Search Results (41)

The direct deposition of highly concentrated polyelectrolyte complexes based on poly(ethyleneimine) (PEI) and poly(sodium methacrylate) (PMANa) onto inorganic sand microparticles (F100 and F200) resulted in the formation of versatile core-shell composites with fast removal properties in dynamic conditions toward anionic charged pollutants. Herein, in situ-generated nonstoichiometric PEI/PMANa polyelectrolyte complexes were directly precipitated as a soft organic shell onto solid sand microparticles at a 5% mass ratio (organic/inorganic part = 5%, w/w%). The sorption of an anionic model pollutant (Indigo Carmine (IC)) onto the composite particles in dynamic conditions depended on the inorganic core size, the flow rate, the bed type (fixed or fluidized) and the initial dye concentration. The maximum sorption capacity, after 10 cycles of sorption/desorption of IC onto F100@P5% and F200@P5%, was between 16 and 18 mg IC/mL composite. The newly synthesized core-shell composites could immobilize IC at a high flow rate (8 mL/min), either from concentrated (C_IC = 60 mg/L) or very diluted (C_IC = 0.2 mg/L) IC aqueous solution, demonstrating that this type of material could be promising in water treatment or efficient in solid-phase extraction (concentration factor of 2000). Full article

Controlling bacterial growth and biofilm formation remains a major challenge in the treatment of chronic wounds and in preventing infection after biomedical device implantation. Thus, creating materials with inherent antibacterial potential is necessary. Here, we report silk fibroin–polyethylenimine-based (SF-PEI) microparticles to control the growth of Pseudomonas aeruginosa, which is a highly infectious and biofilm-forming pathogen. SF-PEI microparticles were fabricated using a solvent displacement method, and their microparticle formation was confirmed using Fourier-transform infrared spectroscopy (FTIR). The morphology and size of the microparticles were characterized using scanning electron microscopy (SEM) and dynamic light scattering (DLS). The SEM and DLS methods revealed that the microparticles formed showed a uniform, spherical morphology with a consistent size distribution, showing a Z-average of 834.82 nm. The antibacterial and biofilm inhibition properties of the SF-PEI microparticles were tested against P. aeruginosa. The results show significant control of bacterial growth and biofilm formation when treated with the SF-PEI particles. Further, a cell viability assay was evaluated using human dermal fibroblasts, and the results demonstrated that the SF-PEI microparticles developed demonstrated cytocompatibility, with no significant cytotoxic effects observed. These results suggest that SF-PEI microparticles offer a promising biocompatible strategy for reducing bacterial growth and their biofilm-associated infections, particularly in wound healing and medical device applications. Full article

Ethylene imine-based porous polymer nanocomposites were prepared by ring-opening polymerization of 2,2-bishydroxymethylbutanol-tris [3-(1-aziridinyl)propionate] (3AZ), a tri-functional aziridine compound, in the presence of commercially available metal oxide nanoparticles, SiO₂ or ZrO₂, accompanied by polymerization-induced phase separation. The reactions with SiO₂ and ZrO₂ nanoparticles successfully yielded nanocomposite porous polymers as rigid materials. The nanocomposite porous polymers with SiO₂ and ZrO₂ nanoparticles showed characteristic surface morphologies composed of gathered particles with diameters less than 1 micrometer. These nanocomposites were effective in increasing Young’s moduli of the porous polymers due to an increase in their bulk densities. The presence of SiO₂ and ZrO₂ nanoparticles in the porous polymers efficiently retarded thermal decomposition. Full article

Prussian blue nanoparticles (PBNPs) have been identified as a promising candidate for biomimetic peroxidase (POD)-like activity, specifically due to the metal centres (Fe³⁺/Fe²⁺) of Prussian blue (PB), which have the potential to function as catalytically active centres. The decoration of PBNPs with desired functional polymers (such as amino- or carboxylate-based) primarily facilitates the subsequent linkage of biomolecules to the nanoparticles for their use in biosensor applications. Thus, the elucidation of the catalytic POD mimicry of these systems is of significant scientific interest but has not been investigated in depth yet. In this report, we studied a series of poly(ethyleneimine) (PEI)-mediated PBNPs (PB/PEI NPs) prepared using various synthesis protocols. The resulting range of particles with varying size (~19–92 nm) and shape combinations were characterised in order to gain insights into their physicochemical properties. The POD-like nanozyme activity of these nanoparticles was then investigated by utilising a 3,3′,5,5′-tetramethylbenzidine (TMB)/H₂O₂ system, with the catalytic performance of the natural enzyme horseradish peroxidase (HRP) serving as a point of comparison. It was shown that most PB/PEI NPs displayed higher catalytic activity than the PBNPs, with higher activity observed in particles of smaller size, higher Fe content, and higher Fe²⁺/Fe³⁺ ratio. Furthermore, the nanoparticles demonstrated enhanced chemical stability in the presence of acid, sodium azide, or high concentrations of H₂O₂ when compared to HRP, confirming the viability of PB/PEI NPs as a promising nanozymatic material. This study disseminates fundamental knowledge on PB/PEI NPs and their POD-like activities, which will facilitate the selection of an appropriate particle type for future biosensor applications. Full article

There are great challenges in the field of natural product isolation and purification and in the pharmacological study of oligosaccharide monomers. And these isolation and purification processes are still universal problems in the study of natural products (NPs), traditional Chinese medicine (TCM), omics, etc. The same polymer-modified materials designed for the special separation of oligosaccharides, named Sil-epoxy-PEI and Sil-chloropropyl-PEI, were synthesized via two different methods and characterized by scanning electron microscopy combined with energy spectrum analysis, Fourier transform infrared spectroscopy, thermogravimetric analysis, zeta potential as well as surface area analysis, etc. Several nucleotide/nucleoside molecules with different polarities and selectivities were successfully isolated in our laboratory using stainless-steel columns filled with the synthesized material. In addition, the separation of saccharide probes and oligosaccharides mixtures in water extracts of Morinda officinalis were compared in HILIC mode. The results showed that the resolution of separations for the representative analytes of the Sil-epoxy-PEI column was higher than for the Sil-chloropropyl-PEI column, and the developed stationary phase exhibited improved performance compared to hydrothermal carbon, amide columns and other HILIC materials previously reported. Full article

Pharmaceuticals and heavy metals pose significant risks to human health and aquatic ecosystems, necessitating their removal from water and wastewater. A promising alternative for this purpose involves their removal by adsorption on composite sorbents prepared using a conventional layer-by-layer (LbL) method or an innovative coacervate direct deposition approach. In this study, four novel composite materials based on a silica core (IS) and a polyelectrolyte coacervate shell were used for the investigation of dynamic adsorption of three heavy metals (lead, nickel and cadmium) and an organic drug model (diclofenac sodium salt, DCF-Na). The four types of composite sorbents were tested for the first time in dynamic conditions (columns with continuous flow), and the column conditions were similar to those used in wastewater treatment plants. The influence of the polyanion nature (poly(acrylic acid) (PAA) vs. poly(sodium methacrylate) (PMAA)), maintaining a constant poly(ethyleneimine) (PEI), and the cross-linking degree (r = 0.1 and r = 1.0) of PEI chains on the immobilization of these pollutants (inorganic vs. organic) on the same type of composite was also studied. The experiments involved both single- and multi-component aqueous solutions. The kinetics of the dynamic adsorption process were examined using two non-linear models: the Thomas and Yoon–Nelson models. The tested sorbents demonstrated good adsorption capacities with affinities for the metal ions in the following order: Pb²⁺ > Cd²⁺ > Ni²⁺. An increase in the initial diclofenac sodium concentration led to an enhanced adsorption capacity of the IS/(PEI-PAA)_c-r1 sorbent. The calculated sorption capacities were in good agreement with the adsorption capacity predicted by the Thomas and Yoon–Nelson models. The substantial affinity observed between DCF-Na and a column containing composite microparticles saturated with heavy metal ions was explained. Full article

Increased life expectancy in industrialized countries is causing an increased incidence of osteoporosis and the need for bioactive bone implants. The integration of implants can be improved physically, but mainly by chemical modifications of the material surface. It was recognized that amino-group-containing coatings improved cell attachment and intracellular signaling. The aim of this study was to determine the role of the amino group density in this positive cell behavior by developing controlled amino-rich nanolayers. This work used covalent grafting of polymer-based nanocoatings with different amino group densities. Titanium coated with the positively-charged trimethoxysilylpropyl modified poly(ethyleneimine) (Ti-TMS-PEI), which mostly improved cell area after 30 min, possessed the highest amino group density with an N/C of 32%. Interestingly, changes in adhesion-related genes on Ti-TMS-PEI could be seen after 4 h. The mRNA microarray data showed a premature transition of the MG-63 cells into the beginning differentiation phase after 24 h indicating Ti-TMS-PEI as a supportive factor for osseointegration. This amino-rich nanolayer also induced higher bovine serum albumin protein adsorption and caused the cells to migrate slower on the surface after a more extended period of cell settlement as an indication of a better surface anchorage. In conclusion, the cell spreading on amine-based nanocoatings correlated well with the amino group density (N/C). Full article

Graphene oxide (GO)—branched poly(ethyleneimine) (BPEI) hydrated mixtures were studied by means of fully atomistic molecular dynamics simulations to assess the effects of the size of polymers and the composition on the morphology of the complexes, the energetics of the systems and the dynamics of water and ions within composites. The presence of cationic polymers of both generations hindered the formation of stacked GO conformations, leading to a disordered porous structure. The smaller polymer was found to be more efficient at separating the GO flakes due to its more efficient packing. The variation in the relative content of the polymeric and the GO moieties provided indications for the existence of an optimal composition in which interaction between the two components was more favorable, implying more stable structures. The large number of hydrogen-bonding donors afforded by the branched molecules resulted in a preferential association with water and hindered its access to the surface of the GO flakes, particularly in polymer-rich systems. The mapping of water translational dynamics revealed the existence of populations with distinctly different mobilities, depending upon the state of their association. The average rate of water transport was found to depend sensitively on the mobility of the freely to move molecules, which was varied strongly with composition. The rate of ionic transport was found to be very limited below a threshold in terms of polymer content. Both, water diffusivity and ionic transport were enhanced in the systems with the larger branched polymers, particularly with a lower polymer content, due to the higher availability of free volume for the respective moieties. The detail afforded in the present work provides a new insight for the fabrication of BPEI/GO composites with a controlled microstructure, enhanced stability and adjustable water transport and ionic mobility. Full article

The modification of inorganic surfaces with weak cationic polyelectrolytes by direct deposition through precipitation is a fast approach to generating composites with high numbers of functional groups. The core/shell composites present very good sorption capacity for heavy metal ions and negatively charged organic molecules from aqueous media. The sorbed amount of lead ions, used as a model for priority pollutants such as heavy metals, and diclofenac sodium salt, as an organic contaminant model for emerging pollutants, depended strongly on the organic content of the composite and less on the nature of contaminants, due to the different retention mechanisms (complexation vs. electrostatics/hydrophobics). Two experimental approaches were considered: (i) simultaneous adsorption of the two pollutants from a binary mixture and (ii) the sequential retention of each pollutant from monocomponent solutions. The simultaneous adsorption also considered process optimization by using the central composite design methodology to study the univariate effects of contact time and initial solution acidity with the purpose of enabling further practical applications in water/wastewater treatment. Sorbent regeneration after multiple sorption-desorption cycles was also investigated to assess its feasibility. Based on different non-linear regressions, the fitting of four isotherms (Langmuir, Freundlich, Hill, and Redlich–Peterson models) and three kinetics models (pseudo-first order (PFO), pseudo-second order (PSO), and two-compartment first order (TC)) has been carried out. The best agreement with experiments was found for the Langmuir isotherm and the PFO kinetic model. Silica/polyelectrolytes with a high number of functional groups may be considered efficient and versatile sorbents that can be used in wastewater treatment processes. Full article

The application of lignin-based adsorbents in the efficient removal of phosphate from wastewater has attracted much attention and been intensively studied in recent years. However, most currently reported lignin-based adsorbents are difficult to recover and recycle. Herein, we have developed a recyclable, nanostructured bio-adsorbent, poly(ethyleneimine) (PEI)-modified lignin (LG) integrated with Fe₃O₄ and Zr-La dual-metal hydroxide (LG-NH₂@Fe₃O₄@Zr-La), by the Mannich reaction followed by the chemical coprecipitation method. Multilayer adsorption existed on the surface of LG-NH₂@Fe₃O₄@Zr-La based on the isotherm fitting curve, and its adsorption capacity reached 57.8 mg P g⁻¹, exhibiting a higher phosphate uptake than most reported metallic oxide-based composites. The adsorption process was dominated by inner-sphere complexation of ligand-exchange and electrostatic interactions. Moreover, LG-NH₂@Fe₃O₄@Zr-La exhibited excellent selectivity against coexisting anions, and the adsorption was more efficient under acidic conditions. When the phosphate concentration was 2.0 mg P L⁻¹, the removal efficiency of phosphate reached 99.5% and the residual concentration was only 10 μg P L⁻¹, which meets the United States Environmental Protection Agency (USEPA) standard for eutrophication prevention. In addition, the LG-NH₂@Fe₃O₄@Zr-La displayed excellent reusability, maintaining 91.8% of removal efficiency after five cycles. Importantly, owing to the magnetic properties of the loaded Fe₃O₄, the resulting composite could be separated within 30 s under an external magnetic field. Thus, the separable and recyclable biobased magnetic adsorbent developed in this work exhibited promising application in phosphate capture from real sewage. This research study provides a new perspective for lignin valorization in lignocellulose biorefineries and establishes an approach for developing an economical and efficient bio-adsorbent for phosphate removal from wastewater. Full article

The aim of this work was to investigate the ability of a solid-state material, prepared by crosslinking chitosan with a phenothiazine-based aldehyde, to remove copper (II) ions from aqueous solutions, in a fast and selective manner. The metal uptake experiments, including the retention, sensibility, and selectivity against eight different metal ions, were realized via batch adsorption studies. The capacity of the material to retain copper (II) ions was investigated by spectrophotometric measurements, using poly(ethyleneimine) complexation agent, which allowed detection in a concentration range of 5–500 µM. The forces driving the copper sorption were monitored using various methods, such as FTIR spectroscopy, X-ray diffraction, SEM-EDAX technique, and optical polarized microscopy, and the adsorption kinetics were assessed by fitting the in vitro sorption data on different mathematical models. The phenothiazine-imine-chitosan material proved high ability to recover copper from aqueous media, reaching a maximum retention capacity of 4.394 g Cu (II)/g adsorbent when using a 0.5 M copper solution, which is an outstanding value compared to other chitosan-based materials reported in the literature to this date. It was concluded that the high ability of the studied xerogel to retain Cu (II) ions was the result of both physio- and chemo-sorption processes. This particular behavior was favored on one hand by the porous nature of the material and on the other hand by the presence of amine, hydroxyl, imine, and amide groups with the role of copper ligands. Full article

The rise of gas-sensing applications and markets has led to microwave sensors associated to polymer-based sensitive materials gaining a lot of attention, as they offer the possibility to target a large variety of gases (as polymers can be easily functionalised) at ultra-low power and wirelessly (which is a major concern in the Internet of Things). A two-channel microstrip sensor with one resonator coated with 1,2 epoxybutane-functionalised poly(ethyleneimine) (EB-PEI) and the other left bare was designed and fabricated for humidity sensing. The sensor, characterised under controlled laboratory conditions, showed exponential response to RH between 0 and 100%, which is approximated to −1.88 MHz/RH% (−0.03 dB/RH%) and −8.24 MHz/RH% (−0.171 dB/RH%) in the RH ranges of 30–80% and 80–100%, respectively. This is the first reported use of EB-PEI for humidity sensing, and performances, especially at high humidity level (RH > 80%), as compared with transducer working frequencies, are better than the state of the art. When further tested in real outdoor conditions, the sensor shows satisfying performances, with 4.2 %RH mean absolute error. Most importantly, we demonstrate that the sensor is selective to relative humidity alone, irrespective of the other environmental variables acquired during the campaign (O₃, NO, NO₂, CO, CO₂, and Temperature). The sensitivities obtained outdoors in the ranges of 50–70% and 70–100% RH (−0.61 MHz/%RH and −3.68 MHz/%RH, respectively) were close to lab results (−0.95 MHz/%RH and −3.51 MHz/%RH, respectively). Full article

Coacervation is a self-assembly strategy based on the complexation of polyelectrolytes, which is utilized in biomedicine and agriculture, as well as automotive and textile industries. In this paper, we developed a new approach to the on-demand periodic formation of polyelectrolyte complexes through a Liesegang-type hierarchical organization. Adjustment of reaction conditions allows us to assemble materials with a tunable spatiotemporal geometry and establish materials’ production cycles with a regulated periodicity. The proposed methodology allows the membrane to self-assemble when striving to reach balance and self-heal after exposure to external stimuli, such as potential difference and high pH. Using chronopotentiometry, K⁺ ion permeability behavior of the PEI–PSS coacervate membranes was demonstrated. The periodically self-assembled polyelectrolyte nanomembranes could further be integrated into novel energy storage devices and intelligent biocompatible membranes for bionics, soft nanorobotics, biosensing, and biocomputing. Full article

This study aimed to develop novel elastic films based on chitosan and poly(3-hydroxypropyl ethyleneimine) or P3HPEI for the rapid delivery of haloperidol. P3HPEI was synthesized using a nucleophilic substitution reaction of linear polyethyleneimine (L-PEI) with 3-bromo-1-propanol. ¹H-NMR and FTIR spectroscopies confirmed the successful conversion of L-PEI to P3HPEI, and the physicochemical properties and cytotoxicity of P3HPEI were investigated. P3HPEI had good solubility in water and was significantly less toxic than the parent L-PEI. It had a low glass transition temperature (T_g = −38.6 °C). Consequently, this new polymer was blended with chitosan to improve mechanical properties, and these materials were used for the rapid delivery of haloperidol. Films were prepared by casting from aqueous solutions and then evaporating the solvent. The miscibility of polymers, mechanical properties of blend films, and drug release profiles from these formulations were investigated. The blends of chitosan and P3HPEI were miscible in the solid state and the inclusion of P3HPEI improved the mechanical properties of the films, producing more elastic materials. A 35:65 (%w/w) blend of chitosan–P3HPEI provided the optimum glass transition temperature for transmucosal drug delivery and so was selected for further investigation with haloperidol, which was chosen as a model hydrophobic drug. Microscopic and X-ray diffractogram (XRD) data indicated that the solubility of the drug in the films was ~1.5%. The inclusion of the hydrophilic polymer P3HPEI allowed rapid drug release within ~30 min, after which films disintegrated, demonstrating that the formulations are suitable for application to mucosal surfaces, such as in buccal drug delivery. Higher release with increasing drug loading allows flexible dosing. Blending P3HPEI with chitosan thus allows the selection of desirable physicochemical and mechanical properties of the films for delivery of haloperidol as a poorly water-soluble drug. Full article

Demand for direct chemical modification of functional material on a surface is increasing in various fields. A new approach for a functionalized surface is investigated by applying a conventional laser in order to generate chemical activation by photothermal energy. Poly(ethyleneimine) (PEI), with a high density of amino groups, is chemically grafted on poly(methyl methacrylate) (PMMA) by irradiation of a CO₂ laser (10.6 μm). Laser parameters such as power, scan rate, and focal length are observed to play an important role in order to introduce effective photothermal energy for the chemical reaction between PEI and PMMA. By optimization of laser parameters, the amide compound is produced as a result of the reaction of amine from PEI and the ester of PMMA successfully. The PMMA surface modified with PEI is analyzed by XPS and TOF-SIMS to identify the functional groups. Furthermore, the surface is characterized in terms of wettability, adhesion force, and surface charge for various applications. Finally, reaction with dye and metal on the amine-terminated PMMA shows promising results in supplying a selective and reliable functional substrate. Full article