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Several neurological disorders, including Parkinson's disease, schizophrenia, human immunodeficiency virus infection, and restless leg syndrome, majorly result from disruption in the dopamine (DA) level. Thus, useful information about the treatment and prevention of various genetic majorly mental health problems can be obtained through precise and real-time monitoring of DA. Herein, we report the fabrication of novel N-rich carbon-coated Au nanoparticles (NC@Au-NPs) by deriving from melamine-crosslinked citrate-stabilized Au NPs. NC@Au-NPs offer fast electro-oxidation efficacy towards DA, because of strong electrostatic attraction between negatively charged NC@Au-NPs and positively charged DA. The catalytic efficacy and shelf life of the designed system were further boosted by applying a mixture of polydopamine (PDA) and benzimidazolium-1-acetate ionic liquid (IL) as a sandwich between the working electrode surface (graphitic pencil electrode: GPE) and the designed nanohybrid NC@Au-NPs as a redox mediator. The results indicate that the designed novel NC@Au/PDA-IL/GPE exhibits excellent sensitivity, selectivity, and reproducibility over a wide linear range (50-1000 nm) and a low detection limit of 0.002 μM ± 0.001 as well. The developed sensor was successfully applied to monitor DA in the blood of COVID-19 quarantined patients and pharmaceutical samples with high accuracy, thus suggesting a powerful tool for the diagnosis of mental problems.

The present study aimed to synthesize poly(acrylic acid) hydrogel embedded with magnetic cobalt (Co) nanoparticles and to investigate their potential in adsorption and catalysis. The hydrogel was prepared by facile free radical polymerization reaction and Co nanoparticles were fabricated within hydrogel by reducing Co (II) ions using NaBH4 as reducing agent. Co nanoparticles within hydrogel system imparted magnetic properties to the resulting composite gel and also increased the adsorption capacity. The swelling study of hydrogel was carried out by gravimetric analysis. Different functional groups were identified by Fourier Transform Infrared Spectroscopy and Transmission Electron Microscopy analysis was done to investigate dispersion of Co nanoparticles in hydrogel. The bare hydrogel along with Co nanoparticles loaded gel were tested as adsorbent systems for the removal of a cationic dye (methylene blue) from aqueous solution. 95% removal of methylene blue was achieved with a highest adsorption capacity of 836.5 mg/g of adsorbent. The famous adsorption isotherms were used to evaluate adsorption data. Results showed that Freundlich isotherm model was followed with R2 value of 0.95. The hydrogel was also used for catalytic reduction in a toxic pollutant, i.e., 4-nitrophenol. Experimental data for 4-nitrophenol reduction followed pseudo first order kinetics model. Activation energy and apparent rate constant were calculated as 9.24 kJ/mol and 0.24 min−1, respectively. Recycling of the magnetic poly(acrylic acid) hydrogel fabricated with Cobalt nanoparticles was carried out for four consecutive cycles and no significant loss in catalytic activity was observed.

Homopolymer bulk hydrogel of methacrylic acid was synthesized through a new single-step facile rout and used as a template for the fabrication of nickel (Ni) nanoparticles and as adsorbent to remove methylene blue (MB) and Rhodamine-6G (Rh-6G) from water. The Ni nanoparticles containing composite hydrogel was applied as catalyst for the degradation of a nitro compound. The carboxylic groups acted as highly efficient adsorption sites and their high degree was responsible for the removal of huge amounts of MB and Rh-6G from water. The maximum adsorption capacity of poly (methacrylic acid) hydrogel was 685 mg g−1 for MB and 1571 mg g−1 for Rh-6G. The adsorption data of MB was best fitted with Langmuir adsorption isotherm while that of Rh-6G with Temkin adsorption isotherm. Catalytic property of prepared hydrogel integrated with Ni nanoparticles was evaluated by using it as a catalyst for the degradation of 4-nitrophenol (4-NP). The apparent rate constant (k app) observed in this study for the reduction of 4-NP was as high as 0.038 min−1. It was found that this catalyst system can be used repetitively with a slight decrease in catalytic activity.

Herein, we synthesized hollow cubic caves of CuO (HC) and wrapped it with N-rich graphitic C (NC), derived from a novel biogenic mixture composed of dopamine (DA) and purine. The synthesized NC wrapped HC (NC@HC) sensor shows enhanced electrocatalytic efficacy compared to unwrapped CuO with shapes including HC, sponge (SP), cabbage (CB), and solid icy cubes (SC). The shape and composition of synthesized materials were confirmed through field-emission scanning electron microscopy (FE-SEM), X-ray diffraction (XRD), Raman spectroscopy, and X-ray photoelectron spectroscopy (XPS), whereas interfacial surface energy was calculated through contact angle measurement. The designed NC@HC sensor shows a remarkable response toward the simultaneous detection of uric acid (UA) and xanthine (Xn) with detection limits of 0.017 ± 0.001 (S/N of 3) and 0.004 ± 0.001 μM (S/N of 3), respectively. In addition, this platform was successfully applied to monitor UA from the gout patient serum. To the best of our knowledge, this is the first report on using such novel NC@HC materials for the simultaneous monitoring of UA and Xn.

Anionic hydrogel was prepared by free radical copolymerization of acrylamide and acrylic acid. The anionic groups acted as adsorption sites to load Ni(II) ions and the subsequent reduction of loaded Ni(II) ions into nanoparticles enabled the prepared hydrogels to act template for the preparation of nanostructured Ni particles. The characteristics of the prepared hydrogel and hydrogel–nickel nanoparticle composite were studied with Fourier transform infrared spectroscopy, transmission electron microscopy, thermal gravimetric analysis, X-ray photoelectron spectroscopy and X-ray diffraction technique. Swelling behaviour of hydrogel in aqueous medium was analysed by gravimetric analysis. Catalytic performance of the prepared poly(acrylamide-co-acrylic acid)–nickel nanoparticle hydrogel composite was investigated in the reduction of 4-nitrophenol (4-NP). Effects of temperature and catalyst dose on the reduction rate were also studied. Activation energy (Ea) for the reduction of 4-NP was found to be 43.46 kJ/mol. A maximum reduction rate of 0.40 min−1 was observed at room temperature.

Design of effective and efficient nanoscale sensor for the selective monitoring of hydrogen peroxide (H 2 O 2 ) in environmental samples is of great requirement to avoid several diseases; not only but also include diabetes, cancer, cardiovascular disorders, aging and Alzheimer. Herein, we report the fabrication of highly stable silver nanoparticles (Ag NPs) with three different phases (i.e spherical (Sp), star (St) and pyramidal (Py)) via simple wet chemical approach. Among all the three phases, St-Ag-NPs with more exposed catalytic active sites, poor dipolar non-radiative plasmons multipoles and large number of surface defects which in turn enhance ion(s) diffusion between electrode-electrolyte interfaces; shows highest performance in terms of linear range, limit of detection and sensitivity. We observe no interference between electro-active organic compounds (ascorbic acid (AA), uric acid (UA), dopamine (DA) and glucose) and inorganic (NaCl, KCl, Na 2 SO 4 and K 2 SO 4 ) species on the as-fabricated St-Ag-NPs based electrode. Furthermore, We were able to account for the amount of H 2 O 2 generated in the discharged water (effluent) from a poultry firm using the designed St-Ag-NPs based electrode over a wide linear range (∼5 mM) in the presence of co-existing electro-active species. These results show reliability of our designed electrode as useful sensing materials for the detection and monitoring of H 2 O 2 mismanagement in an immediate environment.

Polysaccharides derived from plants are one of the largest groups of natural compounds that offer potentially beneficial functions and properties. Glucomannan, a bioactive polymer belonged to mannan family of polysaccharides is fairly abundant in nature along with superior gelling and film forming properties. Glucomannan and its derivative with several synthetic polymers are used in a biomedical and food sector especially. Polyurethanes (PUs), a commercially useful class of polymers are extensively used in both industry and everyday life because they retain exceptional properties of both plastics and elastomers. This review addresses the properties and applications of glucomannan based materials with the aim to be explored this less attempted polymer further. Furthermore this paper also presents an overview of current status and perspectives of glucomannan based polyurethane materials.

The transition metal complexes (Cu(II) and Co(II)) of ferrocene-based thiosemicarbazones hitherto were synthesized (compounds 13–39) by the condensation of different thiosemicarbazides with acetylferrocene in presence of catalytic amount of acetic acid, characterized and their inhibitory potential against acetylcholinesterase (AChE) and butyrylcholinesterase (BChE) was evaluated. Both the ligands and their metal complexes in general showed moderate to potent inhibition activity against the said enzymes. All the Cu(II) complexes were found more potent than their respective ligands or with complexes of other metals. Similarly, the studied Co(II) complexes also showed potent inhibition of enzymes inhibition and was found even higher than the standard “Eserine” but with slightly higher IC50 values than that of Cu(II) complexes. In silico studies supported the structure activity relationship of the compounds.

This study reports on a simple approach for the fabrication of an electrode modified with biocompatible C-dot wrapped ZnO nanoparticles for selective photoelectrochemical monitoring of H2O2 released from living cells. The biocompatibility of the ZnO nanoparticles was confirmed through in-vitro cellular testing using the MTT assay on Huh7 cell lines. The ZnO nanoparticles wrapped with dopamine-derived C-dots possess numerous catalytically active sites, excessive surface defects, good electrical conductivity, and efficient separation ability of photo-induced electrons and holes. These properties offer highly sensitive and selective non-enzymatic photo-electrochemical monitoring of H2O2 released from HeLa cells after stimulation with N-formylmethionyl-leucyl-phenylalanine. The sensor has a wide linear range (20–800 nM), low detection limit (2.4 nM), and reliable reproducibility, this implying its suitability for biological and biomedical applications.

Some novel imine derivatives (1-14) of a broad spectrum antibiotic amoxicillin were prepared by condensation with different carbonyl compounds. The amoxicillin imine derivatives were characterized using elemental analysis and spectroscopic techniques such as FT-IR and 1 H NMR. The prepared imine derivatives were evaluated for antimicrobial activities against some pathogens using disc diffusion method. The results of present studies demonstrate enhanced antimicrobial activity of the novel imine derivatives of amoxicillin as compared to the parent drug.

Arsenic contamination in drinking water is alarming for human beings; especially for those people who use ground water directly for drinking purposes. Attempts were made to design adsorbents for the removal of arsenic. Silica gel has been tested as adsorbent for such removal. After optimizing concentration, time and amount of adsorbent, Langmuir, Freundlich and D-R isotherms are drawn to determine different parameters for the evaluation of arsenic adsorption. Kinetics of adsorption is also calculated by using pseudo first order and pseudo second order rate equations. Zerovalent iron and manganese nanoparticles have been coated on silica gel and efficiency of removal of arsenic have been determined. Iron and manganese particles have been stabilized with polyvinyl alcohol (PVA). Similarly mixtures of iron-silver and manganese-silver nanoparticles have been synthesized by stabilizing with PVA, which show better efficiency than individual nanoparticles of iron and manganese coated silica gel. The newly synthesized adsorbents are very much effective for not only arsenic but also for antimicrobial activity. Concentration of arsenic in water has been determined spectrophotometrically using variamine blue as indicator.

The applications of thioureas in crystal engineering have increased dramatically over the past few years. However, their analogs namely N-imino thioureas/thiosemicarbazones are largely ignored, despite the fact that these can be more interesting with respect to crystal engineering applications due to the presence of an additional N-imino moiety. Aiming to highlight their importance in crystal engineering/supramolecular chemistry, three structurally related coumarin–thiosemicarbazone hybrids (3a–3c) have been designed, synthesized and crystallographically characterized. All of the compounds showed a general preference for the adoption of the cis, trans conformation around the central thiourea moiety; a conformation which is ideal for the formation of a dimeric hydrogen-bonded R22(8){⋯H–N–CS}2 synthon as the building block. Therefore, this dimeric synthon is observed in all of the compounds, regardless of the formation of layered to cage-like three dimensional supramolecular networks depending on different substituents. The prevalence of the cis, trans conformation and the robustness of the thioamide dimer synthon in thiosemicarbazones indicate its potential use as a design element in crystal engineering.

The role of thioureas in crystal engineering as robust supramolecular synthons is now recognized, but their analogs, namely thiosemicarbazones/N-iminothioureas, have not received the attention they deserve. A series of five structurally related ferrocene-based thiosemicarbazones 1–5 have been designed, synthesized and crystallographically characterized in order to investigate the prevalence of the thioamide dimer synthon and carbon bonding. All of the compounds have shown a general preference for the adoption of the cis, trans conformation about the central thiourea moiety which is ideal for the formation of a dimeric hydrogen-bonded R22(8) {⋯H–N–CS}2 synthon as the building block. Therefore, this dimeric synthon is observed in all of the compounds, with the methyl group particularly set for playing its supportive stabilization role through C–H⋯S and carbon bonding interactions. Carbon bonding has been observed in all of the compounds except compound 2. The centrosymmetrically arranged thioamide protons present in trans conformation through N–H⋯H–C interactions give rise to the formation of tapes of varying topology in all of the compounds except 3, where a staircase arrangement of dimeric molecules is observed. Another notable feature of the crystal packing of 1–5 is the presence of thioamide–thioamide stacking, which has been observed in all five compounds. The prevalence of the thioamide dimer synthon, carbon bonding, and observation of new thioamide–thioamide stacking interactions indicate a much larger role for this class of compounds as a design element in crystal engineering than anticipated so far.

Arsenic and nitrate are ill-famed environmental pollutants that are responsible for various lethal diseases. Their removal from drinking water is very essential. In present study, newly synthesized alumina supported nano zero- valent zinc (Alumina-nZvZ) has been tested to remove arsenic and nitrate. Quantitative analyses of arsenic have been performed spectrophotometrically and while that of nitrates ions colorimetrically. After optimization of time and amount of adsorbent, Langmuir, Freundlich and D-R isotherms were applied to determine different parameters for the assessment of adsorption. Synthesized samples were characterized by scanning electron microscopy (SEM) to evaluate porosity and void size. Alumina coated with reduced ZnCl2 showed better efficiency for removal of arsenic and nitrate ions. Kinetics of adsorption was evaluated by using pseudo first-order and pseudo second-order rate equations.

Sulfonamide Schiff bases were doped uniformly in silica sol–gels prepared from liquid precursors by a fast and easy way at room temperature and processed to form xerogels. Schiff bases are efficient chelating agents, bioactive and catalytically active compounds. The structures of the newly synthesized Schiff base doped xerogels were elucidated by their physical (morphology, surface area, porosity), spectral (FTIR) and analytical (CHNSO/Si) data. The powder X-ray diffraction studies were carried out to confirm the formation of single phase. Characterization confirmed that Schiff base molecules are entrapped inside the pores as well as physically bound onto the silica surface. All Schiff base doped xerogels are stable mesoporous materials showing hydrophilic properties. Loadings of Schiff bases from 0.10 to 0.23 g/g of xerogel were obtained resulting amorphous materials. The doping of Schiff bases with xerogel caused change in surface area, pore volume and pore diameter of xerogel without damaging the main framework of siliceous skeleton. Morphology and colour of xerogel was also changed after doping. The entrapment of Schiff bases in xerogel caused increase in their decomposition temperatures. The final Schiff base doped xerogels show remarkable thermal stability.

The effect of solvent concentration and time on the extraction efficiency of tannins from root, stem, leaves, and seeds of Cichorium intybus L. was studied. A 22-factorial central composite design was employed by using response surface methodology to optimize the extraction conditions. The analysis of variance showed the significant effect of both variables on the extraction yield of tannins. The lower P-values (P < 0.05) indicated the positive significant effect of both variables on the extraction of tannins from different parts ofC. intybus. The values of correlation coefficient (R2) indicated that more than 96% of the variability in tannins content of C. intybus could be explained by response surface model. The 3D surface plots showed a quadratic effect of methanol concentration and linear effect of time on the extraction efficiency of tannins from C. intybus. The optimum tannins yield of 0.607, 0.529, 0.26, and 0.431 g/100 g dry weight from root, stem, leaves, and seeds of C. intybus, respectively was observed at 60% methanol concentration and extraction time of 80 min. Moreover, the data suggests that C. intybus is a rich source of tannins and can be preferably used to fulfil the requirements of tannins in medicinal field. Key words: Cichorium intybus L., chicory, medicinal plants, tannins extraction, central composite design (CCD), response surface methodology (RSM).

The condensation of homophthalic acid 6 with the appropriate acid chlorides 7a-c yield the respective isocoumarins 8a-c, which are converted to keto-acids 9a-c by alkaline hydrolysis. The 3,4-dihydroisocoumarins 12a-c areobtained by reduction of the keto-acids 9a-c to hydroxy-acids 11a-c followed by cyclodehydration using acetic anhydride.