Showing papers by "Inamuddin published in 2020"

Nano-engineered Adsorbent for the Removal of Dyes from Water: A Review

Abstract: The huge quantity of wastewater, containing poisonous and hazardous dyes, is released by various industries which pollute water in direct and indirect ways. Most of the dyes are a dangerous class of water contaminants which have affected the environment drastically. Some dyes such as congo red, rhodamine B, methylene blue, methyl violet, and crystal violet are a serious threat to human beings. Numerous methods are available for the removal of dyes from water. Adsorption, being a superior and eco-friendly technique, has advantage of eliminating organic dyes because of the availability of materials as adsorbents. The inexpensive nanomaterials are a more attractive choice for remediation of various dyes due to their unique properties and offer an adequate pathway to adsorb any organic dye from water to overcome its hazardous effects on human health. In this review, we have discussed the latest literature related to various types of synthesis, characterization and uses as adsorbent for highly adsorptive removal capacity of nanoparticles for organic dyes. Adsorption technology provides an attractive pathway for further research and improvement in more efficient nanoparticles, with higher adsorption capacity, for numerous dyes to eliminate the dyes discharged from various industries and thus reduce the contamination of water. Therefore, nanocomposites may contribute to future prospective water treatment process.

Carbon nanotube-based adsorbents for the removal of dyes from waters: A review

Abstract: Contamination of water is calling for new techniques to provide safe and clean water for drinking and other usages. Among existing techniques of wastewater treatment, adsorption is one of the most efficient methods. Recently, carbon nanotube-based adsorbents are attracting research and industrial attention due to their large surface area, cylindrical hollow structure and well-flourished mesopores. Raw carbon nanotubes can be modified and adapted to the intended applications and targeted pollutants. Here we review the efficacy of unmodified and modified carbon nanotubes for the removal of dyes from wastewater. Reports show that chemical modification leads to an improvement of the adsorption capacity. The adsorption of dyes on carbon nanotubes depends on the nature of the adsorbent and adsorbate. Adsorption mechanisms involve van der Waals forces, π–π stacking, hydrophobic interactions, hydrogen bonding and electrostatic interactions. Nonetheless, hydrophobicity and cost actually restrict practical applications.

Green synthesis of ZnO nanoparticles decorated on polyindole functionalized-MCNTs and used as anode material for enzymatic biofuel cell applications.

Abstract: Presently, one of the most important aspects for the development of enzymatic biofuel cells (EBFCs) is to synthesize the novel electrode materials that possess high current density, low open-circuit voltage (OCV) and long-term stability. To achieve the above attributes, lots of new strategies are being used by the researchers for the development of advanced materials. Nowadays, nanomaterials and nanocomposites are the promising material that has been utilized as effective electrode material in solar cells, supercapacitors and biofuel cells application. Herein, we account for a novel electrocatalyst as electrode material that comprised ZnO nanoparticles decorated on the surface of polyindole (PIn)-multi-walled carbon nanotube (MWCNT), for the immobilization of glucose oxidase (GOx) enzyme and mediator (Ferritin). The PIn-MWCNT scaffold is prepared via in situ chemical oxidative polymerization of indole on the surface of MWCNT and assessed by myriad techniques. The micrograph of scanning electron microscopy (SEM) designated the interconnected morphology of MWCNTs in the polymer matrix. X-ray diffraction spectroscopy (XRD) and Fourier transform infrared spectroscopy (FTIR), confirm the crystallinity and different functional groups available in the synthesized material, respectively. The electrochemical assessment demonstrates that the ZnO/PIn-MWCNT/Frt/GOx nanobiocatalyst exhibits much higher electrocatalytic activity towards the oxidation of glucose with a maximum current density of 4.9 mA cm-2 by consuming 50 mM glucose concentration in phosphate buffer saline (PBS) (pH 7.4) as the testing solution by applying 100 mVs-1 scan rates. The outcomes reflect that the as-prepared ZnO/PIn-MWCNTs/Frt/GOx biocomposite is a promising bioanode for the development of EBFCs.

Applications of chitosan (CHI)-reduced graphene oxide (rGO)-polyaniline (PAni) conducting composite electrode for energy generation in glucose biofuel cell

Abstract: A glassy carbon electrode (GC) immobilized with chitosan (CHI)@reduced graphene (rGO)-polyaniline (PAni)/ferritin (Frt)/glucose oxidase (GOx) bioelectrode was prepared The prepared electrode was characterized by using cyclic voltammetry (CV), linear sweep voltammetry (LSV) and electrochemical impedance spectroscopy (EIS) techniques The morphological characterization was made by scanning electron microsopy (SEM) and Fourier transform infrared (FTIR) spectroscopy This bioelectrode provided a stable current response of 35 ± 002 mAcm−2 in 20 mM glucose The coverage of enzyme on 007 cm2 area of electrode modified with CHI@rGO-PAni/Frt was calculated to be 380 × 10−8 mol cm−2

Thermal energy storage and thermal conductivity properties of Octadecanol-MWCNT composite PCMs as promising organic heat storage materials

Abstract: Fatty alcohols have been identified as promising organic phase change materials (PCMs) for thermal energy storage, because of their suitable temperature range, nontoxicity and can be obtained from both natural and synthetic sources. Like all other organic PCMs, octadecanol (OD) as PCM suffers from low thermal conductivity (TC). In this work, to enhance its TC, it was grafted on the functionalized MWCNT and were used as a conductive filler to enhance overall thermal properties of OD in a composite PCM (CPCMs) structure. The OD/OD-g-MWCNT sample showed better dispersion within the composites and the presence of additional OD boosted the overall heat storage enthalpy compared to that of plane composite sample with OD/MWCNT. In a non-quantitative approach, it was observed that, any increase in grafting ratio of OD increases the heat storage enthalpy of the composites. The heat storage enthalpy of (267.7 J/g) OD/OD-g-MWCNT(4:1)-5wt% composite PCM had reached very close to the heat storage enthalpy value of pure OD (269.3 J/g), and much higher than that of OD/MWCNT-5wt% (234.5 J/g). Champion sample i.e. OD/OD-g-MWCNT (4:1)-5wt%, showed good heat storage enthalpy, cycling performance, thermal stability and TC enhancement by 262.5%.

Green Synthesis of Silver Nanoparticles and Evaluation of Their Antibacterial Activity against Multidrug-Resistant Bacteria and Wound Healing Efficacy Using a Murine Model.

Abstract: Green nanotechnology has significant applications in various biomedical science fields. In this study, green-synthesized silver nanoparticles, prepared by using Catharanthus roseus and Azadirachta indica extracts, were characterized using UV-Vis spectroscopy, dynamic light scattering, X-ray diffraction, scanning electron microscopy, and transmission electron microscopy. Silver nanoparticles (Ag NPs) synthesized from leaf extracts of C. roseus and A. indica effectively inhibited the growth of multidrug-resistant (MDR) bacteria isolated from patients with septic wound infections. The maximum bacteriolytic activity of the green-synthesized Ag NPs of C. roseus and A. indica against the MDR bacterium K. Pneumoniae was shown by a zone of inhibition of 19 and 16 mm, respectively. C. roseus Ag NPs exhibited more bacteriolytic activity than A. indica Ag NPs in terms of the zone of inhibition. Moreover, these particles were effective in healing wounds in BALB/c mice. Ag NPs of C. roseus and A. indica enhanced wound healing by 94% ± 1% and 87% ± 1%, respectively. Our data suggest that Ag NPs from C. roseus and A. indicia ameliorate excision wounds, and wound healing could be due to their effective antimicrobial activity against MDR bacteria. Hence, these Ag NPs could be potential therapeutic agents for the treatment of wounds.

Thermal energy storage and thermal conductivity properties of fatty acid/fatty acid-grafted-CNTs and fatty acid/CNTs as novel composite phase change materials

Abstract: In recent year, fatty acids (FAs) are heavily studied for heat storage applications and they have shown promising advantages over other organic phase change materials (PCMs). Among the FAs; capric, palmitic and stearic acids are the most studied PCMs. Several researchers have investigated these FAs and tried to improve their thermal properties, mainly by adding different high conducting fillers, such as graphite, metal foams, CNTs, graphene etc. In most cases, these fillers improved the thermal conductivity and heat transfer property but reduce the heat storage capacity considerably. These composites also lose the mixing uniformity during the charging and discharging process. To overcome these issues, selected FAs were grafted on the functionalized CNT surfaces and used as conductive fillers to prepare FA based composite PCMs. This process significantly contributed to prevent the drastic reduction of the overall heat storage capacity and also showed better dispersion in both solid and liquid state. Thermal cycling test showed the variations in the thermal energy storage values of all composite PCMs, however, within the tolerable grade and they had appreciable phase change stability and good chemical stability even after 2,000 cycles.

One-pot biosynthesis of silver nanoparticle using Colocasia esculenta extract: Colorimetric detection of melamine in biological samples

Abstract: Here we report an eco-friendly and robust silver nanoparticles (AgNPs) as a simple and sensitive probe for the detection of melamine in biological samples. The AgNPs were synthesized using the extract of Colocasia esculenta. The spherical shaped and monodispersed AgNPs were obtained with an average particle size of 20 nm. The as synthesized colorimetric probe was morphologically and spectroscopically characterized using transmission electron microscope and fourier-transform infrared and UV–vis spectrometry respectively. This method is based on the melamine induced aggregation of AgNPs, hence, color changes from yellow to orange red. Various experimental parameters such as effect of pH and time on the detection of melamine was investigated to enhance the sensitivity of the developed method. Under optimized conditions, the limit of detection and limit of quantification were found to be 0.070 ppm and 1.60 ppm respectively with a recovery values ranging from 95.0–103%. The findings of this study resulted in the development of highly sensitive and selective sensing probe for the detection of melamine in biological samples.

Application of Electrically Conducting Nanocomposite Material Polythiophene@NiO/Frt/GOx as Anode for Enzymatic Biofuel Cells.

Abstract: In this work, nano-inspired nickel oxide nanoparticles (NiO) and polythiophene (Pth) modified bioanode was prepared for biofuel cell applications. The chemically prepared nickel oxide nanoparticles and its composite with polythiophene were characterized for elemental composition and microscopic characterization while using scanning electron microscopy. The electrochemical characterizations of polythiophene@NiO composite, biocompatible mediator ferritin (Frt) and glucose oxidase (GOx) catalyst modified glassy carbon (GC) electrode were carried out using cyclic voltammetry (CV), linear sweep voltammetry (LSV), and charge-discharge studies. The current density of Pth@NiO/Frt/GOx bioanode was found to be 5.4 mA/cm2. The bioanode exhibited a good bio-electrocatalytic activity towards the oxidation of the glucose. The experimental studies of the bioanode are justifying its employment in biofuel cells. This will cater a platform for the generation of sustainable energy for low temperature devices.

Simultaneous detection of ethambutol and pyrazinamide with IL@CoFe2O4NPs@MWCNTs fabricated glassy carbon electrode.

Abstract: For the first time, we report a novel electrochemical sensor for the simultaneous detection of ethambutol (ETB) and pyrazinamide (PZM) using 1-ethyl-3-methylimidazolium tetrafluoroborate ([Emim][BF4]) ionic liquid (IL) assimilated with multiwalled carbon nanotubes (MWCNTs) decorated cobalt ferrite nanoparticles (CoFe2O4NPs) on the surface of glassy carbon electrode (GCE). The surface morphological and electrochemical properties of the IL@CoFe2O4NPs@MWCNTs was characterized with X-ray diffraction (XRD), transmission electron microscope (TEM), thermogravimetric analysis (TGA), fourier transform infrared spectroscopy (FTIR) and cyclic voltammetry (CV), differential pulse voltammetry (DPV) respectively. Moreover, the obtained results of CV demonstrated that the 9-folds enhancement in the electrochemical signals was achieved with IL@CoFe2O4NPs@MWCNTs@GCE compared to that of a bare GCE. Additionally, the simultaneous electrochemical detection of ETB and PZM was successfully accomplished using IL@CoFe2O4NPs@MWCNTs over a wide-range of concentration with good limit of detection (3S/m) of 0.0201 and 0.010 μM respectively. The findings of this study identify IL@CoFe2O4NPs@MWCNTs@GCE has promising abilities of simultaneous detection of ETB and PZM in pharmaceutical formulations.

Optimization of rGO-PEI/Naph-SH/AgNWs/Frt/GOx nanocomposite anode for biofuel cell applications

Abstract: The present study reports a new nanocomposite design using surface modified silver nanowires decorated on the surface of polyethyleneimine (PEI), a cationic polymer acting as glue for anchoring nanowires and reduced graphene oxide (rGO). The synthesized nanocomposite was employed as a promising electrode material for immobilization of biomolecules and effective transportation of electron, in enzymatic biofuel cell (EBFCs) application. The synthesized nanocomposite was confirmed by analytical techniques, for instance, Fourier transform infrared spectroscopy (FTIR), scanning electron microscopy (SEM), transmission electron microscopy (TEM). The electrochemical behaviour of the nanobioelectrocatalysts rGO-PEI/Frt/GOx, rGO-PEI/AgNWs/Frt/GOx, and rGO-PEI/Naph-SH/AgNWs/Frt/GOx was determined by cyclic voltammetry (CV), electrochemical impedance spectroscopy (EIS), and linear sweep voltammetry (LSV). The maximum current density obtained by the modified bioanode was found to be 19.9 mA cm−2 at the limiting glucose concentration of 50 mM in PBS (pH 7.0) as supporting electrolyte at a scan rate of 100 mVs−1.

Improved separation of dyes and proteins using membranes made of polyphenylsulfone/cellulose acetate or acetate phthalate

Abstract: Industrial wastewater often contains xenobiotics such as heavy metals, dyes and proteins, yet there is a lack of efficient cleaning methods. Therefore, here we fabricated hollow fiber membranes using polyphenylsulfone containing 1, 3 and 5 wt% of cellulose acetate and cellulose acetate phthalate by non-solvent induced phase separation. Membrane morphology was characterized by field emission scanning electron microscopy. The hydrophilicity of the membranes was measured by contact angle, water uptake and porosity measurement. The thermal miscibility of the membrane with additives was assessed by thermogravimetric analysis. Hollow fiber membranes were tested for separation of azo dyes, e.g., reactive orange 16 and reactive black 5, and of proteins: bovine serum albumin, egg albumin and pepsin. Results show increasing rejection of dyes and proteins with the content of cellulose acetate and cellulose acetate phthalate. Water permeability was 41.26 L/m2 h bar for the polyphenylsulfone membrane, 64.47 L/m2 h bar for the polyphenylsulfone/5 wt% cellulose acetate membrane and 72.60 L/m2 h bar for the polyphenylsulfone/5 wt% cellulose acetate phthalate membrane.

Experimental and Computational Studies of a Laccase Immobilized ZnONPs/GO-Based Electrochemical Enzymatic Biosensor for the Detection of Sucralose in Food Samples

Abstract: Monitoring of high intensity artificial sweeteners in the food industry for environmental and human health has become relevant in recent years. This work exploits the electrocatalytic properties of the laccase enzyme for sensing of a high intensity sweetener sucralose experimentally and supported by computational modeling. The fabrication of the laccase biosensor was achieved using laccase immobilized onto zinc oxide nanoparticles (ZnONPs) capped with p-amino thiophenol (ATP) and covalently attached to graphene oxide (GO) modified glassy carbon electrode (Lac/ZnONPs-ATP-GO/GCE). The developed biosensor exhibited an 8-fold enhancement of differential pulse voltammetry signals compared with the bare GCE at pH 5.0 in a 0.1 M phosphate buffer. The amplification of signals was due to a firm binding of laccase onto the surface of GO through high isoelectric point ZnONPs, exhibiting an enzymatic catalytic activity towards the oxidation of sucralose (SUC) at + 0.25 V (vs. Ag/AgCl). Under the optimized experimental conditions, the anodic peak current linearly increased with the sucralose concentrations ranging from 0.025–0.1 mM (R2 = 0.9984) and 0.25–1.0 mM (R2 = 0.9979) with a detection limit (S/N = 3) of 0.32 μM. Furthermore, the proposed strategy was confirmed by assessing the interactions between the sucralose and the laccase using computational tools. First, the density functional theory (DFT) calculations of SUC revealed a HOMO–LUMO energy gap of − 0.2555 eV, suggesting a great tendency to act as an electron donor. Furthermore, adsorption and sucralose-laccase docking studies were carried out to better understand the redox mechanisms. These results revealed that SUC forms hydrogen bonds with ILE 230 and GLN 228 and other amino acids of the hydrophobic channel of the binding sites, thereby facilitating the redox reaction for the detection of sucralose.

Kinetics of Cross-Linking Reaction of Epoxy Resin with Hydroxyapatite-Functionalized Layered Double Hydroxides.

Abstract: The cure kinetics analysis of thermoset polymer composites gives useful information about their properties. In this work, two types of layered double hydroxide (LDH) consisting of Mg2+ and Zn2+ as divalent metal ions and CO32- as an anion intercalating agent were synthesized and functionalized with hydroxyapatite (HA) to make a potential thermal resistant nanocomposite. The curing potential of the synthesized nanoplatelets in the epoxy resin was then studied, both qualitatively and quantitatively, in terms of the Cure Index as well as using isoconversional methods, working on the basis of nonisothermal differential scanning calorimetry (DSC) data. Fourier transform infrared spectroscopy (FTIR) was used along with X-ray diffraction (XRD) and thermogravimetric analysis (TGA) to characterize the obtained LDH structures. The FTIR band at 3542 cm-1 corresponded to the O-H stretching vibration of the interlayer water molecules, while the weak band observed at 1640 cm-1 was attributed to the bending vibration of the H-O of the interlayer water. The characteristic band of carbonated hydroxyapatite was observed at 1456 cm-1. In the XRD patterns, the well-defined (00l) reflections, i.e., (003), (006), and (110), supported LDH basal reflections. Nanocomposites prepared at 0.1 wt % were examined for curing potential by the Cure Index as a qualitative criterion that elucidated a Poor cure state for epoxy/LDH nanocomposites. Moreover, the curing kinetics parameters including the activation energy (Eα), reaction order, and the frequency factor were computed using the Friedman and Kissinger-Akahira-Sunose (KAS) isoconversional methods. The evolution of Eα confirmed the inhibitory role of the LDH in the crosslinking reactions. The average value of Eα for the neat epoxy was 54.37 kJ/mol based on the KAS method, whereas the average values were 59.94 and 59.05 kJ/mol for the epoxy containing Zn-Al-CO3-HA and Mg Zn-Al-CO3-HA, respectively. Overall, it was concluded that the developed LDH structures hindered the epoxy curing reactions.

Assessment of sulfonated homo and co-polyimides incorporated polysulfone ultrafiltration blend membranes for effective removal of heavy metals and proteins.

Abstract: Sulfonated homo and co- polyimide (sPI) were synthesized with new compositional ratios, and used as additives (0.5 wt%, 0.75 wt%, and 1.0 wt%) to prepare blend membranes with polysulfone (PSf). Flat sheet membranes for ultrafiltration (UF) were casted using the phase inversion technique. Surface morphology of the prepared UF membranes were characterized by atomic force microscopy (AFM) and scanning electron microscopy (SEM). Surface charge of the membranes were determined by zeta potential, and hydrophilicity was studied by contact angle measurement. The contact angle of the membrane decreased with increasing sPI additive indicates increasing the hydrophilicity of the blend membranes. Filtration studies were conducted for rejection of heavy metals (Pb2+ and Cd2+) and proteins (pepsin and BSA). Blend membranes showed better rejection than pure PSf membrane. Among the blend membranes it was observed that with increasing amount of sPIs enhance the membrane properties and finally, PSf-sPI5 membrane with 1 wt% of sPI5 showed the improved permeability (72.1 L m−2 h−1 bar−1), and the best rejection properties were found for both metal ions (≈98% of Pb2+; ≈92% of Cd2+) and proteins (>98% of BSA; > 86% of Pepsin). Over all, this membrane was having better hydrophilicity, porosity and higher number of sites to attach the metal ions. Its performance was even better than several-reported sulfonic acid based UF membranes. All these intriguing properties directed this new UF membrane for its potential application in wastewater treatment.

Wastewater Treatment and Biomedical Applications of Montmorillonite Based Nanocomposites: A Review

Abstract: Rapid industrialisation, population growth and technological race worldwide have brought adverse consequences on water resources and as a result affect human health. Toxic metal ions, non-biodegradable dyes, organic pollutants, pesticides, pharmaceuticals are among the chief hazardous materials released into the water bodies from various sources. These hazardous contaminants drastically affect the flora and fauna globally leading to health deterioration there by giving rise to new biomedical challenges. Montmorillonite based nanocomposites (MMTCs) have drawn an attention of the researchers to design environmental friendly, advanced and hygienic nanocomposites for wastewater treatment and biomedical purposes. Montmorillonite clay possesses peculiar physical and chemical properties that include enhanced surface reactivity, improved rheological performance, exorbitant miscibility in water due to which it shows highly favourable interactions with polymers, drugs, metals, mixed metals and metal oxides leading to the fabrication of different types of advanced montmorillonite based nanocomposites that have remarkable applications Here we review the structural characteristics of montmorillonite clay, advances in the synthetic techniques involved in the fabrication of montmorillonite nanocomposites, their applications in waste water treatment and in bio medical field. The recently developed montmorillonite nanocomposites for (1) waste water treatment as nano-adsorbents for the elimination of toxic inorganic species such as metal ions and heterogeneous photo-catalysts for photo degradation of dyes, pesticides and pharmaceuticals (2) biomedical utilization viz drug delivery, wound amelioration, bone cement, tissue engineering etc. are presented The review exclusively focuses on recent research on montmorillonite based nanocomposites and their application in wastewater treatment and in biomedical field

Electrochemical Biosensor for the Detection of Amygdalin in Apple Seeds with a Hybrid of f-MWCNTs/CoFe2O4 Nanocomposite

Abstract: Amygdalin is a natural compound known for curing cancer. It is seen in several plants including in bitter almonds, apricots, peaches, apples, and plum seeds (kernels). Amygdalin is a toxic molecule containing a nitrile group, due to which toxic cyanide anion releases by the action of a β-glucosidase. The consumption of amygdalin may lead to cyanide poisoning in the human body. Therefore, for the first time, this work is aimed at developing a novel electrochemical biosensor for the detection of Amygdalin (AMG) in apple seed samples. The proposed electrochemical biosensor was fabricated by immobilizing cytochrome c (Cyt c) on a Glassy Carbon Electrode (GCE) with nanocomposite of cobalt ferrite nanoparticles (CoFe2O4 NPs) and functionalised multiwalled carbon nanotubes (f-MWCNTs). The characterization of the synthesized nanocomposite was performed with FTIR, TEM, TGA/DSC, and XRD techniques. Moreover, various experimental parameters such as the effect of pH, deposition time, sweep rate, potential, and enzyme incubation time and interference were also studied. The fabricated biosensor enhanced the peak current by 10-folds compared to unmodified GCE. Under optimized experimental conditions, the biosensor exhibited linear response from 2 to 20 μM, with a linear regression equation Ipa (μA) = 8.4989 c + 6.6307 (R² = 0.9927). The LOD’s and LOQ’s were found to be 0.0112 μM and 0.2213 μM, respectively. The designed biosensor was successfully applied for the analysis of AMG content in the apple seed samples. The outcomes of this study identify the efficient electrocatalytic activity of the fabricated nanocomposite as significant electronic factors as major contributors to the electron transfer mechanism, with promising scope for the design of biosensor to sense toxic molecules.

Tuning the surface properties of Fe 3 O 4 by zwitterionic sulfobetaine: application to antifouling and dye removal membrane

Abstract: In this paper, zwitterionic polysulfobetaine@Fe3O4 (PSBMA@Fe3O4) nanoparticles were synthesized via covalent grafting and free radical polymerization and characterized. The PSBMA@Fe3O4 noparticles had a zeta potential of − 36 mV (pH 6.3), which guaranteed the high colloidal stability. The as-synthesized nanoparticles were employed as a nanofiller to prepare superior antifouling polysulfone hybrid hollow fiber membranes. The FM-2 membrane exhibited the maximum pure water permeability of 61.1 L/m2 h bar with humic acid (HA) removal efficiency of 98%. The fouling resistance was evaluated using HA as a foulant, and the results suggested that the FM-2 membrane had less amount of HA adsorption with flux recovery ratio of 88.4%. Furthermore, the FM-2 membrane was demonstrated the reactive black-5 and reactive orange-16 removal of above 99% and 84% without much reduction in the dye solution permeability.

An in-silico layer-by-layer adsorption study of the interaction between Rebaudioside A and the T1R2 human sweet taste receptor: modelling and biosensing perspectives.

Abstract: The human sweet taste receptor (T1R2) monomer-a member of the G-protein coupled receptor family that detects a wide variety of chemically and structurally diverse sweet tasting molecules, is known to pose a significant threat to human health. Protein that lack crystal structure is a challenge in structure-based protein design. This study focused on the interaction of the T1R2 monomer with rebaudioside A (Reb-A), a steviol glycoside with potential use as a natural sweetener using in-silico and biosensing methods. Herein, homology modelling, docking studies, and molecular dynamics simulations were applied to elucidate the interaction between Reb-A and the T1R2 monomer. In addition, the electrochemical sensing of the immobilised T1R2-Reb-A complex with zinc oxide nanoparticles (ZnONPs) and graphene oxide (GO) were assessed by testing the performance of multiwalled carbon nanotube (MWCNT) as an adsorbent experimentally. Results indicate a strong interaction between Reb-A and the T1R2 receptor, revealing the stabilizing interaction of the amino acids with the Reb-A by hydrogen bonds with the hydroxyl groups of the glucose moieties, along with a significant amount of hydrophobic interactions. Moreover, the presence of the MWCNT as an anchor confirms the adsorption strength of the T1R2-Reb-A complex onto the GO nanocomposite and supported with electrochemical measurements. Overall, this study could serve as a cornerstone in the development of electrochemical immunosensor for the detection of Reb-A, with applications in the food industry.

Pervaporation dehydration of bio-fuel (n-butanol) by dry thermal treatment membrane

Abstract: In the present investigation, laboratory Synthesized Graphene Oxide (GO) as a nano-filler was used in Polyetherimide (PEI) flat-sheet membranes (PM). The PEI flat-sheet membrane was fabricated through a dry-thermal treatment (DTT) method. The effects of fabrication method were investigated on Polyetherimide-GO membrane prepared by dry-thermal treatment (PMDTT). The morphological structure was investigated via different characterization; Fourier transform infrared spectroscopy (FTIR), scanning electron microscopy (SEM), X-ray diffraction (XRD), transmission electron microscopy (TEM), Contact angle measurement and Raman spectra. The results indicated that, the hybrid PMDTT membrane displayed reasonably better pervaporation separation performance in comparison to neat PMDTT membranes. The concentrations of water at the permeate side of hybrid and neat PMDTT membrane were 99.3 and 90.9 wt.% respectively. Hybrid membranes showed a 78.3% enhanced permeation rate. Enhancement of pervaporation property of hybrid PMDTT membrane could be ascribed mainly due to the presence of graphene oxide in the dense top layer. Overall, the blending of graphene oxide in hybrid PMDTT membranes could be a promising approach for enhancing the pervaporation properties of the membranes.

Fabrication and Characterization of Polysorbate/Ironmolybdophosphate Nanocomposite: Ion Exchange Properties and pH-responsive Drug Carrier System for Methylcobalamin

Abstract: Nanocomposites are of great interest due to their competency to show multifunctional properties. They have been recently given much attention due to their credibility to offer the synergistic feature of organic material with those of inorganic constituents. Different types of nanocomposites have been prepared to date and are being used for different applications. The delivery of drugs in the human body at a particular site was one of the major problems in the medicinal field. The nanocomposite formulations can be used to provide controlled release and they can be combined with ligands for targeted drug delivery. Applications of the nanocomposites as ion exchangers are also increasing at a faster rate. Due to this, they help in the softening of the water. They can also be easily recharged by washing them with a solution containing a high concentration of sodium ions. In the present paper, we have worked on the synthesis and applications of the polysorbate/ironmolybdophosphate (PS/FMP) nanocomposite. Polysorbate/ironmolybdophosphate (PS/FMPS) was synthesized by co-precipitation method in the presence of polysorbate. The material was well characterized using X-ray diffraction (XRD) analysis, Fourier transform infrared spectroscopy, (FTIR) scanning transmission microscopy (SEM), and transmission electron microscopy (TEM). Physicochemical properties of material were studied in detail. Drug delivery behavior of polysorbate/ironmolybdophosphate was investigated by using methylcobalamin as a test drug. The polysorbate/ironmolybdophosphate nanocomposite show enhanced Na+ ion exchange capacity of 2.1 meq/g. It has been revealed that PS/FMP nanocomposite was thermally stable as it retained the ion exchange capacity of 40.4 % at 400°C. An optimum concentration of sodium nitrate (eluent) was found to be 1.0 M for the complete removal of H+ ions from the PS/FMP column. The optimum volume of sodium nitrate (eluent) was found to be 230 mL. The FTIR spectra showed the changes in intensities of characteristic peaks in PS/FMP and in drug loaded on PS/FMP nanocomposite. The characteristic peak at 1043-1061 cm-1 was observed for ionic phosphate stretching, 560-567 cm-1 for iron group and 959 cm-1 due to molybdate present in the material. The additional peak at 3390 cm-1 and 1711 cm-1 were due to -OH and C=O stretching due to the presence of these groups in the structure of polysorbate. The peak present at 430 cm-1 might be due to the presence of Co-O stretching of methylcobalamin. The XRD results confirmed the semicrystalline structure of FMP and PS/FMP. Scanning electron micrographs results revealed the beaded surface of FMP changes to fibrous surface in case of PS/FMP nanocomposite. The TEM images indicate the appearance of smooth surfactant layer on the surface of FMP. The size of the nanocomposite is between 10- 70 nm. The drug loading efficiency and encapsulation efficiency were found to be 35.2%. and 60.4%, respectively. The cumulative drug release of methylcobalamin was studied for the PS/FMP nanocomposite. The order of drug release was found to be pH 9.4 (54.6%) > pH 7.4 (46.4%) > saline (pH 5.7) (36.2%) > pH 2.2 (33.9%). The release at pH 9.4 was higher. As the pH of medium changes from acidic to basic i.e. 2.2 - 9.4, there is an appreciable increase in drug release from the PS/FMP nanocomposite due to the presence of more OH- ions resulting in neutralization of cationic nanocomposite and thus increasing the rate of drug release by ion exchange process and matrix deterioration. The novel nanocomposite PS/FMP has been synthesized by a simple co-precipitation method. The increase in Na+ ion exchange capacity for nanocomposite is due to the binding of organic part (Polysorbate) with inorganic ironmolybdophosphate. The physiochemical properties of PS/FMP were found to be superior. Fourier transform infrared spectra of PS/FMP and drug loaded PS/FMP confirmed the formation of materials. The SEM results indicated the surface of synthesized FMP is bead-like appearance whereas the beaded surface of FMP changes to fibrous surface on the addition of polysorbate thus indicated the fabrication of nanocomposite. The cumulative drug release of methylcobalamin was studied and the order of drug release was found to be pH 9.4 > pH 7.4 > saline (pH 5.7) > pH 2.2. Thus PS/FMP is a promising multifunctional nanocomposite.