Mediator-Free Self-Powered Bioassay for Wide-Range Detection of Dissolved Carbon Dioxide.

Electrochemical sensors for the dissolved CO2 (dCO2) measurement have attracted great interest because of their simple setup and the resulting low costs. However, the developed sensors suffer from the requirement of the external electrical power supply throughout the sensing. Here, the fabrication and evaluation of a self-powered biosensor based on biofuel cells (BFCs) for dCO2 measurements are described. In this device, AuNPs-multiwalled carbon nanotubes/GOx-modified carbon paper (CP) served as a bioanode for the oxidation of glucose, while imine-linked covalent triazine framework (I-CTF)-modified CP was employed as the cathode for the reduction of Fe(CN)63-. I-CTF is a porous organic polymer with a high CO2 capture capacity. Voltammetry and electrochemical impedance spectroscopy confirmed that the electron transfer of Fe(CN)63- on the I-CTF-modified electrode decreases after contacting I-CTF with dCO2. In the designed BFC, by capturing CO2 by the I-CTF-modified cathode, a significant decrease in open-circuit voltage (EOCV) of the BFC was observed, which can be used for the sensitive measurement of dCO2. In addition to the self-powering feature, the EOCV of the BFC sensor can be restored when the captured CO2 is desorbed from the I-CTF-modified cathode by increasing the temperature of the cathode. Finally, the BFC is integrated into a circuit containing a matching capacitor; the charges generated by the BFC are accumulated on the capacitor, and then the instantaneous current is quickly detected using a switching regulator and a digital multimeter. Under optimal conditions, the instantaneous current of the BFC sensor was found to sensitively respond to dCO2 in a wide concentration range from 1.3 × 10-5 to 0.252 atm with a low detection limit of 5 × 10-6 atm.

An ultrasensitive electrochemical aptasensor based on a single-stranded aptamer-Au@Fe-MIL-88 complex using methylene blue as an electrochemical probe for insulin detection.

This work introduces an electrochemical aptasensor based on a single-stranded aptamer-Au@Fe-MIL-88 complex for sensitive and selective determination of insulin using differential pulls voltammetry. Au@Fe-MIL-88 with a large surface area was synthesized and employed as a suitable substrate for immobilization of the aptamer (APT-Au@Fe-MIL-88). Methylene blue (MB), as an electrochemical probe, was intercalated into the aptamer. Graphene oxide (GO) and zinc sulfide (ZnS) were placed on the Au electrode to amplify the MB current. Also, ZnS improves the immobilization of APT-Au@Fe-MIL-88 into the aptasensor through the strong interaction of Au-S. In the presence of the insulin, MB is released from the aptamer due to DNA conformational change, and as a result, the peak intensity of the intercalated MB was decreased. Under optimal conditions, the change in the current of MB was proportional to the insulin concentration in the range of 5.0 × 10-16-5.0 × 10-11 mol L-1, with a superior ultra-low detection limit of 1.3 × 10-16 mol L-1. It was observed that the aptasensor is suitable for determining insulin in serum samples with good sensitivity and reproducibility and with recoveries ranging from 96.4 to 102.0%. The relative standard deviations (RSD) were lower than 3.8% (n = 3).

Electrochemical sensor based on glassy carbon electrode modified by polymelamine formaldehyde/graphene oxide nanocomposite for ultrasensitive detection of oxycodone.

Polymelamine formaldehyde/graphene oxide (PMF/GO) nanocomposite was used, for the first time, to study the ultrasensitive and selective electrochemical detection of oxycodone (OXC). The successful characterization of PMF/GO was verified based on scanning electron microscopy (SEM), transmission electron microscopy (TEM), Fourier transform infrared (FT-IR), X-ray diffraction (XRD), energy-dispersive spectroscopy (EDS), and Raman spectroscopy. The modified GCE (PMF/GO-GCE) proved its electrocatalytic effect on OXC determination according to cyclic, linear sweep, and differential pulse voltammetry (CV, LSV, and DPV) and electrochemical impedance spectroscopy (EIS) studies. The developed sensor under optimal conditions offered a linear relationship in a limited range of  0.01 to 45 µmol L-1 with the limit of detection (LOD) of 2.0 nmol L-1. The proposed PMF/GO-GCE sensor was effectively employed for the OXC detection in human urine and serum samples. Graphical abstract.

A novel three-dimensional network of CuCr2O4/CuO nanofibers for voltammetric determination of anticancer drug methotrexate.

Considering the importance of measuring anticancer drugs, a carbon paste electrode (CPE) modified with CuCr2O4/CuO nanofibers in the presence of hydrophobic ionic liquid (IL) was fabricated for methotrexate (MTX) sensing. CuCr2O4/CuO nanofibers were prepared by electrospinning method. Then, the morphology and structure of the nanofibers were studied by scanning electron microscopy, thermal analysis, X-ray diffraction, energy-dispersive X-ray, map analysis, and FT-IR spectroscopy. The electrochemical behavior of MTX at CuCr2O4/CuO/IL/CPE surface was studied using cyclic voltammetry, differential pulse voltammetry, and electrochemical impedance spectroscopy. After optimization of the experimental parameters, the prepared sensor showed a low detection limit of 25 nM MTX, based on signal-to-noise (S/N = 3), and it can determine in a wide range of 0.1-300 µM in Britton-Robinson buffer solution at pH 2.5. The modified electrode was used to determine MTX concentration in blood and urine samples with good recoveries of 94.1-104.3. This sensor has several advantages such as low cost, easy preparation, high-performance speed and high sensitivity, selectivity, stability, and repeatability. Graphical abstract Scheme of preparation of CuCr2O4/CuO nanofibers by electrospinning method and design of a carbon past electrode using prepared nanofibers (CuCr2O4/CuO/IL/CPE). This electrode was used for methotrexate determination in plasma and urine samples using differential pulse voltammetry.

Development of an electrochemical biosensor for impedimetric detection of tetracycline in milk.

ABSTRACT: This study dealt with the fabrication of an impedimetric biosensor based on nanomaterial modified with pencil graphite electrode for the detection of tetracycline (TET) in milk samples. For response of the impedimetric aptasensor to be improved, the influence of different parameters (immobilization time of reduced grapheme oxide, time of aptamer, and TET binding, and concentration of aptamer) was optimized. In optimum conditions, the aptasensor provided a concentration range within 1 × 10-16 - 1 × 10-6 M and with a limit of detection of 3 × 10-17 M TET. The proposed impedimetric aptasensor was then used in milk samples analysis, and the acceptable recovery was achieved ranging from 92.8 to 102.1%. According to this study, the combination of an aptamer and electrochemical impedance spectroscopy is a promising method for detection of TET in milk samples with high reproducibility and stability.

Simple and green synthesis of carbon dots (CDs) from valerian root and application of modified mesoporous boehmite (AlOOH) with CDs as a fluorescence probe for determination of imipramine.

A novel, sensitive, rapid, and simple fluorescent probe has been developed based on green-synthesized carbon dots (CDs). In this work, CDs have been synthesized from valerian root by hydrothermal method. Transmission electron microscopy (TEM) and dynamic light scattering (DLS) results confirm the formation of CDs with sizes of less than 10 nm. Fluorescence quenching of CDs was due to the aggregation of the negative charges of CDs with the positive charge of imipramine (IMI) and was then used as the signal for determination of IMI. In addition, the cytotoxicity of CDs was determined using the MTT assay. The probe responses under optimum conditions were linear in the range of 1.0-200.0 ng mL-1 with a limit of detection of 0.6 ng mL-1. Afterwards, mesoporous boehmite (MB) was modified with synthesized CDs (CDs/MB). TEM images confirmed MB modification with CDs. In this case, the variations in the fluorescence signal for different concentrations of IMI increased leading to the higher sensitivity for IMI detection. The limit of detection and linear range for determination of IMI with CDs/MB were obtained as 0.2 and 0.5-200.0 ng mL-1, respectively. To evaluate the fluorescent probe, IMI was measured in real samples. Graphical abstract.

An impedimetric aptasensor for ultrasensitive detection of Penicillin G based on the use of reduced graphene oxide and gold nanoparticles.

The authors describe an impedimetric aptasensor for Penicillin G (PEN) which is an important antibiotic. The method is based on the use of a pencil graphite electrode (PGE) modified with reduced graphene oxide (RGO) and gold nanoparticles (GNPs) for ultrasensitive detection of PEN. The morphology of a bare PGE, RGO/PGE, and GNP/RGO/PGE, and the functional groups on graphene oxide (GO) and RGO were studied using scanning electron microscopy and Fourier transform infrared spectroscopy. Electrochemical impedance spectroscopy was used for detection of PEN by measuring the charge transfer resistance (Rct). Also, cyclic voltammetry was recorded at potential range of 0.30 to +0.70 V for PGE treatment. This aptamer-based assay has a wide linear range that extends from 1.0 fM to 10 µM, and a limit of detection as low as 0.8 fM. The method was applied to the determination of PEN in spiked milk from cow, sheep, goat and water buffalo. Recoveries ranged from 92% to 104%. The assay is fast, ultrasensitive, high reproducible, and selective over antibiotics such as streptomycin, tetracycline, and sulfadiazine. Graphical abstract Schematic presentation of an impedimetric aptasensor for Penicillin G antibiotic using a pencil graphite electrode (PGE) modified with reduced graphene oxide (RGO) and gold nanoparticles (GNPs). This aptamer based assay has limit of detection as low as 0.8 fM.

Application of modified mesoporous boehmite (γ-AlOOH) with green synthesis carbon quantum dots for a fabrication biosensor to determine trace amounts of doxorubicin.

An important form of carbon nanoparticles that are used for a wide range of applications, are carbon dots (CDs). In this study, a very easy, in expensive and green process was described for the preparation of CDs by using hydrothermal treatment of Tragacanth Gum (TG). A rapid assay for the determination of trace amounts of an anticancer medication doxorubicin (DOX) was developed, based on the quenching of the CDs derived from their aggregation. Electrostatic interaction between CDs and DOX could lead to fluorescence quenching. The optimized biosensor showed a detection range from 1 to 400 ng mL-1 and a limit of detection of 0.4 ng mL-1 . In the following, the synthesized CDs modified the Boehmite (Boh) mesoporous surface based on hydrogen bonding. The Boh has been used as supports and ideal hosts in this method, in which the particle size distribution of CDs in the pores of Boh is limited and they have controlled pore sizes. Accordingly, the surface-to-volume ratio and the presence of high-volume pores increased the longevity and sustainability of CDs; also prevented the aggregation of the CDs and improved their photo stability. The advantages of Boh are large pore volume, high surface area, and narrow size distribution. Variable factors influencing optical sensor response in DOX measurement were evaluated and optimized. In optimal conditions, the linear range was calculated from 1 to 500 ngmL-1 and the detection limit was 0.2 ng mL-1 . The sensors were used for measuring DOX in human blood plasma.

Molecularly imprinted electrochemical aptasensor for the attomolar detection of bisphenol A.

Gold nanoparticles (AuNPs) were electrodeposited on the surface of a glassy carbon electrode (GCE) and then treated with a mixture of a thiolated DNA sequence (p-63; with high affinity for bisphenol A) and free bisphenol A (BPÀ). Pyrrole was then electropolymerizaed on the surface of the GCE to entrap the BPA@p-63 complex. BPA is then extracted with acetic acid solution to obtain MIP cavities where the embedded DNA sequence acts as the binding site for BPA. Scanning electron microscopy, electrochemical impedance spectroscopy, and cyclic voltammetry were employed to characterize the surface of the modified GCE. Under the optimum conditions, the assay has a dynamic range that covers the 0.5 fM to 5 pM BPA concentration range and an 80 aM detection limit. It was applied to the quantitation of BPA in (spiked) milk, milk powder and water samples and gave acceptable recoveries. Graphical Abstract Schematic of the procedure for aptamer-based detection of BPA using unique features of the aptamer-based modified electrodes and MIP-based sensors. This assay has high sensitivity and good selectivity. It can presumably be transferred to other detection schemes for small molecules.

An impedimetric aptasensor for Shigella dysenteriae using a gold nanoparticle-modified glassy carbon electrode.

This work describes an aptasensor for the foodborne pathogen Shigella dysenteriae (S. dysenteriae). A glassy carbon electrode (GCE) was modified with gold nanoparticles (AuNPs) by electrodeposition. Then, thiolated aptamer for S. dysenteriae detection was self-assembled on the surface of the modified GCE, and any free residual AuNPs were blocked with 6-mercapto-1-hexanol. The size, morphology, and distribution of the AuNPs were characterized by field emission scanning electron microscopy. Detection of S. dysenteriae was performed measurement of the charge transfer resistance (Rct) before and after addition of S. dysenteriae using hexacyanoferrate as an electrochemical probe. The interaction between the aptamer and outer-membrane proteins of S. dysenteriae lead to an increase in the Rct of the sensor. The assay has a linear dynamic range that extends from 101 to 106 CFU.mL-1 and a limit of detection of 100 CFU.mL-1. It can differentiate between alive S. dysenteriae and other pathogens. Dead S. dysenteriae cells do not have any effect on selectivity. Unpasteurized and pasteurized skim milk and some water samples were spiked with S. dysenteriae and then successfully examined by this method. The results were validated by real-time PCR. The method is fast, low-cost, highly sensitive, and specific. Hence, it represents a valuable tool in food quality control. Graphical abstract Schematic presentation of a label free impedimetric aptasensor for Shigella dysenteriae using a glassy carbon electrode modified with gold nanoparticles (AuNPs) and 6-mercapto-1-hexanol (MCH). The limit of detection of this aptasensor is as low as 1 CFU.mL-1 for target bacteria.

A simple and sensitive label-free fluorescence sensing of heparin based on Cdte quantum dots.

A rapid, simple and sensitive label-free fluorescence method was developed for the determination of trace amounts of an important drug, heparin. This new method was based on water-soluble glutathione-capped CdTe quantum dots (CdTe QDs) as the luminescent probe. CdTe QDs were prepared according to the published protocol and the sizes of these nanoparticles were verified through transmission electron microscopy (TEM), X-ray diffraction (XRD) and dynamic light scattering (DLS) with an average particle size of about 7 nm. The fluorescence intensity of glutathione-capped CdTe QDs increased with increasing heparin concentration. These changes were followed as the analytical signal. Effective variables such as pH, QD concentration and incubation time were optimized. At the optimum conditions, with this optical method, heparin could be measured within the range 10.0-200.0 ng mL(-1) with a low limit of detection, 2.0 ng mL(-1) . The constructed fluorescence sensor was also applied successfully for the determination of heparin in human serum. Copyright © 2015 John Wiley & Sons, Ltd.

Graphene/nano-porous silicon and graphene/bimetallic silicon nanostructures (Pt-M, M: Pd, Ru, Rh), efficient electrocatalysts for the hydrogen evolution reaction.

In this work nano-porous silicon flour (Nano-PSiF) was synthesized first and then there was an investigation into its electrocatalytic activity for the electrochemical hydrogen evolution reaction (HER). The results showed that Nano-PSiF has good electrocatalytic activity for the HER when compared with PSiF. In the second section, Pt and Pt-M (M = Pd, Rh, Ru) bimetallic silicon nanostructures were prepared by a direct reduction of the metal (Pt, Pt-Pd, Pt-Rh and Pt-Ru) on the surface of the PSiF by a galvanic exchange mechanism. The electrocatalytic activity of the bimetallic silicon nanostructures (Pt-M/PSiF) were evaluated for the HER. The results showed that all of the Pt-M/PSiFs have excellent electrocatalytic activity for the HER in a 0.5 mol L(-1) H2SO4 solution. For the Pt/PSiF, the Tafel slope of Pt/PSiF was 46.9 mV dec(-1), indicating its excellent electrocatalytic activity for the HER and it is comparable with commercial Pt/C. On the other hand, the bimetallic silicon nanostructures showed better electrocatalytic activity than Pt/PSiF for the HER (lower Tafel slope, and higher α). Finally, exfoliated graphene oxide was electro-deposited on the surface of a glassy carbon electrode (eRGO/GCE) and used as a sub-layer for the Pt-M/PSiF. Then, the electrocatalytic activities of the bimetallic silicon nanostructures on the eRGO/GCE were investigated for the HER. The results showed that there was a higher electrocatalytic activity for Pt-M/PSiF-eRGO/GCE when compared with Pt-M/PSiF-GCE.

Fabrication of binary metal-organic frameworks of Ni-Mn@ZIFs(Cox·Zn1-xO) decorated on CF/CuO nanowire for high-performance electrochemical pseudocapacitors.

Herein, metal-organic frameworks (MOFs) derived nanoflower-like based binary transition metal (Ni-Mn) are successfully fabricated by a simple synthesis method. The fabricated nanoflower-like structure displays a unique nanoflower-like architecture and internal porous channels constructed by MOF coated on CuO/CF/ZIFs (Cox·Zn1-xO) substrate, which is beneficial for the penetration of electrolyte and electron/ion transportation. The as-prepared CF/CuO/ZIFs (Cox·Zn1-xO)@BMOF(Ni-Mn) electrode materials present significant synergy among transition metal ions, contributing to enhanced electrochemical performances. The as-prepared CF/CuO/ZIFs (Cox·Zn1-xO)@BMOF(Ni-Mn) hybrid nanoflower-like display a high specific capacity of 1249.99 C g-1 at 1 A g-1 and the specific capacitance retention is about 91.74% after 5000 cycles. In addition, the as-assembled CF/CuO/ZIFs (Cox·Zn1-xO)@BMOF(Ni-Mn)//AC asymmetric supercapacitor (ASC) device exhibited a maximum energy density of 21.77 Wh·kg-1 at a power density of 799 W kg-1, and the capacity retention rate after 5000 charge and discharge cycles was 88.52%.

Design and fabrication of electrochemical sensor based on NiO/Ni@C-Fe3O4/CeO2 for the determination of niclosamide.

In this study, we aimed to enhance and accelerate the electrochemical properties of a glassy carbon-based voltammetric sensor electrode. This was achieved through the modification of the electrode using a nanocomposite derived from a metal-organic framework, which was embedded onto a substrate consisting of metal oxide nanoparticles. The final product was an electrocatalyst denoted as NiO/Ni@C-Fe3O4/CeO2, tailored for the detection of the drug niclosamide. Several techniques, including FT-IR, XRD, XPS, FE-SEM, TEM, and EDS, were employed to characterize the structure and morphology of this newly formed electroactive catalyst. Subsequently, the efficiency of this electrocatalyst was evaluated using cyclic voltammetry and electrochemical impedance spectroscopy techniques. Differential pulse voltammetry was also utilized to achieve heightened sensitivity and selectivity. A comprehensive exploration of key factors such as the catalyst quantity, optimal instrumental parameters, scan rate influence, and pH effect was undertaken, revealing a well-regulated reaction process. Furthermore, the sensor's analytical performance parameters were determined. This included establishing the linear detection range for the target compound within a specified concentration interval of 2.92 nM to 4.97 µM. The detection limit of 0.91 nM, repeatability of 3.1%, and reproducibility of 4.8% of the sensor were calculated, leading to the observation of favorable stability characteristics. Conclusively, the developed electrochemical sensor was successfully employed for the quantification of niclosamide in urine samples and niclosamide tablets. This application highlighted not only the sensor's high selectivity but also the satisfactory and accurate outcomes obtained from these measurements.

Impact of temperature on the binding interaction between dsDNA and curcumin: An electrochemical study.

In this study, we investigated the binding mode between double-stranded deoxyribonucleic acid (dsDNA) and curcumin (CU) using differential pulse voltammetry (DPV), UV-Vis spectroscopy, and molecular docking. By employing these techniques, we predicted the binding within the minor groove region of dsDNA and CU. Significantly, we employed electrochemistry, specifically cyclic voltammetry (CV), to explore the temperature effect on the dsDNA and CU binding. To the best of our knowledge, this is the first study to utilize electrochemical methods for investigating the temperature-dependent behavior of this binding interaction. Our findings revealed temperature-dependent variations in the binding constants: 2.42 × 103 M-1 at 25 °C, 4.26 × 103 M-1 at 30 °C, 5.44 × 103 M-1 at 35 °C, 6.29 × 103 M-1 at 40 °C, and 7.52 × 103 M-1 at 45 °C. Notably, the binding constant exhibited an increasing trend with elevated temperatures, indicating a temperature-dependent enhancement of the binding interaction.

DNA-based biosensor for comparative study of catalytic effect of transition metals on autoxidation of sulfite.

The transition metal-catalyzed oxidation of sulfur(IV) oxides has been known for more than 100 years. However, to the best of the authors' knowledge, no electrochemical quantitative study has yet been carried out to determine its nature. In view of the transition metal catalyzed oxidation of sulfur(IV) oxides, a series of radicals are involved in the overall reaction process whereby the sulfite, in the presence of transition metals, may cause damages to DNA through the generation of these highly reactive species. In the present work, {MWCNTs-PDDA/DNA}(2) layer-by-layer (LBL) films were prepared to detect DNA damage induced by radicals generated from sulfite autoxidation using cyclic voltammetry (CV) and electrochemical impedance spectroscopy (EIS). The change in the peak potential separation (ΔE(p)) and charge transfer resistance (R(p)) after incubation of the DNA biosensor in the damaging solution for a certain time was used as indicators of DNA damage. It was found that sulfite in the presence of Co(II), Cu(II), Cr(VI), Fe(III), and Mn(II) caused damage to DNA while neither sulfite alone nor metal ions alone did have the same effect. The results suggest that sulfite is rapidly autoxidized in the presence of Co(II), Cu(II), Cr(VI), Fe(III), and Mn(II), producing radicals that cause the DNA damage. These radicals can be ranked in a descending order of their ability to induce DNA damage with sulfite as follows: Fe(III) > Co(II) > Cu(II) > Cr(VI) > Mn(II). The DNA damage induced by sulfite plus Co(II), Cr(VI), and Fe(III) was inhibited by primary alcohols, but they were not when superoxide dismutase (SOD) and tert-butyl alcohol were used. Comparison of methods used to determine the minimum concentration of a transition metal for sulfite induced DNA damage revealed that electrochemical impedance spectroscopy and cyclic voltammetry outperformed the quantitative comparison of different reagents.

A chemiluminescent metalloimmunoassay based on copper-enhanced gold nanoparticles for quantification of human growth hormone.

A chemiluminescence (CL) immunoassay was developed to determine human growth hormone (hGH) based on copper-enhanced gold nanoparticles. In this method, gold nanoparticles were deposited on polystyrene wells for adsorption of human growth antibodies as well as catalyst for reducing of copper ions from the copper enhancer solution. The reduction of copper ions was prevented where the gold nanoparticles were covered by the antibody-antigen immunocomplex. The deposited copper on Au nanoparticles was then dissolved in HNO3 solution and quantified using the CL method. The CL intensity response was logarithmically dependent on the hGH concentrations over the range 0.2-50 ng/mL, with a detection limit (3σ) of 0.036 ng/mL.

H-CoNiSe2/NC dodecahedral hollow structures for high-performance supercapacitors.

The synergistic effect between metal ions and increasing the surface area leads to the fabrication of supercapacitor materials with high capacities. It is predicted that transition metal selenide compounds will be ideal electrode materials for supercapacitors. However, the defects of poor conductivity and volume expansion of the compounds are fundamental problems that must be solved. In this work, we successfully synthesized the cobalt-nickel selenide nitrogen-doped carbon (H-CoNiSe2/NC) hollow polyhedral composite structure using ZIF-67 as a precursor. The CoSe2 and NiSe2 nanoparticles embedded in the NC polyhedral framework offer a wealth of active sites for the whole electrode. Moreover, the presence of the NC structure in the proposed composite can simultaneously lead to improved conductivity and reduce the volume effect created during the cycling procedure. The H-CoNiSe2/NC electrode provides high specific capacity (1131 C/g at 1.0 A/g) and outstanding cyclic stability (90.2% retention after 6000 cycles). In addition, the H-CoNiSe2/NC//AC hybrid supercapacitor delivers ultrahigh energy density and power density (81.9 Wh/kg at 900 W/kg) and excellent cyclic stability (92.1% of the initial capacitance after 6000 cycles). This study will provide a supercapacitor electrode material with a high specific capacity for energy storage devices.Please confirm the corresponding affiliation for the 'Ali A. Ensafi' author is correctly identified.Error during converting author query response. Please check the eproofing link or feedback pdf for details.

Flexible and sewable electrode based on Ni-Co@PANI-salphen composite-coated on textiles for wearable supercapacitor.

Flexible electrodes with high deformability and energy density are critical for electronic textiles. The key factor for achieving high-performance supercapacitors with superior power and energy density is the evaluation of materials that exhibit exceptional capacitive performance. Herein, we have prepared Ni-Co nanoparticles at the surface of polyaniline-salphen (Ni-Co@PS). Then, followed by casting Ni-Co@PS on a conductive carbon cloth (CC) as a substrate through a facile in-situ polymerization strategy. The morphologies of Ni-Co@PS composite were characterized by different methods such as FE-SEM, XPS, XRD, BET, and electrochemical methods. This nanocomposite showed high tolerability and a large surface area with excellent behavior as a new nanomaterial for supercapacitor application. Thus, the optimum composite designed with a metal ratio (nickel-cobalt 3:1 w/w) satisfactorily possesses a specific capacitance of up to 549.994 C g-1 (1447.2 F g-1) under 0.5 A g-1 and long-term cyclic stability featuring capacity retention of 95.9% after 5000 cycles at a current density of 9.0 A g-1. The Ni-Co@PS-CC, is a material with great potential as an electrode in asymmetric wearable supercapacitor (AWSC) apparatus, demonstrating a remarkable specific capacity of 70.01, and accompanied by an energy density of 23.46 Wh k g-1 at a power density of 800 W k g-1.

Chemical Sensors Based on Molecularly Imprinted Polymers Can Determine Drug Release Kinetics from Nanocarriers without Filtration, Centrifugation, and Dialysis Steps.

With the development of drug delivery systems, the use of nanomaterials for slow, targeted, and effective drug release has grown significantly. To ensure the quality of performance, it is essential to obtain drug release profiles from therapeutic nanoparticles prior to in vivo testing. Typically, the methods of monitoring the drug release profile from nanoparticle drug delivery systems include one or more filtration, separation, and sampling steps, with or without membrane, which cause several systematic errors and make the process time-consuming. Here, the release rate of doxorubicin as a model drug from liposome as a nanocarrier was determined via highly selective binding of released doxorubicin to the doxorubicin-imprinted electropolymerized polypyrrole as a molecularly imprinted polymer (MIP). Incubation of the MIP-modified substrate with imprinted cavities complementary to doxorubicin molecules in the releasing medium leads to the binding of released doxorubicin molecules to cavities. The drug trapped in the cavities is determined by one of the analytical methods depending on its signaling properties. In this work, due to the favorable electrochemical properties of doxorubicin, the voltammetry method was used for quantitative analysis of released doxorubicin. The voltammetric oxidation peak current intensity of doxorubicin on the surface of the electrode was enhanced by increasing the release time. This membranelle platform allows fast, reliable, and simple monitoring of drug release profiles without any sample preparation, filtration, and centrifugation in buffer and blood serum samples.