Polyethylenimine Modification Research Articles

Coupling of nanostraws with diverse physicochemical perforation strategies for intracellular DNA delivery

Effective intracellular DNA transfection is imperative for cell-based therapy and gene therapy. Conventional gene transfection methods, including biochemical carriers, physical electroporation and microinjection, face challenges such as cell type dependency, low efficiency, safety concerns, and technical complexity. Nanoneedle arrays have emerged as a promising avenue for improving cellular nucleic acid delivery through direct penetration of the cell membrane, bypassing endocytosis and endosome escape processes. Nanostraws (NS), characterized by their hollow tubular structure, offer the advantage of flexible solution delivery compared to solid nanoneedles. However, NS struggle to stably self-penetrate the cell membrane, resulting in limited delivery efficiency. Coupling with extra physiochemical perforation strategies is a viable approach to improve their performance. This study systematically compared the efficiency of NS coupled with polyethylenimine (PEI) chemical modification, mechanical force, photothermal effect, and electric field on cell membrane perforation and DNA transfection. The results indicate that coupling NS with PEI modification, mechanical force, photothermal effects provide limited enhancement effects. In contrast, NS-electric field coupling significantly improves intracellular DNA transfection efficiency. This work demonstrates that NS serve as a versatile platform capable of integrating various physicochemical strategies, while electric field coupling stands out as a form worthy of primary consideration for efficient DNA transfection.

Novel montmorillonite/jute composites functionalized with polyethyleneimine and cetyltrimethylammonium bromide for Cr(VI) adsorption

Industrial wastewater containing heavy metal ions of Cr(VI) has drawn increasing attention because of extreme toxicity and detrimental effects on human health. This paper reported a novel nanocomposite adsorbent for Cr(VI) removal from water, consisting of montmorillonite (Mt), jute and the functional modifiers of polyethyleneimine (PEI) and cetyltrimethylammonium bromide (CTAB), i.e., Mt/Jute-PEI-CTAB. The Mt/Jute-PEI-CTAB adsorbent was synthesized via a synergistic method of ultrasonic treatment and sand milling. Various methods were used to characterize the Mt/Jute-PEI-CTAB adsorbent, and the effects of different components on Cr(VI) adsorption behaviors were systematically investigated. The adsorption experiments indicated that Mt/Jute-PEI-CTAB exhibits an excellent Cr(VI) adsorption performance, with a maximum adsorption amount of 59.3 mg/g, 4 times higher that of the Mt/Jute adsorbent without PEI or CTAB. A high Cr(VI) removal efficiency of 99% was achieved, and it is superior to most of clay/biomass-based adsorbents reported. The significantly improved Cr(VI) adsorption capacity can be attributed to the amino functional groups in Mt/Jute-PEI-CTAB through the modification of biomass, CTAB and PEI. The Cr(VI) adsorption process on Mt/Jute-PEI-CTAB can well be described using the pseudo-second order kinetic model and the Langmuir isotherm model. This work provides a novel and environmentally friendly method to design high-performance Cr(VI) adsorbents using clay minerals and biomass for environmental remediation.

Metallization of Polyamide-imide for High-Frequency Communication by Polyethylenimine Modification and Electroless Copper Plating

Metallization of Polyamide-imide for High-Frequency Communication by Polyethylenimine Modification and Electroless Copper Plating

Influence of Polyethylenimine (PEI) in enhancement of microstructure and surface morphology of recycled construction and demolition waste aggregate in concrete by carbonation

This investigation explores the influence of Polyethylenimine (PEI) on the improvement of carbon dioxide (CO2) uptake, surface texture, and pore structure of construction and demolition waste (CDW) through carbonation. The study focuses on the coarser fraction of CDW (10 mm), which is pre-treated with varying concentrations of PEI before being carbonated. The resulting changes in pore structure, mineralogical composition, physical properties, and surface morphologies of the CDW are characterized using various techniques. The study also evaluates the impact of carbonated CDW on compressive strength. The results indicate that PEI modification of CDW enhances carbonation efficiency by reducing pores more effectively than non-treated CDW. This microstructural refinement is possible due to the formation of calcite and its products, facilitated by PEI adsorption into CDW, enhanced CO2 uptake, and formation of calcite products through carbonation. Additionally, PEI modification results in the formation of undulated plate-like structures that enhance surface morphology and compressive strength when used in concrete. The carbonation behavior of PEI-modified CDW in concrete was also investigated by analyzing carbonation depth and pH value. The results reveal that the optimal PEI concentration for enhancing the performance of CDW is 0.2. Overall, the study highlights the potential of PEI modification as an effective approach to improve the properties of CDW and its potential as a sustainable construction material.

Rapid and Sensitive Fluorescence Detection of Staphylococcus aureus Based on Polyethyleneimine-Enhanced Boronate Affinity Isolation.

There are increasing demands for fast and simple detection of pathogens in foodstuffs. Fluorescence analysis has demonstrated significant advantages for easy operation and high sensitivity, although it is usually hindered by a complex matrix, low bacterial abundance, and long-term bacterial enrichment. Effective enrichment procedures are required to meet the requirements for food detection. Here, boronate-functionalized cellulose filter paper and specific fluorescent probes were combined. An integrated approach for the enrichment of detection of Staphylococcus aureus was proposed. The modification of polyethyleneimine demonstrated a significant effect in enhancing the bacterial enrichment, and the boronate affinity efficiency of the paper was increased by about 51~132%. With optimized conditions, the adsorption efficiency for S. aureus was evaluated as 1.87 × 108 CFU/cm2, the linear range of the fluorescent analysis was 104 CFU/mL~108 CFU/mL (R2 = 0.9835), and the lowest limit of detection (LOD) was calculated as 2.24 × 102 CFU/mL. Such efficiency was validated with milk and yogurt samples. These results indicated that the material had a high enrichment capacity, simple operation, and high substrate tolerance, which had the promising potential to be the established method for the fast detection of food pathogens.

A Sensitive Immunochromatographic Test Strip Based on Hydrophobic Quantum Dots Incorporated into Mg/Fe Nanoflowers for HCG Detection

As the most widely used disposable paper-based diagnostic tool in the world, immunochromatographic test strips (ICTS) have occupied more and more positions in the field of rapid diagnosis due to their ease of operation and affordability. Therefore, the development of an easily prepared, sensitive, and accurate signal reporter is of great significance for the detection of some low-abundance biomarkers in clinical diagnosis. Herein, Mg/Fe layered double hydroxide nanoflowers (MF NFs) were selected as adsorption templates and sulfhydryl-functionalized, followed by one-step loading of hydrophobic CdSe/ZnS quantum dots in the organic phase via a metal-thiol covalent bond. After coating the reporter with branched polyethyleneimine (PEI), a novel ICTS fluorescent reporter was prepared. The modification of PEI not only improved the hydrophilicity of MF@CdSe/ZnS NFs but also introduced amino functional groups on the surface of the reporter for subsequent conjugation with antibodies. X-ray photoelectron spectroscopy, UV-vis absorption, X-ray diffraction, fluorescence spectroscopy, and infrared spectroscopy were used to characterize the composition of MF@CdSe/ZnS NFs. Under the optimal experimental conditions, the detection range of MF@CdSe/ZnS@PEI-ICTS for the model analyte HCG was 0.1–500 mIU/mL, and the limit of detection (LOD) reached was 0.1 mIU/mL. The potential for practical application was validated by the detection of HCG in spiked healthy human serum, showing overall recoveries between 90.48 and 116.1% with coefficients of variation that ranged from 3.66 to 12.91%.

Boosting photocatalytic H2O2 production in pure water over a plasmonic photocatalyst with polyethylenimine modification

A novel TiO2/PEI/AgNP plasmonic photocatalyst fabricated via electrostatic assembly and in situ polyethylenimine reduction for boosted H2O2 production is reported.

Balancing gene transfection and cytotoxicity of nucleic acid carriers with focus on ocular and hepatic disorders: evaluation of hydrophobic and hydrophilic polyethyleneimine derivatives.

Polyethyleneimine (PEI) derivatives substituted by lactose, succinic acid or alkyl domains were evaluated as nonviral gene delivery vectors towards balancing gene transfection and cytotoxicity. The investigations were focused on pDNA transfection into arising retinal pigment epithelia (ARPE-19) and human hepatocellular carcinoma (HepG2) cell lines. The first mentioned cell line was chosen as motivated by the non-negligible number of ocular disorders linked to gene aberrations, whereas the second one is a cell line overexpressing the asialoglycoprotein receptor (ASGP-R), which can bind to galactose residues. The presence of short alkyl domains (C4 and C6), and particularly the succinylation of the PEI chains, improved the biological outputs of the gene vectors. The presence of hydrophobic units possibly enhances lytic activity, whereas the incorporation of succinic acid slightly reduces polymer-DNA interaction strength, thereby enabling more efficient intracellular unpacking and cargo release. Succinylation is also supposed to decrease cytotoxicity and avoid protein adsorption to the polyplexes. The presence of long carbon chains (for instance, C12) nevertheless, results in higher levels of cytotoxicity and respective lower transfection rates. The sugar-decorated polyplexes are overall less cytotoxic, but the presence of lactose moieties also leads to larger polyplexes and notably weak polymer-DNA binding, which compromise the transfection efficiency. Yet, along with the presence of short lytic alkyl domains, the double-substitution of PEI synergistically boosts gene transfection probably due to the uptake of higher DNA and polymer amounts without cell damage. Overall, the experimental data suggest that ocular and hepatic gene therapies may be potentialized by fine-tuning the hydrophobic-to-hydrophilic balance, and succinic acid is a favorable motif for the modification of PEI.

Polyethylenimine modified ultrafine palladium nanocrystals on reduced graphene oxide for hexavalent chromium reduction

Palladium-catalytic hydrogenation is an efficient method for remediating inorganic/organic contaminants. Herein, a very simple adsorption-reduction strategy is applied to synthesize the polyethylenimine (PE) modified ultrafine palladium nanocrystals on reduced graphene oxide (RGO) hybrids (PE@Pd-RGO). The surface composition, structure, and morphology of PE@Pd-RGO hybrids are minutely characterized by various physical characterization techniques and the formation mechanism of PE@Pd-RGO hybrids is defined according to experimental observation. Physical characterizations demonstrate that palladium nanocrystals with only 2.91 nm size uniformly anchor at RGO surface and PE modification endows PE@Pd-RGO hybrids with eminent water-solubility. When applied as catalyst for hexavalent chromium reduction, PE@Pd-RGO hybrids reveal excellent catalytic activity (rate constant: 0.0785 min−1, turnover frequency: 1.166 molCr molPd−1 min−1) and stability due to the small particle size of palladium nanocrystals, excellent colloidal stability, and distinctive electrostatic attraction between PE with –NH3+ and Cr2O72- ion.

Polyethyleneimine-modified magnetic carbon nanotubes as solid-phase extraction adsorbent for the analysis of multi-class mycotoxins in milk via liquid chromatography-tandem mass spectrometry.

Polyethyleneimine-modified magnetic multi-walled carbon nanotubes were developed to extract 10 mycotoxins. Simple modification of polyethyleneimine was achieved on the magnetic substrate by using an epoxy-containing silane agent as a linker. The resultant magnetic adsorbent was integrated with reverse phase and anion exchange interaction sites. Under optimal extraction conditions, only 20.0mg adsorbent was used to extract the mycotoxins from 50.0mL loading solution. The maximum adsorption capacities of the adsorbent toward the mycotoxins ranged from 4.9 to 10.2mg/g. Adsorption and desorption were completed within 3.0 and 2.0min, respectively. The adsorbent could be used for six repeated runs without evident change in extraction performance. The adsorbent combined with liquid chromatography-tandem mass spectrometry was applied further to analyze the mycotoxins in milk. The absolute recoveries of the 10 mycotoxins ranged from 88.3 to 103.5% with relative standard deviations that ranged from 2.4 to 6.5%, and their limits of detection were 0.003 to 0.442μg/kg. The proposed adsorbent has great potential in the routine analysis of mycotoxins in ordinary analytical chemistry laboratory.

Poly-(Lactic-co-Glycolic) Acid Nanoparticles for Synergistic Delivery of Epirubicin and Paclitaxel to Human Lung Cancer Cells.

Combination therapy using chemically distinct drugs has appeared as one of the promising strategies to improve anticancer treatment efficiency. In the present investigation, poly-(lactic-co-glycolic) acid (PLGA) nanoparticles electrostatically conjugated with polyethylenimine (PEI)-based co-delivery system for epirubicin and paclitaxel (PLGA-PEI-EPI-PTX NPs) has been developed. The PLGA-PEI-EPI-PTX NPs exhibited a monodispersed size distribution with an average size of 240.93 ± 12.70 nm as measured through DLS and 70.8–145 nm using AFM. The zeta potential of 41.95 ± 0.65 mV from −17.45 ± 2.15 mV further confirmed the colloidal stability and PEI modification on PLGA nanoparticles. Encapsulation and loading efficiency along with in vitro release of drug for nanoparticles were done spectrophotometrically. The FTIR analysis of PLGA-PEI-EPI-PTX NPs revealed the involvement of amide moiety between polymer PLGA and PEI. The effect of nanoparticles on the cell migration was also corroborated through wound healing assay. The MTT assay demonstrated that PLGA-PEI-EPI-PTX NPs exhibited considerable anticancer potential as compared to the naïve drugs. Further, p53 protein expression analysed through western blot showed enhanced expression. This study suggests that combination therapy using PLGA-PEI-EPI-PTX NPs represent a potential approach and could offer clinical benefits in the future for lung cancer patients.

Enhanced adsorptive removal of Cr(VI) in aqueous solution by polyethyleneimine modified palygorskite

Abstract Polyethyleneimine (PEI) modified palygorskite (Pal) was used for the adsorption of Cr(VI) in aqueous solution. The absorbent was characterized by Fourier transform infrared spectroscopy (FT-IR) and thermogravimetric analysis (TGA). Characterized results confirmed that the Pal has been successfully modified by PEI. The modification of PEI increased the Cr(VI) adsorption performance of the Pal by the adsorption combined reduction mechanism, and amino groups of the adsorbent play the main role in the enhanced Cr(VI) adsorption. The maximum adsorption capacity was 51.10 mg·g−1 at pH 4.0 and 25 °C. The adsorption kinetics of Cr(VI) on the adsorbent conforms to the Langmuir isotherm model. The maximum adsorption occurs at pH 3, and then the adsorption capacity of PEI-Pal was decreased with the increase of pH values. The adsorption kinetics of Cr(VI) on PEI-Pal was modeled with pseudo-second-order model. The addition of Cl−, SO42− and PO43− reduced the Cr(VI) adsorption by competition with Cr(VI) for the active sites of PEI-Pal. The Cr(VI) saturated PEI-Pal can be regenerated in alkaline solution, and the adsorption capacity can still be maintained at 30.44 mg·g−1 after 4 cycles. The results demonstrate that PEI-Pal can be used as a potential adsorbent of Cr(VI) in aqueous solutions.

Synthesis of polyethylenimine-impregnated Al-fumarate metal-organic framework and its CO<sub>2</sub> adsorption characteristics

Carbon capture and storage (CCS) can effectively reduce CO2 emissions from fossil-fuel combustion and mitigate global warming. Among the many CCS technologies, solid-amine based CO2 adsorption exhibits simple operation, great environmental sustainability, and good adsorption performance under post-combustion conditions of humidity, high temperature, and low CO2 partial pressure. Solid amine is always composed of porous solid support and organic amine. However, the disadvantages of complex preparation limit the application of traditional support materials. Therefore, the preparation of a kind of support with convenient synthesis, low cost, and high performance is of great significance for the preparation of solid-amine CO2 adsorbent. In this study, a method for the rapid preparation of an aluminum fumarate metal-organic framework (AlFu) is proposed based on sodium fumarate as the source of the organic ligand and water as the reaction solvent. Post-treatment of AlFu is not required due to the good water solubility of the reactants. The synthesized materials were characterized by X-ray diffraction (XRD), Fourier-transform infrared spectroscopy (FTIR), scanning electron microscopy (SEM), Brunauer-Emmett-Teller (BET) nitrogen adsorption/desorption, and thermogravimetric analysis (TGA) techniques. The results show that AlFu can be successfully synthesized at room temperature in 10 min. AlFu shows a typical porous morphology with a specific surface area of 828.44 m2/g. The TGA results show that AlFu is thermally stable up to 400°C. AlFu is a kind of superior solid-amine support material. Polyethylenimine (PEI) was then introduced into the AlFu support by an impregnation method to prepare solid-amine CO2 adsorbent, and the functionalized materials were characterized. The results show that the impregnation method can successfully introduce PEI into the AlFu framework. PEI modification did not destroy the crystal structure, but decreased the XRD characteristic peak intensity of AlFu. Increasing PEI loading leads to the agglomeration of the AlFu skeleton and the decrease of the specific surface area and pore volume of the samples. PEI modification will reduce the thermal stability of the material, but all samples showed good thermal stability below 200°C. Subsequently, the CO2 adsorption performance of the samples was investigated by TGA. The results showed that the optimum PEI content is 50 wt%, and the optimum adsorption temperature of PEI modified AlFu is 75°C, and that the highest CO2 adsorption capacity, 2.68 mmol/g, was obtained under optimum conditions. The CO2 adsorption kinetics onto PEI-AlFu with different PEI loadings was investigated by employing the pseudo-first/second-order kinetic models and fractional-order kinetic model. The results show the fractional-order kinetic model fitted well with the CO2 adsorption experiment data, and that the CO2 adsorption processes of PEI-AlFu were controlled by chemical reaction and physical transmission. Cyclic CO2 adsorption experiments revealed that PEI-AlFu has superior reproducibility after nine CO2 adsorption-desorption cycles. These results suggest that PEI-AlFu has high CO2 adsorption capacity and good reproducibility, and shows great potential for practical CO2 adsorption applications under post-combustion conditions.

Facile assembly of mesoporous silica nanoparticles with hierarchical pore structure for CO2 capture

In the work, we propose an efficient one-pot approach for synthesis of a new type of mesoporous silica nanoparticles (MSNs). That can be successfully realized by using tetraethylorthosilicate (TEOS) and N-[3-(trimethoxysilyl)propyl]ethylenediamine (TSD) as the silica precursors and cetyltrimethylammonium bromide (CTAB) as the structure-directing agent through a facile assembly process. The as-synthesized MSNs possess a spherical morphology with about 230 nm, a relatively high surface area of 133 m2/g, and a hierarchical pore size distribution. When applied as the sorbents, the amine-functioned MSNs demonstrate the enhanced adsorption capacity for CO2 capture (at 1 bar, 15 vol% CO2, up to 80.5 mg/g at 75 °C), high selectivity, and good cycling durability, benefiting from the suitable modification of polyethyleneimine.

Self-powered multifunctional monitoring system using hybrid integrated triboelectric nanogenerators and piezoelectric microsensors

Battery-less internet of things (IoT) devices and flexible electronics are attracting increasing attention worldwide for diverse applications ranging from human healthcare to environment monitoring. A flexible multifunctional monitoring system with the integration of triboelectric nanogenerator (TENG) for energy harvesting, piezoelectric micromachined ultrasonic transducer (pMUT) array and TENG sensor for simultaneous detection of multiple amenity parameters (i.e., temperature, relative humidity and CO2 concentration) has been developed. With modification of polyethyleneimine (PEI) on the friction surface, the CO2 concentration can be sensed by the electrical output of the TENG sensor in a wide range up to 12,000 ppm. To precisely calibrate the effect of humidity on the TENG sensor, pMUT array is integrated that can be potentially powered by another unmodified TENG through harvesting ambient mechanical energy. The pMUT array is coated partially with PEI/graphene oxide (GO) composite and adopted to simultaneously detect relative humidity using functionalized pMUT elements and room temperature using unfunctionalized elements. After optimization of PEI volume fraction in the composite, the pMUT humidity sensor exhibits an extremely high sensitivity (748 Hz/% RH) and relative sensitivity (290 ppm/% RH), an excellent linearity over a wide range, rapid response/recovery, small hysteresis, good stability and significant selectivity over CO2 gas. Additionally, the pMUT temperature sensor shows an excellent linear response, which is much advantageous to eliminate the temperature interference of the humidity sensor due to the shared array structure. This work demonstrates not only a new and effective route of ultrasensitive and linear humidity detection, but also a new strategy to configure an “all-in-one” flexible self-powered multifunctional sensing system, which complementally combines the advantages of TENG and micro-electromechanical-system (MEMS) technology enabled devices and is highly promising to facilitate various applications.

Polyethyleneimine (PEI) incorporated Cu-BTC composites: Extended applications in ultra-high efficient removal of congo red

Recently, metal-organic frameworks (MOFs) have been applied in the efficient removal of persistent organic dyes owing to their high porosity, large surface area and tunable pore size. In this paper, polyethyleneimine (PEI) incorporated Cu-BTC composites have been applied in the efficient removal of congo red for the first time. Some means such as Field emission scanning electron microscope (FESEM), X-ray diffraction (XRD), X-ray photoelectron spectroscopy(XPS), Fourier-transform infrared spectroscopy (FT-IR), Thermal gravity analysis (TG) and Zeta potential measurement have been employed to character these Cu-BTC composites. The modification of PEI with a certain loading amount can alter the morphology and also change the surface charge of Cu-BTC evidently, as a result the PEI-modified Cu-BTC composites present the positive zeta potential within a wide pH range, that is beneficial for the effective adsorption toward anionic dyes. Four persistent anionic dyes including congo red (CR), acid blue 1(AB1), methyl orange(MO) and direct blue 80 (DB80) are used to evaluate the adsorption activity of PEI-modified Cu-BTC, and among them CR displays the best adsorption selectivity, which capacity is about 20 times of the values of other three dyes. And the adsorption capacity of CR is also higher than the most reported removal rate by other MOF-based adsorbents. The adsorption kinetics analyses demonstrate that a combined physical and chemical interaction have worked in the CR adsorption at room temperature, and the adsorption thermodynamics indicates a endothermic, increase of entropy and spontaneous process with a negative ΔGƟ. The adsorption mechanism is also discussed, and the hydrogen bond formed between PEI-modified Cu-BTC and CR might be responsible for the ultra-high adsorption capacity of CR. The better reusability indicates that these PEI-modified Cu-BTC can be applied in the efficient removal of CR from practical waste water.

Surface Charge Modification of Polyethyleneimine for Enhanced Renal Clearance and Bioimaging

Polyethyleneimine (PEI) has emerged as a potentially effective carrier for gene delivery. To overcome the cytotoxicity of PEI in vivo, the biodistribution and clearance of PEI conjugated with near-infrared fluorophores (NIRF) were imaged in mice. To confirm the effect of surface charge on enhanced renal clearance, PEI was conjugated with three different types of NIRF: positively charged PEI-NIRF+, negatively charged PEI-NIRF-, and zwitterionic PEI-NIRF± conjugates, which were intravenously injected into mice. The biodistribution and body clearance were monitored under an NIR fluorescence imaging system at 4 h and 24 h postinjection. All organs and tissues were resected to further compare the distribution of each PEI-NIRF conjugate in two mice at 4 h and 24 h. The results showed that the zwitterionic PEI-NIRF± conjugate was most rapidly cleared, primarily through the kidneys of the mice within 24 h postinjection. In conclusion, the biodistribution of zwitterionic PEI-NIRF± was found to be significantly different from that of positively and negatively charged PEI-NIRF conjugates with increased renal clearance. Thus, zwitterionic PEI-NIRF± could be a promising gene delivery carrier that can potentially reduce the side effects of conventional cationic polymers such as cytotoxicity and non-specific binding in vivo.

Polyethylenimine-functionalized silk sericin beads for high-performance remediation of hexavalent chromium from aqueous solution

The enhancement of the metal adsorption and remediation performance of biomass-based adsorbents is an important challenge in heavy metal removal processes. One of the most viable and practical approaches in accomplishing a high metal removal efficiency is the surface modification of natural polymer adsorbents with functional polymeric materials. In the present study, polyethylenimine (PEI)-modified silk sericin beads were fabricated. The PEI modification process was confirmed and analyzed by Fourier transform infrared spectroscopy (FTIR), field emission-scanning electron microscopy (FE-SEM), and energy-dispersive X-ray spectroscopy (EDS)-based elemental analysis. The Cr(VI) remediation capabilities of PEI-modified sericin beads were analyzed by testing Cr(VI) removal from contaminated water. The results show that the Cr(VI) removal capacity of PEI-modified sericin beads was 365.3 mg/g, which is significantly higher than that of pristine sericin beads (34.56 mg/g). During the Cr(VI) removal process, Cr(VI) adsorption and reduction to Cr(III) occurred simultaneously. The results herein reveal that the synthesized PEI-modified sericin beads are a promising material for Cr(VI) adsorption and detoxification of aqueous solution.

Low-Pressure Nanofiltration Hollow Fiber Membranes for Effective Fractionation of Dyes and Inorganic Salts in Textile Wastewater.

In this work, novel loose nanofiltration (NF) hollow fiber membranes with ultrahigh water permeability and well-defined nanopore and surface charge characteristics were developed for effective fractionation of dyes and inorganic salts in textile wastewater treatment. The as-spun NF hollow fiber possesses a high pure water permeability (PWP) of 80 L·m-2·h-1·bar-1 with a small pore size of 1.0 nm in diameter and a MWCO of 1000 Da. The surface modification by means of hyperbranched polyethylenimine (PEI) further lowers the pore diameter to 0.85 nm and MWCO to 680 Da. The membrane surface also becomes more hydrophilic and positively charged after the PEI modification. Because of the synergistic effects from size exclusion and charge repulsion, the newly developed NF hollow fibers show high permeation fluxes of 7.0-71.2 L·m-2·h-1 and great rejections of 95.5-99.9% to various dyes at a low operating pressure of 1 bar. At the same time, they have ultralow rejections of less than 10% to inorganic salts (i.e., Na2SO4), suggesting that more than 90% of the salts would permeate through the fibers. In addition, the two hollow fibers exhibit outstanding performance stability, low fouling tendency, and great fouling reversibility. Their fluxes can be brought back to be more than 80% of the original values by a simple physical backwash. The newly developed loose NF hollow fiber membranes may have great potential for effective fractionation and treatment of textile wastewater.

Folic acid-modified Fe3O4@Au core/shell nanostars for multimode imaging and photothermal therapy of tumors

Event Abstract Back to Event Folic acid-modified Fe3O4@Au core/shell nanostars for multimode imaging and photothermal therapy of tumors Xiangyang Shi1, Yong Hu1, Ruizhi Wang2 and Mingwu Shen1 1 Donghua University, College of Chemistry, Chemical Engineering and Biotechnology, China 2 Zhongshan Hospital, Fudan University,, Interventional Radiography, China Iron oxide (Fe3O4) nanoparticles (NPs) have been generally used as T2-negative magnetic resonance (MR) imaging contrast agents because of their ability to shorten the T2 relaxation time of water protons[1]. On the other hand, gold (Au) NPs have been widely used as CT imaging contrast agents due to their high X-ray attenuation coefficient[2]. In addition, AuNPs with particular shapes such as nanorods, nanocages, or nanostars (NSs) display strong surface plasmon resonance (SPR) absorption in near infrared (NIR) region, enabling their uses for photoacoustic (PA) imaging, thermal imaging and photothermal therapy of cancer[3],[4]. In this work, a facile mild reduction method was employed to synthesize Fe3O4@Ag nanoparticles (NPs)[1] and the thus-prepared NPs were used as seeds to form Fe3O4@Au NSs in the Au growth solution. Further sequential modification of polyethyleneimine (PEI) and folic acid (FA)-conjugated polyethylene glycol (PEG-FA) affords the NSs with excellent colloidal stability, good biocompatibility, and targeting specificity to cancer cells over-expressing FA receptors. With the Fe3O4 core NPs and the star-shaped Au shells, the formed Fe3O4@Au-PEI.Ac-PEG-FA NSs are able to be used as a nanoprobe for efficient of MR and computed tomography (CT) imaging of cancer cells in vitro and the xenografted tumor model in vivo. Likewise, the NIR absorption property enables the developed Fe3O4@Au-PEI.Ac-PEG-FA NSs to be used as a nanoprobe for PA and thermal imaging of tumors in vivo and photothermal ablation of cancer cells in vitro and the xenografted tumor model in vivo. This study fully demonstrates a unique multifunctional theranostic nanoplatform for multimode imaging and photothermal therapy of tumors. National Natural Science Foundation of China (21273032, 81341050, and 81371623); Sino-German Center for Research Promotion (GZ899); Program for Professor of Special Appointment (Eastern Scholar) at Shanghai Institutions of Higher Learning; Fundamental Research Funds for the Central Universities; Innovation Funds of Donghua University Master Dissertation of Excellence