Silver-Chitosan Nanocomposite Prepared With Aqueous Sodium-hydroxide and Aqueous Acetic Acid Solutions: Characteristics and Their Cytotoxic Effects

In this study cytotoxic effects of silver-chitosan nanocomposites with aqueous sodium-hydroxide solution (SCNC-ASHS), and aqueous acetic acid solution (SCNC-AAAS) were evaluated, in vitro. The morphology of the synthesized nanoparticles were characterized by Fourier-Transform Infrared Spectroscopy (FTIR), and Scanning Electron Microscopy (SEM). Their cytotoxicity were then evaluated using 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyl-2H-tetrazolium bromide (MTT) in concentrations of 1.56 to 400 µg/ml, and acridine orange/ethidium bromide (AO/EB) staining after 24h and 48h. Results showed the cytotoxicity of 400 µg/ml of SCNC-ASHS on Vero and HT-29 cells of 80.57% and 84.37% after 24h, and 82.20% and 84.84% after 48h. While, the values for SCNC-AAAS on Vero and HT-29 cell-lines were respectively 80.63% and 87.64% after 24h, and 83.60% and 87.44% after 48h. The most toxicity on HT-29 cells was belonged to SCNC-AAAS with IC50 of 40.4 µg/ml. In the staining procedure, cell viability for 25 µg/ml concentration of SCNC-AAAS was 41.84% in HT-29 cell and, for 6.25 µg/ml of SCNC-AAAS was 37.51% in Vero cells. A considerable decrease in cell viability was observed. Types of nanoparticles, synthesis methods, and different cell lines play role in inducing cytotoxicity. Anti-cancer effect of the nanoparticles on the colon cancerous cells (HT-29), of that SCNC-AAAS displayed higher effect than SCNC-ASHS.

GC-MS Analysis of Biological Nitrate and Nitrite Using Pentafluorobenzyl Bromide in Aqueous Acetone: A Dual Role of Carbonate/Bicarbonate as an Enhancer and Inhibitor of Derivatization

Carbon dioxide (CO2) and carbonates, which are widely distributed in nature, are constituents of inorganic and organic matter and are essential in vegetable and animal organisms. CO2 is the principal greenhouse gas in the atmosphere. In human blood, CO2/HCO3− is an important buffering system. Inorganic nitrate (ONO2−) and nitrite (ONO−) are major metabolites and abundant reservoirs of nitric oxide (NO), an endogenous multifunctional signaling molecule. Carbonic anhydrase (CA) is involved in the reabsorption of nitrite and nitrate from the primary urine. The measurement of nitrate and nitrite in biological samples is of particular importance. The derivatization of nitrate and nitrite in biological samples alongside their 15N-labeled analogs, which serve as internal standards, is a prerequisite for their analysis by gas chromatography–mass spectrometry (GC-MS). A suitable derivatization reagent is pentafluorobenzyl bromide (PFB-Br). Nitrate and nitrite are converted in aqueous acetone to PFB-ONO2 and PFB-NO2, respectively. PFB-Br is also useful for the GC-MS analysis of carbonate/bicarbonate. This is of particular importance in conditions of pharmacological CA inhibition, for instance by acetazolamide, which is accompanied by elevated concomitant excretion of nitrate, nitrite and bicarbonate, as well as by urine alkalization. We performed a series of experiments with exogenous bicarbonate (NaHCO3) added to human urine samples (range, 0 to 100 mM), as well as with endogenous bicarbonate resulting from the inhibition of CA activity in healthy subjects before and after ingestion of pharmacological acetazolamide. Our results indicate that bicarbonate enhances the derivatization of nitrate with PFB-Br. In contrast, bicarbonate decreases the derivatization of nitrite with PFB-Br. Bicarbonate is not a catalyst, but it enhances PFB-ONO2 formation and inhibits PFB-NO2 formation in a concentration-dependent manner. The effects of bicarbonate are likely to result from its reaction with PFB-Br to generate PFB-OCOOH. Nitrate reacts with concomitantly produced PFB-OCOOH to form PFB-ONO2 in addition to the direct reaction of nitrate with PFB-Br. By contrast, nitrite does not react with PFB-OCOOH to form PFB-NO2. Sample acidification by small volumes of 20 wt.% aqueous acetic acid abolishes the effects of exogenous and endogenous bicarbonate on nitrite measurement.

LC-ESI-tandem MS and in silico ADMET analysis of polyphenols from Rhus coriaria L. and Micromeria fruticosa (L.) Druce ssp. brachycalyx P. H. Davis

Background Micromeria fruticosa (L.) Druce ssp. brachycalyx P. H. Davis and Rhus coriaria L., which are Lamiaceae species, are used both as spices in food and medicinally. Lamiaceae species are known to contain high amounts of polyphenols. In this study, liquid chromatography–quadrupole time-of-flight–tandem mass spectrometry (LC-QTOF-MS/MS) was used for analysis of polyphenols in the plants. Under gradient elution with using 0.1% aqueous acetic acid solution and acetonitrile mobile phases, an Agilent Poroshell C18 reversed phase column was used for the simultaneous determination of 18 polyphenols, and separation was performed in 30 min. Pharmacokinetic properties of these polyphenols such as drug-like and toxicity were estimated using open-source software, pkCSM and SwissADME. Results These compounds were determined to represent different classes of polyphenols, including phenolic acids, flavonoids, coumarin and tannins. ADMET predictions of polyphenols indicated that these compounds are easily absorbed and do not have toxic effects. Conclusion While the Rhus coriaria L. includes anthocyanidins, tannins, phenolic acid and flavonoids, the Micromeria fruticosa (L.) Druce ssp. brachycalyx P. H. Davis has phenolic acid, coumarin and flavonoids, according to these results. In silico ADME/Tox predictions revealed that these bioactive components are to be drug-like and non-mutagenic. These data are supportive for future analysis that can lead to their therapeutic use of the plants, suggesting that this species may be used as a natural medicinal source in the future after detailed analysis tests. Graphical abstract

Formulation and Evaluationation of Anti-Alzheimer Drug MEM HCL Nanogel

The object of present study was to formulate and evaluate MEM HCl loaded thermo sensitive in situ nanogel for 08 nasal delivery formulations. In present project a novel drug delivery system i.e. in situ polymeric gel was designed in the manner that the gel load MEM HCl in better concentration and it also incorporates penetration enhancer as a way to enhance the absorption of release drug from gel to the systemic circulation. In this research work Different Nanoparticles were (NP) prepared, using ionotropic gelation method with slight medication in which chitosan (0.4% w/v) was dissolved in aqueous acetic acid solutions (1 % v/v) (pH 6.1), while TPP (0.1% w/v) was dissolved in deionized water. Dried nanoparticles are incorporated with in situ gel. In situ gel was prepared by cold method using the solutions of Poloxamer-188 and Carbopol-934. From this study, it is concluded that, among all formulations prepared, NG8 was the best optimized formulation. Prepared gel can be used as promising nasal drug delivery system for the anti-Alzheimer drug MEM HCl, which enhance nasal residence time owing to increased viscosity and mucoadhesive characteristics; furthermore, it also exhibited a permeation enhancing effect.

Low temperature chemical sintering of inkjet-printed Zn nanoparticles for highly conductive flexible electronic components

This study illustrates an innovative way to fabricate inkjet-printed tracks by sequential printing of Zn nanoparticle ink and curing ink for low temperature in situ chemical sintering. Employing chemical curing in place of standard sintering methods leads to the advantages of using flexible substrates that may not withstand the high thermal budgets of the standard methods. A general formulation engineering method is adopted to produce highly concentrated Zn ink which is cured by inkjet printing an over-layer of aqueous acetic acid which is the curing agent. The experimental results reveal that a narrow window of acid concentration of curing ink plays a crucial role in determining the electrical properties of the printed Zn nanoparticles. Highly conductive (~105 S m−1) and mechanically flexible printed Zn features are achieved. In addition, from systematic material characterization, we obtain an understanding of the curing mechanism. Finally, a touch sensor circuit is demonstrated involving all-Zn printed conductive tracks.

Using Sound to Synthesize Covalent Organic Frameworks in Water

Most covalent organic frameworks (COFs) are synthesized using solvothermal conditions (>120 °C, >72 h) in harmful organic solvents. We report a strategy for rapidly synthesizing imine-linked COFs (< 60 min) in aqueous acetic acid using sonochemistry, avoiding most of the downsides of solvothermal methods. We first synthesized seven known COFs using this method and obtained crystallinity and porosity comparable to or better than materials from previously reported solvothermal routes. This sonochemical method even works in highly sustainable solvents, such as food-grade vinegar. The generality of the method was demonstrated by preparing two unreported COFs. Finally, we showed that one sonochemical COF is an excellent photocatalyst for sacrificial hydrogen evolution from water with a more sustained catalytic performance than its solvothermal analog. The speed, ease and generality of this sonochemical method with no sacrifice in material quality makes it an enabling methodology for rapid discovery of new functional COF materials.

Using Sound to Synthesize Covalent Organic Frameworks in Water

Most covalent organic frameworks (COFs) are synthesized using solvothermal conditions (>120 °C, >72 h) in harmful organic solvents. We report a strategy for rapidly synthesizing imine-linked COFs (< 60 min) in aqueous acetic acid using sonochemistry, avoiding most of the downsides of solvothermal methods. We first synthesized seven known COFs using this method and obtained crystallinity and porosity comparable to or better than materials from previously reported solvothermal routes. This sonochemical method even works in highly sustainable solvents, such as food-grade vinegar. The generality of the method was demonstrated by preparing two unreported COFs. Finally, we showed that one sonochemical COF is an excellent photocatalyst for sacrificial hydrogen evolution from water with a more sustained catalytic performance than its solvothermal analog. The speed, ease and generality of this sonochemical method with no sacrifice in material quality makes it an enabling methodology for rapid discovery of new functional COF materials.

Preparation of Nanochitin/Polystyrene Composite Particles by Pickering Emulsion Polymerization Using Scaled-Down Chitin Nanofibers

In this study, we investigate the Pickering emulsion polymerization of styrene using scaled-down chitin nanofibers (SD-ChNFs) as stabilizers to produce nanochitin/polystyrene composite particles. Prior to emulsion polymerization, an SD-ChNF aqueous dispersion was prepared by disintegrating bundles of the parent ChNFs with an upper hierarchical scale in aqueous acetic acid through ultrasonication. After styrene was added to the resulting dispersions, the mixtures at the desired weight ratios (SD-ChNFs to styrene = 0.1:1–1.4:1) were ultrasonicated to produce Pickering emulsions. Radical polymerization was then conducted in the presence of potassium persulfate as an initiator in the resulting emulsions to fabricate the composite particles. The results show that their average diameters decreased to a minimum of 84 nm as the weight ratios of SD-ChNFs to styrene increased. The IR and 1H-NMR spectra of the composite particle supported the presence of both chitin and polystyrene in the material.