Introduction Of Polyethylenimine Research Articles

Eco-friendly multifunctional coating for polyester-cotton blended fabrics with superior flame retardancy and antibacterial properties

Since the fire hazards of polyester-cotton blended (PTCO) fabrics and the hidden dangers of bacterial infection concerns caused by the contained cotton fiber, the design of flame retardant and antibacterial PTCO fabrics has received considerable attention. In this work, flame-retardant PTCO fabrics with satisfactory antibacterial properties were fabricated via a convenient and eco-friendly impregnation treatment involving guanidine phosphate (GP) and polyethylenimine (PEI). The prepared PTCO fabrics demonstrated excellent flame retardancy with a high limiting oxygen index value of 30.5 % and self-extinguishing capability, the damaged length was only 34 mm in the vertical flammability test. Furthermore, the peak heat release rate and the total heat release of coated PTCO fabrics were reduced significantly by 49 % and 38 %, respectively, indicating a substantial enhancement in fire safety. According to the analysis of the char residues and volatiles, GP presented great catalytic carbonization property, and PEI assisted the formation of the dense and stable carbon layer. The stable carbon layer effectively restricted mass and oxygen transfer between the PTCO fabrics and the environment. In addition, the introduction of PEI also produced more nonflammable gases to enhance the flame retardancy of the PTCO fabrics. Importantly, the GP/PEI coating barely deteriorate the physical and mechanical properties of the PTCO fabrics. The antibacterial rate of the GP/PEI-coated PTCO fabrics against Escherichia coli and Staphylococcus aureus was 99.99 %, similar to that of GP-coated fabrics, indicating the efficacy antibacterial properties of GP, and the addition of PEI did not compromise the antibacterial properties of GP. This work offers an efficient and simple approach to producing multifunctional PTCO fabrics with excellent flame retardancy and antibacterial properties, which are hopeful to expand the promising application of PTCO fabrics.

Structurally robust cellulosic triboelectric materials under high moisture conditions for self-powered sensing

Eco-friendly cellulosic fibers-based triboelectric nanogenerators (TENGs) are enormously and increasingly demanded for self-powered flexible electronics. However, under high moisture conditions (e.g. sweat, sailing and rain day), the mechanical behaviors of hydrophilic paper were severely reduced due to the weak wet strength and the cellulosic paper-based sensors were easily destroyed under external force, leading to the device failure and invalid signal acquisition. Herein, an industrial-friendly polyethylenimine (PEI)-assisted pulping strategy was developed to produce advanced cellulosic papers, which possessed reinforced wet strength and tribopositive performance. During pulping procedure, the cationic PEI molecules could be quickly in situ bonded onto the surface of fibers under electrostatic interaction and the interfacial interaction between fibers was significantly enhanced through the formation of hydrogen bonds between the amino groups on PEI and the hydroxyl groups on cellulose fibers. The wet strength was significantly enhanced from 1.93 MPa for pristine paper to 8.33 MPa for cellulose/PEI1.5% with an enhancement of 4.32 times. Moreover, originating from the enhanced dielectric behaviors upon the introduction of PEI, the optimized cellulose/PEI1.5% TENG delivered the maximum VOC of 157.3 V, ISC of 3.47 μA, QSC of 42.73 nC and instantaneously maximum power density of 145.93 mW·m−2. Our findings proposed a new perspective for fabricating high-performance tribopositive cellulosic materials that withstand high humid conditions.

Fabrication of double imprinted anchor points in cellulose nanocrystals-based hierarchical porous polyHIPEs for selective separation of flavoniods under physiological pH

Previous research had proved that molecular imprinted polymers can be used as separation material for removing Naringin (NRG) from agricultural pomelo wastes effectively. But the adsorption amounts of NRG molecules from traditional MIPs was quite low by using boronic acid as functional monomer because of single affinity interaction. Therefore, we developed the new combination of bifunctional monomers (i.e. low pKa boronate affinity monomer 2,4-difluoro-3-formylphenylboronic acid and dopamine) based on cellulose nanocrystals (CNCs) mixed with polymerized high internal phase emulsion (polyHIPE, PH) through an double layer surface imprinted method. The introduction of polyethylenimine (PEI) can offer abundant anchor units for the growth of more anchor sites to immobilization template molecules. Importantly, largely improved selective adsorption amounts (50.79 μmol g−1), which may be attribute to the fabrication of the uniform growth of double imprinted layers onto the polydopamine (PDA)/boronic acid-based surfaces. In addition, the resulting double recognition molecular imprinted polymers (MIPs) based on hypercrosslinked PH (DR-HCLPH@MIPs) not only exhibited fast adsorption kinetic of NRG molecule, but also possessed excellent selectivity and high adsorption capacities at physiological pH. Meanwhile, the coarse NRG from pomelo waste can be high selectively extracted to 94.74%. Overall, this study provides a versatile approach for fabrication of the sandwich-biscuit-like double imprinting layer porous MIPs for precise identification and ultrafast transport separation of NRG from complex samples.

NMR investigation on the thermogelation of partially hydrolysed polyacrylamide/polyethylenimine mixtures.

Since the introduction of polyethylenimine (PEI)/acrylamide-based polymer gel systems in the late 90's, the literature knowledge on the crosslinking mechanisms between the various polymers (PAM, PHPA, and PatBA) and the crosslinker (PEI) was only limited to observations on gelation times and gel strength variations compared to other gel systems. In this paper, classic proton and carbon nuclear magnetic resonance "NMR" experiments and advanced 2D DOSY and NOESY techniques were employed for studying the interactions between the amine groups of PEI and amide or carboxylate groups of partially hydrolysed polyacrylamide (PHPA). Among the many possibilities, we showed that the interaction occurring during thermogelation is mainly due to covalent bonding. The latter results from a transamidification reaction between the polymer amide groups and the primary amines of the crosslinker. The reaction, at high temperatures, was accompanied by some hydrolysis of the polymer amide groups. Consequently, the kinetics of the reaction and hydrolysis were evaluated and fitted using pseudo first-order equations where the hydrolysis kinetics was found to be three times lower than that of the reaction.

Suppressing interfacial defect formation derived from in-situ-generated polyethylenimine-based 2D perovskites to boost the efficiency and stability NiOx-based inverted planar perovskite solar cells

Recently, NiOx-based inverted planar perovskite solar cells (PSCs) have achieved great progress. However, the lattice mismatch between NiOx hole-transport layers (HTLs) and perovskite active layers will result in interfacial defect formation, which severely influences device efficiency and stability. In this work, this is alleviated by coating of polyethylenimine cations (PEI•HI) on the surface of NiOx HTLs. The introduction of PEI•HI can not only effectively passivate the surface defects of NiOx films, but also induce the in-situ-generation of polyethylenimine (PEI)-based two-dimensional (2D) perovskite interlayers between NiOx and CH3NH3PbI3 (MAPbI3). Such PEI-based 2D perovskite interlayer can dramatically mitigate the lattice mismatch between NiOx and perovskites to suppress the interfacial defects formations and promote the high-quality crystal nucleation and growth of above perovskite films. Meanwhile, it is demonstrated that the molecular weights of PEI act the pivotal part in controlling the nucleation quality of perovskites. When employing PEI with molecular weight of 10,000 (PEI-1000), the high-crystalline perovskite film with large-sized grains and reduced interfacial defects is obtained and the champion PSC delivers a power conversion efficiency (PCE) of 19.23% with weak hysteresis effect and improved reproducibility and stability. Our work provides a promising approach to improve the lattice match between NiOx and perovskites for high-performance NiOx-based inverted planar PSCs.

TiO2 hybrid material film with high CO2 adsorption for CO2 photoreduction

To integrate the CO2 capture and photoreduction processes into a single system, MOFs-derived TiO2 was loaded onto polyethersulfone (PES) or polyethylenimine (PEI)/PES electrospun mats using electrospray method. The mats incorporated with PEI has exhibited excellent CO2 capture capacity and MOFs-derived TiO2 doped with C (denoted as C/TiO2) extended the absorption edge to >400 nm. The introduction of PEI that resulted in the C/TiO2-PEI/PES sample has significantly increased the CO2 photoreduction yield by 81% when compared to C/TiO2-PES sample. The C/TiO2-PEI/PES sample could still capture and convert CO2 into CO even in the low CO2 atmosphere.

Evaluation of in vivo antitumor effects of ANT2 shRNA delivered using PEI and ultrasound with microbubbles.

Gene therapy using RNA interference can be directed against tumors through various strategies, but has been hindered owing to the inefficiency of non-viral delivery. To evaluate the antitumor effects of adenine nucleotide translocase-2 (ANT2) short hairpin RNA (shRNA) by intraperitoneal injection using the polyethylenimine (PEI) and an ultrasound gene delivery method, human breast carcinoma MDA-MB-231 cells were injected subcutaneously into NOG (NOD/Shi-scid/IL-2Rγ(null)) mice. The results showed greater tumor regression (*P<0.05) as well as an increased survival rate in the group receiving ANT2 shRNA+two types of enhancer relative to the groups receiving ANT2 shRNA without enhancer. These findings demonstrate that the introduction of PEI and ultrasound with SonoVue exerted enhanced antitumor effects in vivo. Although the combination of jet-PEI and ultrasound provided the best results with respect to tumor regression, the antitumor effects from the individual enhancers were approximately equivalent. In addition, we confirmed that there was no toxicity on aspartate aminotransferase and alanine aminotransferase levels in the liver and albumin, blood urea nitrogen or creatine kinase levels in the kidney following the various gene delivery methods.

Solution-Based Fabrication and Characterization of a Logic Gate Inverter Using Random Carbon Nanotube Networks

Semiconducting carbon nanotubes (CNTs) are considered as one of the most promising candidates to replace silicon in future nano-electronics. Single-walled carbon nanotubes (SWNTs) have been used as an active channel material in field-effect transistors (FETs). The nanotube-based circuits show great potential in future electronics and computer technology. Integrating SWNT FETs to form logic gates-the basic units of integrated circuits (ICs)-needs both p- and n-type SWNT FETs. However, without doping, annealing, or other special treatment, the as-obtained SWNT FETs are typically p-type. Here we report a SWNT-based logic device-a logic gate inverter (or a NOT gate)-using simple fabrication methods. The critical components of the inverter including a p-type SWNT FET and an n-type SWNT FET are fabricated using low-cost materials and an easy-to-control solution-based process. The introduction of polyethylenimine (PEI), a polymer with high electron-donating ability, to the device successfully converts the p-type FET to an n-type device. The resulting devices are air-stable outside a vacuum or an inert environment. Electrical characterization of these devices demonstrates that both p-type and n-type FETs produce typical field effects and the resulting logic gate inverter exhibits satisfactory switching characteristics. We believe that the combination of the simple fabrication methods, easy conversion of the transistors, and satisfactory logic gate switching performance can influence fundamental research in nano-materials and practical applications of nano-electronics.

Solution-based fabrication of p-channel and n-channel field-effect transistors using random and aligned carbon nanotube networks

We report both p-channel and n-channel single-walled carbon nanotube (SWNT) film-effect transistors (FETs) using low-cost materials and easy-to-control procedures. The introduction of polyethylenimine (PEI), which has high electron-donating ability, successfully realizes the conversion from p-channel FETs to n-channel devices. The resulting n-channel devices are air-stable outside a vacuum or an inert environment. Instead of conventional chemical vapor deposition method, here in this project, p-channel SWNT FETs are fabricated using two solution-based processes. One method is using layer-by-layer self-assembly to create SWNT random networks and the other is based on dielectrophoresis-aligned SWNTs. By coating a polyethylenimine (PEI) layer on the surface, the transistor demonstrates typical n-channel characteristics. The electrical characteristics of random-network and aligned SWNT transistors are studied comparatively. Our results demonstrate that both p-channel and n-channel devices based on the self-assembly method produce stronger field effects with much higher on/off ratios (Ion/Ioff). The combination of fabrication and conversion methods reported here can lead to the development of more complicated SWNT-based devices such as complementary logic gates, which require both p- and n-channel transistors.

Gel and solid matrix systems for the controlled delivery of drug carrier-associated nucleic acids

In order to achieve a sustained pharmacological activity of oligonucleotides (ODNs) and avoid repeated administrations, we have developed a new concept of delivery system that combine sustained release and improved intracellular penetration. These systems are designed for the intravitreal delivery of antisense ODNs. The first concept consisted in using liposomes dispersed in a thermosensitive gel (poloxamer 407). After intravitreal administration in a rabbit model, liposomes and liposomes-gel formulations provided, 1-day postinjection, significantly higher drug levels than the control solution of the oligothymidilate pdT16. In addition, there was no significant difference in the amounts of pdT16 found in the vitreous humor between the liposomes and liposomes-gel. Nevertheless, because of their better stability in the absence of poloxamer, liposomes alone allowed to a larger extent to control the delivery of ODNs as compared to liposome-gel formulations since 37% of the ODNs were still found in the vitreous 15 days after administration. In addition, the ODNs found in the vitreous humor were protected against degradation by their encapsulation within liposomes. The second approach consisted in designing microspheres allowing to release in a controlled fashion pdT16. The ODN was encapsulated within poly(lactide-co-glycolide) microspheres alone or associated with polyethylenimine (PEI) at different nitrogen/phosphate (N/P) ratios. The introduction of PEI in the internal aqueous phase resulted in a strong increase of the ODN encapsulation efficiency. PEI affected microsphere morphology inducing the formation of very porous particles yielding to an accelerated release of pdT16. Porosity and controlled delivery was prevented by introducing sodium chloride in the external preparation medium. When incubated with HeLa cells, microspheres encapsulating pdT16/PEI complexes allowed an improvement of the intracellular penetration of the released ODN. Both liposomes and microspheres are suitable for local delivery of ODNs.

Biodegradable microparticles for the controlled delivery of oligonucleotides.

Microspheres allowing the controlled release of the model oligonucleotide pdT16 were designed. The oligonucleotide, alone or associated with polyethylenimine (PEI) at different nitrogen/phosphate ratios, was encapsulated within poly(lactide-co-glycolide) microspheres prepared by the multiple emulsion-solvent evaporation technique. The introduction of PEI in the internal aqueous phase resulted in a strong increase of the oligonucleotide encapsulation efficiency. PEI affected also microsphere morphology inducing the formation of very porous particles and yielding to an accelerated release of pdT16. However, when incubated with HeLa cells, microspheres encapsulating pdT16/PEI complexes allowed an improvement of the intracellular penetration of the released oligonucleotide. The developed strategy appears to be a very interesting tool to obtain a sustained release system for oligonucleotides with an efficient cellular delivery.

Poly(lactide-co-glycolide) microspheres for the controlled release of oligonucleotide/polyethylenimine complexes

In this article, microspheres able to induce the controlled release of oligonucleotide/polyethylenimine complexes are proposed. A model oligonucleotide (the oligothymidilate pdT16) was encapsulated within poly(lactide-co-glycolide) microspheres alone or associated with polyethylenimine (PEI) at different nitrogen/phospate (N/P) ratios. Microspheres were prepared by the multiple emulsion–solvent evaporation technique and characterized for morphology, diameter, encapsulation efficiency, and release kinetics. The introduction of PEI in the internal aqueous phase resulted in the formation of a soluble complex with pdT16 and in a strong increase of the oligonucleotide encapsulation efficiency. PEI affected microsphere morphology inducing the formation of very porous particles yielding to an accelerated release of pdT16. When incubated with HeLa cells, microspheres encapsulating pdT16/PEI complexes allowed both a reduction of the complex toxicity and an improvement of the intracellular penetration of the released oligonucleotide. We conclude that biodegradable microspheres encapsulating oligonucleotides/PEI complexes have a great potential as controlled release system because they allow the sustained release of an oligonucleotide carrier that crosses biological membranes and locates in nucleus. © 2002 Wiley-Liss, Inc. and the American Pharmaceutical Association J Pharm Sci 91:790–799, 2002

Effect of Polyethylenimine on the Selectivity of Determining Silver(I) by Stripping Voltammetry in the Presence of Copper(II)

It has been proposed that a water-soluble complexing polymer, polyethylenimine (PEI), be used to lower intermetallic interactions at the surface of solid electrodes in the determination of Ag(I) by stripping voltammetry in the presence of Cu(II). The introduction of PEI in the binary Ag(I)–Cu(II) system weakened the effect of Cu(II) on the anodic peak of Ag(I) and enhanced the selectivity in determining Ag(I) in the presence of excess amounts of Cu(II). With the use of PEI, Ag(I) can be determined at a Cu(II)-to-Ag(I) concentration ratio of 1000 : 1, compared to that of 20 : 1 in the absence of the polymer.