μM For Guanine Research Articles

Synthesis and Characteristics of Cu/N-Codoped Ti3C2T x MXene Using Copper-Aniline Solid Complex and Application to Simultaneous Electrochemical Sensing of Adenine and Guanine in Artificial Sweat

This work evaluates the electrochemical performance of copper and nitrogen codoped Ti3C2T x MXene (or Cu@N − Ti3C2T x ) for purine sensing. Aniline/cupric ion solid complex was synthesized by reaction of aniline with CuCl2 (Cu(aniline)2Cl2). Subsequently, the obtained CuCl2-aniline coordination complex was mixed with Ti3C2T x MXene and carbonized in an autoclave. Subsequently, a new electrochemical sensor was designed based on a hybrid of Cu/N-codoped Ti3C2T x MXene on a glassy carbon electrode modified to be a Cu@N − Ti3C2T x electrode. The nanomaterials were characterized using Fourier transform infrared spectroscopy, X-ray diffraction, scanning electron microscopy, transmission electron microscopy, and X-ray photoelectron spectroscopy techniques. The analytes were determined using differential pulse voltammetry. The detection limits were 0.01 for adenine and 0.02 μM for guanine, while the linear response ranges of both analytes were from 0.1 to 10 μM. This sensing device has been further employed in the individual and simultaneous detection of adenine and guanine in artificial sweat with 98–102% recoveries.

Hybrid Nanomaterial of Graphene Oxide Quantum Dots with Multi-Walled Carbon Nanotubes for Simultaneous Voltammetric Determination of Four DNA Bases.

In this proof-of-concept study, a novel hybrid nanomaterial-based electrochemical sensor was developed for the simultaneous detection of four DNA bases. For the modification of the working electrode surface, graphene oxide quantum dots (GOQDs) were synthesized using a solvothermal method. GOQDs were then used for the preparation of a hybrid nanomaterial with multi-walled carbon nanotubes (GOQD-MWCNT) using a solvothermal technique for the first time. Transmission electron microscopy (TEM) was used to characterize the GOQDs-MWCNTs. A glassy carbon electrode (GCE) was modified with the GOQDs-MWCNTs using Nafion™ to prepare a GOQD-MWCNT/GCE for the simultaneous determination of four DNA bases in phosphate buffer solution (PBS, pH 7.0) using differential pulse voltammetry (DPV). The calibration plots were linear up to 50, 50, 500, and 500 µM with a limit of detection at 0.44, 0.2, 1.6, and 5.6 µM for guanine (G), adenine (A), thymine (T) and cytosine (C), respectively. The hybrid-modified sensor was used for the determination of G, A, T, and C spiked in the artificial saliva samples with the recovery values ranging from 95.9 to 106.8%. This novel hybrid-modified electrochemical sensor provides a promising platform for the future development of a device for cost-effective and efficient simultaneous detection of DNA bases in real biological and environmental samples.

Synergistic impact of nanoarchitectured GQDs-AgNCs(APTS) modified glassy carbon electrode in the electrochemical detection of guanine and adenine

In this work, a facile green approach for the synthesis of graphene quantum dots (GQDs) embedded on silicate network silver nanocrystals (GQDs-AgNCs(APTS)) is reported. Moreover, glassy carbon-GC electrodes were modified with the prepared nanocomposite containing graphene quantum dots supported on silver nanocrystals (GQDs-AgNCs(APTS)) and applied for simultaneous detection of guanine (GA) and adenine (AD). The chemically modified electrode was assessed during the determination of purine bases by cyclic voltammetry-CV and differential pulse voltammetry-DPV. The incorporation of GQDs-AgNCs(APTS) nanocomposites over the surface of the GC electrode considerably enhances the anodic peak currents and decreases the adenine and guanine peak potentials. Compared to other electrodes, GQDs-AgNCs(APTS)/GC improved the electrochemical behavior towards the detection of adenine and guanine. At optimal conditions, calibration curves were obtained by DPV being linear in the range of 0.1–6.0 μM and 0.1–5.0 μM for guanine and adenine, respectively. The detection limits of both guanine and adenine were estimated as 0.1 μM. Additionally, interferences analyses were performed on the existence of other interferent compounds. Furthermore, the method developed for the identification of GA and AD was proved using fish sperm DNA samples.

Electrocatalytic Behavior of TiO2/MWCNTs Nanocomposite Decorated on Glassy Carbon Electrode for Individual and Simultaneous Voltammetric Determination of Adenine and Guanine in Real Samples

An electrochemical sensor based on titanium dioxide (TiO2) and multi-walled carbon (MWCNTs) nanocomposite was fabricated to simultaneous detection of guanine (GU) and Adenine (AD). Nanocomposite was dispersed in water/ethanol with a certain aspect ratio and drop cast onto a glassy carbon electrode. FT-IR, scanning electron microscopy (SEM) and EDX methods as well as electrochemical technique, such as cyclic voltammetry (CV), linear sweep voltammetry (LSV) and differential pulse voltammetry (DPV) were performed to characterize the TiO2−MWCNTs nanocomposite and describe the electrochemical oxidation process. Fabricated sensor shows separate and well-defined peaks for AD and GU, by which one can determine these purine bases individually or simultaneously. Response to GU and AD are linear in the 2.84 to 125 μM concentration range, and the detection limits are 0.97 and 0.4 μM for GU and AD, respectively. The sensor was successfully utilized for the measurement of GU and AD in a diluted human serum sample. The fabricated sensor exhibited high sensitivity, good reproducibility, long-term stability and could be used to quantify of GU and AD in real samples sample successfully

Electrochemical behavior of MOF-801/MWCNT-COOH/AuNPs: A highly selective electrochemical sensor for determination of guanine and adenine

In this work, a novel sensor based on gold nanoparticle-modified zirconium-metal-organic frameworks (MOF-801) and carboxyl-functionalized carbon nanotube (MWCNT-COOH) composite material was built successfully for electrochemical detection of guanine and adenine in DNA sample, which exhibits diverse advantages such as fast, convenience and high efficiency. Guanine and adenine were detected by the cyclic voltammetry (CV) and differential pulse voltammetry (DPV). Under the optimal conditions, MOF-801/MWCNT-COOH/ AuNPs/GCE delivered linear DPV responses to guanine in the range of 0.8 ~ 60, 60 ~ 180 μM and the adenine in the range of 0.8 ~ 60, 60 ~ 180 μM with the low detection limit of 0.09 μM for guanine and 0.08 μM for adenine, respectively. The advantages of this method include simplicity, rapidity, high sensitivity, good selectivity as well as low cost. The modified GCE was successfully applied to the analysis of guanine and adenine in DNA samples. • A new electrochemical sensor MOF-801/MWCNT-COOHs/AuNPs/GCE is prepared to simultaneously detecting guanine and adenine. • MWCNT-COOHs and AuNPs greatly improve the conductivity of the sensor and the resulted sensitivity. • This electrochemical sensor has good selectivity and sensitivity.

Effect of different SWCNT-BODIPY hybrid materials for selective and sensitive electrochemical detection of guanine and adenine

In this study; the synthesis, structural characterization and electrochemical sensor properties of SWCNTs covalently functionalized with different BODIPY derivatives toward guanine and adenine were investigated. The target SWCNTs-BODIPY hybrids (CB, CB1 and CB2) were synthesized by the reaction of azido functionalized SWCNT with the BODIPY derivatives containing terminal ethynyl group via the Click reaction. Structural characterization of SWCNT-BODIPY hybrid materials was performed by Raman, UV–visible, FTIR spectroscopies and thermogravimetric analysis. The surface morphologies of the new hybrids were evaluated by SEM and TEM. The sensing behavior of these hybrid materials was investigated to detect guanine and adenine in PBS. CB1 hybrid material showed the better sensor properties with the detection limits of 1.07μM and 2.91μM for guanine (G) and adenine (A), respectively. The quantification limits were found to be 3.21μM for guanine and 18.6μM for adenine in PBS. The applicability of the modified electrode for the detection of G and A in DNA from calf thymus was demonstrated with the standard addition method.

Facile Synthesis of Cyclodextrin Functionalized Reduced Graphite Oxide with the Aid of Ionic Liquid for Simultaneous Determination of Guanine and Adenine

AbstractHere, a facile reduction approach for synthesis of β‐cyclodextrin functionalized reduced graphite oxide with the aid of ionic liquid (βCD/IRGO) was reported. This strategy relies on the simple mixing of pre‐pared aqueous βCD/GO with ionic liquid (IL) at high temperatures, which can bring about a well dispersed βCD/RGO in the utilized IL (βCD/IRGO) with a synchronous evaporation of water. The as‐prepared βCD/IRGO product can be stably re‐dispersed in water (up to 1.0 mg/mL) after washed and dried. And the presented βCD/IRGO composites possess high supramolecular recognition capability and good conductivity for realizing enhanced electrochemical response towards simultaneous detection of guanine and adenine compared with other βCD/carbon (RGO or carbon nanotube) based composites. In the presence of one of analysts, the linear response ranges is 0.03–10.0 μM for guanine and 0.02–7.0 μM for adenine, respectively, with detection limit of 0.01 μM for both guanine and adenine (S/N=3). This ease of making the βCD/IRGO composite will open up possibilities of its diversifier applications.

An Electrochemical Sensor Based on Gold Nanoparticles Incorporated in Mesoporous MFI Zeolite for Determination of Purine Bases in DNA

AbstractAn electrochemical sensor was developed based on gold nanoparticles incorporated in mesoporous MFI zeolite for the determination of purine bases. Au nanoparticles (AuNPs) were incorporated into the mesoporous MFI zeolite (AuNPs/m‐MFI) by post‐grafting reaction. The composite materials were characterized by transmission electron microscopy (TEM), X‐ray photoelectron spectroscopy (XPS) and electrochemical methods. Au nanoparticles with a size of 5‐20 nm are uniformly dispersed in the pores of mesoporous MFI zeolite. And the morphology of MFI zeolite can be perfectly kept after pore expansion and Au nanoparticles incorporation. The electrocatalytic oxidation of purine bases (guanine and adenine in DNA) is investigated by cyclic voltammetry (CV) and differential pulse voltammetry (DPV). The surface‐confined Au nanoparticles provide the good catalytic activity for oxidation of purine bases. The simultaneous detection of guanine and adenine can be achieved at AuNPs/m‐MFI composites modified glassy carbon electrode (GCE). The electrochemical sensor based on AuNPs/m‐MFI exhibits wide linear range of 0.5–500 μM and 0.8–500 μM with detection limit of 0.25 and 0.29 μM for guanine and adenine, respectively. Moreover, the electrochemical sensor is applied to evaluation of guanine and adenine in herring sperm DNA samples with satisfactory results.

8-aminoquinoline functionalized graphene oxide for simultaneous determination of guanine and adenine

The nanocomposite graphene oxide/8-aminoquinoline (GAQ) was prepared as modified electrode material for simultaneous determination of guanine and adenine. The prepared GAQ was characterized by SEM, TEM, FTIR, Raman, and UV-vis, which confirmed that the 8-aminoquinoline had been functionalized by covalent modification. The differential pulse voltammetry (DPV) proved the electrochemical properties of the GAQ, which exhibited good electrocatalytic activity and prominent synergistic effect for sensitive determination of guanine and adenine. The guanine and adenine both were detection by DPV showed good linearity with linear range covering 0.1–160 μM, and the detection limits (LOD) (S/N = 3) both were estimated to be 0.033 μM for guanine and adenine, respectively.

A sensitive porphyrin/reduced graphene oxide electrode for simultaneous detection of guanine and adenine

In this study, we prepared the porphyrin/reduced graphene oxide (porphyrin/RGO) nanocomposite which combined the excellent electrical conductivity and high specific surface area of RGO and the catalytic effect on the oxidation of guanine and adenine of porphyrin for simultaneous detection of guanine and adenine. Since the nanocomposite had remarkable synergistic effect between porphyrin and RGO, the modified glassy carbon electrode (GCE) exhibited excellent electrochemical catalytic activities and high sensitivity toward the detection of guanine and adenine. The nanocomposite was successfully applied to simultaneous quantitative detection of guanine and adenine with a linear range covering 0.05–150 and 0.2–100 μM, respectively, and the detection limits (LOD) (S/N = 3) were estimated to be 0.016 μM for guanine and 0.06 μM for adenine. The porphyrin/RGO/GCE was applied for simultaneous detection of trace amounts of guanine and adenine in hydrochloric calf thymus DNA. Moreover, the porphyrin/RGO/GCE was simply fabricated and displayed good reproducibility.

Determination of Adenine and Guanine by a Dopamine-Melanin Nanosphere–Polyaniline Nanocomposite Modified Glassy Carbon Electrode

ABSTRACTA novel electrochemical sensor has been developed for guanine and adenine determination based on a dopamine-melanin nanosphere/polyaniline nanocomposite. The nanocomposite was characterized by scanning electron microscopy, transmission electron microscopy, and infrared spectroscopy. The oxidations of guanine and adenine were studied by cyclic voltammetry and differential pulse voltammetry. The modified electrode exhibited favorable electrocatalytic activity and stability for the simultaneous determination of guanine and adenine. The sensor showed long linear dynamic ranges from 0.05 to 100 µM with limits of detection of 0.01 µM and 0.008 µM for guanine and adenine, respectively. The fabricated electrode was used to determine guanine and adenine in denatured DNA, demonstrating its potential application as an electrochemical sensor.

Silver nanoparticles-β-cyclodextrin-graphene nanocomposites based biosensor for guanine and adenine sensing

Graphene deposited with silver nanoparticles (AgNPs-β-CD-Gr) has been synthesized by thermal reduction of graphene oxide and silver nitrate via β-cyclodextrin (β-CD). It offers a simple, green, and efficient procedure to yield nanocomposites with silver nanoparticles anchored on graphene support, uniformly and stably. Guanine and adenine were simultaneously detected on the modified electrode (AgNPs-β-CD-Gr/GCE) by differential pulse voltammograms. The AgNPs-β-CD-Gr/GCE obviously improved the voltammetric response of guanine and adenine demonstrating that the synergistic effect of silver nanoparticles and graphene can significantly enhance the detecting sensitivity of guanine and adenine. The electrochemical biosensor based on AgNPs-β-CD-Gr exhibits wide linear ranges of 0.3–200 and 0.5–250 μM with detection limits of 0.09 and 0.15 μM for guanine and adenine, respectively. The proposed method was also applied for the measurement of trace-level of these purine bases in herring sperm DNA (dsDNA). The results suggest that the nanocomposite has a potential application for electrocatalytic biosensing.

Simultaneous determination of guanine and adenine on CuO shuttle-like nanocrystals/poly(neutral red) film on glassy carbon electrode

CuO shuttle-like nanocrystals on a poly(neutral red) glassy carbon electrode (nano-CuO/PNR/GCE) has been fabricated and used to simultaneously detect guanine and adenine. The sample is characterized by scanning electron microscopy (SEM), X-ray diffraction (XRD), cyclic voltammetry (CV), electrochemical impedance spectroscopy (EIS), and differential pulse voltammetry (DPV). It has been shown that the oxidation peak current of guanine and adenine could be greatly enhanced with the nano-CuO/PNR/GCE. Under optimal conditions, the anodic peak current of differential pulse voltammetry is proportional to the concentration of the guanine and adenine in the range of 0.05 to 3.0 μM. The corresponding detection limits are 1.6 × 10−2 μM for guanine and 2.3 × 10−2 μM for adenine (S/N = 3). The nano-CuO/PNR/GCE exhibits good storage stability and reproducibility for practical application. It could be applied to simultaneously determination of guanine and adenine for the samples with good anti-interference ability.

Electrochemical biosensor for simultaneous determination of guanine and adenine based on dopamine-melanin colloidal nanospheres–graphene composites

Dopamine-melanin colloidal nanospheres (Dpa-melanin CNDs)–graphene composites-modified glassy carbon electrode (GCE) was prepared by a simple procedure and then successfully used to simultaneously determine guanine and adenine. Scanning electron microscopy (SEM) images and transmission electron microscopy (TEM) were used to characterize the morphology of the Dpa-melanin CNSs–graphene composite. Cyclic voltammetry (CV) and electrochemical impedance spectroscopy (EIS) were used to characterize the electrode modifying process. Differential pulse voltammetry (DPV) was used to study the electrocatalytic activity toward the electrochemical oxidation of guanine and adenine. The modified electrode exhibited enhanced electrocatalytic behavior and good stability for the simultaneous determination of guanine and adenine compared with bare GCE. The electrochemical biosensor exhibited wide linear range of 0.5 to 150 μM with detection limit of 0.05 and 0.03 μM for guanine and adenine detection (S/N = 3), respectively. Furthermore, the biosensor showed high sensitivity, good selectivity, good reproducibility, and long-term stability to guanine and adenine detection. At the same time, the fabricated electrode was successfully applied for the determination of guanine and adenine in denatured DNA samples with satisfying results. These results demonstrated that Dpa-melanin CNSs–graphene composite was a promising substrate for the development of high-performance electrochemical biosensor.

Electrocatalytic oxidation and the simultaneous determination of guanine and adenine on (2,6-pyridinedicarboxylic acid)/graphene composite film modified electrode

An electrochemical sensor was fabricated and used to simultaneously determine guanine and adenine in DNA. In this work, the poly (2,6-pyridinedicarboxylic acid)/chemically reduced graphene oxide modified glass electrode (PPDA/CRGO/GCE) was constructed. The PPDA/CRGO/GCE was characterized by scanning electron microscopy. The modified electrode displayed greatly improved voltammetric response to guanine (G) and adenine (A). Differential pulse voltammetry (DPV) was used for individual or simultaneous determination of guanine and adenine. The electrode showed good reproducibility with linear ranges of 0.05–4.5μM and 0.1–6.0μM, detection limits of 0.01μM and 0.02μM for guanine and adenine, respectively. The electrochemical method for the measurement of guanine and adenine in calf thymus DNA was also developed and the result was satisfactory.

Electrochemical determination of purine and pyrimidine DNA bases based on the recognition properties of azocalix[4]arene

The azocalix[4]arene film modified glassy carbon electrode was established for the convenient and sensitive detection of four DNA bases (guanine, adenine, thymine and cytosine). Field emission scanning electron microscopy, attenuated total reflectance-FTIR and X-ray photoelectron spectroscopy were used to characterize the film. The azocalix[4]arene film exhibited excellent electrocatalytic activity toward the oxidation of all bases. Well-separated voltammetric peaks were obtained among guanine, adenine, thymine and cytosine, which lead to the feasibility for the simultaneous determination of all of them in a mixture without separation or pretreatment. Linear calibration curves were obtained from 0.125 to 200.0μM for adenine, 0.125 to 175.0μM for guanine, 2.50 to 650.0μM for thymine, and 2.50 to 650.0μM for cytosine. This sensor also exhibits good stability, reproducibility and long lifetime.

Electrochemical behaviors and simultaneous determination of guanine and adenine based on graphene–ionic liquid–chitosan composite film modified glassy carbon electrode

A graphene sheets (GS), ionic liquid (IL) and chitosan (CS) modified electrode was fabricated and the modified electrode displayed excellent electrochemical catalytic activities toward guanine and adenine. The transfer electron number (n) and the charge transfer coefficient (α) were calculated with the result as n=2, α=0.58 for guanine, and n=2, α=0.51 for adenine, which indicated the electrochemical oxidation of guanine and adenine on GS/IL/CS modified electrode was a two-electron and two-proton process. The oxidation overpotentials of guanine and adenine were decreased significantly compared with those obtained at the bare glassy carbon electrode and multi-walled carbon nanotubes modified electrode. The modified electrode exhibited good analytical performance and was successfully applied for individual and simultaneous determination of guanine and adenine. Low detection limits of 0.75μM for guanine and 0.45μM for adenine were obtained, with the linear calibration curves over the concentration range 2.5–150μM and 1.5–350μM, respectively. At the same time, the proposed method was successfully applied for the determination of guanine and adenine in denatured DNA samples with satisfying results. Moreover, the GS/IL/CS modified electrode exhibited good sensitivity, long-term stability and reproducibility for the determination of guanine and adenine.