Applications In Aqueous Media Research Articles

Pseudohalide Anion Passivation for Aqueous‐Stable Pure Red Perovskite Nanocrystals

AbstractRecently emerging perovskite nanocrystals (PNCs) have drawn considerable attention due to the superior optoelectronic performances. However, the terrible stability of red emissive PNCs (r‐PNCs) limits their broader application in aqueous media. Despite various encapsulation methods are proposed, the preparation of aqueous r‐PNCs with facile operation and excellent durability is still challenging. Herein, aqueous green emissive PNCs (g‐PNCs) by employing water as an external stimulus to treat oleyamine‐capped CsPbBr3 PNCs are synthesized initially, and then aqueous‐stable pure red emissive PNCs by anion‐exchange reaction and subsequently thiocyanate (SCN‐) passivation treatment (SCN‐r‐PNCs) are prepared. The obtained aqueous‐stable SCN‐r‐PNCs display high brightness, outstanding stability, and extended photoluminescence lifetime. Moreover, by combining aqueous r‐PNCs and portable smartphones, a fluorescence chemosensor for the detection of aqueous SCN− ions is constructed, which exhibits simple operation, high sensitivity, high selectivity, low detection limit, and visualized sensing. This work not only provides a new and facile strategy to prepare aqueous‐stable red emissive PNCs, but also further extends the application of red emissive PNCs in aqueous‐based fields.

Water Adsorption on π-Surfaces of Open-Fullerenes.

Understanding the water adsorptive behavior of fullerenes is of particular importance for their material application in aqueous media. The conventional fullerenols usually provide complex physical pictures of water adsorption due to their uncontrollable hydroxylation degree and substitution pattern. Herein, we focus on poorly hydroxylated fullerenes with well-defined structures. The water adsorptive behavior was examined by synchrotron IR spectroscopy and computational studies. As a result, three types of IR bands were observed for adsorbed water. The population of the three states was considerably altered by the orientational difference of the hydroxy groups. Nevertheless, water adsorption could not occur for 9-fluorenol and catechol. This indicates that the Lewis acidic fullerene π-surface plays a prominent role in water adsorption, while the rather Lewis basic π-surface of 9-fluorenol is unable to attract much water at a boundary with humid air.

Rare Earth alb-MOFs: From Synthesis to Their Deployment for Amine-Sensing Application in Aqueous Media.

The pursuit of developing sensors, characterized by their fluorescence-intensity enhancement or "turn-on" behavior, for accurately detecting noxious small molecules, such as amines, at minimal levels remains a significant challenge. Metal-organic frameworks (MOFs) have emerged as promising candidates as sensors as a result of their diverse structural features and tunable properties. This study introduces the rational synthesis of a new highly coordinated (6,12)-connected rare earth (RE) alb-MOF-3, by combining the nonanuclear 12-connected hexagonal prismatic building units, [RE9(μ3-O)2(μ3-X)12(OH)2(H2O)7(O2C-)12], with the 6-connected rigid trigonal prismatic extended triptycene ligand. The resulting Y-alb-MOF-3 material is distinguished by its high microporosity and Brunauer-Emmett-Teller surface area of approximately 1282 m2/g, which offers notable hydrolytic stability. Remarkably, it demonstrates selective detection capabilities for primary aliphatic amines in aqueous media, as evidenced by fluorescence turn-on behavior and photoluminescence (PL) titration measurements. This work emphasizes the potential of MOFs as sensors in advancing their selectivity and sensitivity toward various analytes.

Anthracene and tetraphenylsilane based conjugated porous polymer nanoparticles for sensitive detection of nitroaromatics in water

Conjugated porous polymers (CPPs) are a kind of promising sensing materials for the detection of nitroaromatic compounds, but their sensing applications in aqueous media are limited because of their poor dispersity or solubility in water. In this study, we prepared anthracene and tetraphenylsilane based CPPs named PSiAn by conventional Suzuki coupling and Suzuki-miniemulsion polymerization, respectively. The structure, morphology and porosity of the CPPs were characterized by Fourier Transform infrared spectroscopy (FT-IR), proton nuclear magnetic resonance (1H NMR), transmission electron microscope (TEM) and N2 sorption isotherm, respectively. Both of the CPPs have porous structure which is beneficial for the adsorption and diffusion of the analytes within them. The particle size of PSiAn nanoparticles prepared by Suzuki-miniemulsion polymerization is 10–40 nm from the TEM image, which facilitates the dispersion in the aqueous phase. Combined with the porosity and nanoparticle morphology, PSiAn nanoparticles realized the efficient photoluminescence (PL) sensing of nitroaromatic explosives in aqueous phase. The limit of detection (LOD) and limit of quantitation (LOQ) of PSiAn nanoparticles for 2,4,6-trinitrophenol (TNP) detection in the pure aqueous phase are 0.33 μM and 1.11 μM, respectively. Meanwhile, the good selectivity and anti-interference in presence of other nitro-compounds were observed. Furthermore, the spike/recovery test for the TNP detection in real water samples by PL sensing based on PSiAn nanoparticles indicates the quantitative recovery of TNP from 100.74 % to 101.00 %. The electrochemical test, ultraviolet–visible absorption spectra, excitation and emission spectra, and time-resolved PL spectra were investigated to explore the PL sensing mechanism. As a result, it is found that the fluorescence inner filter effect might be the predominant quenching mechanism during the detection of nitrophenolic compounds such as TNP and 4-nitrophenol (4-NP).

A hydrazine-based unsymmetrical bis-imine-Schiff base as a chemosensor for turn-off fluorescence and naked-eye detection of Cu2+ ion: Application in aqueous media using test strips

A new hydrazine-based unsymmetrical bis-imine-Schiff base 1-((((5-bromothiophen-2-yl)methylene)hydrazono)methyl)naphthalen-2-ol (L1) was synthesized and characterized with FT-IR, 1H NMR, 13C NMR, UV–visible spectroscopy, ESI-MS, and elemental analysis. The solution of L1 in dichloromethane/methanol (9.8:0.2,v/v) mixture shows a rapid change in color from yellow to yellowish brown in the presence of Cu2+ ions. In addition, L1 displays “turn-off” fluorescence preferentially for Cu2+ ions which was attributed to the Chelation Enhanced Quenching (CHEQ) effect caused due to the reversible binding of L1 to paramagnetic Cu2+ in a 2:1 stoichiometric ratio. No interference was caused in the sensing process by other metal ions such as Ag+, Na+, Ni2+, Co2+, Hg2+, Cr3+ Ba2+, Ca2+, Cd2+, Pb2+, Sn2+, Zn2+, Fe3+, Al3+, K+, and Sr2+. The limit of detection was determined to be 2.809 µM. Furthermore, the test strips coated with L1 show a change in color from pale yellow to brownish-yellow in the presence of Cu2+ions in the aqueous medium, and the limit of visual detection was found to be 15 µM, which is well under the maximum recommended limit (31.5 µM) of Cu2+ for drinking water as per WHO guidelines. These observations establish L1 as an efficient reversible chemosensor for sensing Cu2+ in both aqueous and non-aqueous media with high sensitivity and selectivity.

Binding of CsPbBr3 Nanocrystals to MOF-5 for the Detection of Cadmium Ions in Aqueous Media

CsPbBr3 perovskite nanocrystals (CNCs) have emerged as promising candidates for optoelectronics, although instability issues have retarded their progress toward commercialization. As a solution to this core issue, herein CNCs are bound to the metal–organic framework MOF-5 to form a stable composite MOF:CNC for sensing applications in aqueous media. The electrostatic interaction of Pb2+ and Br– ions of CNCs with the terephthalate and Zn2+ ions of MOF-5 do not disturb the structural integrity of the MOFs and the photoluminescence (PL) properties of the CNCs but renders more stability to both the MOFs and CNCs in a water medium. As a proof-of-concept experiment, this water-resistant MOF:CNC probe was successfully validated for the detection of Cd2+ in a water medium. The mechanism of fluorescence enhancement during the sensing of Cd2+ is elucidated using X-ray photoelectron spectroscopy, temperature-dependent, and time-resolved PL studies. The high stability and photoefficiency exhibited by this MOF:CNC composite proves that it is a viable system for applications in aqueous media.

Tetrafluorinated versus hydrogenated azobenzene polymers in water: Access to visible-ligh stimulus at the expense of responsiveness

Photo-responsive polymers are at the core of numerous applications as actuators in biology but often exhibit the drawback of activation in the UV range. This work describes a methacrylate-based terpolymer presenting tetra-ortho-fluoroazobenzene groups showing activation through visible light illumination. The presence of poly(ethylene oxide) side chains and maleimide functions ensures that it can be easily used for biological applications in aqueous media. The terpolymer was shown to form unimolecular micelles in water. The tetra-ortho-fluoroazobenzene moiety was reversibly switched from trans to cis upon visible light irradiation without significant modification of the unimolecular morphology. The deprotection of the maleimide function resulted in a reactive polymer which was used to obtain hydrogels by reaction with poly(ethylene oxide) tetra-thiols or bioconjugates by reaction with a model peptide or a poly(ethylene oxide) mono-thiol exhibiting a biotin group. Hydrogels incorporating β-cyclodextrin molecules were also obtained. Contrary to polymers bearing hydrogenated azobenzenes, the terpolymer bearing tetra-ortho-fluoroazobenzene moieties did not form a complex with β-cyclodextrin and none of the presented hydrogels exhibited macroscopic changes upon irradiation although the trans/cis isomerization occurred. This was explained by the burial of tetra-ortho-fluoroazobenzene groups towards the polymer backbone, therefore completely hindering its access.

Applying of C8-BTBT-Based EGOFETs at Different pH Values of the Electrolyte

Electrolyte-gated organic field-effect transistors (EGOFETs) is a popular platform for numerous sensing and biosensing applications in aqueous media. In this work, the variation of electrical characteristics of EGOFETs based on small-molecule organic semiconductor C8-BTBT and polystyrene blend in water solutions at different pH values was investigated. A positive shift of the threshold voltage with near-Nernstian pH sensitivity was demonstrated in the pH range from 4.9 to 2.8, while no measurable pH dependence in the range from 4.9 to 8.6 pH was registered. These results indicate chemical doping of the molecules of organic semiconductors by protons from the electrolyte in the acidic region. In order to check the applicability of the EGOFETs in a flow mode, a flow chamber was designed and assembled. The preliminary results obtained in the flow mode measurements showed a fast response to pH variation.

Green synthesis of CdS Quantum dots for photocatalytic and anti-corrosive applications in aqueous media

Inorganic pollutants are the leading cause of water pollution, which harms human health and the environment. The most highly efficient nanoparticles with enhanced photocatalytic activity are semiconductor quantum dots (QDs). The heterogeneous photocatalysis using UV radiation on quantum dots is a fascinating technique for treating polluted sewage with a naturally available plant-based product. In this study, CdS QDs were synthesized using a facile green synthetic protocol in the presence of Coccinia grandis (CG) and Punica granatum (PG) fruit sap as capping and stabilizing agents. XRD, HR-TEM, FT-IR, UV-DRS, and photoluminescence spectroscopy were used to analyze the synthesized CdS QDs. The photocatalytic degradation activity of CdS quantum dots was performed against anionic and cationic dyes under UV light irradiation. The results revealed that PG-capped CdS QDs have the best photocatalytic activity compared to CG-capped CdS QDs.Further, the pseudo-first-order model is used to analyze the kinetics studies. Moreover, the electrochemical measurements of pure zinc and CdS QDs coated Zn (Zn/CdS QDs) plate were tested in three electrolytes: sodium chloride, potassium hydroxide, and hydrochloric acid, which demonstrated the corrosion inhibition ability of prepared CdS QDs. The electrochemical impedance spectra, Tafel plot, and in-situ SPM analysis depict the improving corrosion resistance of the Zn metal plate due to the prepared CdS QDs coatings. Based on the results, the prepared CdS QDs by the green method can be a potential candidate in the water purification and corrosion resistance field.

Nitrogen doped graphene supported mixed metal sulfide photocatalyst for high production of hydrogen using natural solar light

We have developed a strategy to prevent the photo-corrosion of cadmium sulfide nanorods (CdSNRs) by coating them with cerium sulfide (Ce2S3) as co-catalyst and N-doped Graphene (NG) for a solar light-driven H2 production application. The uniform deposition and coating of Ce2S3 and NG over the CdSNRs were confirmed by both FESEM and HRTEM analyses. The incorporation of Ce2S3 and NG into CdSNRs not only increased its stability but also extended its absorption in visible and NIR regions. As a result, the prepared CdSNRs/Ce2S3 photocatalysts produced ∼16,181 µmol h−1 g–1 of H2 under solar light irradiation, which was ∼ 10 times higher than the pure CdSNRs. Interestingly, N atom doped graphene-supported CdSNRs/Ce2S3 photocatalysts has shown a paramount effect on the H2 production by 24 times higher compared to bare CdSNRs (35,946 µmol h−1g–1). In addition, the NG-CdSNRs/Ce2S3 photocatalysts exhibited high stability up to 5 continuous cycles. The high stability was achieved due to the covering of CdSNRs by Ce2S3 and NG, which may effectively prevent the leaching out of S2- ions from CdSNRs. On the other hand, the NG played a dual role by preventing the photo-corrosion and also improving the charge carrier separation as evidenced by the PL, TRPL, and Impedance studies. The present work may open a new direction in designing a highly photostable metal sulfide photocatalyst for energy conversion applications in aqueous medium.

Highly sensitive, selective and reliable detection of picric acid in aqueous media based on conjugated porous polymer nanoparticles

Conjugated porous polymer is known as a promising sensing material for detecting nitroaromatic compounds, however, the sensing application in aqueous media is restricted, due to their poor solubility/dispersity in water. Herein, two novel conjugated porous polymer nanoparticles (PTPA-TPE1 and PTPA-TPE2) containing triphenylamine in the backbone and tri/tetraphenylethene as side groups were designed and synthesized. PTPA-TPE1 and PTPA-TPE2 were fully characterized by FT-IR, 1H NMR, TEM, N2 sorption isotherms, UV–vis absorption spectra, photoluminescence (PL) spectra and cyclic voltammetry. The electron-rich triphenylamine backbones benefit the interaction with nitroaromatics and the porosity could promote the adsorption/diffusion of the analytes. The PL sensing properties of the polymers were evaluated in aqueous dispersion, and the detection limits of PTPA-TPE1 and PTPA-TPE2 towards picric acid (PA) are 72 ppb and 111 ppb, respectively. Importantly, the PL quenching effect towards PA exhibits no noticeable change upon the addition of other nitroaromatic compounds, indicating the anti-interference characteristic and selective detection of PA. Furthermore, at 95 % confidence level, there was no significant difference between the results of our sensing method and HPLC analysis for detecting PA in real environmental water samples by the t-test.

Two novel 3D Zn(II)/Cd(II) MOFs with tri- or di-nuclear cluster units for multifunctional sensing applications in aqueous media

With flexible 2-methylenesuccinate acid (H2MSA) and rigid 4, 4′-bipyridine (bpy) as mixed ligands, two three-dimensional (3D) metal−organic frameworks (MOFs), {[Zn3(μ2-OH)2(MSA)2(bpy)2]·4H2O}n (1) and {[Cd(MSA)(bpy)]·2H2O}n (2), were obtained solvothermally. Complexes 1 and 2 both have a 3D framework structures, which include respectively a linear trinuclear [Zn3] or a rare dinuclear [Cd2] cluster node that consisting of two seven-coordinated Cd(II) ions. The adjacent [Zn3] or [Cd2] nodes in 1 and 2 are firstly linked together by the MSA2− ligand to form a 1D chain or a 2D layer unit respectively, which are further bridged by the bpy linkers to produce the 3D framework structures. If treating the [Zn3] and [Cd2] cluster as 4- and 6-connected nodes, the 3D frameworks of 1 and 2 can be simplified into a CdSO4 topological network with a Schläfli symbol of (65.8) and a rob network with a Schläfli symbol of (48.66.8), respectively. The PXRD patterns suggest that 1 and 2 have good stability when soaked in water for at least 48 h. The fluorescence sensing properties of 1 and 2 toward different metal inorganic ions were investigated, and two complexes both could sense Fe3+, MnO4− and Cr2O72− in aqueous solution with high sensitivity and selectivity (the LODs were 3.20 μM, 1.54 μM and 1.95 μM for 1, 1.15 μM, 0.48 μM and 1.23 μM for 2, respectively) as well as good recircularity. In addition, the mechanism of the selective luminescence quenching response for Fe3+, MnO4− and Cr2O72− could be attributed to the energy competition between the excitation of complex 1/2 and the ultraviolet absorption of responsive substances.

Glycerol carbonate structuring in aqueous solutions as inferred from mutual diffusion coefficient, density and viscosity measurements in the temperature range 283.15–313.15 K

Glycerol Carbonate (4-hydroxymethyl-2-oxo-1,3-dioxolane, GC) is an emerging green reactant for many organic chemistry applications. GC popularity stems from its high reactivity, which makes it attractive for many chemical transformations and for its easy synthesis from glycerol, a byproduct of biodiesel production. While extensive literature covers the synthesis and chemical reactivity of GC, its transport properties are poorly studied, especially in water. Here, we measured for the first time the diffusion coefficient of GC in water in the temperature range 283.15–313.15 K and for concentrations up to 0.1 M. By taking advantage of the Taylor Dispersion Analysis (TDA) we found D0=9.53±0.06×10-10 m2/s at 298.15 K and an activation energy for the diffusion process Ea=3.74±0.09 kcal/mol. Density and dynamic viscosity were also measured in the same temperature interval to calculate the hydrodynamic radius of GC. Experimental data helped in assessing the structure of GC aggregates formed in aqueous solutions and provided an estimation of the equilibrium constant for the dimer formation. Our findings can be useful for studying the fate of GC in the environment and to improve its use for applications in aqueous media.

Fabrication of water‐resistant, thermally stable, and antibacterial fibers through in situ multivalent crosslinking

AbstractFibers are emerging materials for biomedical applications, including drug delivery, sensing, tissue engineering, and wound dressing. However, fibers produced from water‐soluble polymers usually lose their morphology and quickly dissolve after exposure to water. Here, we developed a combined strategy of using multivalent crosslinkers along with in situ crosslinking to synthesize water‐resistant and thermally stable hybrid fibers. In our design, polyvinyl alcohol (PVA), aldehyde‐modified polyxylitol sebacate‐co‐polyethylene glycol (Ald_PXS‐co‐PEG, APP), and neomycin (Neo) were mixed to fabricate hybrid fibers through electrospinning. Several crosslinking chemistries were occurred in the hybrid fibers of PVA/APP/Neo, including the acetal bonds between PVA and APP, imine bonds between APP and Neo, and hydrogen bonds between PVA, APP, and Neo. These multiple chemical bonds allowed the PVA/APP/Neo fibers to maintain their fiber morphology after the immersion in the PBS solution, preserving the advantages of fibers (e.g., large surface‐to‐volume ratio and porosity) for applications in aqueous media. Particularly, the presence of Neo also provided the hybrid fibers with antimicrobial ability. Taken together, the in situ multivalent crosslinking has been demonstrated as a promising strategy to prepare stable and functional fibers for advanced applications.

Sol–gel synthesis of mesoporous NiO/ZnO heterostructure nanocomposite for photocatalytic and anticorrosive applications in aqueous media

Nanocomposites (NCs) of p-type NiO/n-type ZnO heterojunction with varied NiO content (0−10) wt% were produced by spreading NiO nanoparticles (NPs) on the ZnO (NPs) surface by sol-gel technique with Triton X-100 as a structuring & templating agent. The crystalline phase, structure, characterization, and surface morphology of the gel powde0r of the produced NiO/ZnO nanocomposites were investigated using different spectroscopic techniques such as FTIR, XRD, FESEM, EDX, HRTEM, BET and UV–Vis DRS. The photocatalytic performance of the produced NiO/ZnO nanocomposites was estimated by continuously degrading the methylene blue dye (MB) as an organic contaminant in aqueous media. The effects of several factors, such as dopant concentration, pH, photocatalytic dose, point of zero charge (PZC), and chemical oxygen demand (COD) were assessed and discussed. When pure ZnO (NPs) is compared to NiO/ZnO (NCs), both exhibit superior photocatalytic activity under UV and sunlight irradiation. The corrosion resistance of the NiO/ZnO (NCs) gel coatings was assessed via potentiodynamic polarization (PDP) and electrochemical impedance spectroscopy (EIS). The photodegradation data shown that the NiO/ZnO (5 wt%) semiconductor is the best photocatalyst for methylene blue dye (MB) degradation among the manufactured semiconductors. Furthermore, when compared to alternative gel coatings and the untreated surface at various doping doses, the gel coating based on NiO/ZnO (NCs) with a concertation of (5 wt%) displayed the highest activity as a coating system for aluminum electrode. In addition, increasing the layer thickness of NiO/ZnO (NCs) gel films and co-dopant concentration in coating systems increase corrosion resistance. AFM micrographs revealed the creation of a protective multilayer of NiO/ZnO (NCs) coating films on the surface of aluminum. The experimental and spectral results confirmed that the synthesized novel mesoporous mixed NiO/ZnO (NCs) had potential photocatalytic and anticorrosive behaviors.

4-Azidocinnoline-Cinnoline-4-amine Pair as a New Fluorogenic and Fluorochromic Environment-Sensitive Probe.

A new type of fluorogenic and fluorochromic probe based on the reduction of weakly fluorescent 4-azido-6-(4-cyanophenyl)cinnoline to the corresponding fluorescent cinnoline-4-amine was developed. We found that the fluorescence of 6-(4-cyanophenyl)cinnoline-4-amine is strongly affected by the nature of the solvent. The fluorogenic effect for the amine was detected in polar solvents with the strongest fluorescence increase in water. The environment-sensitive fluorogenic properties of cinnoline-4-amine in water were explained as a combination of two types of fluorescence mechanisms: aggregation-induced emission (AIE) and excited state intermolecular proton transfer (ESPT). The suitability of an azide–amine pair as a fluorogenic probe was tested using a HepG2 hepatic cancer cell line with detection by fluorescent microscopy, flow cytometry, and HPLC analysis of cells lysates. The results obtained confirm the possibility of the transformation of the azide to amine in cells and the potential applicability of the discovered fluorogenic and fluorochromic probe for different analytical and biological applications in aqueous medium.

Molecular simulation studies of self-assembly for a chromonic perylene dye: All-atom studies and new approaches to coarse-graining

Perylene tetracarboxylic acid bisimides are compounds that show intense visible light absorption and exhibit excellent chemical, photochemical and thermal stability. As such, they have been widely used as dyes and have a range of industrial applications. These dyes have also been investigated for various applications in aqueous media as chromonic liquid crystals: lyotropic systems characterised by the association of aromatic mesogenic cores into stacked structures. In this study, we focus on one perylene dye bis-(N,N-diethylaminoethyl) perylene-3,4,9,10-tetracarboxylic diimide dihydrochloride, PER, and study its self-assembly in aqueous solution through both atomistic and coarse-grained molecular models. All-atom molecular dynamics simulations demonstrate spontaneous self-assembly into chromonic H-aggregate stacks with an interparticle twist between molecules. The coarse-graining of complex chromonic mesogens introduces a wealth of subtle complexities that presents a significant challenge to overcome. Consequently, we developed coarse-grained (CG) models using both bottom-up and top-down approaches: the multiscale coarse-graining method (MS-CG) in the form of hybrid force matching (FM) and the MARTINI 3 force field, respectively. We discuss the successes/deficiencies of these approaches and introduce changes to improve upon their performance and representability. For the MARTINI 3 model, careful optimisation of parameters allows it to exactly reproduce the atomistic self-assembly behaviour including the relevant thermodynamic properties in solution. The bottom-up CG model, produced using a conventional MS-CG treatment, fails to reproduce most of the target properties, but the implementation of the potentials into a combined FM-MARTINI 3 framework allows the recovery of the correct self-assembly behaviour in solution.

Influence of structurally and morphologically different nanofillers on the performance of polysulfone membranes modified by the assembled PDDA/PAMPS-based hybrid multilayer thin film

A highly efficient nanofiltration membrane should exhibit high separation performance in removing divalent salts and organic solutes, as well as high permeation to meet practical separation and purification applications in aqueous media. Here, we designed a series of hybrid multilayer thin film membranes filled with the structurally and morphologically different nanofillers such as hexagonal boron nitride (HBN) nanosheets and metal-organic framework (MOF) nanoparticles, consisting of 3 and 6 layer pairs of polyelectrolyte through the layer-by-layer self-assembly technique (LBL) and characterized them in terms of dye and salt separation, as well as permeation. The rejection performance and permeability of the designed membranes manifested that HBN nanosheets were more effective than MOF nanoparticles in achieving a high-performance membrane. As compared to the bare multilayer thin film membrane, the addition of HBN nanosheets within the negatively-charged layers of the multilayer thin film membrane consisting of 6 bilayers resulted in good retention of up to 93% and 92% for acid blue (ACB) and bromophenol blue (BPB) dye molecules, respectively. Besides, this membrane exhibited 60% and 45% improvement in the water flux for ACB and BPB solutions, respectively, while the rejection of the sulfate ions maintained an acceptable value around 78%. Furthermore, it was found that this HBN-embedded hybrid multilayer membrane had superior potential for the removal of coherent foulant compared to all samples.

Evaluation of ovalbumin nanocarriers to promote the vehiculization and antifungal properties of cinnamaldehyde in aqueous media

This paper is aimed to evaluate the vehiculization of trans-cinnamaldehyde (CIN) through the formation of complexes with ovalbumin (OVA) and heat-induced OVA nanoparticles (OVAn) to promote its application in aqueous media. OVAn production variables (pH and protein concentration) and some physicochemical features (size, surface hydrophobicity, and molecular weight) were explored. Complex formation was examined in terms of stoichiometric and thermodynamic (ΔH°, ΔS°, and ΔG°) parameters by applying fluorescence spectroscopy. Results revealed the strong influence of the OVA conformational state (native or aggregated) on CIN vehiculization. However, all systems showed similar encapsulation efficiencies (~62%). Besides, nanosized complexes were colloidally stable at pH 3.0 and 7.0. Finally, their antifungal properties against the Aspergillus niger species (as a microbial model) were determined, being the OVA-CIN complex the most efficient. The preservation of the conformational structure of OVA as a nanocarrier was relevant to promote the CIN antifungal properties in aqueous media.

Label-free immunosensor for cardiac troponin I detection based on aggregation-induced electrochemiluminescence of a distyrylarylene derivative

Herein, the aggregation-induced electrochemiluminescence (AIECL) of a distyrylarylene derivative, 4,4′-bis(2,2-diphenylvinyl)-1,1′-biphenyl (DPVBi), was investigated for the first time. This luminophore exhibits significantly enhanced photoluminescence (PL) and electrochemiluminescence (ECL) emission with the increases of water content in organic/water mixtures. This high luminescence efficiency of DPVBi in aggregate state is due to the fact that the aggregates can reduce the energy loss by restricting the intramolecular motions. The ECL behavior of DPVBi in acetonitrile was investigated by ECL transients and so-called “half-scan” technology, where singlet-singlet annihilation ECL was generated under continuous potential switching. The DPVBi nanobulks (DPVBi NBs) were prepared to improve its application in aqueous media, which could be conveniently cast on electrode surface for developing sensing platform due to its good film-forming nature. The constructed heterogeneous AIECL platform can produce reductive-oxidative and oxidative-reductive ECL by using trimethylamine (TEA) and potassium peroxodisulfate (K2S2O8) as coreactant. On the basis of the higher ECL efficiency of DPVBi NBs/TEA system, a label free immunosensor for cardiac troponin I (cTnI) was developed with the assistance of electrodeposited gold nanoparticles, and it showed a wide linear range of 20 ng/mL~100 fg/mL and low detection limit of 43 fg/mL. Moreover, the constructed immunosensor also exhibited good specificity, stability and satisfied performance in practical sample analysis.