A comparative study of electropolymerization and photopolymerization for the determination of molnupiravir and their application in an electrochemical sensor via computationally designed molecularly imprinted polymers.

A comparative analysis of molecularly imprinted polymers based on different synthesis techniques was performed for the recognition of molnupiravir (MOL). The polymerizations were performed with 3-thienyl boronic acid (3-TBA) as a functional monomer by electropolymerization (EP) and with guanine methacrylate (GuaM) as a functional monomer by photopolymerization (PP). Morphological and electrochemical characterizations of the developed sensors were investigated to verify the constructed sensors. Moreover, quantum chemical calculations were used to evaluate changes on the electrode surface at the molecular and electronic levels. The dynamic linear range of both designed sensors under optimized experimental conditions was found to be 7.5 × 10-12-2.5 × 10-10 M and 7.5 × 10-13-2.5 × 10-11 M for EP and PP, respectively. The effect of various interfering agents on MOL peak current was assessed for the selectivity of the study. In the presence of 100 times more interfering agents, the RSD and recovery values were determined. The RSD values of GuaM/MOL@MIP/GCE and poly(Py-co-3-PBA)/MOL@MIP/GCE sensors were found to be 1.99% and 1.72%, respectively. Furthermore, the recovery values of the MIP-based sensors were 98.18-102.69% and 98.05-103.72%, respectively. In addition, the relative selectivity coefficient (k') of the proposed sensor was evaluated, and it exhibited good selectivity for MOL with respect to the NIP sensor. The prepared sensor was successfully applied to determine MOL in commercial serum samples and capsule form. In conclusion, the developed sensors provided excellent reproducibility, repeatability, high sensitivity, and selectivity against the MOL molecule.

SnO2 nanoparticles/waste masks carbon hybrid materials for DNA biosensor application on voltammetric detection of anti-cancer drug pazopanib.

This present study is the first investigation of pazopanib-dsDNA binding using bare and modified GCE. The interaction was mainly evaluated based on the decrease of voltammetric signal of deoxyadenosine by differential pulse voltammetry using three different ways, including the incubated solutions, dsDNA biosensor, and nanobiosensor. The nanobiosensor was fabricated with the help of SnO2 nanoparticles and carbon hybrid material. The carbon material is derived from the waste mask, the most used personal protective equipment for the ongoing COVID-19 pandemic. Both materials were synthesized via the green synthesis technique and characterized by various techniques, including BET, TEM, SEM-EDX, AFM, XPS, and XRD. Spectrophotometric and molecular docking studies also evaluated the pazopanib-dsDNA binding. All calculations showed that pazopanib (PZB) was active in the minor grove region of DNA.

Human hair rich in pyridinic nitrogen-base DNA biosensor for direct electrochemical monitoring of palbociclib-DNA interaction.

Carbon material derived from the waste-based biomass human hair (H), which is naturally rich in pyridinic nitrogen, provides a significant benefit in biosensor applications with its dominant conductivity character. The carbon material was synthesized from human hair waste by the hydrothermal carbonization (HTC) method, which is a promising green synthesis. A morphological characterization of the carbon materials was performed. In this study, H and amine-functionalized multi-walled carbon nanotubes (NH2-MWCNT) were combined for the first time as a modifier, which enhanced the glassy carbon electrode (GCE) surface area for deoxyribonucleic acid (DNA) biosensor studies. Palbociclib (PLB) is clinically used in the treatment of breast cancer. The novel electrochemical nanobiosensor was used to investigate the dsDNA-PLB interaction to evaluate the possibility that PLB causes conformational changes in DNA structure and/or oxidative damage. The interaction was conducted based on the voltammetric signals of deoxyguanosine (dGuo) and deoxyadenosine (dAdo) by differential pulse voltammetry (DPV) on a bare and H + NH2-MWCNT modified GCE. The proposed analytical method was applied to a pharmaceutical dosage form with a satisfactory recovery of 98.25 %. The nanobiosensor was tested in the presence of some interfering agents. The binding mechanism of dsDNA-PLB was also evaluated by spectroscopic and theoretical calculations.

Synthesis, Structure, Thermal Decomposition and Computational Calculation of Heterodinuclear NiII - ZnII Complexes.

Mononuclear NiL complex was prepared by the use of bis-N,N'-salicylidene-1,3-propanediamine and Ni(II) salts. NiL was treated with ZnBr2 and pyrazole and 3,5-lutidine coligands in a dioxane medium to prepare the following diheteronuclear complexes: [NiL·ZnBr2·(pyrazole)2] and [NiL·ZnBr2·(3,5-lutidine)2]. The complexes were characterized by elemental analysis, TG, IR and mass spectrometry. The effects of heterocyclic one- and two- nitrogen atoms containing co-ligands were also examined. Theoretical formation enthalpies, dipole moments and the relative levels of HOMO and LUMO energies were determined by the use of Gaussian09 program. The occupancy levels of the atomic orbitals were determined by the NBO analysis of Gaussian09. The effect of pyrazole and lutidine upon the complex formation was evaluated by the use of X-ray diffraction, TG and theoretical calculations. NiL complex with lutidine forms a square pyramidal conformation since lutidine is a much stronger coligand than pyrazole.

Some Nitrogen Rich Energetic Material Synthesis by Nucleophilic Substitution Reaction from Polynitro Aromatic Compounds.

Three new nitrogen-rich energetic compounds, N-(5-chloro-2,4-dinitrophenyl)hydrazine (1), N-(5-chloro-2,4-dinitrophenyl)guanidine (2) and N-(5-chloro-2,4-dinitrophenyl)-4-aminopyrazole (3) prepared by the nucleophilic substitution reaction of 1,3-dichloro-4,6-dinitrobenzene with hydrazine, guanidinium carbonate and 4-aminopyrazole. The compounds were characterized by 1H NMR, 13C NMR, IR and mass spectroscopy. Only compound 2 could be prepared in a suitable crystal and molecular model was determined by X-ray analysis. Compounds were investigated by TG and DSC. Thermal degradation and thermokinetic behavior were investigated by Ozawa-Flynn-Wall and Kissinger-Akahira-Sunose techniques. Compounds were observed to be prone to exothermical thermal decomposition. HOMO and LUMO levels, theoretical formation enthalpy and electrostatic maps were calculated by Gaussian09. The detonation velocity and pressure were calculated by Kamlet-Jacobs equation. The compounds were assayed for antimicrobial properties.

Graphene Oxide Nanosheets Interact and Interfere with SARS-CoV-2 Surface Proteins and Cell Receptors to Inhibit Infectivity.

Nanotechnology can offer a number of options against coronavirus disease 2019 (COVID-19) acting both extracellularly and intracellularly to the host cells. Here, the aim is to explore graphene oxide (GO), the most studied 2D nanomaterial in biomedical applications, as a nanoscale platform for interaction with SARS-CoV-2. Molecular docking analyses of GO sheets on interaction with three different structures: SARS-CoV-2 viral spike (open state - 6VYB or closed state - 6VXX), ACE2 (1R42), and the ACE2-bound spike complex (6M0J) are performed. GO shows high affinity for the surface of all three structures (6M0J, 6VYB and 6VXX). When binding affinities and involved bonding types are compared, GO interacts more strongly with the spike or ACE2, compared to 6M0J. Infection experiments using infectious viral particles from four different clades as classified by Global Initiative on Sharing all Influenza Data (GISAID), are performed for validation purposes. Thin, biological-grade GO nanoscale (few hundred nanometers in lateral dimension) sheets are able to significantly reduce copies for three different viral clades. This data has demonstrated that GO sheets have the capacity to interact with SARS-CoV-2 surface components and disrupt infectivity even in the presence of any mutations on the viral spike. GO nanosheets are proposed to be further explored as a nanoscale platform for development of antiviral strategies against COVID-19.

2D MXenes with antiviral and immunomodulatory properties: A pilot study against SARS-CoV-2.

Two-dimensional transition metal carbides/carbonitrides known as MXenes are rapidly growing as multimodal nanoplatforms in biomedicine. Here, taking SARS-CoV-2 as a model, we explored the antiviral properties and immune-profile of a large panel of four highly stable and well-characterized MXenes - Ti3C2Tx, Ta4C3T x , Mo2Ti2C3T x and Nb4C3T x . To start with antiviral assessment, we first selected and deeply analyzed four different SARS-CoV-2 genotypes, common in most countries and carrying the wild type or mutated spike protein. When inhibition of the viral infection was tested in vitro with four viral clades, Ti3C2T x in particular, was able to significantly reduce infection only in SARS-CoV-2/clade GR infected Vero E6 cells. This difference in the antiviral activity, among the four viral particles tested, highlights the importance of considering the viral genotypes and mutations while testing antiviral activity of potential drugs and nanomaterials. Among the other MXenes tested, Mo2Ti2C3T x also showed antiviral properties. Proteomic, functional annotation analysis and comparison to the already published SARS-CoV-2 protein interaction map revealed that MXene-treatment exerts specific inhibitory mechanisms. Envisaging future antiviral MXene-based drug nano-formulations and considering the central importance of the immune response to viral infections, the immune impact of MXenes was evaluated on human primary immune cells by flow cytometry and single-cell mass cytometry on 17 distinct immune subpopulations. Moreover, 40 secreted cytokines were analyzed by Luminex technology. MXene immune profiling revealed i) the excellent bio and immune compatibility of the material, as well as the ability of MXene ii) to inhibit monocytes and iii) to reduce the release of pro-inflammatory cytokines, suggesting an anti-inflammatory effect elicited by MXene. We here report a selection of MXenes and viral SARS-CoV-2 genotypes/mutations, a series of the computational, structural and molecular data depicting deeply the SARS-CoV-2 mechanism of inhibition, as well as high dimensional single-cell immune-MXene profiling. Taken together, our results provide a compendium of knowledge for new developments of MXene-based multi-functioning nanosystems as antivirals and immune-modulators.

Ribavirin shows antiviral activity against SARS-CoV-2 and downregulates the activity of TMPRSS2 and the expression of ACE2 in vitro.

Ribavirin is a guanosine analog with broad-spectrum antiviral activity against RNA viruses. Based on this, we aimed to show the anti-SARS-CoV-2 activity of this drug molecule via in vitro, in silico, and molecular techniques. Ribavirin showed antiviral activity in Vero E6 cells following SARS-CoV-2 infection, whereas the drug itself did not show any toxic effect over the concentration range tested. In silico analysis suggested that ribavirin has a broad-spectrum impact on SARS-CoV-2, acting at different viral proteins. According to the detailed molecular techniques, ribavirin was shown to decrease the expression of TMPRSS2 at both mRNA and protein levels 48 h after treatment. The suppressive effect of ribavirin in ACE2 protein expression was shown to be dependent on cell types. Finally, proteolytic activity assays showed that ribavirin also showed an inhibitory effect on the TMPRSS2 enzyme. Based on these results, we hypothesized that ribavirin may inhibit the expression of TMPRSS2 by modulating the formation of inhibitory G-quadruplex structures at the TMPRSS2 promoter. As a conclusion, ribavirin is a potential antiviral drug for the treatment against SARS-CoV-2, and it interferes with the effects of TMPRSS2 and ACE2 expression.

Anti microbial corrosion properties of electrospun cellulose acetate nanofibers containing biogenic silver nanoparticles for copper coatings.

Nanofibers with inorganic nanoparticles are novel hybrid nanocomposites that have great potential in various areas. In the present study, cellulose acetate nanofibers (CA-Nf) loaded with biogenic silver nanoparticles were prepared and characterized. In situ synthesis of silver nanoparticles was accomplished using a bacteria free solution as a reducing agent. Nanofibers incorporated with silver nanoparticles were fabricated using the electrospinning technique. Upright microscopy and SEM micrographs depicted that the CA-Nf coatings consist of dense and compact entangled nanofibers that completely cover the copper surface. Corrosion measurements were performed by potentiodynamic polarization measurements and electrochemical impedance spectroscopy (EIS) techniques on the bare copper and CA-Nf and CA-Nf_5% AgNp coated copper surfaces in artificial seawater (ASW) and Escherichia coli ATCC 13883 inoculated solutions. Weight loss and electrochemical corrosion test results revealed that the CA-Nf-coated copper had greater corrosion resistance than bare copper. The additional electrospun CA-Nf_5% AgNp coating also had greater antibacterial behavior toward model biofilm bacterium Pseudomonas aeruginosa than uncoated copper specimens. Therefore, this nanofiber with AgNps was demonstrated as an efficient anticorrosive material in both corrosive and biocorrosive marine solutions.

Utilization of heat-dried Pseudomonas aeruginosa biomass for voltammetric determination of Pb(II).

In this research, thermally dried Pseudomonas aeruginosa cells were used as a biological material for the construction of a microbial biosensor. The preparation, optimization and application of the developed microbial biosensor, which analyzed Pb(II), are presented. The method was based on stripping of adsorbed metal ions from the modified electrode surface. Modified carbon paste electrodes were preconcentrated at open circuit, and then electrochemically measured by using cyclic voltammetry (CV) and differential pulse stripping voltammetry (DPSV) techniques. It was found that the thermally dried cells were capable of adsorbing Pb(II) ions from aqueous solutions and could determine the ions prominently at optimum experimental conditions. Many important parameters to acquire the best electrochemical response were carried out, including effect of different electrolyte solutions, pH, deposition potential, deposition time, ionic strength, preconcentration time, and effect of interference ions. Finally, a calibration graph was obtained with a linear range from 1.0×10(-6) to 2.0×10(-5) M Pb(II) (R(2)=0.9916) and detection limit was found as 6.0×10(-7) M Pb(II) by using 3×S(b)/m formula. Other analytical properties of the developed microbial biosensor were also investigated. The suggested usage format of P. aeruginosa for the determination of Pb(II) does not require complicated immobilization procedure, easy to handle, and not time consuming.

An advanced investigation on a new algal sensor determining Pb(II) ions from aqueous media.

It has been well documented that heavy metal accumulation in environment is harmful for living organisms at even trace levels. A new voltammetric algal sensor based on Phormidium sp. modification for Pb(II) determination from aqueous solutions was developed, and selectivity of the biomass to Pb(II) was investigated comprehensively. Many important experimental parameters were performed by using electrochemical techniques, including cyclic voltammetry and differential pulse stripping voltammetry. The preconcentrated ions at open circuit were reduced by scanning the potential from -1.5 to 1.5 V and current values obtained were related to the concentration of Pb(II) in the solutions. The best peak values belonging to Pb(II) were achieved at pH 8.0 with 0.05 M Tris-HCl solution. Preconcentration time was selected as 10 min, and the sensor was found in a linear range from 5.0×10(-8) M to 2.0×10(-5) M Pb(II) (0.01-4.0 mg L(-1)) with a detection limit of 2.5×10(-8) M. Other analytical properties of the developed microbial biosensor were also investigated. According to the Fourier transform infrared attenuated total reflectance (FTIR-ATR) analyses, the possible functional groups involved in Pb(II) accumulation in the Phormidium sp. were defined as carboxyl, sulphoxide and alcoholic groups. A simple chemical modification by formaldehyde both enhanced Pb(II) determination and content of functional groups involving Pb(II) binding. The proposed usage form of Phormidium sp. does not need complicated immobilization procedures and expensive preliminary preparations.

Using of Rhizopus arrhizus as a sensor modifying component for determination of Pb(II) in aqueous media by voltammetry.

For the sensitive determination of Pb(II) from aqueous solutions, a new voltammetric biosensor based on carbon paste electrode modified with Rhizopus arrhizus was developed. The preconcentrated ions at open circuit were reduced by using differential pulse stripping voltammetry technique. The obtained current values were related to the concentration of Pb(II) in the solutions. The best results were achieved at pH 7 with 0.01 M Tris-HCl buffer solution applying a preconcentration time of 12 min. The linear range for the biosensor was found to be within 1.0 x 10(-7)-1.25 x 10(-5) M, with a detection limit of 0.5 x 10(-8) M. The selectivity of the microbial biosensor was explored by adding interfering heavy metals to accumulation medium one by one, and their matrix effects were also investigated in the model metal solutions. Energy dispersive X-ray spectra analysis were applied to show the specific effect of the fungal biomass on the Pb(II) determination.

A voltammetric Rhodotorula mucilaginosa modified microbial biosensor for Cu(II) determination.

It is the first report about the usage of Rhodotorula mucilaginosa as a biomaterial to construct a microbial biosensor based on carbon paste for determination of copper. Cu(II) was preconcentrated electrode surface at open circuit and then detected with electrochemical techniques, including Cyclic Voltammetry (CV) and Differential Pulse Stripping Voltammetry (DPSV). Some parameters such as pH of preconcentration solution, preconcentration time, scan rate and effect of interfering heavy metal ions were carried out for optimum responses. The best defined cathodic peak was obtained at pH 5 with 0.05 M NaNO(3) and a scan rate of 100 mV/s. The linear range for the developed microbial biosensor was found in the range of 1.0 x 10(-7) and 1.0 x 10(-5)M (0.0064 and 0.64 mg/L) at the response time of 15 min (R(2)=0.98). The easy fabrication, sensitivity, low cost and fast response time showed the advantages of the biosensor to conventional techniques.