Photoelectrochemical conversion for ion-selective electrodes based on CdS semiconductor film.

Background: This study presents a novel photoelectrochemical (PEC) conversion method for ion-selective electrodes (ISEs) based on CdS semiconductor film. The motivation stems from the need to enhance the sensitivity and precision of ISEs for various analytical applications.

Results: We synthesized CdS film on FTO conductive glass via a hydrothermal method and utilized this electrode as the working electrode.

Chemical Cyclic Amplification: Hydroxylamine Boosts the Fenton Reaction for Versatile and Scalable Biosensing.

Nucleic acid detection is undoubtedly one of the most important research fields to meet the medical needs of genetic disease diagnosis, cancer treatment, and infectious disease prevention. However, the practical detection methods based on biological amplification are complex and time-consuming and require highly trained operators. Herein, we report a simple, rapid, and sensitive method for the nucleic acid assay by fluorescence or naked eye using chemical cyclic amplification.

When Fluorescent Sensing Meets Electrochemical Amplifying: A Powerful Platform for Gene Detection with High Sensitivity and Specificity.

Ultrasensitive and ultraselective detection of the gene requires emergency development to meet the medical demands and infectious disease control. Herein we report a versatile and scalable method based on electrochemical-chemical-cyclic amplification (EC-CA) and fluorescence detection for ultrasensitive gene sensing. The EC-CA is achieved by an electro-Fenton reaction (EFR).

Electrochemical determination of artemisinin based on signal inhibition for the reduction of hemin.

A novel electrochemical sensor was constructed for the determination of artemisinin (ART) based on the inhibition of redox for hemin caused by ART. As far as we know, this strategy for ART determination may be proposed for the first time. In this work, untreated multi-walled carbon nanotubes were cast on the glassy carbon electrode (GCE) as conductive carrier.

Determination of hydrogen peroxide released from cancer cells by a Fe-Organic framework/horseradish peroxidase-modified electrode.

Multi-walled carbon nanotubes (MWCNTs) were used as conductive carrier on the glassy carbon electrode (GCE), and the hybrid of metal organic framework [NH-MIL-53(Fe)] and horseradish peroxidase (HRP) was prepared by simple physical mechanical mixture. The GCE modified by the above material with immobilization, namely NH-MIL-53(Fe)/HRP/MWCNTs/GCE, was used to construct an electrochemical biosensor toward HO. The results indicated that the addition of NH-MIL-53(Fe) had a good synergistic effect on the electron transfer of HRP and the detection of HO.

A "MOF-Protective-Pyrolysis" Strategy for the Preparation of Fe-N-C Catalysts and the Role of Fe, N, and C in the Oxygen Reduction Reaction in Acidic Medium.

M-N-C electrocatalysts for the oxygen reduction reaction (ORR) have been considered as the most promising alternatives to precious metal catalysts. However, the catalytic activity of M-N-C especially in an acidic medium is still unable to meet the practical requirement, and the corresponding ORR mechanism also remains unclear. Herein, an "MOF-protective-pyrolysis" strategy was adopted to synthesize an Fe-N-C catalyst (P-FeMOF@ZIF-8) with Fe-N4 as the predominant Fe species.

Reliable method for the detection of horseradish peroxidase activity and enzyme kinetics.

Enzyme-catalyzed reactions are complicated and their kinetics depend on various chemical and physical factors. In a simple enzyme-catalyzed reaction, the enzyme kinetics often involve two or more substrates. However, this complexity is often ignored when studying enzyme kinetics or determining enzyme activity.

A facile approach for synthesizing Fe-based layered double hydroxides with high purity and its exfoliation.

Transition metal (e.g., Fe, Co, Ni)-based layered double hydroxides (LDHs) and their exfoliated nanosheets have great potential applications due to their redox and magnetic properties.

Intumescent flame retardant-derived P,N co-doped porous carbon as an efficient electrocatalyst for the oxygen reduction reaction.

An intumescent flame retardant (IFR), including melamine (MA), ammonium polyphosphate (APP), and polydopamine (PDA), was utilized as the precursor to prepare P,N co-doped hierarchically porous carbon which exhibited high electrocatalytic activity and durability for the oxygen reduction reaction (ORR). This finding indicates that an ingenious design of the precursor can lead to functional carbon materials using a simple process.

Selecting water-alcohol mixed solvent for synthesis of polydopamine nano-spheres using solubility parameter.

The solvent plays an important role in a given chemical reaction. Since most reaction in nature occur in the mixed-solvent systems, a comprehensive principle for solvent optimization was required. By calculating the Hansen solubility parameters (HSP) distance Ra, we designed a model experiment to explore the influence of mixed solvents on the chemical synthesis.

Horseradish peroxidase immobilization on carbon nanodots/CoFe layered double hydroxides: direct electrochemistry and hydrogen peroxide sensing.

Carbon nanodots and CoFe layered double hydroxide composites (C-Dots/LDHs) were prepared via simply mixing C-Dots and CoFe-LDHs. The as-prepared composites were used for the immobilization of horseradish peroxidase (HRP) on the glass carbon (GC) electrode. The electrochemical behavior of the HRP/C-Dots/LDHs/GC electrode and its application as a H2O2 biosensor were investigated.

Bifunctional polydopamine@Fe3O4 core-shell nanoparticles for electrochemical determination of lead(II) and cadmium(II).

The present paper has focused on the potential application of the bifunctional polydopamine@Fe3O4 core-shell nanoparticles for development of a simple, stable and highly selective electrochemical method for metal ions monitoring in real samples. The electrochemical method is based on electrochemical preconcentration/reduction of metal ions onto a polydopamine@Fe3O4 modified magnetic glassy carbon electrode at -1.1 V (versus SCE) in 0.

MgFe-layered double hydroxide modified electrodes for direct electron transfer of heme proteins.

In this study, the Fe-based layered double hydroxides (Mg(3)Fe LDH) were used to immobilize heme proteins including hemoglobin (Hb), myoglobin (Mb) and horseradish peroxidase (HRP) for fabrication of heme/Mg(3)Fe LDH film on glassy carbon electrode (Mg(3)Fe-heme/GCE). The possible role of iron in framework of LDH to promote direct electron transfer (DET) of heme proteins was investigated using an LDH containing non-iron as a reference. Hb was selected as a model protein for studying the electrocatalytic activity of immobilized heme in LDH film.

Multifunctional carbon nanotubes for direct electrochemistry of glucose oxidase and glucose bioassay.

Polydopamine (Pdop) has recently been shown to adsorb to a wide variety of surfaces and serves as an adhesion layer to immobilize biological molecules. In this work, the multifunctional carbon nanotube (CNT) composites were prepared though the oxidation of dopamine at room temperature and subsequent electroless silver deposition by mildly stirring. The stable immobilization and direct electron transfer of glucose oxidase were achieved on the composite film modified glassy carbon electrode.

A DNA hybridization detection based on fluorescence resonance energy transfer between dye-doped core-shell silica nanoparticles and gold nanoparticles.

A novel and efficient method to evaluate the DNA hybridization based on a fluorescence resonance energy transfer (FRET) system, with fluorescein isothiocyanate (FITC)-doped fluorescent silica nanoparticles (SiNPs) as donor and gold nanoparticles (AuNPs) as acceptor, has been reported. The strategy for specific DNA sequence detecting is based on DNA hybridization event, which is detected via excitation of SiNPs-oligonucleotide conjugates and energy transfer to AuNPs-oligonucleotide conjugates. The proximity required for FRET arises when the SiNPs-oligonucleotide conjugates hybridize with partly complementary AuNPs-oligonucleotide conjugates, resulting in the fluorescence quenching of donors, SiNPs-oligonucleotide conjugates, and the formation of a weakly fluorescent complex, SiNPs-dsDNA-AuNPs.

Enantioselective heterocyclic synthesis of spiro chromanone-thiochroman complexes catalyzed by a bifunctional indane catalyst.

Novel asymmetric domino reactions of benzylidenechroman-4-ones and 2-mercaptobenzaldehydes for efficient construction of spiro chromanone-thiochroman complexes were accomplished with high yields and excellent selectivities via a novel bifunctional indane catalyst.

The electrochemical behavior and direct determination of tyrosine at a glassy carbon electrode modified with poly (9-aminoacridine).

9-Aminoacridine was firstly immobilized on the surface of a glassy carbon electrode to form a poly (9-aminoacridine) film modified electrode. The results demonstrated that the modified electrode exhibited a high degree of catalytic activity towards the oxidation of tyrosine and can resolve the interference of tryptophan in the determination of tyrosine. Compared with the bare electrode, the peak current had obviously increased, and the peak potential had shifted in a negative direction.

Label-free electrochemical detection of DNA using ferrocene-containing cationic polythiophene and PNA probes on nanogold modified electrodes.

A label-free electrochemical method for the detection of DNA-PNA hybridization using a water-soluble, ferrocene-functionalized polythiophene transducer and single-stranded PNA probes on the nanogold modified electrode is investigated. Nanogold modified electrodes can largely increase the immobilization amount of ss-PNA capture probe and lead to an increase of the electrical signal. The ferrocene-containing cationic polythiophene do not interact electrostatically with the PNA probes due to the absence of the anionic phosphate groups on the PNA probes.

Study on electrochemical behavior of tryptophan at a glassy carbon electrode modified with multi-walled carbon nanotubes embedded cerium hexacyanoferrate.

Electrochemical behavior of cerium hexacyanoferrate (CeHCF) incorporated on multi-walled carbon nanotubes (MWNTs) modified GC electrode is investigated by scanning electron microscopy (SEM) and electrochemical techniques. The CeHCF/MWNT/GC electrode showed potent electrocatalytic activity toward the electrochemical oxidation of tryptophan in phosphate buffer solution (pH 7.0) with a diminution of the overpotential of 240mV.

A flow injection chemiluminescence method for the determination of fluoroquinolone derivative using the reaction of luminol and hydrogen peroxide catalyzed by gold nanoparticles.

Based on the enhancement of chemiluminescence (CL) of luminol-hydrogen peroxide-gold nanoparticles system by fluoroquinolones (FQs), a novel and rapid CL method is reported for the determination of FQs derivatives. Under the optimum conditions, the CL intensity is proportional to the concentration of FQs derivative in solution. The corresponding linear regression equations are established over the range of 0.

Simultaneous determination of uric acid and ascorbic acid at a ferrocenium-thioglycollate modified electrode.

Self-assembled monolayers (SAMS) of chemisorbed thioglycollate on a gold electrode surface have been used as a base interface for the electrostatic adsorption of ferrocenium ion. Electrochemical impedance spectra (EIS) and cyclic voltammetry (CV) were used to evaluate the electrochemical properties of the supramolecular film. The bare gold electrode failed to distinguish the oxidation peaks of ascorbic acid (AA) and uric acid (UA) in phosphate buffer solution (PBS, pH 7.

Electrochemical determination of 6-mercaptopurine at silver microdisk electrodes.

The electrochemical behaviour of 6-mercaptopurine (6-MP) at a microdisk electrode is investigated by cyclic voltammetry (CV) and electrochemical impedance spectroscopy (EIS). The results indicate that 6-MP can be strongly adsorbed on the surface of the static mercury drop electrode (SMDE) and reacts with Ag+ ions which are produced at positive potentials. 6-MP yields a well-defined cathodic stripping signal during the negative scan at about -0.

Electrocatalytical oxidation of hydroquinone with ferrocene covalently bound to L-cysteine self-assembled monolayers on a gold electrode.

The preparation of a gold electrode modified by ferrocenecarboxylic acid (FcA) covalently bound to L-cysteine self-assembled monolayer (FcA-SAM) is described. The modified electrode shows an excellent electrocatalytic activity for the oxidation of hydroquinone (QH2) and accelerates the electron transfer rate. The anodic overpotential is reduced by ca.