Biologically active sulfur-containing polyamides as promising anticancer materials

Thiazol-based molecules have practically infinite biological implementation. Today, there are many medical applications for compounds containing the thiazole moiety owing to their presence in most clinically applied anticancer drugs, such as dasatinib, dabrafenib, ixabepilone, patellamide A and epothilone. In this study, the polycondensation, of a new group of thiazole-containing polyamides with the formulas PA1-4 was carried out by the interaction of 2-aminothiazole diphenyl sulfide and variable diacid chlorides in dimethyl formamide in the presence of potassium carbonate anhydrous as a catalyst. Fourier transform-infrared spectroscopy (FTIR) was initially used to figure out the PA1-4 structures, which were further characterized using solubility, gel permeation chromatography (GPC), X-ray diffraction analyses (XRD) and scanning electron microscopy (SEM). The solubility results revealed that the presence of heteroaromatic thiazole ring units and sulfur content in the polyamides main chain, made the solubility easier as it increases the chain packing distance. From the values of average molecular weight, it was clear that all synthesized polyamides have almost the same chain length which ranged from 37,561.80 to 39,827.66. Moreover, the thermogravimetric analysis (TGA) confirm that PA1-4 were thermally stable even at high temperatures especially the polyamides which were synthesized from aromatic diacid chlorides. Furthermore, the newly synthesized polyamides were investigated for their antimicrobial properties against different species of Gram-positive and Gram-negative bacteria and also against different fungi. The results revealed that compound PA2 showed the highest antibacterial activity. Also, their inhibitory activity against breast carcinoma cells (MCF-7 cell line) and colon carcinoma cells (HCT cell line) was evaluated. It was clear that there was an enhancement in the anticancer activity for the synthesized polyamides owing to the presence of the thiazole moiety as well as sulfur linkage. According to the results of the 50% inhibitory concentration (IC50), the synthesized polymers were found to be more active against the MCF-7 cell line than the HCT cell line.

Conductive polythiophene/graphitic-carbon nitride nanocomposite for the detection of ethanol mixing in petrol

The automobile vehicles must be operated on fuel containing no more than 10% ethanol. Use of fuel having more than 10% ethanol may cause engine malfunction, starting and running issues, and material degradation. These negative impacts could cause irreversible damage to the vehicles. Therefore, ethanol mixing in petrol should be controlled below 10% level. The current work is the first to report sensing of ethanol mixing in petrol with reference to the variation in the DC electrical conductivity of polythiophene/graphitic-carbon nitride (PTh/gC₃N₄) nanocomposite. The in situ chemical oxidative method of polymerization was used for synthesizing PTh and PTh/gC₃N₄ nanocomposite. Fourier transform infrared spectroscopy (FT-IR), X-rays diffraction (XRD), thermo-gravimetric analysis (TGA), transmittance electron microscopy (TEM) as well as scanning electron microscopy (SEM) analysis were used for confirmation of the structure along with morphology of the PTh and PTh/gC₃N₄ nanocomposite. The thermal stability of DC electrical conductivity of PTh and PTh/gC₃N₄ nanocomposite were tested under isothermal and cyclic ageing condition. The sensing response of PTh and PTh/gC₃N₄ nanocomposite as a function of DC electrical conductivity were recorded in petrol and ethanol atmosphere. The sensing response of PTh/g-C₃N₄ nanocomposite in petrol atmosphere was 6.1 times higher than that of PTh with lower detection limit to 0.005 v/v% of ethanol prepared in n-hexane.

A Review on Conducting Polymers for Colorimetric and Fluorescent Detection of Noble Metal Ions (Ag+, Pd2+, Pt2+/4+, and Au3+)

Conducting polymers (CPs) are conductive materials composed of organic polymers. CPs have excellent properties such as easy synthesis and effortless fabrication, tunable electrical property, high environmental stability, high mechanical and optical properties. These unique properties have attracted researchers to discover a wide variety of uses, such as batteries, solar cells, sensors, supercapacitors, electrochromic devices, and biochemical applications. Although CPs have many limitations in their pristine form, hybridization with other materials overcomes these limitations. Here in this review article, we discuss different CPs based chemosensors for colorimetric and fluorimetric detection and determination of noble metal ions (Ag+, Pd2+, Pt2+/4+, and Au3+) in different environmental, agricultural, and biological samples. Further, the sensing performances of these chemosensors have been compared and discussed. We hope this article will help the readers with the future design of CPs based optical sensor (colorimetric and fluorescent) for detecting noble metal cations.

Cellulose Acetate-Cellulose Nanowhisker Nanocomposite Immobilized with a DCDHF-Hydrazone Chromophore toward a Smart Test Strip for Colorimetric Detection of Diethyl Chlorophosphate as a Nerve Agent Mimic

Exposure to nerve agents, which are usually colorless and odorless gases, may cause organ failure, paralysis, or even quick death. Diethyl chlorophosphate (DCP) has been recognized as one of the most well-known chemical warfare nerve agent mimics. In the current study, we introduce a simple strategy for the development of a portable and reversible nanocomposite-based microporous strip for naked-eye detection of DCP within a few seconds. A dicyanomethylenedihydrofuran hydrazone (DCDHF-H) chromophore was synthesized by an easy azo-coupling reaction and encapsulated in situ during the preparation of cellulose acetate/cellulose nanowhisker/hydrazone (CA-CNW-H) nanocomposites. These CA-CNW-H nanocomposites displayed a bathochromic shift in the absorption intensity of about 142 nm from 438 to 580 nm with the increase of the DCP concentration. The present CA-CNW-H sensor strip displayed a detection limit for DCP ranging from 25 to 200 ppm. The color change of CA-CNW-H from yellow to purple due to exposure to DCP was detected by CIE Lab analysis. The morphology, fibrous crystallinity, thermal stability, and mechanical properties of the prepared CA-CNW-H sensor strips were investigated.

Development of a Fluorescent Nanofibrous Template by In Situ SNAr Polymerization of Fluorine-Containing Terphenyls with Aliphatic Diols: Self-Assembly and Optical and Liquid Crystal Properties

Stimulus-responsive supramolecular organogels have been broadly studied, but the assembly of a liquid crystalline organogel with a thermoreversible response remains a challenge. This could be attributed to the difficulty of designing organogelators with liquid crystalline properties. Nucleophilic aromatic substitution (S_NAr) has been utilized to produce a diversity of pentafluorobenzene-containing aromatics, which are very regioselective to para positions. Those pentafluorobenzene-functionalized aromatics have been ideal compounds for the preparation of calamitic liquid crystals. In this context, novel fluoroterphenyl-containing main-chain polyether (FTP@PE) was synthesized using in situ S_NAr polymerization as a convenient and effective synthetic strategy toward the development of fluorescent liquid crystals bearing fluoroterphenyl and ether groups. The fluoroterphenyl unit was synthesized by Cu(I)-supported decarboxylation cross-coupling of potassium pentafluorobenzoate and 1,4-diiodobenzene. The chemical structures of FTP@PE were studied with ¹H/¹³C/¹⁹F nuclear magnetic resonance and infrared spectra. The liquid crystal mesophases were determined with differential scanning calorimetry and polarizing optical microscopy. Ultraviolet-visible absorbance and emission spectral profiles showed solvatochromic activity. The nanofibrous morphologies were studied with a scanning electron microscope. The organogels of FTP@PE were developed in a number of solvents via van der Waals attraction forces of aliphatic moieties and π stacking of fluoroterphenyl groups. They demonstrated thermoreversible responsiveness.

Responses of consumers with food allergy to the new allergen-labelling legislation in Saudi Arabia: a preliminary survey

OBJECTIVE

Preventing a food allergy reaction depends primarily on eliminating allergens from the diet. In October 2019, the Saudi Food and Drug Authority (SFDA) introduced new legislation requiring food establishments providing and selling non-prepacked foods to state the presence of the top fourteen food allergens on their menus. The current study aimed to assess the allergen-labelling knowledge, practices, preferences and perceptions towards the new SFDA allergen-labelling legislation among consumers with food allergy in Saudi Arabia.

DESIGN

Observational cross-sectional study using an online questionnaire.

SETTING

Saudi Arabia; February - March 2020.

PARTICIPANTS

Residents of Saudi Arabia with food allergy (n 427), aged 18-70 years.

RESULTS

Among participants, only 28·1 % knew that there were governmental regulations in Saudi Arabia regarding food-allergen labelling and approximately two-thirds (67 %) check labels on prepacked food products for allergens. The majority of the participants preferred food products carrying safety statements (84·1 %) and symbols (80·1 %). A total of 47·1 % were aware that regulations in Saudi Arabia require allergens to be declared in ingredient lists, while 51·3 % were aware that advisory allergen labelling is not required by law. Only 26·2 % were aware of the new SFDA legislation regarding provision of allergen information by food establishments. However, the majority (94·4 %) were supportive of the new legislation, and most of them were more likely to eat at restaurants that reported allergen information for food items on the menu.

CONCLUSIONS

The new SFDA food allergen-labelling legislation needs to be more widely and effectively disseminated to increase the level of awareness among adults with food allergy in Saudi Arabia.

Modification of Sulfonated Polyethersulfone Membrane as a Selective Adsorbent for Co(II) Ions

In the current study, a variety of sulfonated polyethersulfone (SPES)-based ion-exchange membranes were prepared and utilized as efficient and selective solid adsorbents for the detection of Co(II) ions in aquatic solutions. SPES membranes were treated with a variety of cations at a 2:1 ratio overnight. The produced materials were assessed via XRD, FT-IR, SEM, and TGA analyses. The structure of these materials was confirmed by FT-IR and XRD, which also confirmed the inclusion of Na⁺, NH₄⁺, and amberlite on the SPES surface successfully. TGA analysis showed that the thermal stabilities of these materials were enhanced, and the order of stability was NH₄-SPES > SPES > Na-SPES > A-SPES. Furthermore, the efficiency of these modified membranes for the determination and adsorption of a variety of metal ions was also examined by the ICP-OES analytical technique. A-SPES expressed a powerful efficiency of adsorption, and it showed an efficient as well as quantitative adsorption at pH = 6. Moreover, A-SPES displayed the highest adsorption capacity of 90.13 mg/g for Co(II) through the Langmuir adsorption isotherm.

Network structure-based decorated CPA@CuO hybrid nanocomposite for methyl orange environmental remediation

A unique network core-shell hybrid design-based cross-linked polyaniline (CPA), which was coated with CuO nanoparticles (NPs) and decorated with nitrogen-doped SWCNT/GO/cellulose N-SWCNTS-GO-CE, has been fabricated using the oxidative polymerization technique. This hybrid nanocomposite shows excellent photocatalytic degradation and an acceptable adsorption capability for Methyl Orange (MO) dye in aqueous solutions with a very slight effect for the N-SWCNTS-GO-CE CuO component. The prepared nanocomposites were used for the removal of a carcinogenic and noxious dye, Methyl Orange, from aqueous samples under various adsorption conditions. Approximately 100% degradation of 10 mg/L of Methylene orange dye was observed within 100 min at pH 6.0 using 50 mg/L CPA/N-SWCNTS-GO-CE/CuO nanocomposite under UV radiation. Additionally, significant factors were investigated on the degradation process including the contact time, MO initial concentration (Ci), solution pH, and dosage of the CuO nanocomposite. All investigated experiments were performed under UV radiation, which provided significant data for the MO degradation process. Furthermore, the recovery of the nanocomposite was studied based on the photocatalytic process efficiency. The obtained data provide the high opportunity of reusing CPA/N-SWCNTS-GO-CE/CuO nanocomposite for numerous photocatalytic processes. The CPA/N-SWCNTS-GO-CE/CuO nanocomposite was prepared via chemical oxidative copolymerization of polyaniline (PANI) with p-phenylenediamine (PPDA) and triphenylamine (TPA) in the presence of N-SWCNTS-GO-CE and CuO NPs. The morphology, structure and thermal properties of the CPA/N-SWCNTS-GO-CE/CuO nanocomposite were investigated using various techniques, including FTIR, XRD, RAMAN, SEM, MAP, EDX, TEM, TGA and DTG. Therefore, CPA/N-SWCNTS-GO-CE/CuO nanocomposite can be effectively used as a convenient and reusable adsorbent to remove hazardous dye from wastewater.

Time course evaluation of lacosamide alone and in polypharmacy on behavioral manifestations and oxidative stress in lithium-pilocarpine-induced model

The lithium-pilocarpine model in rats is commonly used to study the characteristic events of acute status epilepticus (SE), epileptogenesis and temporal lobe epilepsy (TLE). Here we investigated the impact of lacosamide alone and in combination with other drugs (pregabalin, piracetam and scopolamine) on spontaneous recurrent seizures (SRSs) and behavioral parameters during the time frame of 6 weeks after SE. In addition, the level of oxidative stress in the hippocampus was accessed by real-time microdialysis study (8-isoprostanes) and antioxidants enzymes in the homogenate. Results revealed severe behavioral deficits with the control epileptic group and animals displayed hyperexcitability, aggression apprehension and memory insufficiency. Pharmacological manipulation for 6 weeks with lacosamide (L) - 80 mg/kg; in polypharmacy with pregabalin (L/P) - 50/50 mg/kg and piracetam (L/Pi) - 50/140 mg/kg significantly (P < 0.05) ameliorated the anxiety-related behavior (open filed, elevated plus maze, light/dark tests), depression (forced swim test) and improved spatial/reference memory (Morris water maze). There were low incidences of seizures in L, L/P and L/Pi groups revealing disease-modifying effects of employed drugs. Furthermore, the chronic use of scopolamine (L/P/S; 50/50/2 mg/kg) as polypharmacy with the concept of antagonizing the cholinergic inputs in the epileptogenic phase aberrated the behavioral situation further worse. Treatments with L/P and L/Pi significantly attenuated (P < 0.05) the oxidative stress by reducing 8-isoprostanes and malondialdehyde (MDA) levels. Furthermore, superoxide dismutase (SOD) and glutathione peroxidase (GPx) levels in the L/P group were significantly (P < 0.05) improved. Overall, our findings support the use of a combination of drugs (L/P and L/Pi) in lithium-pilocarpine model which remarkably ameliorated SRSs, reduced anxiety-related behaviors, retention of spatial/reference memory and lowered oxidative stress in a time-course evaluation 6 weeks post- SE insult.