Immobilization Of Ligands Research Articles

Colorimetric allergenic fungal spore detection using peptide-modified gold nanoparticles

The rapid and sensitive detection of allergenic fungal spores is of great interest owing to the potentially negative impact of these spores on personal and public health and safety. We present a simple and prompt colorimetric strategy for detecting Aspergillus niger based on interactions between fungal spores and gold nanoparticles (AuNPs) modified with a specific binding peptide. The A. niger spore-binding peptide ligand was identified by phage display screening, which exhibited enhanced affinity through multivalent effects with specificity over common airborne bacteria. Immobilization of peptide ligands on AuNPs enabled rapid binding to A. niger spores, resulting in a visible change in the color intensity of the supernatant after sedimentation of the spores. This simple colorimetric approach displayed a high sensitivity of ∼50 spores and a rapid detection time of <10 min when used with a smartphone-based image analysis application. This strategy can be adapted for the simple and rapid detection of target microorganisms of relatively large size by exploiting the specificity of ligands and the optical properties of gold nanoparticles.

Abstract 3477: Dietary polyphenols as epigenetic ‘reader' inhibitors

Abstract Introduction: There is continued interest in targeting epigenetic "readers, writers, and erasers" for the treatment of cancer and other pathologies. Bromodomain (BRD)-containing proteins act as epigenetic readers by recognizing lysine acetylation on histone and non-histone proteins and regulating various transcriptional processes. Treatment with the BRD inhibitor JQ1, synergized with the dietary deacetylase inhibitor sulforaphane (SFN) in colon cancer cells and suppressed tumor development in animal models of colorectal cancer1, providing a mechanistic basis for potential new therapeutic avenues involving epigenetic combination treatments. In the current work, we explored dietary compounds to identify potential JQ1-like natural BRD inhibitors that may provide a safer alternative to using JQ1. Methods: Docking of BRD1, BRD2, BRD3 and BRD4 was performed using STRAP, following multiple sequence alignment, and analyzed by AutoDock Vina1. Ligand-protein interactions were analyzed using PDBePISA and LPC/CSU1. The structures of natural molecules were created using Protein Data Bank2. Subsequently, selected compounds were screened at 10 µM, using BROMOscan®-Bromodomain assay panel to identify compounds that bind to BRD1, BRD2(1), BRD2(2), BRD3(1), BRD3(2), BRD4(1) and BRD4(2) active sites and prevent them from binding to the immobilized ligand, using qPCR to detect the associated DNA label3. Results: In silico screening identified several dietary polyphenols, including tea catechins, genistein, luteolin, and resveratrol as BRD inhibitors, with binding energy ≤ -7.0 kcal/mol, mimicking acetyl-lysine interactions. The BROMOscan® screening revealed that some of these dietary polyphenols only moderately inhibited BRD binding to their respective ligands, by less than 40% when tested at 10 µM. However, genistein inhibited BRD4(2) by 80%, and orientin inhibited BRD3(1) by 73%, prioritizing them as candidates for further investigation. Conclusions: In silico docking and BROMOscan® screening implicated natural polyphenols as potential BRD inhibitors. Ongoing investigations will determine their dissociation constant (Kd) via isothermal titration calorimetry and/or surface plasmon resonance for assessing their binding affinity. Natural BRD inhibitors and their metabolites will be further evaluated for the inhibition of cell growth and BRD protein expression in human colon cancer cells. Our results suggest that dietary polyphenols have the potential to recognize epigenetic reader domains by interacting with BRDs, providing new insights in the field of nutrigenomics and precision medicine. Acknowledgements: Research supported by NCI grant CA122959, John S. Dunn Foundation, Texas A&amp;M AgriLife Research, and a Chancellor's Research Initiative.

Direct Detection of Low-Molecular-Weight Compounds in 2D and 3D Aptasensors by Biolayer Interferometry.

The direct biolayer interferometry (BLI) measurement of low-molecular-weight (LMW) analytes (<200 Da) still represents a challenge, in particular, when low receptor densities are used. BLI is a powerful optical technique for the label-free, real-time characterization and quantification of biomolecular interactions at interfaces. We demonstrate herein that the quantification of biomolecular recognition is possible by BLI using either 2D-like or 3D platforms for aptamer ligand immobilization. The influence of the aptamer density on the interaction was evaluated and compared for the two sensor architectures. Despite the LMW of the analyte, BLI monitoring led to signals that are exploitable for affinity and kinetic studies, even at low aptamer density. We demonstrate that the immobilization format as well as the aptamer density has a crucial influence on the determination of the recognition parameters.

Optimized Immobilization Strategy for Dirhodium(II) Carboxylate Catalysts for C-H Functionalization and Their Implementation in a Packed Bed Flow Reactor.

Herein we demonstrate a packed bed flow reactor capable of achieving highly regio- and stereoselective C-H functionalization reactions using a newly developed Rh2 (S-2-Cl-5-CF3 TPCP)4 catalyst. To optimize the immobilized dirhodium catalyst employed in the flow reactor, we systematically study both (i) the effects of ligand immobilization position, demonstrating the critical factor that the catalyst-support attachment location can have on the catalyst performance, and (ii) silica support mesopore length, demonstrating that decreasing diffusional limitations leads to increased accessibility of the active site and higher catalyst turnover frequency. We employ the immobilized dirhodium catalyst in a simple packed bed flow reactor achieving comparable yields and levels of enantioselectivity to the homogeneous catalyst employed in batch and maintain this performance over ten catalyst recycles.

Optimized Immobilization Strategy for Dirhodium(II) Carboxylate Catalysts for C−H Functionalization and Their Implementation in a Packed Bed Flow Reactor

AbstractHerein we demonstrate a packed bed flow reactor capable of achieving highly regio‐ and stereoselective C−H functionalization reactions using a newly developed Rh2(S‐2‐Cl‐5‐CF3TPCP)4 catalyst. To optimize the immobilized dirhodium catalyst employed in the flow reactor, we systematically study both (i) the effects of ligand immobilization position, demonstrating the critical factor that the catalyst‐support attachment location can have on the catalyst performance, and (ii) silica support mesopore length, demonstrating that decreasing diffusional limitations leads to increased accessibility of the active site and higher catalyst turnover frequency. We employ the immobilized dirhodium catalyst in a simple packed bed flow reactor achieving comparable yields and levels of enantioselectivity to the homogeneous catalyst employed in batch and maintain this performance over ten catalyst recycles.

Ligand Diffusion Enables Force-Independent Cell Adhesion via Activating α5β1 Integrin and Initiating Rac and RhoA Signaling.

Cells reside in a dynamic microenvironment in which adhesive ligand availability, density, and diffusivity are key factors regulating cellular behavior. Here, the cellular response to integrin-binding ligand dynamics by directly controlling ligand diffusivity via tunable ligand-surface interactions is investigated. Interestingly, cell spread on the surfaces with fast ligand diffusion is independent of myosin-based force generation. Fast ligand diffusion enhances α5β1 but not αvβ3 integrin activation and initiates Rac and RhoA but not ROCK signaling, resulting in lamellipodium-based fast cell spreading. Meanwhile, on surfaces with immobile ligands, αvβ3 and α5β1 integrins synergistically initiate intracellular-force-based canonical mechanotransduction pathways to enhance cell adhesion and osteogenic differentiation of stem cells. These results indicate the presence of heretofore-unrecognized pathways, distinct from canonical actomyosin-driven mechanisms, that are capable of promoting cell adhesion.

Adsorption of Copper(II) on Dithizone-Immobilized Coal Fly Ash

The adsorption of Cu (II) ions onto selective adsorbent of coal fly ash from Sugar Factory Madukismo, Yogyakarta, Indonesia modified with dithizone has been investigated in batch mode. Some parameters influencing immobilization of dithizone and adsorption of Cu (II) were optimized including an effect of pH, contact time and initial concentration of Cu (II) ions. The FT-IR and XRD analytical results show that the surface of coal fly ash can be modified by immobilization of selective organic ligand towards Cu (II) ions. The optimum conditions for adsorption of Cu (II) are achieved at pH 5, the optimum mass of DICFA and ACFA for copper adsorption were 0.2 g. Kinetics adsorption for copper ions follows pseudo-second-order kinetics with optimum adsorption contact time 60 min for DICFA and ACFA. Isotherms adsorption for Cu ion follow the Langmuir isotherms with chemisorption process and optimum concentration of Cu ion adsorption of 70 mg.L-1 for DICFA and ACFA.

Covalently Immobilizing Interferon-γ Drives Filopodia Production through Specific Receptor-Ligand Interactions Independently of Canonical Downstream Signaling.

Immobilizing a signaling protein to guide cell behavior has been employed in a wide variety of studies. This approach draws inspiration from biology, where specific, affinity-based interactions between membrane receptors and immobilized proteins in the extracellular matrix guide many developmental and homeostatic processes. Synthetic immobilization approaches, however, do not necessarily recapitulate the in vivo signaling system and potentially lead to artificial receptor-ligand interactions. To investigate the effects of one example of engineered receptor-ligand interactions, we focus on the immobilization of interferon-γ (IFN-γ), which has been used to drive differentiation of neural stem cells (NSCs). To isolate the effect of ligand immobilization, we transfected Cos-7 cells with only interferon-γ receptor 1 (IFNγR1), not IFNγR2, so that the cells could bind IFN-γ but were incapable of canonical signal transduction. We then exposed the cells to surfaces containing covalently immobilized IFN-γ and studied membrane morphology, receptor-ligand dynamics, and receptor activation. We found that exposing cells to immobilized but not soluble IFN-γ drove the formation of filopodia in both NSCs and Cos-7, showing that covalently immobilizing IFN-γ is enough to affect cell behavior, independently of canonical downstream signaling. Overall, this work suggests that synthetic growth factor immobilization can influence cell morphology beyond enhancing canonical cell responses through the prolonged signaling duration or spatial patterning enabled by protein immobilization. This suggests that differentiation of NSCs could be driven by canonical and non-canonical pathways when IFN-γ is covalently immobilized. This finding has broad implications for bioengineering approaches to guide cell behavior, as one ligand has the potential to impact multiple pathways even when cells lack the canonical signal transduction machinery.

Thiol-ene photo-click immobilization of a chiral chromatographic ligand on silica particles

This work reports procedures for the immobilization of vinyl ligands on silica particles by UV-initiated thiol-ene radical addition reaction (photo-click immobilization). tert‑Butylcarbamoyl quinine was the functional ligand (ene component) for the synthesis of chiral stationary phases. Two distinct surface chemistries were evaluated. In one approach, the ligand was directly attached to 3-mercaptopropyl-silica triggered by radicals generated by UV irradiation from a photoinitiator. In another approach, the ligand was immobilized onto vinyl silica via poly(3-mercaptopropyl-methylsiloxane) (PMPMS) as crosslinker by a photoinitiated double click reaction in which functionalization with chiral ligand and crosslinking to vinylsilica occurred simultaneously in one synthesis step. PMPMS-bonded CSPs were prepared from suspension (slurry method) or solventless after coating of the polythiol onto the vinylsilica surface (film method). Optimization by a design of experiment approach showed that the reaction time is the prime variable to optimize the surface coverage of chiral selector which also increased with PMPMS concentration. When the film formation of the latter approach was assisted by a minute volume of toluene during photo-click immobilization, selector coverage could be significantly increased to 0.73 µmol/m2 in a 2 h synthesis compared to 0.44 µmol/m2 by the solventless film method and 0.47 µmol/m2 by the slurry method under otherwise comparable conditions. The solvent assistance improved the chromatographic efficiency of the film method and resulted equal minimal reduced plate height of 2.6 as the slurry method for a chiral probe (Fmoc-Phe). The mass transfer resistance was around factor 2 smaller with the solvent-assisted film method as compared to the film approach without toluene, presumably due to a more homogenous distribution of the thin polymer film owing to lower dynamic viscosity in presence of toluene.

In situ neutron scattering of antibody adsorption during protein A chromatography

A deeper understanding of the nanoscale and mesoscale structure of chromatographic adsorbents and the distribution of proteins within the media, is critical to a mechanistic understanding of separation processes using these materials. Characterisation of the media's architecture at this scale and protein adsorption within, is challenging using conventional techniques. In this study, we propose a novel resin characterisation technique that enables in-situ measurement of the structure of the adsorbed protein layer within the resin, under typical chromatographic conditions. A quartz flow-through cell was designed and fabricated for use with Small Angle Neutron Scattering (SANS), in order to measure the nanoscale to mesoscale structures of a silica based protein A chromatography resin during the monoclonal antibody sorption process. We were able to examine the pore-to-pore (˜133 nm) and pore size (˜63 nm) correlations of the resin and the in-plane adsorbed antibody molecules (˜ 4.2 nm) correlation at different protein loadings and washing buffers, in real time using a contrast matching approach. When 0.03 M sodium phosphate with 1 M urea and 10 % isopropanol buffer, pH 8, was introduced into the system as a wash buffer, it disrupted the system's order by causing partial unfolding of the adsorbed antibody, as evidenced by a loss of the in-plane protein correlation. This method offers new ways to investigate the nanoscale structure and ligand immobilisation within chromatography resins; and perhaps most importantly understand the in-situ behaviour of adsorbed proteins within the media under different mobile phase conditions within a sample environment replicating that of a chromatography column.

Simplification of affinity macroporous monolith microfluidic column synthesis and its ability for protein separation

A generic multi-component approach was designed to perform simultaneous in situ polymerization and ligand immobilization to develop affinity porous polymer based chromatography resin in a facile mode. This strategy exploits the regioselective ring opening reaction between epoxy group of monomer and native functional group of ligand (i.e. amine) under aqueous condition (pH 9.7).As a proof-of-concept, reaction of iminodiacetic acid (IDA) with allyl glycidyl ether (AGE) in presence of other monomer (HEMA) and crosslinkers (DATD, PDA) for 4 h via thermal initiation process (temperature of 65 °C) was shown. Successful polymerization (both ex situ &in situ) was confirmed by visual observation, surface morphology of the polymer by scanning electron microscope and ligand immobilization by FT-IR analysis. Chelation of the metal-ion i.e. copper (Cu (II)) with IDA in the monolith showed IgG adsorption capacity (27.8 mg/g monolith) over IDA-monolith without metal-ion. The affinity column has shown efficient capture of high abundant proteins such as IgG, transferrin and albumin from human plasma.

Identification of Target Protein for Bio-active Small Molecule Using Photo-cross Linked Beads and MALDI-TOF Mass Spectrometry

Development of methods for protein identification is one of the important aspects of proteomics. Here, we report a protocol for the preparation of compound conjugated beads by photo-crosslinking, affinity purification, gel electrophoresis, and highly sensitive mass spectrometric assay for drug-target identification. Although there are several other methods used for drug-target identification, such as biochemical fractionation or radioactive ligand binding assay, affinity purification is widely used for its straight-forward and easy approach. To identify the target protein of an inhibitor of cancer cell-accelerated fibroblast migration, we prepared the inhibitor-conjugated beads by photo-crosslinking. Proteins were pulled down from cell lysates by the compound beads and separated by SDS-PAGE, and a specifically pulled down protein was cut out, trypsin-digested, analyzed using matrix-assisted laser desorption ionization/time of flight mass spectrometry (MALDI-TOF-MS) and identified by peptide mass fingerprinting (PMF) method. Since the photo-crosslinking enables the immobilization of ligands on an affinity matrix in a functional group-independent manner, we do not have to determine the functional group of the compound to conjugate the matrix. In addition, as compared to other MS techniques such as electrospray ionization, MALDI offers a less complex sample preparation procedure and higher sensitivity, and thus is better suited for the rapid identification of proteins isolated by gel electrophoresis.

An Effect of the Nature of Immobilized Components on the Adsorption and Mass Transfer Properties of Ultrafiltration Membranes Based on Sulfonate-containing Сopolyamide

Ultrafiltration membranes based on aromatic copolyamide, comprising 10% of units with sulfonate groups were produced. The possibility of their use as a matrix for the immobilization of ligands used in affinity chromatography: metal cations, amino acids, and dyes, is shown. The components of immobilization were copper(II) ions, histidine, lysine, and 3,6-diamino-10-methylacridine chloride. It was found that immobilization mainly occurs due to the electrostatic interaction of the corresponding functional groups of the component and copolyamide and is not accompanied by a decrease in the specific membrane productivity in water. The investigations of adsorption (under static conditions and ultrafiltration of protein solutions) were performed as well as mass transfer properties of modified membranes. The nature of the effect of the modification was revealed on the mass transfer characteristics of the obtained materials. For an unmodified membrane, the optimal combination of selectivity and specific productivity was realized at pH of the protein solution above its isoelectric point. Depending on the nature of the immobilized component, selectivity of 0.96–0.99 can be achieved at the pH below or equal to the isoelectric point of the protein.

Ethylene oligomerization reactions catalyzed by homogeneous and silica immobilized NˆO Fe(II) and Co(II) complexes

Treatment of 2-phenyl-2-((3(triethoxysilyl)propyl)imino)ethanol (L1) and 4-nitro-2-((3(triethoxysilyl)propyl)imino)methyl)phenol (L2) with MCM-41 support afforded the respective immobilized ligands (L1im) and (L2im). Reactions of synthons L1, L2, L1im and L2im with either FeCl2·4H2O or CoCl2 led to the formation of their respective homogeneous and immobilized metal complexes [Fe(L1)2] (Fe1), [Co(L1)2] (Co1), [Fe(L2)2] (Fe2), [Co(L2)2] (Co2), [Fe(L1im)2] (Fe1im), [Co(L1im)2] (Co1im), [Fe(L2im)2] (Fe2im), and [Co(L2im)2] (Co2im). The compounds were characterized by FT-IR, NMR, ESI-MS, SEM-EDX and elemental analysis. Activation of the Fe(II) and Co(II) complexes with EtAlCl2, resulted in active catalysts for the tandem ethylene dimerization and Friedel-Crafts alkylation of the toluene solvent to produce mainly alkyltoluenes. On the other hand, the use of chlorobenzene solvent and MAO co-catalyst led to the formation of mainly butenes. Generally, the immobilized catalysts exhibited lower catalytic activities, but with comparable selectivity to the homogeneous catalysts. Recycling studies established that the immobilized catalysts were active for three runs without loss of selectivity.

A ligand based innovative composite material for selective lead(II) capturing from wastewater

The ligand based composite material is an effective material for the removal of diverse contaminants from wastewater. However, the performance of some ligands functionality is limited in many cases due to the functional complexation ability. Therefore, the high immobilization of ligand anchoring by the building-block approach is a better way for high amount adsorption of pollutants. The present study was carried out for the successful detection and removal of lead (Pb(II)) ion from aqueous solution by a novel functionalized composite material. The composite material was successfully prepared by the building-block immobilization of (3-(3-(methoxycarbonyl)benzylidene) hydrazinyl)benzoic acid onto the highly ordered mesoporous silica. The factor affecting Pb(II) detection and adsorption by composite material was carried out in a batch-mode with the parameters of solution pH, color optimization, competing ions, initial concentrations, contact time and reuses. The material was enhanced the color formation by stable complexation during the Pb(II) ion detection and adsorption operations. The limit of detection was 0.51 μg/L. The effective pH for Pb(II) ions capturing was 5.50, and the maximum adsorption capacity of the composite material was found to 214.15 mg/g. The data revealed that the capturing system was in a one-step and ultra-trace Pb(II) was captured without using highly sophisticated instrumentations. The results clarified that composite material was exhibited high selectivity toward the Pb(II) ion even in the presence of the high amount of common metal ions. The adsorbed Pb(II) was eluted with 0.20 M HCl and the material were simultaneously regenerated into an initial form for the next capturing operations after rinsing with water. Therefore, composite material is an effective, low-cost and recyclable material and was a great potential to be a promising technique for Pb(II) remediation for safe-guarding the public health.

Activated Cross-linked Agarose for the Rapid Development of Affinity Chromatography Resins - Antibody Capture as a Case Study.

The purification of monoclonal antibodies (mAbs) is commonly achieved by Protein A affinity chromatography, which can account for up to 25% of the overall process costs. Alternative, cost-effective capture steps are therefore valuable for industrial-scale manufacturing, where large quantities of a single mAb are produced. Here we present a method for the immobilization of a DsRed-based epitope ligand to a cross-linked agarose resin allowing the selective capture of the HIV-neutralizing antibody 2F5 from crude plant extracts without using Protein A. The linear epitope ELDKWA was first genetically fused to the fluorescent protein DsRed and the fusion protein was expressed in transgenic tobacco (Nicotiana tabacum) plants before purification by immobilized metal-ion affinity chromatography. Furthermore, a method based on activated cross-linked agarose was optimized for high ligand density, efficient coupling and low costs. The pH and buffer composition and the soluble ligand concentration were the most important parameters during the coupling procedure, which was improved using a design-of-experiments approach. The resulting affinity resin was tested for its ability to selectively bind the target mAb in a crude plant extract and the elution buffer was optimized for high mAb recovery, product activity and affinity resin stability. The method can easily be adapted to other antibodies with linear epitopes. The new resins allow gentler elution conditions than Protein A and could also reduce the costs of an initial capture step for mAb production.

Compact Grating-Coupled Biosensor for the Analysis of Thrombin

A compact optical biosensor for direct detection of thrombin in human blood plasma (HBP) is reported. This biosensor platform is based on wavelength spectroscopy of diffraction-coupled surface plasmons on a chip with a periodically corrugated gold film that carries an antifouling thin polymer layer consisting of poly[(N-(2-hydroxypropyl)methacrylamide)-co-(carboxybetaine methacrylamide)] (poly(HPMA-co-CBMAA)) brushes. This surface architecture provides superior resistance to nonspecific and irreversible adsorption of abundant compounds in the analyzed HBP samples in comparison to standard surface modifications. The carboxylate groups along the polymer brushes were exploited for the covalent immobilization of aptamer ligands. These ligands were selected to specifically capture the target thrombin analyte from the analyzed HBP sample in a way that does not activate the coagulatory process at the biosensor surface with poly(HPMA-co-CBMAA) brushes. Direct label-free analysis of thrombin in the medically relevant concentration range (1-20 nM) is demonstrated without the need for diluting the HBP samples or using additional steps for signal enhancement. The reported platform constitutes the first step toward a portable and sensitive point-of-care device for direct detection of thrombin in human blood.

Magnetic nanoparticles coated with aminated starch for HSA immobilization- simple and fast polymer surface functionalization

Magnetic nanoparticles coated with polymer shell containing reactive functional groups are of great interest especially as substrates for immobilization of ligands in biomedicine and catalysis. This article describes synthesis of novel functional MNPs coated with aminated starch via simple, fast and efficient method of functionalization of the surface by one-minute pounding in mortar. The concept is based on simplifying the synthesis of the magnetic support and obtaining a material that allows for effective bioligand immobilization. Basing on our previous research in the area of MNPs synthesis and biomedical applications, the high yield (149.96 mg/g of support) and effective immobilization of HSA was demonstrated for these nanoparticles without loss of protein activity. Obtained materials were characterized with ATR-FTIR spectroscopy, scanning (SEM) and transmission (TEM) electron microscopy, dynamic light scattering (DLS), X-ray diffraction, TGA-DTA and SQUID analysis. The developed method allows for modification of polysaccharides and nanoparticles towards materials enriched with amino groups in a quick and easy way. It can be expected that this method of quick solvent-free amination will find application in the chemistry of materials and polymers. In addition, the new obtained amino-rich MNPs may find use as carriers for the immobilization of bioligands in catalysis and pharmaceutical analysis.

Innovative composite material for efficient and highly selective Pb(II) ion capturing from wastewater

In the present study, highly porous composite material (PCM) was fabricated by novel ligand immobilization onto the silica monolith for Pb(II) ion detection and adsorption from wastewater by the solid-liquid separation method. The material was systematically characterized to know the material morphology and functional group. In addition, the Pb(II) capturing performance of PCM toward Pb(II) in aqueous media was explored. The PCM was enhanced the color upon addition of different concentration Pb(II) ion. The low-level limit detection was determined, and the value was 0.33 μg/L, which was lower than the permissible limit of Pb(II) ion in water. Factors affecting the adsorption of Pb(II) ion such as solution acidity, reaction time, initial Pb(II) concentration, competing ion and regeneration were investigated systematically in batch mode by the PCM. The solution pH was played the key role both in the detection and adsorption of Pb(II) ion. The pH dependent was exhibited due to the complexation bonding ability. The kinetic performance was rapid as the Pb(II) ion adsorption was equilibrated within short time, and this was confirmed the chemisorption process. The adsorption isotherm of Pb(II) onto PCM was well fitted to the Langmuir isotherm models as expected from the material homogeneity. In addition, the maximum monolayer adsorption capacity was 204.34 mg/g. The competing ions were not affected the Pb(II) detection or adsorption, and this were evident to the high selectivity toward the Pb(II) ion at the optimum condition. The adsorbed Pb(II) from PCM was desorbed with 0.15 M HCl and then simultaneously regenerated for next Pb(II) capturing process. Therefore, the proposed PCM can be considered as a potential material for Pb(II) ion detection and adsorption from the wastewater sample.

Novel composite material for selective copper(II) detection and removal from aqueous media

The mesoporous composite material (MeCM) was fabricated using functional organic ligand of 2-methyl-8-quinolinol immobilization onto the porous silica by direct conjugation and employed as an effective material for the detection and removal of copper (Cu(II)) ion from aqueous media. The material characterization was evaluated in detail to understand the material morphology for complexation during the Cu(II) ion capturing. The variation of pH solution, reaction time, detection limit, initial Cu(II) concentration and competing ion parameters were measured systematically. The MeCM was sensitively evolved the color upon addition of Cu(II) ion even in the low concentration level. The detection limit was 0.33 μg/L. The solution pH was highly influenced both in the detection and adsorption operation. However, the neutral pH 7.0 was effective for efficient detection and removal of Cu(II) ion. The application of MeCM was significantly enhanced the removal capacity as well as selectivity. The Langmuir isotherm model was applied to validate the adsorption isotherms as the MeCM exhibited the homogeneous ordered frameworks. The adsorption capacity was 197.15 mg/g as expected due to the high surface area of MeCM even after ligand immobilization onto the porous silica. The competing ion was not affected significantly during the Cu(II) ion detection and removal because of the high affinity Cu(II) ion to MeCM at this optimum experimental protocol. Moreover, the Cu(II) ion was desorbed from the MeCM with using 0.20 M HCl and able to reuse in several cycles without deterioration in its original performances. Therefore, the designing method with experimental condition makes the MeCM to adopt for various environmental applications dealing with monitoring and separation processes.