Selective detection of salivary cortisol using screen-printed electrode coated with molecularly imprinted polymer

A novel electrochemical sensor was developed for the detection of salivary cortisol levels. The sensor employs a combination of a molecularly imprinted polymer (MIP) and gold nanoparticles (AuNPs) that are electrodeposited onto a screen-printed electrode (SPE). The study utilised density functional theory and molecular docking techniques to determine the geometry of molecular orbitals, electrostatic potential energies, and binding energy of cortisol and the polymers. The thin film of cortisol-imprinted polymer on the SPE was created by electro-polymerizing pyrrole and thiophene-3-carboxylic acid on the electrode surface along with cortisol as the template molecule. The MIP film was characterised using scanning electron microscopy (SEM), Fourier-transform infrared spectroscopy (FTIR), and electrochemical techniques. The sensor exhibited a linear response in the concentration range of 0.05 nmol L-1 to 2.5 μmol L-1, with a limit of detection of 0.01 nmol L-1, as determined by differential pulse voltammetry. This method offers a simple yet efficient and sensitive approach to detecting cortisol levels in human saliva samples.

Role of Statins on Cognition and Section Memory: A Case-control Study

Introduction: Statins are a class of lipid lowering medication which can effectively lower cardiovascular mortality and morbidity by the beneficial effects in atherosclerotic cardiovascular disease. Recently, there are increasing concerns over the relationship between statins and cognitive deficits. On the contrary, some studies have indicated an improvement in memory functions with the use of statins. However, the impact of statins on cognition is still unclear. Aim: To analyse the effect of statins on cognition and memory using Mini-Mental Scale Examination (MMSE). Materials and Methods: The case control study was conducted in Department of Cardiology at PSG Institute of Medical Sciences and Research, Coimbatore, Tamil Nadu, India (tertiary care teaching hospital), from June 2019 to December 2019. Out of total 127 participants, case group included 63 adult patients of both gender, on statin therapy for at least 12 weeks duration and control group included 64 age and gender matched adults who were not on statin therapy. After obtaining a written informed consent, MMSE questionnaire was administered by a trained blinded interviewer to both groups. Pearson’s correlation was done to evaluate any significant correlation between duration of statin therapy with MMSE and individual domain scores. Data was analysed using Statistical Package for Social Sciences (SPSS) version 24.0, and p-value <0.05 was considered significant. Results: The mean age of the cases was 61.1±7.90 years, and that of the control group was 60.6±7.68 years. Using the cut-off score of 23 to diagnose dementia, 21 (33.3%) cases and 24 (37.5%) control participants had cognitive deficits, with no statistically significant difference. The mean score of patients on statin therapy for more than one year (26.45±3.03) was higher compared to those with less than or equal to one year duration of therapy (24.48±4.11), but did not reach statistical significance. But, statistically significant difference between mean scores of cases and controls was evident in cognitive domains like registration (p-value=0.01) and recall (p-value=0.04) in addition to a significant correlation (p-value=0.03) between the duration of statin therapy and orientation score. Conclusion: This study refutes the possibility of an association of statin therapy with cognitive decline in the study population. On the other hand, the results are illustrative of a potential cognitive benefit with the use of statins.

Dose-Dependent Molecular Responses of Labeo rohita to Triphenyl Phosphate

Triphenyl phosphate (TPhP) is a broad-spectrum organophosphate compound widely used as an additive in several products to prevent ignition. However, its utilization produces a hazardous impact on various organisms. So far, very few studies have investigated the acute toxicity of TPhP at environmentally relevant concentrations in nontarget aquatic species. This study aimed to assess whether the short-term exposure of TPhP (4, 20, and 100 μg L^-1) affects the oxidative stress, antioxidant activity, biomolecule metabolism, DNA stability, chromosomal integrity, apoptosis, and pathological changes in various organs of Labeo rohita fingerlings. The results illustrated that the reactive oxygen species (ROS) production and lipid peroxidation (LPO) rates were significantly higher in tissues (brain, liver, and kidney) of TPhP-treated groups. Interestingly, superoxide dismutase (SOD) and catalase (CAT) activities were remarkably decreased in tissues following TPhP exposure. The levels of protein, glucose, total cholesterol (TC), triglycerides (TG), low-density lipoprotein (LDL), and high-density lipoprotein (HDL) in various tissues were also found to be significantly altered in TPhP-exposed fish fingerlings. These significant alterations in the antioxidant system and biochemical profile induced genotoxic responses such as DNA and chromosomal damage in the fish fingerlings. Furthermore, the incidence of the observed genotoxic responses was also found to be dose-dependent. Likewise, the apoptotic responses were also significantly altered following TPhP acute exposure in L. rohita fingerlings. The subsequent effects on oxidative stress, antioxidant inhibition, dysregulated biomolecule metabolism, and genotoxicity might be the possible reason for the observed pathological changes in various tissues of L. rohita. Taken together, the present findings showed that the toxicity of TPhP is principally associated with exposure concentrations. Therefore, this study illustrates the toxicity risks of TPhP to vertebrate organisms at real-world concentrations.

Molecularly imprinted polymer-based electrochemical sensor for the determination of endocrine disruptor bisphenol-A in bovine milk

Bisphenol A (BPA) contamination from food packaging material has been a major concern in recent years, due to its potential endocrine-disrupting effects on humans, especially infants and children. This paper reports the detection of BPA using an electrochemical sensor based on molecularly imprinted polymer (MIP). Electrochemically reduced graphene oxide coated glassy carbon electrode used for this study. Density functional theory (DFT) at B3LYP/6-31 + G (d,p) level was used to calculate the molecular-level interaction between BPA and MIP. The pyrrole electrochemically polymerized in the presence of template molecule BPA on the electrode surface. BPA imprinted cavities were formed by removing entrapped BPA molecules from the polypyrrole film. MIP electrode was used for the determination of BPA in standard and real samples by differential pulse voltammetry. The peak current shows the linear relationship to the logarithmic concentration of BPA between 750 and 0.5 nmolL^-1 with a correlation coefficient, R² = 0.992. The limit of detection was found to be 0.2 nmolL^-1 (S/N = 3). The reproducibility and repeatability of the sensor were also studied.

A simple and efficient Agrobacterium-mediated in planta transformation protocol for horse gram (Macrotyloma uniflorum Lam. Verdc.)

Background

Recalcitrant nature is a major constraint for the in vitro regeneration and genetic transformation of leguminous species members. Therefore, an improved genetic transformation in horse gram has been developed via in planta method, in which Agrobacterium strain harboring binary vector pCAMBIA2301 was used for the transformation. Several factors affecting in planta transformations were put forth viz. Agrobacterium cell density, co-cultivation, and sonication combined with vacuum infiltration duration which were optimized.

Results

Germinated seeds were sonicated and vacuum infiltrated with different densities of Agrobacterium culture and co-cultivated in half-strength MS medium with 100 μM of acetosyringone for 48 h. Seedlings were washed with cefotaxime and sowed in vermiculite soil for maturation. T₁ plants were subjected to histochemical and molecular analysis to ensure transformation efficiency. Among various combinations analyzed, maximum transformation efficiency (20.8%) was attained with seeds of 5 min sonication combined with vacuum infiltration with 0.6 optical density of Agrobacterium culture.

Conclusions

It concludes that a different Agrobacterium cell density with sonication combined with vacuum infiltration has improved transgenic efficiency in horse gram plants. This simple and efficient method is feasible for the stable expression of foreign genes that could be beneficial for future food security.

Poly(ethylene glycol)–poly(propylene glycol)–poly(ethylene glycol) and polyvinylidene fluoride blend doped with oxydianiline-based thiourea derivatives as a novel and modest gel electrolyte system for dye-sensitized solar cell applications

Unique symmetrical thiourea derivatives with an oxydianiline core were synthesized using cost-effective and simple methods. A new gel electrolyte system was prepared using these thiourea additives along with a highly conductive PEG–PPG–PEG block copolymer, PVDF, and an iodide/triiodide redox couple. The PEG units present in the electrolyte are well-known for their intense segmental motion of ions, which can degrade the recombination rate and favour the charge transfer. The thiourea additives interacted well with the redox couple to limit iodine sublimation and their adsorption induced a negative potential shift for TiO₂. The highest efficiency attained by utilizing such gel polymer electrolytes was 5.75%, especially with 1,1′-(oxybis(4,1-phenylene))bis(3-(6-methylpyridin-2-yl) thiourea) (OPPT), under an irradiation of 100 mW cm⁻². The electrochemical impedance spectroscopy, UV-vis absorption spectroscopy, differential scanning calorimetry, and FTIR spectroscopy data of such gel polymer electrolytes favoured the PCE order of the additives used in DSSCs. The improvement in the DSSC performance with symmetrical thioureas having electron-rich atoms was practically attributed to the reduction of back electron transfer, dye regeneration, and hole transport.

A unique gel polymer electrolyte was prepared using PVDF and PEG–PPG–PEG block copolymer with I⁻/I₃⁻ for DSSC application. This is a cost-effective method used for the synthesis of thiourea additives. The GPE with OPPT thiourea additive achieved a good efficiency of 5.7%.

Synthesis and Electro-Catalytic Properties of Platinum Supported on Graphene for Methanol Oxidation

Graphene serves as excellent support material in the synthesis of metal nanoparticle-graphene electrocatalysts. Highly active and stable Pt/Graphene electrocatalysts for the application of direct methanol fuel cells were developed. The oxygen/carbon ratio of graphene supports were tuned by various chemical methods. Pt nanoparticles with a narrow distribution of particle sizes were well dispersed on graphene. An increased catalytic activity and stability were achieved due to an increased graphitization degree of graphene when the Pt/Graphene was deoxidized during Ar/H2 reduction. The activity of Pt/Graphene towards methanol oxidation reaction and its stability was higher compared to Pt/Carbon. This study suggests a bi-functional effect of both graphitization and the oxygenated groups on the catalytic activity.

Phosphorus-doped exfoliated graphene for supercapacitor electrodes

Graphene, a single atom thick carbon material with high surface area and electrical conductivity provides an ideal platform for designing high performance electrochemical devices. This paper reports the synthesis of phosphorous doped graphene from reduced graphene sheets, its characterization by scanning electron microscopy (SEM), Fourier transform infrared spectroscopy (FTIR) and Raman spectroscopy and its use for supercapacitor applications. The specific capacitance was found to be 367 Fg(-1) from electrochemical measurements. These samples show a high power density of 9 kW kg(-1) and energy density of 59 Wh kg(-1) in an aqueous electrolyte solution, which is much higher than other graphene-based supercapacitors. The phosphorus-doped graphene showed a high potential for use in low cost energy storage devices.