Inhibition Capability Research Articles

Porous polyimide separator promotes uniform lithium plating for lithium‐free cells

AbstractElectrospun polyimide (PI) separators were found to reduce the charge‐transfer resistance of Li plating/stripping and the overpotentials of Li nucleation/growth onto Cu foils in the 1.2 M LiPF6/(ethylene carbonate/dimethyl carbonate = 1/1) electrolyte without any additives in comparison with polyethylene (PE) separators. Lithium deposition through the PI separator led to the formation of a granular morphology of 15–30 µm in diameter compared to lithium dendrites using PE. A similar trend of lithium deposition was observed in LiFePO4//Cu cells. The PI separator was found to enhance the discharge capacity and cycle life of Li plating/stripping in the Li//Cu and LiFePO4//Cu cells containing 40 µl electrolytes, verifying that the PI separator provides dendrite inhibition capability for the lithium‐metal‐free cells.

Smart 131 I-Labeled Self-Illuminating Photosensitizers for Deep Tumor Therapy.

Stimulating photosensitizers (PS) by Cerenkov radiation (CR) can overcome the light penetration limitation in traditional photodynamic therapy. However, separate injection of radiopharmaceuticals and PS cannot guarantee their efficient interaction in tumor areas, while co-delivery of radionuclides and PS face the problem of nonnegligible phototoxicity in normal tissues. Here, we describe a 131 I-labeled smart photosensitizer, composed of pyropheophorbide-a (photosensitizer), a diisopropylamino group (pH-sensitive group), an 131 I-labeled tyrosine group (CR donor), and polyethylene glycol, which can self-assemble into nanoparticles (131 I-sPS NPs). The 131 I-sPS NPs showed low phototoxicity in normal tissues due to aggregation-caused quenching effect, but could self-produce reactive oxygen species in tumor sites upon disassembly. Upon intravenous injection, 131 I-sPS NPs showed great tumor inhibition capability in subcutaneous 4T1-tumor-bearing Balb/c mice and orthotopic VX2 liver tumor bearing rabbits. We believed 131 I-sPS NPs could expand the application of CR and provide an effective strategy for deep tumor theranostics.

Smart 131I‐Labeled Self‐Illuminating Photosensitizers for Deep Tumor Therapy

AbstractStimulating photosensitizers (PS) by Cerenkov radiation (CR) can overcome the light penetration limitation in traditional photodynamic therapy. However, separate injection of radiopharmaceuticals and PS cannot guarantee their efficient interaction in tumor areas, while co‐delivery of radionuclides and PS face the problem of nonnegligible phototoxicity in normal tissues. Here, we describe a 131I‐labeled smart photosensitizer, composed of pyropheophorbide‐a (photosensitizer), a diisopropylamino group (pH‐sensitive group), an 131I‐labeled tyrosine group (CR donor), and polyethylene glycol, which can self‐assemble into nanoparticles (131I‐sPS NPs). The 131I‐sPS NPs showed low phototoxicity in normal tissues due to aggregation‐caused quenching effect, but could self‐produce reactive oxygen species in tumor sites upon disassembly. Upon intravenous injection, 131I‐sPS NPs showed great tumor inhibition capability in subcutaneous 4T1‐tumor‐bearing Balb/c mice and orthotopic VX2 liver tumor bearing rabbits. We believed 131I‐sPS NPs could expand the application of CR and provide an effective strategy for deep tumor theranostics.

Versatile Fluorescent Carbon Dots from Citric Acid and Cysteine with Antimicrobial, Anti-biofilm, Antioxidant, and AChE Enzyme Inhibition Capabilities.

Nanostructured fluorescent particles derived from natural molecules were prepared by a green synthesis technique employing a microwave method. The precursors citric acid (CA) and cysteine (Cys) were used in the preparation of S- and N-doped Cys carbon dots (Cys CDs). Synthesis was completed in 3min. The graphitic structure revealed by XRD analysis of Cys CDs dots had good water dispersity, with diameters in the range of 2-20nm determined by TEM analysis. The isoelectric point of the S, N-doped CDs was pH value for 5.2. The prepared Cys CDs displayed excellent fluorescence intensity with a high quantum yield of 75.6 ± 2.1%. Strong antimicrobial capability of Cys CDs was observed with 12.5mg/mL minimum bactericidal concentration (MBC) against gram-positive and gram-negative bacteria with the highest antimicrobial activity obtained against Staphylococcus aureus. Furthermore, Cys CDs provided total biofilm eradication and inhibition abilities against Pseudomonas aeruginosa at 25mg/mL concentration. Cys CDs are promising antioxidant materials with 1.3 ± 0.1μmol Trolox equivalent/g antioxidant capacity. Finally, Cys CDs were also shown to inhibit the acetylcholinesterase (AChE) enzyme, which is used in the treatment of Alzheimer's disease, even at the low concentration of 100μg/mL.

From Unimolecular Template to Silver Nanocrystal Clusters: An Effective Strategy to Balance Antibacterial Activity and Cytotoxicity.

Silver nanomaterials have attracted a great deal of interest due to their broad-spectrum antimicrobial activity. However, it is still challenging to balance the high antibacterial efficiency with low damage to biological cells of silver nanostructures, especially when the diameter decreases to less than 10 nm. Here, we developed a new type of Ag nanohybrid material via a unimolecular micelle template method, which presents amazing antibacterial activities and almost noncytotoxicity. First, water-soluble multiarm star-shaped brushlike copolymer α-CD-g-[(PEO40-g-PAA50)-b-PEO5]18 was precisely synthesized and its micelle behavior in different solvents was revealed. Then, nanocrystal clusters assembled by Ag grains (Ag@Template NCs) were prepared through an in situ redox route using the unimolecular micelle of α-CD-g-[(PEO40-g-PAA50)-b-PEO5]18 as the soft template, AgNO3 as a precursor, and tetrabutylammonium borohydride (TBAB) as the reducing agent. The overall size of the achieved Ag@Template NCs is controlled by the template structure at around 40 nm (Dh in DMF), and the size of the Ag grain can be easily regulated from ∼1 to ∼5 nm by adjusting the feeding ratio of AgNO3/acrylic acid (AA) units in the template from 1:10 to 1:1. Benefitting from the structural design of the template, all Ag@Template NCs prepared here exhibit excellent dispersibility and chemical stability in different aqueous environments (neutral, pH = 5.5, and 0.9% NaCl physiological saline solution), which play a crucial role in the long-term storage and potential application in a complex physiological environment. The antibacterial and cytotoxicity tests indicate that Ag@Template NCs display much better performance than Ag nanoparticles (Ag NPs), which have a comparable overall size of ∼25 nm. The inhibitory capability of Ag@Template NCs to bacteria strongly depends on the grain size. Specifically, the Ag@Template-1 NC assembled by the smallest grains (1.6 ± 0.3 nm) presents the best antibacterial activity. For E. coli (-), the MIC value is as low as 5 μg/mL (0.36 μg/mL of Ag), while for S. aureus (+), the value is around 10 μg/mL (0.72 μg/mL of Ag). The survival rate of L02 cells and lactate dehydrogenase assay together illustrate the low cytotoxicity possessed by the prepared Ag@Template NCs. Therefore, the proposed Ag@Template NC structure successfully resolves the high reactivity, instability, and fast oxidation issues of the ultrasmall Ag nanoparticles, and integrates high antibacterial efficiency and nontoxicity to biological cells into one platform, which implies its broad potential application in biomedicine.

Anti-Corrosion Behavior of Olmesartan for Soft-Cast Steel in 1 mol dm−3 HCl

This study discusses the effects of temperature on corrosion inhibition for soft-cast steel by the pharmaceutically active drug olmesartan in 1 mol dm−3 HCl. The sufficient number of electron-rich elements and non-bonding π electrons in its structure favored a good capability for coating onto the electron-deficient steel surfaces. Theoretical and electrochemical measurements were carried out at the temperature region of 303 K to 333 K. Therefore, the experiment suggests that the inhibition efficiency of olmesartan increases with its increasing concentrations due to the adsorption. Additionally, even at a higher temperature of 333 K, the inhibitor molecules attain their stability towards corrosion resistance of steel surfaces. The adsorption of inhibitors on steel surfaces is spontaneously found to include the mixture of physisorption and chemisorption, and it obeys Temkin’s adsorption isotherm model. Theoretical and computational considerations were made using quantum chemical parameters and molecular dynamics simulations, which confirmed that the olmesartan has a suitable corrosion inhibitive capability intended for soft-cast steel in 1 mol dm−3 HCl. Additionally, scanning electron microscopic measurement was used to obtain a visual idea of the inhibitive action of the inhibitor attained by forming an adsorbed protective layer onto the steel surfaces. The minute concentration of olmesartan of about 10–50 ppm shows high inhibition efficiency of ~80%, even at elevated temperatures.

Efficacy of Small Molecule Phytochemicals of Petroleum Ether Pod Extract of Prosopis cineraria (L.) Druce on HMG-CoA Reductase and Biomarker Indices of Lipoproteins: In-vitro, In-vivo and In-silico Study

The assigned goals of the study were examined to HMG-CoA reductase inhibition and antioxidants potential of the small molecule phytochemicals of petroleum ether pod extract of Prosopis cineraria (L.) Druce by in-vitro, in-vivo, and in-silico assessments. The phytochemical fingerprinting of the extract was done by LC-MS analysis, and compounds were identified using mass hunter software. In-vitro HMG-CoA reductase assay performed by sigma Aldrich kit. According, in-vivo investigations were conducted by using a hypercholesterolemic rabbit animal model. Further, in-silico analyses of molecular docking and ADMET were conducted by standard protocol. The leading identified compounds, i.e., prosogerin-A, luteolin, and gallic acid, were docked with the target enzyme of HMG-CoA reductase, which demonstrated significant binding energies up to -7.2 to 8.1(Kcal/mol). Subsequently, the ADMET predictions revealed druggability and ideal pharmacokinetics profile. Accordingly, the in-vitro HMG-CoA reductase inhibition assay was showed 53.1% inhibition capability of the test extract. The in-vivo investigation shown that the test extract caused significant reductions in the atherogenic index (log (Total cholesterol/triglyceride), Castelli risk index-I (CRI-I), and Castelli risk -II(CRI-II) along with lipid profile and antioxidants levels. It can be concluded that small-molecule phytochemicals such as Prosogerin A, Luteolin, Gallic acid are present in petroleum ether pod extract of Prosopis cineraria (L.) Druce possesses the capability to subside hypercholesterolemia and ameliorations in biomarker lipoproteins indices through HMG-CoA reductase inhibition and antioxidant potential.

A novel green depressant for flotation separation of scheelite from calcite

Polyaspartic acid (PASP) was used as a novel environmental-friendly depressant, and its inhibition effect on flotation performance of scheelite and calcite using sodium oleate (NaOL) as a collector was investigated by ways of flotation experiments, zeta potential measurement, contact angle measurement and infrared spectroscopic analysis (IR). The results show that PASP exhibits stronger inhibition capability and selectivity than acidified water glass, and the flotation separation of scheelite from calcite can be realized in the presence of 6 mg/L PASP and 20 mg/L NaOL at pH>6. In the presence of PASP, the zeta potential of calcite surface almost keeps unchanged after adding NaOL, and the contact angle decreases sharply. Therefore, it is indicated that PASP significantly decreases the adsorption of NaOL on calcite surface. By contrast, it has no distinct effect on the adsorption of NaOL on the scheelite surface, which is further confirmed by IR results.

The metabolic and biochemical mapping of Agave americana leave juice encode their prospective biotechnological uses

Agave americana (A. americana) is a species that are considered as one of the most studied species and there are a large number of derived products, as well as applications of agave fibers. Here, we have exploited their applied potentialities through metabolic and biochemical abilities. In this case, we monitored the presence of terpenoides, phlobatanins, tannins, anthraquinone, puerarin, apigenin, carbohydrates and vitamin C. The proteins amount was estimated to be 8.13 mg.g−1(FM). In addition, the A. americana leave juice enzymological characterization consists of various enzymatic activities like protease (356 U. mL−1) and α-amylase (264 U. mL−1). The last one (AmyAga) was purified after two purification steps, their optimal activity is showed at 70 °C and pH 9. Eventually, those findings indicate their potential use in baking industry in which AmyAga upgrades some parameter’s like elasticity index, baking strength, humidity and fall time. We note also that vitamin C inhibitory capability towards some enzymes such as glucosidases that was 3 folds higher than those of exhibiting against amylases.

Poor humoral and T-cell response to two-dose SARS-CoV-2 messenger RNA vaccine BNT162b2 in cardiothoracic transplant recipients

AimsImmunocompromised patients have been excluded from studies of SARS-CoV-2 messenger RNA vaccines. The immune response to vaccines against other infectious agents has been shown to be blunted in such patients. We aimed to analyse the humoral and cellular response to prime-boost vaccination with the BNT162b2 vaccine (Pfizer-BioNTech) in cardiothoracic transplant recipients.Methods and resultsA total of 50 transplant patients [1–3 years post heart (42), lung (7), or heart–lung (1) transplant, mean age 55 ± 10 years] and a control group of 50 healthy staff members were included. Blood samples were analysed 21 days after the prime and the boosting dose, respectively, to quantify anti-SARS-CoV-2 spike protein (S) immunoglobulin titres (tested by Abbott, Euroimmun and RocheElecsys Immunoassays, each) and the functional inhibitory capacity of neutralizing antibodies (Genscript). To test for a specific T-cell response, heparinized whole blood was stimulated with SARS-CoV-2 specific peptides, covering domains of the viral spike, nucleocapsid and membrane protein, and the interferon-γ release was measured (QuantiFERON Monitor ELISA, Qiagen). The vast majority of transplant patients (90%) showed neither a detectable humoral nor a T-cell response three weeks after the completed two-dose BNT162b2 vaccination; these results are in sharp contrast to the robust immunogenicity seen in the control group: 98% exhibited seroconversion after the prime dose already, with a further significant increase of IgG titres after the booster dose (average > tenfold increase), a more than 90% inhibition capability of neutralizing antibodies as well as evidence of a T-cell responsiveness.ConclusionsThe findings of poor immune responses to a two-dose BNT162b2 vaccination in cardiothoracic transplant patients have a significant impact for organ transplant recipients specifically and possibly for immunocompromised patients in general. It urges for a review of future vaccine strategies in these patients.

Synthesis of hairpin DNA mediated Au-Ag bimetallic nanomushrooms for antibacterial application

. Precise control of the synthesis of bimetallic nanoparticles with specific morphology and structure is of great significance due to their excellent catalytic, optical and biological property. DNA molecules are considered as a kind of efficient templates to mediate the precise synthesis of bimetallic nanoparticles with homogeneous morphology due to their specific and controllable structure. In this study specific hairpin DNA strands were successfully utilized as templates to mediate the synthesis of special mushroom-like Au-Ag bimetallic nanoparticles with a high yield of > 90%. Several key factors greatly influencing the precise control of the morphology and UV-Vis characteristics of the proposed Au-Ag nanomushrooms during synthesis were investigated and optimized in detail, including the structure of template DNA, loading amounts of DNA, types of reductant agents and surfactants. Then, the formation mechanism of hairpin DNA mediated Au-Ag nanomushrooms was studied. Finally, the proposed Au-Ag nanomushrooms with good biocompatibility were applied for the antibacterial study by the growth curve of E. coli. The proposed Au-Ag nanomushrooms showed the effective inhibition capability for the growth of E. coli. The results suggested that these DNA mediated Au-Ag nanomushrooms possessed great potential applications for biomedical science in future.

Development of a Novel Antibacterial Hydrogel Scaffold Based on Guar Gum/Poly (methylvinylether-alt-maleic Acid) Containing Cinnamaldehyde-Loaded Chitosan Nanoparticles

In this study, we produced a novel chemical cross-linked Guar gum/Poly(methylvinylether-alt-maleicacid) (GG/PMVE-MA) hydrogels with various blending weight ratio of GG, and PMVE-MAn (GG/P20, GG/P40, and GG/P70). These produced hydrogels were analyzed by Fourier-transform infrared spectroscopy (FTIR), scanning electron microscope (SEM), thermogravimetric analysis (TGA), swelling degree, and mechanical characteristics. The results demonstrated that with increasing PMVE-MAn content, thermal stability, swelling degree, and mechanical characteristics of hydrogels were improved. As a result, the GG/P70 hydrogel was selected as an optimal hydrogel. Moreover, MTT analysis indicated that these hydrogels were non-toxic and any reduction or stop of cells growth wasn't observed over time. Additionally, encapsulation of cinnamaldehyde (CA)-loaded chitosan nanoparticles (CSNPs) into optimal hydrogel formulation significantly (P < 0.05) increased scavenging of 2,2-diphenyl-1-picryl-hydrazyl-hydrate (DPPH) radical about 60%. In addition, the inhibition capability of GG/P70/CA-loaded CSNPs hydrogel against Escherichia coli (E. coli) and Staphylococcus aureus (S. aureus), demonstrating that the hydrogel had high antibacterial and antioxidant activities. The general results showed that this composite hydrogel (GG/P70/CA-loaded CSNPs) could be useful for various applications such as drug delivery, tissue engineering and food industry.

Electrochemical catechol biosensor based on β-cyclodextrin capped gold nanoparticles and inhibition effect of ibuprofen

Herein, β-cyclodextrin-capped gold nanoparticle surface designed for tyrosinase (Tyr)-based nanosensor is proposed and demonstrated. Integration of the β-cyclodextrin-capped gold nanoparticles on graphite electrode surface was achieved via drop-casting method, Tyr was immobilized on the modified electrode and then used as drug inhibition platform with catechol as the substrate. All optimization studies that affect biosensor response were conducted, and catechol was detected in the linear range of 1.56 μM-25μM catechol concentration with a limit of detection of 0.42 μM and sensitivity of 2.094 μA.μM−1. cm-2. Tyr inhibition was followed with ibuprofen drug active compound with a 15 min incubation time, and the I50 value was found as 213 μM. The sensor is the first in the literature to use an electrochemical method for β-cyclodextrin-capped gold nanoparticles based Tyr biosensor and ibuprofen inhibition. This sensor presents an easy fabrication method, excellent sensor properties, and ibuprofen inhibition capabilities. As a result, it is proposed that the designed sensor is an ideal marker for detecting Tyr inhibition using electrochemical methods and an ibuprofen-based cosmetic cream formulation could be a viable option in the cosmetic market.

Biological evaluation of mitochondria targeting small molecules as potent anticancer drugs

Cancer therapy targets specific metabolic pathways or a single gene. This may result in low therapeutic effects due to drug selectivity and drug resistance. Recent studies revealed that the mitochondrial membrane potential and transmembrane permeability of cancerous mitochondria are differed from normal mitochondria. Thus, chemotherapy targeting cancerous mitochondria could be an innovative and competent strategy for cancer therapy. Previously, our work with a novel group of mitochondria targeting small molecules presented promising inhibitory capability toward various cancer cell lines and suppressed adenosine triphosphate (ATP) generation. Therefore, it is critical to understand the anticancer effect and targeting mechanism of these small molecules. This study investigated the inhibitory activity of mitochondria targeting small molecules with human cervical cancer cells – HeLa to further explore their therapeutic potential. HeLa cells were exposed to 10 µM of synthesized compounds and presented elevation in intracellular reactive oxygen species (ROS) level, impaired mitochondrial membrane potential and upregulation of apoptosis as well as necrosis. In vivo, HeLa cell tumor-bearing BALB/c nude mice were treated with mitochondria targeting small molecules for 12 days consecutively. Throughout this chemotherapy study, no deleterious side effects nor the appearance of toxicity was observed. Furthermore, mitochondria targeting small molecules treated groups exhibited significant down-regulation with both tumor volume and tumor weight compared to the Doxorubicin (DOX) treated group. Thus, inhibition of mitochondrial ATP synthesis, activation of intracellular ROS production, down-regulation of mitochondrial membrane potential and upregulation of apoptosis and necrosis rates are the indications of cancer therapy. In this work, we examined the anticancer capability of four mitochondria targeting small molecules in vitro and in vivo, and demonstrated a novel therapeutic approach in cancer therapy with tremendous potential.

The Novel Oral mTORC1/2 Inhibitor TAK-228 Reverses Trastuzumab Resistance in HER2-Positive Breast Cancer Models.

Simple SummaryHyperactivation of the PI3K/AKT/mTOR cell signalling pathway is an important and well-described mechanism of trastuzumab resistance in HER2-positive breast cancer. In cell-line models of acquired trastuzumab resistance generated in our laboratory, we demonstrate this type of activation, which is independent of HER2-mediated regulation. We investigate whether the use of specific mTOR inhibitors, a PI3K/AKT/mTOR pathway effector, could lead to decreased activity of the pathway, influencing trastuzumab resistance. We demonstrate that TAK-228, a mTORC1 and mTORC2 inhibitor, can reverse resistance and increasing response to trastuzumab in models of primary and acquired resistance.The use of anti-HER2 therapies has significantly improved clinical outcome in patients with HER2-positive breast cancer, yet a substantial proportion of patients acquire resistance after a period of treatment. The PI3K/AKT/mTOR pathway is a good target for drug development, due to its involvement in HER2-mediated signalling and in the emergence of resistance to anti-HER2 therapies, such as trastuzumab. This study evaluates the activity of three different PI3K/AKT/mTOR inhibitors, i.e., BEZ235, everolimus and TAK-228 in vitro, in a panel of HER2-positive breast cancer cell lines with primary and acquired resistance to trastuzumab. We assess the antiproliferative effect and PI3K/AKT/mTOR inhibitory capability of BEZ235, everolimus and TAK-228 alone, and in combination with trastuzumab. Dual blockade with trastuzumab and TAK-228 was superior in reversing the acquired resistance in all the cell lines. Subsequently, we analyse the effects of TAK-228 in combination with trastuzumab on the cell cycle and found a significant increase in G0/G1 arrest in most cell lines. Likewise, the combination of both drugs induced a significant increase in apoptosis. Collectively, these experiments support the combination of trastuzumab with PI3K/AKT/mTOR inhibitors as a potential strategy for inhibiting the proliferation of HER2-positive breast cancer cell lines that show resistance to trastuzumab.

Lactic acid production and the inhibitory capability of lactic acid bacteria isolated from poultry feces

This study was performed to isolate lactic acid bacteria (LAB) from poultry feces, identify the lactic acid production capability and its inhibitory effect against pathogenes as a promising probiotic candidate for livestock. Lactic acid bacteria were isolated and cultured on De Man, Rogosa and Sharpe (MRS) media. The parameters of this study are bacterial characterization and antimicrobial activity of LAB Isolates against gram-positive and negative bacteria. LAB characterization was performed by Gram staining test, morphological test, catalase test, and fermentation type test. Microscopic observation of LAB isolated by feces showed that cocci and bacilli morphologies. The gram staining test showed Gram-positive and Gram-negative test results and the catalase test showed all LAB isolates obtained were facultative anaerobic. The results indicated that LAB M1 isolates could produce greater lactic acid with more effective inhibitory capability against Staphylococcus aureus ATCC 25293 and Salmonella typhimurium FNCC 0050 compared to other isolates.

Physico-Chemical Properties, Fractionation and Antioxidant Activity of Some Essential Oils Utilized in Mayonnaise Preparation and Storage

Two types of essential oils (thyme and Stachys) were used in this Estimation. The chemical composition, antioxidant activity (by DPPH assay) and the rancimat method were used to assess the stability effect of these essential oils. The tested oils were added to mayonnaise to evaluate its capability for inhibition of secondary oxidation products. By DPPH assay, antioxidant activity showed that thyme essential oil was the best antioxidant agent as radical scavenging agents at 450 and 500 ppm concentrations, even better than BHT at the 200 ppm concentration. As a typical antioxidant, butylated hydroxytoluene was used for comparison. The mayonnaise samples prepared by adding thyme, stachys essential oils and TBHQ (control +) at concentrations of 200,400, 600 and 200 ppm into the sunflower oil free from antioxidant. At the amounts used in this study, thyme and stachys oils were significantly successful in reducing the oxidation of sunflower oil, especially, at 500 ppm which showed more efficient than BHT. Specifically, in the presence of thyme oil, the induction period of sunflower oil was considerably elongated. However, butylated hydroxytoluene (BHT) was more efficient than thyme and Stachys oils at the 200-ppm concentration against oxidation of oils. all concentrations of thyme and stachys essential oils had an antioxidant activity similar to synthetic antioxidant of TBHQ at a concentration of 200 ppm for inhibition of secondary oxidation products in mayonnaise in comparison with the control sample. As a conveniently available source of natural antioxidants, thyme and stachys essential oils can be used for use in fats, oils and food containing fats.

Synthesis and characterization of antibacterial silver nanoparticles using essential oils of crown imperial leaves, bulbs and petals

In this research, the essential oils obtained from leaves, bulbs and petals of crown imperial plant are used as reducing agents to fabricate silver nanoparticles. The aromatic hydrocarbons, alkenes, ketenes and alkaloids are among the compounds identified in the essential oils as detected by gas chromatography mass spectrometry. The characteristics of silver nanoparticles are investigated by field emission scanning electron microscopy, transmission electron microscopy and XRD. The chemical groups and surface resonance characteristics of the samples are revealed by Fourier transform infrared spectroscopy and UV-Visible spectroscopy, accordingly. The field emission scanning electron microscopy results show that the silver nanoparticles form nanoscale spheres with a mean diameter of 27 ± 14 nm in case of the sample obtained by essential oil of petals as confirmed by transmission electron microscopy. This sample shows a UV-Visible absorption band at 450 nm. The antibacterial activity of the silver nanoparticles shows a remarkable inhibition capability against all of the tested bacteria, with the sample obtained from petals exhibiting the strongest antibacterial effect in agreement with the obtained minimum inhibitory concentration and minimum bactericidal concentration values. The cell viability assay using Vero cell line reveals a nearly constant viability rate above 125 μg/mL of silver nanoparticles.

L-Cysteine as an Irreversible Inhibitor of the Peroxidase-Mimic Catalytic Activity of 2-Dimensional Ni-Based Nanozymes

The ability to modulate the catalytic activity of inorganic nanozymes is of high interest. In particular, understanding the interactions of inhibitor molecules with nanozymes can bring them one step closer to the natural enzymes and has thus started to attract intense interest. To date, a few reversible inhibitors of the nanozyme activity have been reported. However, there are no reports of irreversible inhibitor molecules that can permanently inhibit the activity of nanozymes. In the current work, we show the ability of L-cysteine to act as an irreversible inhibitor to permanently block the nanozyme activity of 2-dimensional (2D) NiO nanosheets. Determination of the steady state kinetic parameters allowed us to obtain mechanistic insights into the catalytic inhibition process. Further, based on the irreversible catalytic inhibition capability of L-cysteine, we demonstrate a highly specific sensor for the detection of this biologically important molecule.

Proline nitrate ionic liquid as high temperature acid corrosion inhibitor for mild steel: Experimental and molecular-level insights

• Anticorrosive impact of [Pro][NO 3 ] IL tested for mild steel. • At 70 °C inhibition capability of the compound was 93.88% at 300 ppm. • Surface morphology by SEM and XPS confirmed considerable surface change. • Various isotherm models supported the adsorption mechanism. • DFT and MC simulation underpinned the experimental findings. The synthesis of novel l -proline nitrate ionic liquid referred to as [Pro][NO 3 ] (IL), was performed and the 1 H, 13 C NMR, and FT-IR spectroscopic techniques were used to elucidate the chemical structure. The inhibition properties of the [Pro][NO 3 ] IL were evaluated for mild steel (MS) corrosion in 1 M HCl using gravimetric measurement, electrochemical impedance spectroscopy (EIS), potentiodynamic polarization (PDP) measurement, FT-IR spectroscopy, X-ray photoelectron spectroscopy (XPS), contact angle measurement, scanning electron microscopy (SEM), density functional theory (DFT) and Monte Carlo (MC) simulation studies. As indicated by electrochemical and weight loss techniques the tested [Pro][NO 3 ] IL was established as an excellent mixed type high-temperature acid corrosion inhibitor for MS; the optimal temperature and concentration being 70 °C and 300 ppm, respectively. Furthermore, the contact angle measurement and surface studies revealed water-repelling property and the protecting capability, respectively of the investigated inhibitor. The electronic property of [Pro][NO 3 ] IL has been explored using density functional theory (DFT) and the sites susceptible for electron sharing were identified through Fukui indices analysis. Furthermore, molecular dynamics simulation based on the Monte Carlo method has been employed to envisage the spontaneous adsorption of [Pro][NO 3 ] IL on MS surface.