimetric mediator/probe to monitor tetracycline (TC) in milk. The nanoporous glassy carbon electrode (NPGCE) modified with polythionine was first prepared by electrochemically and then TetX2 was immobilized onto the NPGCE using polyethyleneimine. The prepared biosensor provided a high electrocatalytic response toward NAD(P)H by significantly reducing its overpotential. The proposed biosensor exhibited a detection limit of 40 nM with a linear range of 0.1-0.8 µM for TC determination. Besides, the thionine probe was used to develop a novel colorimetric assay using a simple enzymatic color reaction within a few minutes. The limit of detection for TC was experimentally achieved as 60 nM, which was lower than the safety levels established by the World Health Organization (225 nM). The correlation between change in the color of the solution and the concentration of TC was used for quality control of milk samples, as confirmed by the standard high-performance liquid chromatography method. The results show the great potential of the proposed assays as portable instruments for on-site TC measurements. [ABSTRACT FROM AUTHOR]

A label free immunosensor was designed for ultra-detection of human epidermal growth factor receptor 2 (HER2) in real samples using a differential pulse voltammetry (DPV) method. In a separate process, antiHER2 antibodies were attached to iron oxide nanoparticles (Fe3O4 NPs) to form stable bioconjugates which were later laid over the gold electrode surface. In this way, by the advantage of their long terminals, the bioconjugates provided the most possible space for the immuno-reaction between biomolecules. Under optimal conditions, the immunosensor was responsive to HER2 concentrations over the ranges of 0.01–10 ng mL−1 and 10–100 ng mL−1 linearly and benefited from a satisfactory detection limit as low as 0.995 pg mL−1 and a favorable sensitivity as sharp as 5.921 μA mL ng−1. The reliability of the method in clinical analysis was proved by successful quantization of HER2 levels in serum samples obtained from patients. Furthermore, the precision and the stability of the method were evaluated and verified to be acceptable in immunoassay studies. [ABSTRACT FROM AUTHOR]

The present paper describes a sensitive electrochemical detection of amlodipine (AMLO) at the poly- l-methionine-gold nanoparticles/multi-walled carbon nanotube modified glassy carbon electrode (PLM-GNPs/MWCNTs/GCE) by differential pulse voltammetry (DPV) technique at physiological pH 7.12. Cyclic voltammetry results demonstrate that the proposed electrode shows excellent electrocatalytic activity toward oxidation of AMLO. Kinetic parameters of the electrochemical reaction are calculated, and analytical variables such as MWCNT volumes, drug accumulation time, electropolymerization cycles and pH values are also optimized. Under optimal conditions, the linear range covering from 5 nM to 2.5 μM along with detection limit of 1 nM is obtained. Moreover, this method is successfully used to detect AMLO in pharmaceutical samples and biological fluids of a dosage received by the volunteer. [ABSTRACT FROM AUTHOR]

Different carbon-based nanostructures were used to investigate direct electron transfer (DET) of TetX2 monooxygenase (TetX2), and an enzyme-based biosensor for sensitive determination of tetracycline (TC) also fabricated. A polyethyleneimine (PEI) with positive charge groups was used for immobilization of TetX2 on modified glassy carbon electrodes. Cyclic voltammetry (CV) was employed to study the electrochemical characteristics of the immobilized enzyme and the performance of the proposed biosensor. Amongst multiple carbon-modified electrodes, nano-porous glassy carbon electrode (NPGCE) was selected because of its amplified signal response for flavin adenine dinucleotide (FAD) and superior electrocatalytic behavior toward oxygen reduction. The cyclic voltammogram of PEI/TetX2/NPGCE showed two couple of well-defined and quasi-reversible redox peaks of FAD, consistent with the realization of DET. The prepared electrode was then successfully introduced as a biosensing interface based on the oxygen reduction peak current, resulting in a linear range response from 0.5 to 5 μM with a good detection limit of 18 nM. The as-fabricated electrode demonstrates a fast response and excellent stability for the detection of TC. The results indicate that this simple, rapid, eco-friendly and economic strategy of PEI/TetX2/NPGCE preparation has potential for the fabrication of an enzyme-based biosensor for the practical detection of TC in food products. Unlabelled Image • Bacterial TetX2 monooxygenase was used for electrochemical sensing of tetracycline. • TetX2 immobilization on modified electrodes was done by polyethylenimine. • Nano-porous glassy carbon electrode enhanced the direct electrochemistry of TetX2. • High selectivity and sensitivity were achieved with a low detection limit of 18 nM. [ABSTRACT FROM AUTHOR]

Background: Recently, some studies have focused on dendrimer nanopolymers as a magnetic resonance imaging (MRI) contrast agent or a vehicle for gene and drug delivery. Considering the suitable properties of these materials, they are appropriate candidates for coating iron-oxide nanoparticles which are applied in magnetic hyperthermia. To the best of our knowledge, the novelty of this study is the investigation of fourth-generation dendrimer-coated iron-oxide nanoparticles (G4@IONPs) in magnetic hyperthermia and MRI.Methods: IONPs were synthesized via co-precipitation and coated with the fourth generation (G4) of polyamidoamine dendrimer. The cytotoxicity of G4@IONPs with different concentrations was assessed in a human breast cancer cell line (MCF7) and human fibroblast cell line (HDF1). Hemolysis and stability of G4@IONPs were investigated, and in addition, the interaction of these particles with MCF7 cells was assessed by Prussian blue staining. Heat generation and specific absorption rate (SAR) were calculated from measurement and simulation results at 200 and 300 kHz. MCF7 and HDF1 cells were incubated with G4@IONPs for 2 h and then put into the magnetic coil for 120 min. Relaxometry experiments were performed with different concentrations of G4@IONPs with T1- and T2-weighted MR images.Results: The TEM results showed that G4@IONPs were 10 ± 4 nm. The in vitro toxicity assessments showed that synthesized nanoparticles had low toxicity. The viability of MCF7 cells incubated with G4@IONPs decreased significantly after magnetic hyperthermia. In addition, MR imaging revealed that G4@IONPs improved transverse relaxivity (r2) significantly.Conclusions: Our results encouraged the future application of G4@IONPs in magnetic hyperthermia and MR imaging. [ABSTRACT FROM AUTHOR]

Graphical abstract Highlights • Use of graphene oxide and reduced graphene oxide as visual labels for lateral flow assay. • Reduced graphene oxide shows higher visual signal than graphene oxide. • It has been applied for one step detection of E. coli O157:H7 in food samples. Abstract In this study, graphene oxide (GO) and reduced graphene oxide (rGO) were used as visual labels in a lateral flow assay for detection of E. coli O157:H7. The color intensity was employed for the quantitative measurements of the target bacteria. Quantitative results showed that in comparison to GO, rGO can provide higher color intensity owing to enhanced light absorption following chemical reduction. Our results confirm that the visual limit of detection of the target bacteria by rGO is ∼105 colony forming unit per milliliter (CFU/ml), which closely compares with current alternative techniques using gold nanoparticles. The performance and practicability of the rGO-based test strips for detection of the target bacteria in milk and drinking water were validated with conventional plating and colony counting techniques. Results suggest that the proposed lateral flow assay is sensitive, specific, and affordable. It has also the potential to become a widely used detection technique for E. coli O157:H7 and a wide variety of other analytes. [ABSTRACT FROM AUTHOR]

Abstract An early on-time detection of breast cancer can effectively affect the outcome of the treatment. Here, we developed an ultrasensitive, simple and reliable immunosensor to detect the lowest alteration of CA 15-3, the standard biomarker of breast cancer patients. The proposed immunosensor was achieved by modification of gold electrode by streptavidin to immobilize the biotinylated anti-CA 15-3 monoclonal antibody (mAb). Bovine serum albumin was used to prevent nonspecific binding. To improve the sensitivity of modified immunosensor, the sandwich signal enhancer consisting of streptavidin-coated magnetic beads conjugated with biotinylated horseradish peroxidase (HRP) and anti-CA 15-3 biotinylated mAb was applied. The electrochemical measurements were obtained in the presence of hydroquinone as a redox agent and H 2 O 2 as the activating agent of HRP. Under optimized condition and using square wave voltammetry, the lower limit of quantification was obtained as 15 × 10−6 U/mL and the linear CA 15-3 concentration range was 50–15 × 10−6 U/mL. While showing significant stability, the immunosensor displayed an excellent sensitivity and specificity for the detection of CA 15-3 even in the human serum as compared to the enzyme-linked immunosorbent assay (ELISA) as a gold standard method. Based on our findings, the engineered immunosensor is proposed as a robust diagnostic tool for the clinical determination of CA 15-3 and other cancer biomarkers. Highlights • An ultrasensitive and reliable immunosensor was developed for the detection of CA 15-3. • An enzymatic sandwich approach was applied to enhance the signals of the biosensor. • A significant lower limit of quantification was achieved. • An excellent performance of proposed immunosensor was observed compared to ELISA as the reference method. [ABSTRACT FROM AUTHOR]

In the present study, the effect of nanosized graphene oxide layer on thermal stability and biocompatibility of gold nanorods has been examined. The graphene oxide-wrapped gold nanorods were prepared by electrostatic interaction between negatively charged graphene oxide and positively charged nanorods. The resulting nanohybrids were then heated at different time intervals to 95 °C in a water bath to assess the effect of heat on the rods morphology. The structural changes in gold nanorods were monitored via UV-Vis spectroscopy measurements and transmission electron microscopy images. In similar experiments, the graphene oxide used to wrap gold nanorods was reduced by ascorbic acid in a 95 °C water bath. Our results indicate that while bare gold nanorods are highly vulnerable to elevated temperatures, graphene oxide and reduced graphene oxide-coated gold nanorods remain thermally stable with no structural changes. We also confirmed that the enhanced thermal stability is highly dependent on the concentration of deposited graphene oxide available on the surface of the gold nanorods. In addition, we performed an MTT (3-[4,5-dimethylthiazol-2yl]-2,5-diphenyltetrazoliumbromide) assay to make a comparison between the cytotoxicity of the nanohybrids and their primary building blocks on human dermal fibroblast cells as a normal cell line. We found evidence that graphene oxide can enhance the biocompatibility of the rods through covering toxic chemicals on the surface of them.ᅟ [ABSTRACT FROM AUTHOR]

Hyperthermia generally means as increasing the temperature of particular region of body to rise 5 °C above the body’s physiological temperature. Here, we investigate the thermal therapy of PEGylated cobalt ferrite nanoparticles prepared by hydrothermal approach on cancerous cell line in the alternative current magnetic field. To characterize of the magnetic nanoparticles (MNPs), scanning electron microscopy, dynamic light scattering, X-ray diffraction, Fourier transform infrared spectroscopy, and vibrating sample magnetometer were used. X-ray diffraction analysis confirmed the spinel phase formation of the MNPs. Cytotoxicity of MNPs using MTT assay on L929 cell lines showed the PEGylated MNPs extraordinary biocompatibility. Specific loss power (SLP) were calculated for neat and PEGylated MNPs in aqueous solution in radio frequency region (300–400 kHz). Power absorbed by neat and PEGylated cobalt ferrite were measured as a function of frequency and MNPs concentration. The maximum SLP was 31.8 W/g for coated nanoparticles (MNPs + PEG) in concentration of 0.0025 gr/mL at applied frequency of 350 kHz. Magnetic fluid hyperthermia of MCF7 breast cancer cells were shown up to 90 percent of cell death in 350 kHz. Simulation studies approved the elevated temperature of the PEGylated MNPs to 42 °C in the tumor after 10 min of MNPs intratumorally injection. This study shows increase in rate of heating in the tumor when the temperature of injected MNPs is approximately equal to the body temperature (i.e. 37 °C). [ABSTRACT FROM AUTHOR]

The sensitive quantification of Human Epidermal growth factor Receptor 2 (HER2), as a key prognostic tumor marker, plays a critical role in screening, early diagnosis and management of breast cancer. This paper describes a sandwich-type immunoassay with silver signal enhancement strategy for highly sensitive detection of HER2. For this purpose, the target capturing step was designed by functionalization of 3-aminopropyltrimethoxysilane coated magnetite nanoparticles with antibody (antiHER2/APTMS-Fe 3 O 4 ), as a platform bioconjugate (PB), and immobilized at a bare GCE. Then, in the presence of label-free immunosensor, the PB was covered by magnetic gold nanoparticles self-assembled with thiolated antibodies (antiHER2/Hyd@AuNPs-APTMS-Fe 3 O 4 ) containing chemically reduced silver ions, as a label bioconjugate (LB). Under optimum conditions, a linear relationship between the differential pulse voltammetric (DPV) stripping signal of silver and the logarithm of HER2 concentrations was obtained in the range of 5.0 × 10 −4 -50.0 ng mL −1 (R 2 = 0.9906) with a detection limit of 2.0 × 10 −5 ng mL −1 . The effectiveness of this protocol was evaluated experimentally through employing of designed immunosensor for detection of the serum level of tumor marker. The good consistency of the results with those obtained by the enzyme-linked immunosorbent assay (ELISA) conventional method ( p- value of < 0.05) showed that this immunosensor can be applied for the testing of HER2 in clinical samples of breast cancer patients. [ABSTRACT FROM AUTHOR]

Graphene/cobalt nanocomposites are promising materials for theranostic nanomedicine applications, which are defined as the ability to diagnose, provide targeted therapy and monitor the response to the therapy. In this study, the composites were synthesized via chemical method, using graphene oxide as the source material and assembling cobalt nanoparticles of 15 nm over the surface of graphene sheets. Various characterization techniques were then employed to reveal the morphology, size and structure of the nanocomposites, such as X-ray diffraction analysis, X-ray photoelectron spectroscopy, Fourier transform infrared spectroscopy, high resolution transmission electron microscopy and ultraviolet visible spectroscopy. Using ion-coupled plasma optical emission spectroscopy, cobalt concentration in the nanocomposites was found to be 80%. In addition, cytotoxicity of graphene/cobalt nanocomposites were evaluated using 3-[4,5-dimethylthiazol-2yl]-2,5-diphenyltetrazolium bromide or MTT assay. MTT viability assay exhibited biocompatibility to L929 mouse fibroblasts cells, under a high dose of 100 μg/mL over 24 h. Hyperthermia results showed the superior conversion of electromagnetic energy into heat at 350 kHz frequency for 0.01 and 0.005 g/L of the nanocomposites solution. The measured heat generation and energy transfer results were anticipated by the finite element analysis, conducted for the 3D structure. Magnetic resonance imaging characteristics also showed that negatively charge graphene/cobalt nanocomposites are suitable for T 1 -weighted imaging. [ABSTRACT FROM AUTHOR]

This paper proposes an artificial neural networks approach to finding the effects of electrospinning parameters on alignment of poly(ɛ-caprolactone)/poly(glycolic acid) blend nanofibers. Four electrospinning parameters, namely total polymer concentration, working distance, drum speed and applied voltage were considered as input and the standard deviation of the angles of nanofibers, introducing fibers alignments, as the output of the model. The results demonstrated that drum speed and applied voltage are two critical factors influencing nanofibers alignment, however their effect are entirely interdependent. Their effects also are not independent of other electrospinning parameters. In obtaining aligned electrospun nanofibers, the concentration and working distance can also be effective. In vitro cell culture study on random and aligned nanofibers showed directional growth of cells on aligned fibers. [ABSTRACT FROM AUTHOR]

The purpose of this work was to fabricate an electrochemical DNA biosensor for detecting hepatitis B virus. Gold nanorods (GNRs), which are known for their conductivity, were used to increase surface area and consequently increase the immobilization of single-stranded DNA (ss-DNA) on the modified gold electrode. The GNRs were characterized via transmission electron microscopy. The morphology of the gold electrode before and after modification with GNRs was characterized by scanning electron microscopy. Atomic-force microscopy was used to evaluate the morphology of the GNR electrode surface before and after interaction with ss-DNA. Cyclic voltammetry was used to monitor DNA immobilization and hybridization, using [Co(phen)] as an electrochemical indicator. The target DNA sequences were quantified at a linear range from 1.0 × 10 to 10.0 × 10 mol L, with a detection limit of 2.0 × 10 mol L by 3 σ. The biosensor had good specificity for distinguishing complementary DNA in the presence of non-complementary and mismatched DNA sequences. [ABSTRACT FROM AUTHOR]

In the recent years, enhanced functionality of treatment systems based on nanostructures has attracted a lot of interest. Photodynamic therapy (PDT) is one such treatment method. Here, the authors report the results of the investigations on synthesis and characterisation of gold nanoparticles (GNPs) and their application in PDT along with 5‐aminolevolenic acid (5‐ALA) (as photosensitiser) with no conjugation. Three sizes of GNPs were synthesised and their cytotoxicity was investigated by using MTT (3‐(4,5‐dimethylthiazol‐2‐yl)‐2,5‐diphenyltetrazolium bromide) assay on epidermal carcinoma cell line. The results showed that the PDT efficiency of ALA increased in presence of GNPs. This effect was more considerable for 4 nm particles. [ABSTRACT FROM AUTHOR]

The development of novel nanoparticles for diagnostic and therapeutic applications has been one of the most crucial challenges in cancer theranostics for the last decades. Herein, we functionalized iron oxide nanoparticles (IONPs) with the fourth generation (G4) of poly amidoamine (PAMAM) dendrimers (G4@IONPs) for magnetic hyperthermia treatment of breast cancer in Bagg albino strain C (BALB/c)mice. The survival of breast cancer cells significantly decreased after incubation with G4@IONPs and exposure to an alternating magnetic field (AMF) due to apoptosis and elevation of Bax (Bcl-2 associated X)/Bcl-2(B-cell lymphoma 2) ratio. After intratumoral injection of G4@IONPs, tumor-bearing BALB/c mice were exposed to AMF for 20 min; this procedure was repeated three times every other day. After the last treatment, tumor size was measured every three days. Histopathological and Immunohistochemical studies were performed on the liver, lung, and tumor tissues in treated and control mice. The results did not show any metastatic cells in the liver and lung tissues in the treatment group, while the control mice tissues contained metastatic breast cancer cells. Furthermore, the findings of the present study showed that magnetic hyperthermia treatment inhibited tumor growth by increasing cancer cell apoptosis, as well as reducing the tumor angiogenesis. [ABSTRACT FROM AUTHOR]

In the current study, we report on the design and development of a novel electrochemical immunosensor for the detection of cancer antigen 125 (CA125) oncomarker. Polyamidoamine/gold nanoparticles (PAMAM/AuNPs) were used to increase the conductivity and enhance the number of antibodies (Abs) immobilized on the electrode surface. Three-dimensional reduced graphene oxide-multiwall carbon nanotubes (3DrGO-MWCNTs) were used to modify the glassy carbon electrode to improve the electrode conductivity and specific surface area. Ab and toluidine blue attached to O -succinyl-chitosan-magnetic nanoparticles (Suc-CS@MNPs) as a tracer. The poor solubility of chitosan (CS) was improved by succinic anhydride using a novel modification method. Under optimum condition, the developed immunosensor exhibited a wide linear range (0.0005–75 U/mL) and an excellent limit of detection around 6 μU/mL. The reliability of the engineered immunosensor in detecting CA125 was verified by standard addition recovery method, which was further compared to enzyme-linked immunosorbent assay (ELISA). The proposed immunosensor exhibited excellent stability, high selectivity and sensitivity, and good reproducibility. Based on the great performance of the engineered immunosensor, it is proposed as a robust and reliable diagnostic tool for the detection of CA125 in the clinic. Image 1 • An immunosensor was developed for detecting CA125 with a wide linear range (0.0005–75 U/mL) and an excellent LOD (6 μU/mL). • PAMAM/AuNPs were synthesized through a one-step method using PAMAM as a stabilizing and reducing agent. • Chitosan water solubility in natural pH was increased using a novel modification method. • Succinyl-chitosan-coated magnetic nanoparticles were synthesized with good dispersity and high surface functional groups. [ABSTRACT FROM AUTHOR]

• Use of reduced graphene oxide as a photothermal label for lateral flow assay. • Reduced graphene oxide shows higher photothermal properties than graphene oxide. • Sensitivity improvement of a lateral flow assay by photothermal quantification. Lateral flow immunoassay (LFA) is a well-known point-of-care technology for the detection of various analytes. However, low sensitivity and lack of quantitative results are some of its critical drawbacks. Here we report a photothermal enhanced lateral flow sensor on the basis of the photothermal properties of reduced graphene oxide (rGO) for the detection of E-coli O157:H7 as a model pathogen. The calibration curve of the photothermal method exhibited a linear range from 5 × 10⁵ to 5 × 10⁷ CFU/ml with a correlation coefficient of R2 = 0.96 and a regression equation of y = 8.1x-43 for standard bacteria solutions in phosphate buffer. The limit of detection was ∼5 × 10⁵ CFU/ml for standard bacteria solutions, which was a 10-fold enhancement in sensitivity compared to the qualitative results. Specificity experiments showed that the photothermal method can only detect the target bacteria among 6 types of bacteria strains. It was confirmed that the developed technique could be a highly potential method for the rapid detection field because it can provide fast quantitative results with improved sensitivity. [ABSTRACT FROM AUTHOR]

Objective: In recently air pollution is motivated by many agents and in the aerosol we can distinguish smallest airways, composed by biological particles, such as pollen grains and particulate of anthropogenic origin. During the last decade the size, shape, composition, sources and effect of these particle matters (PM) on human health have been studied by microscopic methods. Atomic force microscopy (AFM) is therefore a valuable complementary microscopy technique for the comparative study of the pollen grains surface morphology. The main goals of this research we investigated to characterize the elemental differences in the composition of the airborne ash pollen exine wall and to describe the particulate matter found adhered to this pollen in the Tehran, capital city of Iran, using an Energy Dispersive X-Ray analysis (EDX) on the SEM and Atomic force microscopy (AFM). Material and Methods: The first stage, pollen grains were collected in pollutant area (Tehran regions) and nonpollutant area (Parand city near the Tehran).Then used SEM/EDX for pollen grains analysis and advantages of two samples for AFM for the imaging of reside in the sticky PM on the ash pollen surface of the high spatial resolution, compared with SEM images, and the unique three-dimensional rendition of the exine surface topography, which avoids cross sectioning of the samples. Results: Images showed of exine units from the tectum of polluted and non- polluted pollen were done by AFM. These units of polluted sample showed were recorded adhered the PM in exine surface as being 250 to 300nm wide. This particle matter size is lower than PM2.5. We have obtained atomically resolved images on single aerosol particles in Tehran at the first on environmental biological samples. Conclusion: Our results showed AFM images method can be used for identifying pollen surface contamination and evaluation of PM size more exact and showed good agreement with light and electron microscopy micrographs. [ABSTRACT FROM AUTHOR]