Correction: The role of ion solvation in lithium mediated nitrogen reduction.

[This corrects the article DOI: 10.1039/D2TA07686A.].

The role of ion solvation in lithium mediated nitrogen reduction.

Since its verification in 2019, there have been numerous high-profile papers reporting improved efficiency of lithium-mediated electrochemical nitrogen reduction to make ammonia. However, the literature lacks any coherent investigation systematically linking bulk electrolyte properties to electrochemical performance and Solid Electrolyte Interphase (SEI) properties. In this study, we discover that the salt concentration has a remarkable effect on electrolyte stability: at concentrations of 0.6 M LiClO4 and above the electrode potential is stable for at least 12 hours at an applied current density of -2 mA cm-2 at ambient temperature and pressure. Conversely, at the lower concentrations explored in prior studies, the potential required to maintain a given N2 reduction current increased by 8 V within a period of 1 hour under the same conditions. The behaviour is linked more coordination of the salt anion and cation with increasing salt concentration in the electrolyte observed via Raman spectroscopy. Time of flight secondary ion mass spectrometry and X-ray photoelectron spectroscopy reveal a more inorganic, and therefore more stable, SEI layer is formed with increasing salt concentration. A drop in faradaic efficiency for nitrogen reduction is seen at concentrations higher than 0.6 M LiClO4, which is attributed to a combination of a decrease in nitrogen solubility and diffusivity as well as increased SEI conductivity as measured by electrochemical impedance spectroscopy.

Electrochemical biosensing of 16s rRNA gene sequence of Enterococcus faecalis.

Some of microorganisms are potential pathogens that can be infectious agents under some circumstances, and development of new detection methods of the pathogens is of high interest. In the present study, an Enterococcus faecalis (E. faecalis) DNA biosensor (ef-biosensor) was fabricated to quantify the bacterium genome. A specific E. faecalis DNA probe was selected from 16S rRNA sequence of E. faecalis and immobilized on a gold electrode surface in an optimized time to fabricate the ef-biosensor. The ef-biosensor detected a synthetic target of the probe with a detection limit of 3.3 amol L-1 and with a nice selectivity to resolve from one-, two- and three-base mismatched sequences. In addition, the bacterium genomic DNA was quantified with a detection limit of 7.1 × 10-9 ng mL-1 in a concentration range of 1.1 × 10-7 to 1.1 ng mL-1. The ef-biosensor had a long time stability, good fabrication reproducibility and good regeneration ability. The ef-biosensor was successfully applied for E. faecalis detection in human samples.

A molecularly imprinted electrochemical nanobiosensor for prostate specific antigen determination.

Prostate Specific Antigen (PSA) is a biomarker employed for detection of prostate cancer. An electrochemical nanobiosensor is designed and fabricated using a molecularly imprinted polymer for the simple and fast PSA detection. The imprinted polymer served as a PSA artificial receptor fabricated by electrochemical polymerization of pyrrole on screen-printed gold electrode in the presence of PSA. PSA was a molecular template for the polymer. The fabricated nanobiosensor was evaluated by differential pulse voltammetry and using K3[Fe(CN)6]/K4[Fe(CN)6] as an electrochemical marker. The factors influencing the performance of the sensor including electropolymerization cycle umbers (to control the thickness of the polymer film) and time of PSA binding were optimized to attain the best sensitivity. The binding affinity of the nanobiosensor surface was examined by the Freundlich isotherm with Freundlich constant and exponent of 0.89 ng mL-1 and 10.93, respectively. The nanobiosensor demonstrated a fast rebinding rate and a high capacity of PSA recognition with detection limit of 2.0 pg mL-1.

Electrochemical quantitation of Leishmania infantum based on detection of its kDNA genome and transduction of non-spherical gold nanoparticles.

Detecting and monitoring the pathogens with high selectivity and sensitivity is critical for public health. In the present study, we demonstrated a specific analytical strategy for sensitive detection of Leishmania infantum genome. The developed sensor utilized toluidine blue as a hybridization indicator and a Leishmania infantum-specific capture DNA sequence immobilized on a high-surface area gold nanostructure as an electrochemical transducer. The produced analytical response was based on the hybridization of the single-stranded DNA from the target with the immobilized DNA sequence at the electrode surface. The developed DNA sensor in this study was successfully employed to detect a synthetic Leishmania infantum target sequence in a wide concentration range from 1 × 10-18 to 1 × 10-10 mol L-1 with a detection limit of 0.2 amol L-1 with the ability to discriminate the target sequence from mismatched sequences. Moreover, the designed DNA sensor showed a good reproducibility and stability during repeated regeneration and hybridization cycles. The DNA sensor could detect Leishmania infantum genome in a wide concentration range from 15 to 50 ng µL-1 with a detection limit of 29 ng µL-1. Furthermore, clinical trials confirmed the applicability of the developed DNA sensor for practical applications.

A novel and ultrasensitive electrochemical DNA biosensor based on an ice crystals-like gold nanostructure for the detection of Enterococcus faecalis gene sequence.

Bacteria, parasites and viruses are found widely in the environment as potential pathogens, and can be the source of infections. Therefore, sensitive and rapid methods for identification of the pathogens are required to achieve a better quality of life. Enterococcus faecalis commonly colonizes and threatens human health. In the present study, we demonstrate the fabrication of a novel electrochemical DNA biosensor based on electrodeposited gold nanostructures as a transducer substrate combined with toluidine blue (TB) as a redox marker. Binding of TB with the single and double stranded DNA (ssDNA and dsDNA) was shortly investigated, and based on the results, TB could discriminate between ssDNA and dsDNA. A specific thiolated ssDNA sequence was immobilized on the transducer substrate, and DNA hybridization was followed by differential pulse voltammetry. The DNA biosensor showed excellent performances with high sensitivity and good selectivity. The DNA biosensor was applied to detect a synthetic target in a linear range of 1.0 × 10-17-1.0 × 10-10 mol L-1 with a limit of detection (LOD) of 4.7 × 10-20 mol L-1. In addition, LOD of the DNA biosensor for the detection of genomic DNA was found to be 30.1 ng µL-1.

Electrochemical biosensing of influenza A subtype genome based on meso/macroporous cobalt (II) oxide nanoflakes-applied to human samples.

Meso/macroporous cobalt (II) oxide nanoflakes were electrodeposited in a one-step process in the presence of N-methylpyrrolidone. On the surface of nanoflakes, a specific single stranded DNA sequence from the genome of influenza A subtype was then immobilized to fabricate an electrochemical biosensor. Hybridization of the biosensor with complementary, non-complementary and base-mismatch sequences was electrochemically detected. The biosensor was also employed to detect complementary DNA of viral RNA in culture and human samples. The biosensor could detect the complementary sequence with a detection limit of 86.4 amol L-1 and a linear concentration range of 1.0 fmol L-1 to 1.0 nmol L-1. It also detected a complementary DNA sequence converted from viral RNA with a detection limit of 0.28 ng µL-1 in a linear concentration range of 0.5-10 ng µL-1. Low detection limit, simple method of preparation of the transducer and no needing any DNA strand modification and tag are the principal advantages of the biosensor.