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1.
Small ; 20(38): e2403342, 2024 Sep.
Artículo en Inglés | MEDLINE | ID: mdl-38742947

RESUMEN

Perovskite solar cell (PSC) is a promising photovoltaic technology that achieves over 26% power conversion efficiency (PCE). However, the high materials costs, complicated fabrication process, as well as poor long-term stability, are stumbling blocks for the commercialization of the PSCs in normal structures. The hole transport layer (HTL)-free carbon-based PSCs (C-PSCs) are expected to overcome these challenges. However, C-PSCs have suffered from relatively low PCE due to severe energy loss at the perovskite/carbon interface. Herein, the study proposes to boost the hole extraction capability of carbon electrode by incorporating functional manganese (II III) oxide (Mn3O4). It is found that the work function (WF) of the carbon electrode can be finely tuned with different amounts of Mn3O4 addition, thus the interfacial charge transfer efficiency can be maximized. Besides, the mechanical properties of carbon electrode can also be strengthened. Finally, a PCE of 19.03% is achieved. Moreover, the device retains 90% of its initial PCE after 2000 h of storage. This study offers a feasible strategy for fabricating efficient paintable HTL-free C-PSCs.

2.
Small ; 20(40): e2402061, 2024 Oct.
Artículo en Inglés | MEDLINE | ID: mdl-38805742

RESUMEN

Carbon-based CsPbI3 perovskite solar cells without hole transporter (C-PSCs) have achieved intense attention due to its simple device structure and high chemical stability. However, the severe interface energy loss at the CsPbI3/carbon interface, attributed to the lower hole selectivity for inefficient charge separation, greatly limits device performance. Hence, dipole electric field (DEF) is deployed at the above interface to address the above issue by using a pole molecule, 4-trifluoromethyl-Phenylammonium iodide (CF3-PAI), in which the ─NH3 group anchors on the perovskite surface and the ─CF3 group extends away from it and connects with carbon electrode. The DEF is proven to align with the built-in electric field, that is pointing toward carbon electrode, which well enhances hole selectivity and charge separation at the interface. Besides, CF3-PAI molecules also serve as defect passivator for reducing trap state density, which further suppresses defect-induced non-radiative recombination. Consequently, the CsPbI3 C-PSCs achieve an excellent efficiency of 18.33% with a high VOC of 1.144 V for inorganic C-PSCs without hole transporter.

3.
Small ; 20(30): e2310196, 2024 Jul.
Artículo en Inglés | MEDLINE | ID: mdl-38377307

RESUMEN

"Perovskite / Carbon" interface has remained a key bottleneck for the hole-conductor-free perovskite solar cells based on carbon-electrode (CPSCs), due to problems like loose physics contact, defects, energy mismatch, poor chemical coupling, etc. A previous study shows that octylammonium iodide (OAI) blending in carbon paste induced a kind of "in-situ healing" effect for "perovskite / carbon" interface, and improved power conversion efficiency from ≈13% to >19%. Here the beneath mechanism is further explored by careful examination of the interaction between OAI molecule and carbon black (CB) nanoparticles. It comes to show that, the famous "CB adsorption" plays a key role during the "healing" processes. Due to CB adsorption behavior, the mass ratio between OAI and CB influences much on the healing effect. By suitably adjusting the mass ratio between OAI and CB, and increasing the light harvest of perovskite, an efficiency of 19.41% is achieved for the hole-conductor-free CPSCs. Device efficiency and the charge-extraction and recombination process are tracked with the storage period, continuous improvement appears for devices assembled by relatively higher CB mass. A kind of "slow-release effect" is revealed during the OAI-induced "in-situ healing" process, which is caused by the famous "CB adsorption" behavior.

4.
Small ; : e2403267, 2024 Jul 10.
Artículo en Inglés | MEDLINE | ID: mdl-38982953

RESUMEN

Carbon-based perovskite solar cells (PSCs) coupled with solution-processed hole transport layers (HTLs) have shown potential owing to their combination of low cost and high performance. However, the commonly used poly(3-hexylthiophene) (P3HT) semicrystalline-polymer HTL dominantly shows edge-on molecular orientation, in which the alkyl side chains directly contact the perovskite layer, resulting in an electronically poor contact at the perovskite/P3HT interface. The study adopts a synergetic strategy comprising of additive and solvent engineering to transfer the edge-on molecular orientation of P3HT HTL into 3D molecular orientation. The target P3HT HTL possesses improved charge transport as well as enhanced moisture-repelling capability. Moreover, energy level alignment between target P3HT HTL and perovskite layer is realized. As a result, the champion devices with small (0.04 cm2) and larger areas (1 cm2) deliver notable efficiencies of 20.55% and 18.32%, respectively, which are among the highest efficiency of carbon-electrode PSCs.

5.
Small ; : e2311957, 2024 Mar 21.
Artículo en Inglés | MEDLINE | ID: mdl-38511541

RESUMEN

Electrochemical capacitors (ECs) play a crucial role in electrical energy storage, offering great potential for efficient energy storage and power management. However, they face challenges such as moderate energy densities and rapid self-discharge. Addressing self-discharge necessitates a fundamental understanding of the underlying processes. This review sets itself apart from other reviews by focusing on the basic principles of self-discharge processes in carbon-based ECs, particularly examining the nature of the process and the involvement of redox reactions. This study delineates the potential conditions for various self-discharge processes and proposes plausible criteria for differentiation, complemented by mathematical modeling. Additionally, the model selection, curve fitting, and effective tuning methods are explored to control self-discharge processes.

6.
Anal Biochem ; 692: 115557, 2024 Sep.
Artículo en Inglés | MEDLINE | ID: mdl-38718955

RESUMEN

Cytochrome c (cyt c) has been found to play a function in apoptosis in cell-free models. This work presents the creation of molecularly imprinted conducting poly(3, 4-ethylenedioxythiopene) (MIPEDOT) on the surface of a screen printed carbon electrode (SPCE) for cyt c. Cyt c was imprinted by electropolymerization due to the presence of an EDOT monomer hydrophobic functional group on SPCE, using CV to obtain highly selective materials with excellent molecular recognition ability. MIPEDOT was characterized by CV, EIS, and DPV using ferricyanide/ferrocyanide as a redox probe. Further, the characterization of the sensor was accomplished using SEM for surface morphological confirmation. Using CV, the peak current measured at the potential of +1 to -1 V (vs. Ag/AgCl) is linear in the cyt c concentration range from 1 to 1200 pM, showing a remarkably low detection limit of 0.5 pM (sensitivity:0.080 µA pM). Moreover, the applicability of the approach was successfully confirmed with the detection of cyt c in biological samples (human plasma). Similarly, our research has proven a low-cost, simple, and efficient sensing platform for cyt c detection, rendering it a viable tool for the future improvement of reliable and exact non-encroaching cell death detection.


Asunto(s)
Compuestos Bicíclicos Heterocíclicos con Puentes , Carbono , Citocromos c , Técnicas Electroquímicas , Electrodos , Polímeros , Citocromos c/análisis , Citocromos c/química , Polímeros/química , Carbono/química , Técnicas Electroquímicas/métodos , Compuestos Bicíclicos Heterocíclicos con Puentes/química , Polímeros Impresos Molecularmente/química , Humanos , Límite de Detección , Impresión Molecular , Técnicas Biosensibles/métodos
7.
Nanotechnology ; 35(20)2024 Feb 28.
Artículo en Inglés | MEDLINE | ID: mdl-38346336

RESUMEN

All-inorganic CsPbI2Br, as a promising photovoltaic (PV) material, have attracted extensive research attention in society for its outstanding thermal stability and appropriate trade-offs. Carbon-based perovskite solar cells (C-PSCs) without hole transporting layer (HTL) have shown great potential in terms of cost-effectiveness and stability. However, the inevitable defects on the surface of CsPbI2Br films severely hampers the development of high-efficiency CsPbI2Br C-PSCs. Surface engineering has emerged an effective approach to overcome this challenge. Herein, 1-decyl-3-methylimidazolium tetrafluoroborate (DMTT) ionic liquid was introduced between CsPbI2Br and carbon electrode to reduce non-recombination of charges, decrease defect states, minimize the energy-level mismatch, and greatly enhance the device stability. As a result, the HTL-free CsPbI2Br C-PSCs combined with DMTT as an interface modification achieved a higher power conversion efficiency (PCE) of 12.47% than that of the control devices with a PCE of 11.32%. Furthermore, without any encapsulation, the DMTT-optimized C-PSC remained approximately 84% of its initial PCE after over 700 h under room temperature and 25% relative humidity (RH) conditions. Additionally, when exposed to a temperature of 65 °C for over 400 h, the device still retained 74% of the initial PCE, demonstrating its thermal stability.

8.
Anal Bioanal Chem ; 416(21): 4679-4690, 2024 Sep.
Artículo en Inglés | MEDLINE | ID: mdl-38664267

RESUMEN

Prototyping analytical devices with three-dimensional (3D) printing techniques is becoming common in research laboratories. The attractiveness is associated with printers' price reduction and the possibility of creating customized objects that could form complete analytical systems. Even though 3D printing enables the rapid fabrication of electrochemical sensors, its wider adoption by research laboratories is hindered by the lack of reference material and the high "entry barrier" to the field, manifested by the need to learn how to use 3D design software and operate the printers. This review article provides insights into fused deposition modeling 3D printing, discussing key challenges in producing electrochemical sensors using currently available extrusion tools, which include desktop 3D printers and 3D printing pens. Further, we discuss the electrode processing steps, including designing, printing conditions, and post-treatment steps. Finally, this work shed some light on the current applications of such electrochemical devices that can be a reference material for new research involving 3D printing.

9.
Environ Res ; 251(Pt 1): 118648, 2024 Jun 15.
Artículo en Inglés | MEDLINE | ID: mdl-38462090

RESUMEN

The existence of multiple pesticide residues in fruits and vegetables constitutes a direct peril to living organisms. Therefore, it is crucial to develop a low-cost screening method for determining organophosphate pesticides (OPPs) in food samples. This study describes the solvothermal synthesis of a ternary composite comprising multi-walled carbon nanotubes (MWCNT), zirconium oxide, and a zirconium-metal-organic framework (Zr-MOF). The ternary composite was characterised using XRD, FESEM, FTIR, and BET. The ternary composite provides a large surface area (1158 m2/g) compared with the pristine Zr-MOF (868 m2/g). The composite-modified glassy carbon electrode was used to determine nine pesticides, including organophosphate (malathion, dimethoate, chlorpyrifos, monocrotophos, and glyphosate) and non-organophosphate (thiophanate methyl, carbendazim, atrazine, and 2,4, D). In particular, various chemical combinations of OPPs were selected, such as S-P=S, P=S, P=O, and non-OPPs such as C=S (with sulphur), and without sulphur. The sensor results show that the sensor selectivity is high for OPPs containing both phosphorus and sulphur molecules. The low detection limit of the sensor was 2.02, 2.8, 2.5, 1.11, and 2.01 nM for malathion, chlorpyrifos, dimethoate, monocrotophos, and glyphosate, respectively. The electrode exhibited significant chemical stability (93%) after 100 cycles, good repeatability, and a long shelf life. The sensor is reliable for qualitative real-time applications.


Asunto(s)
Nanotubos de Carbono , Plaguicidas , Circonio , Circonio/química , Plaguicidas/análisis , Nanotubos de Carbono/química , Técnicas Electroquímicas/métodos , Técnicas Electroquímicas/instrumentación , Compuestos Organofosforados/análisis , Compuestos Organofosforados/química
10.
Mikrochim Acta ; 191(9): 508, 2024 08 05.
Artículo en Inglés | MEDLINE | ID: mdl-39102114

RESUMEN

A solid-state electrochemiluminescence (ECL) sensor was fabricated by immobilizing luminol, a classical luminescent reagent, on a Zn-Co-ZIF carbon fiber-modified electrode for the rapid and sensitive detection of procymidone (PCM) in vegetable samples. The sensor was created by sequentially modifying the glassy carbon electrode with Zn-Co-ZIF carbon fiber (Zn-Co-ZIF CNFs), Pt@Au NPs, and luminol. Zn-Co-ZIF CNFs, prepared through electrospinning and high-temperature pyrolysis, possessed a large specific surface area and porosity, making it suitable as carrier and electron transfer accelerator in the system. Pt@Au NPs demonstrated excellent catalytic activity, effectively enhancing the generation of active substances. The ECL signal was significantly amplified by the combination of Zn-Co-ZIF CNFs and Pt@Au NPs, which can subsequently be diminished by procymidone. The ECL intensity decreased proportionally with the addition of procymidone, displaying a linear relationship within the concentration range 1.0 × 10-13 to 1.0 × 10-6 mol L-1 (R2 = 0.993). The sensor exhibited a detection limit of 3.3 × 10-14 mol L-1 (S/N = 3) and demonstrated outstanding reproducibility and stability, making it well-suited for the detection of procymidone in vegetable samples.


Asunto(s)
Cobalto , Técnicas Electroquímicas , Oro , Límite de Detección , Mediciones Luminiscentes , Luminol , Verduras , Zinc , Luminol/química , Verduras/química , Técnicas Electroquímicas/métodos , Técnicas Electroquímicas/instrumentación , Mediciones Luminiscentes/métodos , Zinc/química , Oro/química , Cobalto/química , Nanopartículas del Metal/química , Platino (Metal)/química , Carbono/química , Electrodos , Sustancias Luminiscentes/química , Contaminación de Alimentos/análisis , Reproducibilidad de los Resultados
11.
Mikrochim Acta ; 191(9): 549, 2024 08 20.
Artículo en Inglés | MEDLINE | ID: mdl-39162737

RESUMEN

An intense cathodic electrochemiluminescence (ECL) is reported from a polarized glassy carbon electrode (GCE) in peroxydisulfate solution. After the polarization in 1 M Na2SO4 at the potential of - 3.7 V for 3 s, carbon nanosheets (C-NSs) were in situ grown on the surface of the GCE. Measured in 100 mM K2S2O8 solution, the ECL intensity of the GCE/C-NSs is 112-fold that of a bare GCE. The ECL spectrum revealed that the true ECL luminophore in the GCE/C-NSs-peroxydisulfate system is O2/S2O82- which is promoted by C-NSs. When Cu2+ was electrochemically enriched and reduced to Cu(0) on the catalytic sites of C-NSs, the ECL from GCE/C-NSs/Cu in K2S2O8 solution was decreased with increasing logarithmic concentration of Cu2+ in the range from 10 pM to 1 µM, with a limit of detection (LOD) of 3 pM. An immunoanalysis method is proposed via a biometallization strategy using CuS nanoparticles as the tags and carcinoembryonic antigen (CEA) as the model analyte. After the immune recognition in the microplate, the CuS tags in the immunocomplex were dissolved and the resultant Cu2+ was electrochemically enriched and reduced on the catalytic sites of C-NSs, quenching the ECL intensity of GCE/C-NSs-O2/S2O82- system. The proposed ECL immunoanalysis method was used to quantify CEA in actual serum samples with an LOD of 1.0 fg mL-1, possessing the advantages of simple electrode modification, high sensitivity and good reproducibility.


Asunto(s)
Carbono , Antígeno Carcinoembrionario , Cobre , Técnicas Electroquímicas , Electrodos , Mediciones Luminiscentes , Carbono/química , Mediciones Luminiscentes/métodos , Técnicas Electroquímicas/métodos , Técnicas Electroquímicas/instrumentación , Antígeno Carcinoembrionario/sangre , Antígeno Carcinoembrionario/inmunología , Antígeno Carcinoembrionario/análisis , Cobre/química , Límite de Detección , Humanos , Nanoestructuras/química , Inmunoensayo/métodos , Sulfato de Cobre/química , Nanopartículas del Metal/química , Vidrio/química , Sulfatos/química
12.
Mikrochim Acta ; 191(9): 550, 2024 08 21.
Artículo en Inglés | MEDLINE | ID: mdl-39167218

RESUMEN

A novel bacteriophage-targeted electrochemical biosensor designed for accurate and quantitative detection of live Salmonella in food samples is presented. The biosensor is simply constructed by electrostatic immobilizing bacteriophages on MXene-nanostructured electrodes. MXene, renowned for its high surface area, biocompatibility, and conductivity, serves as an ideal platform for bacteriophage immobilization. This allows for a high-density immobilization of bacteriophage particles, achieving approximately 71 pcs µm-2. Remarkably, the bacteriophages immobilized MXene nanostructured electrodes still maintain their viability and functionality, ensuring their effectiveness in pathogen detection. Therefore, the proposed biosensor exhibited enhanced sensitivity with a low limit of detection (LOD) of 5 CFU mL-1. Notably, the biosensor shows excellent specificity in the presence of other bacteria that commonly contaminate food and can distinguish live Salmonella from a mixed population. Furthermore, it is applicable in detecting live Salmonella in food samples, which highlights its potential in food safety monitoring. This biosensor offers simplicity, convenience, and suitability for resource-limited environments, making it a promising tool for on-site monitoring of foodborne pathogenic bacteria.


Asunto(s)
Técnicas Biosensibles , Técnicas Electroquímicas , Microbiología de Alimentos , Límite de Detección , Azul de Metileno , Salmonella , Electricidad Estática , Técnicas Biosensibles/métodos , Técnicas Electroquímicas/métodos , Salmonella/aislamiento & purificación , Salmonella/virología , Microbiología de Alimentos/métodos , Azul de Metileno/química , Bacteriófagos/química , Electrodos , Contaminación de Alimentos/análisis , Nanoestructuras/química
13.
Mikrochim Acta ; 191(8): 500, 2024 08 01.
Artículo en Inglés | MEDLINE | ID: mdl-39088046

RESUMEN

Detecting lipopolysaccharide (LPS) using electrochemical methods is significant because of their exceptional sensitivity, simplicity, and user-friendliness. Two-dimensional metal-organic framework (2D-MOF) that merges the benefits of MOF and 2D nanostructure has exhibited remarkable performance in constructing electrochemical sensors, notably surpassing traditional 3D-MOFs. In this study, Cu[tetrakis(4-carboxylphenyl)porphyrin] (Cu-TCPP) and Cu(tetrahydroxyquinone) (Cu-THQ) 2D nanosheets were synthesized and applied on a glassy carbon electrode (GCE). The 2D-MOF nanosheets, which serve as supporting layers, exhibit improved electron transfer and electronic conductivity characteristics. Subsequently, the modified electrode was subjected to electrodeposition with Au nanostructures, resulting in the formation of Au/Cu-TCPP/GCE and Au/Cu-THQ/GCE. Notably, the Au/Cu-THQ/GCE demonstrated superior electrochemical activity because of the 2D morphology, redox ligand, dense Cu sites, and improved deposition of flower-like Au nanostructure based on Cu-THQ. The electron transfer specific surface area was increased by the improved deposition of Au nanostructures, which facilitates enriched binding of LPS aptamer and significantly improved the detection performance of Apt/Au/Cu-THQ/GCE electrochemical aptasensor. The limit of detection for LPS reached 0.15 fg/mL with a linear range of 1 fg/mL - 100 pg/mL. The proposed aptasensor demonstrated the ability to detect LPS in serum samples with satisfactory accuracy, indicating significant potential for clinical diagnosis.


Asunto(s)
Aptámeros de Nucleótidos , Técnicas Biosensibles , Cobre , Técnicas Electroquímicas , Oro , Límite de Detección , Lipopolisacáridos , Estructuras Metalorgánicas , Estructuras Metalorgánicas/química , Oro/química , Cobre/química , Técnicas Electroquímicas/métodos , Lipopolisacáridos/análisis , Lipopolisacáridos/sangre , Aptámeros de Nucleótidos/química , Técnicas Biosensibles/métodos , Nanopartículas del Metal/química , Electrodos , Nanoestructuras/química , Porfirinas/química , Humanos
14.
Mikrochim Acta ; 191(10): 570, 2024 09 02.
Artículo en Inglés | MEDLINE | ID: mdl-39218927

RESUMEN

Loofah sponge-like carbon nanofibers (LF-Co,N/CNFs) were utilized as a carrier for Ru(bpy)32+, and then combined with CdS to create a novel solid-state electrochemiluminescence sensor capable of detecting trace amounts of fenpropathrin. LF-Co,N/CNFs, obtained through the high-temperature pyrolysis of ZIF-67 coaxial electrospinning fibers, were characterized by a loofah-like morphology and exhibited a significant specific surface area and porosity. Apart from serving as a carrier, LF-Co,N/CNFs also functioned as a luminescence accelerator, enhancing the system's luminescence efficiency by facilitating electron transmission and reducing the transmission distance. The inclusion of CdS in the luminescence reaction, in conjunction with Ru(bpy)32+, further boosted the sensor's luminescence signal. The resulting sensor demonstrated a satisfactory signal, with fenpropathrin causing significant quenching of the ECL signal. Under optimized conditions, a linear relationship between the signal quench value and fenpropathrin concentration in the range 1 × 10-12 to 1 × 10-6 M was observed, with a detection limit of 3.3 × 10-13 M (S/N = 3). This developed sensor is characterized by its simplicity, sensitivity, and successful application in detecting fenpropathrin in real samples. The study not only presents a straightforward detection platform for fenpropathrin but also introduces new avenues for the rapid determination of various food contaminants, thereby expanding the utility of carbon fibers in electrochemiluminescence sensors.


Asunto(s)
Carbono , Técnicas Electroquímicas , Límite de Detección , Mediciones Luminiscentes , Nanofibras , Nanofibras/química , Mediciones Luminiscentes/métodos , Carbono/química , Técnicas Electroquímicas/métodos , Técnicas Electroquímicas/instrumentación , Animales , Contaminación de Alimentos/análisis , Compuestos de Cadmio/química , Piretrinas/análisis , Compuestos Organometálicos
15.
Mikrochim Acta ; 191(10): 611, 2024 Sep 21.
Artículo en Inglés | MEDLINE | ID: mdl-39304581

RESUMEN

A novel electrochemical sensor is constructed by modifying the glassy carbon electrode (GCE) using a binder-free metal-organic framework of V-shaped linker 4,4'oxybis(benzoic acid) (OBA) and various transition metals (M-Zn, Mn, or Ni). The hydrothermally synthesized M-OBA MOFs demonstrated superior electron transfer ability and enhanced electro-reduction behaviour, making it highly effective for metronidazole (MTZ) detection. The optimized sensor demonstrated a linear response from 0.04 to 122.18 µM, a low detection limit (LOD) of 0.009 µM, and high sensitivity (0.48 µA µM-1 cm-2) using cyclic voltammetry (CV) and differential pulse voltammetry (DPV). The sensor also exhibited excellent selectivity in the presence of various ions, organic compounds, and other antibiotics. The Zn-OBA MOF sensor proves practical applicability for detecting MTZ in milk, honey, tap water, and MTZ tablets.

16.
Mikrochim Acta ; 191(8): 460, 2024 07 10.
Artículo en Inglés | MEDLINE | ID: mdl-38987355

RESUMEN

The facile sonochemical synthesis is reported of zinc cobalt oxide (ZnCo2O4) composited with carbon nanofiber (CNF). Structural, chemical, and morphological were characterized by X-ray diffraction (XRD), X-ray photoluminescent spectroscopy (XPS), field emission scanning electron microscopy (FESEM), and transmittance electron microscopy (TEM), respectively. ZnCo2O4/CNF-modified GCE was applied to the detection of bisphenol A (BPA). The modified GCE shows enhanced sensing performance towards BPA, which includes a linear range (0.2 to 120 µM L-1) alongside a low limit of detection (38.2 nM L-1), low interference, and good stability. Detection of lower concentrations of BPA enables real sample analysis in the food industries (milk, orange juice, yogurt, tap water, and baby feeding bottles). Surprisingly, the BPA was detected in milk 510 nM L-1, orange juice 340 nM L-1, yogurt 1050 nM L-1, and tap water 140 nM L-1. Moreover, an interaction mechanism between the BPA analyte and ZnCo2O4 was discussed.


Asunto(s)
Compuestos de Bencidrilo , Carbono , Cobalto , Leche , Nanofibras , Fenoles , Compuestos de Bencidrilo/análisis , Fenoles/análisis , Fenoles/química , Cobalto/química , Carbono/química , Leche/química , Nanofibras/química , Contaminación de Alimentos/análisis , Animales , Óxidos/química , Límite de Detección , Técnicas Electroquímicas/métodos , Jugos de Frutas y Vegetales/análisis , Tecnología Química Verde/métodos , Yogur/análisis
17.
Mikrochim Acta ; 191(8): 492, 2024 07 27.
Artículo en Inglés | MEDLINE | ID: mdl-39066907

RESUMEN

The development and application of an electrochemical sensor is reported for detection of poly(3-hydroxybutyrate) (P3HB) - a bioplastic derived from agro-industrial residues. To overcome the challenges of molecular imprinting of macromolecules such as P3HB, this study employed methanolysis reaction to break down the P3HB biopolymer chains into methyl 3-hydroxybutyrate (M3HB) monomers. Thereafter, M3HB were employed as the target molecules in the construction of molecularly imprinted sensors. The electrochemical device was then prepared by electropolymerizing a molecularly imprinted poly (indole-3-acetic acid) thin film on a glassy carbon electrode surface modified with reduced graphene oxide (GCE/rGO-MIP) in the presence of M3HB. Electrochemical impedance spectroscopy (EIS), cyclic voltammetry (CV), scanning electron microscopy with field emission gun (SEM-FEG), Raman spectroscopy, attenuated total reflection Fourier-transform infrared (ATR-FTIR) and X-ray Photoelectron Spectroscopy (XPS) were employed to characterize the electrode surface. Under ideal conditions, the MIP sensor exhibited a wide linear working range of 0.1 - 10 nM and a detection limit of 0.3 pM (n = 3). The sensor showed good repeatability, selectivity, and stability over time. For the sensor application, the bioproduction of P3HB was carried out in a bioreactor containing the Burkholderia glumae MA13 strain and sugarcane byproducts as a supplementary carbon source. The analyses were validated through recovery assays, yielding recovery values between 102 and 104%. These results indicate that this MIP sensor can present advantages in the monitoring of P3HB during the bioconversion process.


Asunto(s)
Burkholderia , Técnicas Electroquímicas , Electrodos , Grafito , Hidroxibutiratos , Polímeros Impresos Molecularmente , Poliésteres , Grafito/química , Poliésteres/química , Hidroxibutiratos/química , Burkholderia/química , Burkholderia/metabolismo , Técnicas Electroquímicas/métodos , Técnicas Electroquímicas/instrumentación , Polímeros Impresos Molecularmente/química , Límite de Detección , Oxidación-Reducción , Polihidroxibutiratos
18.
Mikrochim Acta ; 191(3): 143, 2024 02 17.
Artículo en Inglés | MEDLINE | ID: mdl-38368295

RESUMEN

An enzyme immunoassay was developed based on the coulometric measurement of immunoglobulin M (IgM) against Hantaan viruses (HTNV) by using virus-like particles (VLPs) as recognition molecules. The surface functionalization of screen-printed carbon electrodes (SPCEs) was achieved through paste-exfoliated graphene that was modified with a COOH group and a thionine mediator through supramolecular-covalent scaffolds, on SPCEs by using the binder contained in the ink. After the covalent immobilization of the antibody, the sensor was used for the sandwich enzyme immunoassay of IgM against HTNV. By using HTNV VLPs as the second recognization molecules, the resulting sensor efficiently monitored the reaction of IgM against HTNV and anti-IgM antibody with high specificity. By attaching HTNV nucleocapsid protein antibody conjugate with horseradish peroxidase (HRP) onto VLPs, the signal response of the assay was derived from the coulometric measurement of H2O2 reduction mediated by thionine on the electrode surface after the application of a potential (- 0.2 V vs. Ag/AgCl). The ratio of charges measured before or after H2O2 addition was used to quantify IgM because these charges could be used as background charges or total charges, respectively. The ratio exhibited good agreement with IgM concentration within a range 0.1 to 1000 pg mL-1, and a detection limit of 0.06 pg mL-1 was obtained. The assay demonstrated high sensitivity and specificity toward HTNV-specific IgM in serum.


Asunto(s)
Técnicas Biosensibles , Grafito , Fenotiazinas , Grafito/química , Carbono/química , Inmunoensayo/métodos , Técnicas Biosensibles/métodos , Peróxido de Hidrógeno/química , Inmunoglobulina M , Electrodos
19.
Mikrochim Acta ; 191(5): 245, 2024 Apr 05.
Artículo en Inglés | MEDLINE | ID: mdl-38578313

RESUMEN

An electrochemical sensor is established using an iron titanate (FeTiO3) modified glassy carbon electrode (GCE) to detect nitrofurazone. Various microscopic and spectroscopic analysis was performed to reveal the properties of the prepared FeTiO3 hexagonal nanoplates. The FeTiO3/GCE presents enhanced electrochemical response to nitrofurazone at the peak reduction potential of - 0.471 V with a larger peak current than the bare GCE due to high electrical conductivity, enhanced specific surface area, and abundant active sites. The superior nitrofurazone detection performance includes the low limit of detection of 0.002 µM and the sensitivity of 0.551 µA µM-1 cm-2 in the linear concentration range of 0.01-162.2 µM. The reproducibility and selectivity studies of the FeTiO3/GCE show excellent results with a relative standard deviation of < 5%. The practicability of FeTiO3/GCE is confirmed by monitoring nitrofurazone in actual samples. This work demonstrates that perovskite-type FeTiO3 has great potential in real-world sample analysis, and provides a new way to develop high-performance electrochemical sensors.

20.
Mikrochim Acta ; 191(5): 247, 2024 04 08.
Artículo en Inglés | MEDLINE | ID: mdl-38587580

RESUMEN

Alumina inorganic molecularly imprinted polymer (MIP) modified multi-walled carbon nanotubes (MWCNTs) on a glassy carbon electrode (MWCNTs-Al2O3-MIP/GCE) was firstly designed and fabricated by one-step electro deposition technique for the detection of uric acid (UA) in sweat. The UA templates were embedded within the inorganic MIP by co-deposition with Al2O3. Through the evaluation of morphology and structure by Field Emission Scanning Electron Microscope (SEM), Energy Dispersive X-ray Spectroscopy (EDS), X-ray Photoelectron Spectroscopy (XPS) and Transmission Electron Microscopy (TEM), it was verified that the specific recognition sites can be fabricated in the electrodeposited Al2O3 molecular imprinted layer. Due to the high selectivity of molecular imprinting holes, the MWCNTs-Al2O3-MIP/GCE electrode demonstrated an impressive imprinting factor of approximately 2.338 compared to the non-molecularly imprinted glassy carbon electrode (MWCNTs-Al2O3-NIP/GCE) toward uric acid detection. Moreover, it exhibited a remarkable limit of detection (LOD) of 50 nM for UA with wide detection range from 50 nM to 600 µM. The MWCNTs-Al2O3-MIP/GCE electrode also showed strong interference resistance against common substances found in sweat. These results highlight the excellent interference resistance and selectivity of MWCNTs-Al2O3-MIP/GCE sensor, positioning it as a novel sensing platform for non-invasive uric acid detection in human sweat.


Asunto(s)
Nanotubos de Carbono , Fosfatos , Sudor , Humanos , Polímeros Impresos Molecularmente , Ácido Úrico , Óxido de Aluminio
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