Neutral Phosphate Buffer Research Articles

Non-Enzymatic Electrochemical Detection of Urine Creatinine Using Cobalt-Gold Bimetallic Nanoparticles

This work presents the development of a non-enzymatic electrochemical sensor for creatinine in a neutral medium using a cobalt-gold bimetallic nanoparticles modified platinum electrode. The voltammetric detection of creatinine in a neutral phosphate buffer was based on the formation of a soluble cobalt-creatinine complex. The sensor exhibited good selectivity and a detection limit (S/N = 3) of 2.25 mM with two linear ranges from 6.4 to 83.2 mM. The sensitivity of the sensor was 0.621 and 1.135 μA mM−1 cm−2 at lower (6.4–51.2 mM) and higher (51.2–83.2 mM) detection ranges, respectively. The sensor performance was validated using urine samples and creatinine spiked urine samples.

CeO2·ZnO@biomass-derived carbon nanocomposite-based electrochemical sensor for efficient detection of ascorbic acid

Ascorbic acid (AA), a prominent antioxidant commonly found in human blood serum, serves as a biomarker for assessing oxidative stress levels. Therefore, precise detection of AA is crucial for swiftly diagnosing conditions arising from abnormal AA levels. Consequently, the primary aim of this research is to develop a sensitive and selective electrochemical sensor for accurate AA determination. To accomplish this aim, we used a novel nanocomposite comprised of CeO2-doped ZnO adorned on biomass-derived carbon (CeO2·ZnO@BC) as the active nanomaterial, effectively fabricating a glassy carbon electrode (GCE). Various analytical techniques were employed to scrutinize the structure and morphology features of the CeO2·ZnO@BC nanocomposite, ensuring its suitability as the sensing nanomaterial. This innovative sensor is capable of quantifying a wide range of AA concentrations, spanning from 0.5 to 1925 μM in a neutral phosphate buffer solution. It exhibits a remarkable sensitivity of 0.2267 μA μM−1cm−2 and a practical detection limit of 0.022 μM. Thanks to its exceptional sensitivity and selectivity, this sensor enables highly accurate determination of AA concentrations in real samples. Moreover, its superior reproducibility, repeatability, and stability underscore its reliability and robustness for AA quantification.

Electrochemical detection of hydroquinone as an environmental contaminant using Ga2O3 incorporated ZnO nanomaterial

The primary objective of this research endeavor is to develop a highly sensitive and selective electrochemical sensor for the accurate detection of hydroquinone (HQ), a prevalent environmental contaminant. To achieve this, we employed a novel nanocomposite consisting of Ga2O3-doped ZnO (Ga2O3.ZnO) as the active nanomaterial for fabricating a glassy carbon electrode (GCE). The structure and morphology of the Ga2O3.ZnO nanocomposite were rigorously analyzed using a diverse range of techniques to ensure its suitability as the sensing nanomaterial. This innovative sensor exhibits remarkable capabilities, enabling the detection of HQ across a broad concentration range, spanning from 1 to 11070 µM, in a neutral phosphate buffer solution. It boasts an exceptionally high sensitivity of 1.0229 µA µM−1 cm−2 and an impressive detection limit of 0.063 µM. Thanks to its exceptional sensitivity and specificity, this sensor can precisely quantify HQ levels in real-world samples. Moreover, its outstanding reproducibility, repeatability, and stability establish it as a dependable and resilient choice for HQ determination.

Facile synthesis of CeO2·CuO-decorated biomass-derived carbon nanocomposite for sensitive detection of catechol by electrochemical technique

Catechol (CC) is renowned for its ability to interact with a wide range of biomolecules, a trait that raises potential health concerns. Consequently, herein we achieved a significant milestone by developing an electrochemical CC sensor with improved performance such as exceptional sensitivity and selectivity. In this CC sensor we used Cerium (IV) oxide-doped Copper (II) oxide decorated biomass-derived carbon (BC) nanocomposite, known as CeO2·CuO@BC as the sensing material. This material has been artfully integrated into the modification of a glassy carbon electrode (GCE), showcasing the synergy of advanced materials and electrode design. The efficacy of the CeO2·CuO@BC nanocomposite as a sensing material underwent rigorous evaluation through comprehensive characterization techniques such as X-ray photoelectron spectroscopy (XPS), X-ray diffraction (XRD), Raman spectrum, Field Emission Scanning Electron Microscopy (FE-SEM), Transmission Electron Microscopy (TEM), and Energy-Dispersive X-ray Spectroscopy (EDS). As a result, we developed a sensor that can quantify CC concentrations across an extensive dynamic range, spanning from 0.5 μM to a remarkable 8470 μM in a neutral phosphate buffer solution. This sensor, boasting a sensitivity of 0.4171 μAμM−1cm−2, coupled with an impressive detection limit of a mere 0.035 μM, stands as a testament to its superior performance. Its exceptional sensitivity and selectivity allow precise catechol level detection in real-world samples, making it invaluable for analytical applications. Beyond its analytical prowess, the sensor demonstrates remarkable durability through excellent reproducibility, repeatability, and stability. This robustness underscores its reliability, establishing it as an indispensable and highly efficient electrode for accurate CC determination across various practical scenarios.

Development of a sensitive and selective catechol amperometric sensor based on a novel In2O3-doped CuO decorated mesoporous carbon nanocomposite

Catechol is known for its reactivity with various biomolecules, posing potential health risks. Therefore, in this research, we have successfully developed an electrochemical sensor with high sensitivity and selectivity for detecting catechol (CC). The sensor utilizes a novel In2O3-doped CuO decorated Mesoporous Carbon Nanocomposite (In2O3.CuO@MC) as the sensing material, which is applied to fabricate a glassy carbon electrode (GCE). The suitability of the In2O3.CuO@MC nanocomposite as a sensing material was thoroughly examined using various characterization techniques. The developed sensor exhibited remarkable performance, enabling the accurate catechol determination across a wide concentration range, from 0.5 to 3031 µM, in a neutral phosphate buffer solution. This sensor demonstrated a high sensitivity of 0.3803 µAµM−1cm−2 and an impressive detection limit of 0.048 µM. The sensor's exceptional sensitivity and selectivity make it capable of precisely quantifying catechol from real samples. Its robustness is further highlighted by its excellent reproducibility, repeatability, and stability. As a result, this sensor proves to be a reliable and effective tool for precise catechol determination.

Oxygen reduction mediated by tetrapyridylalkylamine Cu(II) complexes with diimines

Oxygen reduction reaction (ORR) is important in artificial energy conversion systems such as fuel cells. However, it is kinetically sluggish. It is thereby highly desirable to develop ORR catalysts to improve the efficiency of energy conversion. In this work, three copper(II) complexes based on the hexadentate tetrapyridylalkylamine N,N,N’,N’-tetrakis(2-pyridyl-methyl)-1,4-butanediamine (tpbn), namely [Cu2(tpbn)(CH3OH)4(ClO4)2](ClO4)2 (Cu-tpbn), [Cu2(tpbn)(bpy)2](ClO4)4.2CH3COCH3 (Cu-tpbn-bpy, bpy = 2,2′-bipyridine), and [Cu2(tpbn)(Me2bpy)2](ClO4)4.3CH3CN (Cu-tpbn-Me2bpy, Me2bpy = 4,4′-dimethyl-2,2′-bipyridine), were prepared and their catalytic properties for ORR studied. All three complexes were homogeneous electrocatalysts for ORR in neutral phosphate buffer solutions. The ORR mediated by Cu-tpbn-Me2bpy had the most positive onset potential of 0.461 V vs RHE. In the applied potential window of -0.19 – 0.50 V vs RHE, Cu-tpbn boosted the stepwise four-electron ORR to mainly produce H2O, whereas Cu-tpbn-bpy and Cu-tpbn-Me2bpy mediated the ORR to mainly generate H2O2. The rate constants for the ORR to H2O promoted by Cu-tpbn, Cu-tpbn-bpy and Cu-tpbn-Me2bpy were 1.2 × 103 s−1, 3.2 × 10 s−1 and 7.8 × 10 s−1, respectively. The foot-of-the-wave analysis showed that the turnover frequencies for the reduction of O2 to H2O2 mediated by Cu-tpbn, Cu-tpbn-bpy and Cu-tpbn-Me2bpy were 1.5 × 104 s−1, 7.5 × 10 s−1 and 2.7 × 102 s−1, respectively. Meanwhile, complexes Cu-tpbn-bpy and Cu-tpbn-Me2bpy were more stable than Cu-tpbn. This work unveiled that the catalytic activity and the product selectivity of the ORR were greatly associated with the denticity, the steric effect and the electronic property of the organic ligands.

A novel Ga2O3-doped ZnO decorated SWCNT nanocomposite based amperometric sensor for efficient detection of dopamine in real samples

Our current research focuses on developing an efficient electrochemical Dopamine sensor for diagnosing neurological disorders related to abnormal Dopamine levels. We utilized a Ga2O3-doped ZnO decorated SWCNT (Ga2O3·ZnO@SWCNT) nanocomposite to modify a glassy carbon electrode. The structure and morphology of the Ga2O3·ZnO@SWCNT nanocomposite was examined utilizing a variety of approaches to ensure of their appropriateness as the sensing nanomaterial. The sensor effectively detects Dopamine within a wide range (1.0–2056 μM) in neutral phosphate buffer solution, exhibiting high sensitivity (0.2536 μAμM−1cm−2) and a practical detection limit (0.052 μM). It accurately quantifies Dopamine in human blood serum and commercial dopamine injection samples, displaying excellent reproducibility, repeatability, and stability. This proposed Dopamine sensor proves to be a reliable tool for Dopamine determination.

Low Overpotential Amperometric Sensor Using Yb2O3.CuO@rGO Nanocomposite for Sensitive Detection of Ascorbic Acid in Real Samples.

The ultimate objective of this research work is to design a sensitive and selective electrochemical sensor for the efficient detection of ascorbic acid (AA), a vital antioxidant found in blood serum that may serve as a biomarker for oxidative stress. To achieve this, we utilized a novel Yb2O3.CuO@rGO nanocomposite (NC) as the active material to modify the glassy carbon working electrode (GCE). The structural properties and morphological characteristics of the Yb2O3.CuO@rGO NC were investigated using various techniques to ensure their suitability for the sensor. The resulting sensor electrode was able to detect a broad range of AA concentrations (0.5-1571 µM) in neutral phosphate buffer solution, with a high sensitivity of 0.4341 µAµM-1cm-2 and a reasonable detection limit of 0.062 µM. The sensor's great sensitivity and selectivity allowed it to accurately determine the levels of AA in human blood serum and commercial vitamin C tablets. It demonstrated high levels of reproducibility, repeatability, and stability, making it a reliable and robust sensor for the measurement of AA at low overpotential. Overall, the Yb2O3.CuO@rGO/GCE sensor showed great potential in detecting AA from real samples.

Cost-effective electrodeposited Ni-Co-TiO2 electrodes for boosting hydrogen evolution reaction in acidic and neutral electrolytes

Despite the importance of energy for our life, the rapid consumption of fossil fuels with human population growth worldwide is imperative to find other sustainable sources of energy. A promising strategy is to assess earth-abundant and inexpensive materials as electrocatalysts for efficient green hydrogen production. Herein, nanocrystalline Ni-Co-TiO2 electrodeposited films on copper that have different Co atomic ratios are exploited as target cathodes for hydrogen creation from acid and neutral electrolytes. Different characterization techniques were utilized to identify the chemical composition, morphological structure, crystal lattice system, and unit cell parameters of the obtained bimetals-metal oxide nanocomposites. Ultrasonication with mechanically stirred plating baths was used to ensure the homogenous inclusion of TiO2 nanoparticles inside the bimetallic texture. The electrocatalytic activity of hydrogen evolution reaction (HER) over the designed nanocrystalline cathodes was investigated using voltammetric polarization, chronoamperometry, and electrochemical impedance spectroscopy techniques. The results showed that Ni-Co-TiO2 nanocomposites with somewhat low Co contents (8–9 at.%) displayed superior electrocatalytic HER activity in acid and neutral phosphate buffer (PB) electrolytes, outperforming by many times the other benchmark electrocatalysts. In 0.5 M H2SO4 solution, the Ni-8.2Co-4.8TiO2 cathode demonstrated the highest catalytic activity for the HER, minimal overpotential of 223 mV to deliver a current density of 10 mA cm−2, and small Tafel slope of 74.3 mV dec-1. While the Ni-9.2Co-4TiO2 electrocatalyst required a slightly higher Tafel slope of 79.5 mV dec-1 and an overpotential of 279 mV to convey the same current density of 10 mA cm−2 in 1 M PB electrolyte. The impedance data further confirm these results as these two cathodes showed the lowest resistance for the charge transport process on their surfaces among the other tested ones. The study confirmed that abundant transition bimetals/metal oxide nanocomposites are among the most promising long time stability electrodes for large-scale economic hydrogen fuel production technologies.

Perylene derivative and persulfate as highly efficient electrochemical system for constructing sensitive amperometric aptasensor

To design highly efficient electrochemistry system was important for construct simple and sensitive biosensors, which was crucial in clinical diagnosis and therapy. In this work, a novel electrochemistry probe N,N′-di (1-hydroxyethyl dimethylaminoethyl) perylene diimide (HDPDI) with positive charges was reported to show two-electron redox behavior in neutral phosphate buffer solution between 0 and -1.0 V. And K2S2O8 in solution could significantly increase the reduction current of HDPDI at −0.29 V, which was interpreted with cyclic catalysis mechanism of K2S2O8. Moreover, HDPDI as electrochemical probe and K2S2O8 as signal enhancer was used to design aptasensors for protein detection. Thrombin was used as target model protein. Thiolate ssDNA with thrombin-binding sequence was immobilized on gold electrode to selectively capture thrombin and adsorb HDPDI. The thiolate ssDNA without binding with thrombin was with random coil structure and could adsorb HDPDI through electrostatic attraction interaction. However, the thiolate ssDNA binding with thrombin became G-quadruplex structure and hardly adsorbed HDPDI. Thus, with increasing the concentration of thrombin, the current signal stepwisely decreased and was taken as detection signal. Compared with other aptasensors based on electrochemistry molecules without signal enhancer, the proposed aptasensors exhibited wider linear response for thrombin between 1 pg mL−1 and 100 ng mL−1 with lower detection limit 0.13 pg mL−1. In addition, the proposed aptasensor showed good feasibility in human serum samples.

In-situ scalable fast fabrication of Cu-Cu2+1O nanorods for highly efficient electrocatalytic reduction into ammonia under neutral medium

The development of a highly efficient and durable electrocatalyst for nitrate reduction reaction (NO3RR) wastewater valorization to ammonia (NH3) is a promising strategy. However, it is challenging to design scalable low-cost electrocatalysts with high activity, high selectivity, and long-term stability by a facile and simple method. Herein, we construct this scalable Cu-based nanoarray with muti-oxidation states grown directly on nickel foam (NF) substrate (Cu2+1O@Cu/NF) using a facile molten salt method combined in-situ electrochemical reduction. The as-prepared Cu2+1O@Cu/NF nanoarrays reveal a high NH3 yield of 20.14 mg h−1 cm−2 at −0.95 V vs. a reversible hydrogen electrode (vs. RHE), Faradaic efficiency of 99.38% at −0.55 V vs. RHE in the neutral potassium phosphate (PBS) buffer solution with 50 mM NaNO3, which is ascribed to its electron redistribution with abundant oxygen vacancies and favorable charge/mass transfer.

Semisynthesis of Aminomethyl-Insulin: An Atom-Economic Strategy to Increase the Affinity and Selectivity of a Protein for Recognition by a Synthetic Receptor.

Advancements in the molecular recognition of insulin by nonantibody-based means would facilitate the development of methodology for the continuous detection of insulin for the management of diabetes mellitus. Herein, we report a novel insulin derivative that binds to the synthetic receptor cucurbit[7]uril (Q7) at a single site and with high nanomolar affinity. The insulin derivative was prepared by a four-step protein semisynthetic method to present a 4-aminomethyl group on the side chain of the PheB1 position. The resulting aminomethyl insulin binds to Q7 with an equilibrium dissociation constant value of 99 nM in neutral phosphate buffer, as determined by isothermal titration calorimetry. This 6.8-fold enhancement in affinity versus native insulin was gained by an atom-economical modification (-CH2NH2). To the best of our knowledge, this is the highest reported binding affinity for an insulin derivative by a synthetic receptor. This strategy for engineering protein affinity tags induces minimal change to the protein structure while increasing affinity and selectivity for a synthetic receptor.

Water-Dispersible Carboxymethyl Dextran-Coated Melamine Nanoparticles for Biosensing Applications.

In this study, we developed a simple method for preparing highly dispersed, stable, and streptavidin (SA)-functionalized carboxymethyl dextran (CMD)-coated melamine nanoparticles (MNPs) in an aqueous buffer at neutral pH. Dynamic light scattering (DLS) revealed the agglomeration of MNPs in an aqueous buffer at neutral pH. When CMD, N-hydroxysuccinimide (NHS), and 1-ethyl-3-(3-dimethylaminopropyl) carbodiimide (EDC) were simultaneously mixed with the MNPs, CMD was bound to the MNPs, promoting their dispersibility. Preparation of SA-CMD-MNPs was accomplished simply by adding SA solution to the CMD-MNPs. The amount of SA bound to the CMD-MNPs was quantified by the bicinchoninic assay, and the amount of SA molecules bound to each CMD-MNP was 417 ± 4. SA-CMD-MNPs exhibited high dispersity (polydispersity index = 0.058) in a neutral phosphate buffer and maintained it for 182 days with dispersion using a probe sonicator (5 s) before DLS characterization. The performance of the SA-CMD-MNPs in biosensing was evaluated by immunohistochemistry, which revealed that the nanoparticles could specifically stain MCF-7 cells derived from breast cancer cells with low HER2 expression. This study provides an effective method for synthesizing highly dispersible nanoparticles for biosensing.

Surface structure-sensitivity dependence and mechanistic study of the glucose electro-oxidation on Pt stepped surfaces in neutral solution (pH 7)

• Glucose electro-oxidation in neutral solution is a sensitive-structure reaction. • On Pt-[( n )(1 1 1)x(1 0 0)]: when n ≥ 9 , [1 0 0] steps favor more energetic reactions pathways. • As higher the [1 0 0] steps density on (1 1 1) terraces, lower is the catalytic activity. • On narrow (1 0 0) terraces, [1 1 1] steps conduce the reaction through less poisoned path. • [1 1 0] steps sites favor the CO L adsorption, especially as narrower as the surface is. The electro-oxidation of glucose (0.01 M) in a neutral solution phosphate buffer solution – pH ∼ 7 (0.1 M) is strongly sensitive to the surface structure. On surfaces containing (1 0 0) terraces domains the reaction occurs mainly into these sites due to their higher activity. Higher (1 1 1) step density into (1 0 0) terrace domains conducts the reaction through a less poisoned and energetic pathway because steps inhibit the cyclic carbonate formation. On surfaces containing (1 1 1) terrace sites, on large atom-wide terrace ( n ≥ 9 ) the reactivity of the (1 0 0) steps seems to be mainly associated to the anticipation of the formation of glucuronic acid and favor its oxidation to glucaric acid and/or xylonic acid + CO, that are more energetic reactions. On the other hand, when the step density is increased, the catalytic activity decreases as result of adsorption of intermediates and/products generated during the reaction on (1 0 0) steps. Lower and medium (1 1 0) density steps favor the adsorption of glucose on surfaces containing (1 1 1) terraces symmetry, but independently of the terrace step symmetry, as the (1 1 0) step density is increased the electrocatalytic activity is reduced because the reaction takes place through a more poisoned pathway, with the formation of a greater amount of species that adsorb strongly on the (1 1 0) sites and block the surface.

Highly selective electrocatalytic hydrogenation of cinnamaldehyde over tin dioxide-supported palladium nanocatalysts

Selective hydrogenation of α, β-unsaturated aldehydes has always been a hot research topic owing to favorable thermodynamics in CC hydrogenation. In this work, a series of Pd/SnO2 nanocatalysts were facilely synthesized under mild conditions, via the reduction of Na2PdCl4 by dimethylaminoborane. Under galvanostatic electrolysis at 3.33 mA cm−2 for 8 h, the selective conversion of cinnamaldehyde (CAL) was achieved over Pd/SnO2-coated carbon fiber in neutral phosphate buffer, giving the cinnamyl alcohol (COL) selectivity of 78.85% at the conversion of 84.88%. The Pd/SnO2 nanocatalysts outperform commercial Pd/C catalysts, showing high COL selectivity and faradaic efficiency. The cathodic reduction potential of CAL over Pd4·3/SnO2 occurs at −0.92 V. The SnO2 support is beneficial to promote the CO adsorption of CAL and lower the HER activity of Pd nanocatalysts, thereby contributing to superior activity of Pd4·3/SnO2 for selective hydrogenation of CAL.

Light-activated antibacterial electrospun polyacrylonitrile-graphene quantum dot nanofibrous membranes

Polyacrylonitrile (PAN) nanofibrous membranes incorporating graphene quantum dots (GQD) as photoantibacterial additives were prepared by electrospinning. GQD encapsulation in the composite GQD-PAN membranes proved very stable, with negligible GQD leakage after 1 month immersed in neutral phosphate buffer solutions. A series of GQD-PAN membranes with different GQD content and electrospinning times were prepared to assess the influence of these parameters on the antibacterial activity of the membranes against Escherichia coli under visible light irradiation. Electrospinning time had a pronounced effect on membrane weight/thickness and nanofiber diameter, both parameters increasing with electrospinning time. Membranes with the optimal composition (1% wt. GQD and 1.5 h electrospinning time) showed excellent antibacterial activity against E. coli, with 99.9999% (6 logaritmic units) bacterial inactivation after 24 h illumination with visible light. Different bactericidal reactive oxygen species (ROS) were detected upon illumination of GQD solutions and GQD-PAN membranes, confirming photodynamic inactivation of the bacteria by GQD photosensitization. In terms of ROS production, GQD outperformed well-known photosensitizers crystal violet and toluidine blue O, both with long-established efficiency for photodynamic treatment of drug-resistant bacterial infections.

Self-Co-Electrolysis for Co-Production of Phosphate and Hydrogen in Neutral Phosphate Buffer Electrolyte.

The spontaneous reaction between Zn and H2 O is of critical importance and could plausibly be used to produce H2 gas, especially under neutral conditions. However, this reaction has long been overlooked owing to its sluggish kinetics and Zn consumption. Herein, a unique self-co-electrolysis system (SCES) is reported, which uses a Zn anode, a CoP-based catalytic cathode, and a neutral phosphate buffer solution (PBS) as the electrolyte. In this SCES, Zn is not only a sacrificial anode but also an important precursor of high-value-added NaZnPO4 . Additionally, the composition and phase structure of NaZnPO4 can be well regulated. In this study, a high-performance N,Cu-CoP/carbon cloth (CC) catalyst is synthesized to catalyze the cathodic hydrogen evolution reaction (HER) at an especially low overpotential of 64.7 mV at 10 mA cm- 2 . H2 gas (13.7 mL cm- 2 h- 1 ) and NaZnPO4 (3.73 mg cm- 2 h- 1 ) are obtained at the cathode and anode, respectively, in the N,Cu-CoP/CC||Zn SCES spontaneously. Moreover, the SCES has a favorable open-circuit voltage (OCV) of 0.79 V and a maximum power density of 1.83 mW cm- 2 . Density functional theory (DFT) calculations are performed to elucidate the electronic structure and HER catalytic mechanism of the N and Cu co-doped CoP catalysts.

The Effects of Potential and pH on the Adsorption of Guanine on the Au(111) Electrode.

The adsorption of nucleobase at a gold electrode has been a model system to study the interaction between biomolecule and metal, which is relevant to the development of sensors and molecular electronics. The current study has employed in situ scanning tunneling microscopy (STM) and voltammetry to investigate the adsorption configuration and spatial structure of guanine (G) on a well-defined Au(111) electrode in perchloric acid (HClO4) and neutral phosphate buffer solution (PBS) containing 50 μM G. Potential control had a profound effect on the adsorption of the G molecule on the Au(111) electrode. No adsorption of G was observed at a potential more negative than 0 V in HClO4 and -0.2 V (versus Ag/AgCl) in PBS; shifting potential positively triggered a rapid adsorption of G to yield a well-ordered G array. Different spatial structures of G admolecules were imaged with STM in HClO4 and PBS, suggesting that ions in the electrolyte were important in this adsorption event. Shifting potential positively caused a more compact G adlayer with molecules adopting a tilted orientation. Meanwhile, G molecules continued to deposit on the Au(111) electrode leading to a multilayer G film. These processes were reversible to the potential modulation. G admolecules on the Au(111) electrode could be irreversibly oxidized in 0.1 M PBS, which resulted in a prominent peak at 0.74 V in the voltammogram. This oxidation process could be used to analyze the G molecule in a sample.

Electrochemical characteristics of prednisone and its interaction with dsDNA over functionalized CNSs modified electrode

Herein the electrochemical property of prednisone, a synthetic corticosteroid drug has been investigated using carbon nano sphere (CNSs) modified glassy carbon electrode (GCE) in neutral phosphate buffer medium at pH 7.2. CNSs are functionalized with acidic functional groups and the GCE has been modified with these functionalized CNSs. Significant enhancement in the electrochemical property has been observed while modifying the GCE using the functionalized CNSs. The reduction process of the prednisone over the modified electrode is found to be pH dependent and shows 2e− and 2H+ proton transfer electrochemical reduction kinetics. Interaction of prednisone with transition metal ions (Cu2+) is investigated in the line to understand the biological functioning correlated with the interaction of dsDNA and the transition metal ion Cu2+. The deviation of the electrochemical signal of prednisone due to the presence of some commonly occurring chemical systems has also been investigated. An analytical method of determination of prednisone has been developed using the square wave voltammetric techniques in 0.1 M PBS buffer solution at pH 7.2 and the detection limit obtained as 73 nM.

Biocompatible Electrochemical Sensor Based on Platinum-Nickel Alloy Nanoparticles for In Situ Monitoring of Hydrogen Sulfide in Breast Cancer Cells.

Hydrogen sulfide (H2S), an endogenous gasotransmitter, is produced in mammalian systems and is closely associated with pathological and physiological functions. Nevertheless, the complete conversion of H2S is still unpredictable owing to the limited number of sensors for accurate and quantitative detection of H2S in biological samples. In this study, we constructed a disposable electrochemical sensor based on PtNi alloy nanoparticles (PtNi NPs) for sensitive and specific in situ monitoring of H2S released by human breast cancer cells. PtNi alloy NPs with an average size of 5.6 nm were prepared by a simple hydrothermal approach. The conversion of different forms of sulfides (e.g., H2S, HS−, and S2−) under various physiological conditions hindered the direct detection of H2S in live cells. PtNi NPs catalyze the electrochemical oxidation of H2S in a neutral phosphate buffer (PB, pH 7.0). The PtNi-based sensing platform demonstrated a linear detection range of 0.013–1031 µM and the limit of detection was 0.004 µM (S/N = 3). Moreover, the PtNi sensor exhibited a sensitivity of 0.323 μA μM−1 cm−2. In addition, the stability, repeatability, reproducibility, and anti-interference ability of the PtNi sensor exhibited satisfactory results. The PtNi sensor was able to successfully quantify H2S in pond water, urine, and saliva samples. Finally, the biocompatible PtNi electrode was effectively employed for the real-time quantification of H2S released from breast cancer cells and mouse fibroblasts.