Polyethyleneimine as a novel desorbent for anionic organic dyes on layered double hydroxide surface

Double-Stranded RNA Targeting White Mold Sclerotinia sclerotiorum Argonaute 2 for Disease Control via Spray-Induced Gene Silencing

Sclerotinia sclerotiorum, the causal agent of white mold infection, is a cosmopolitan fungal pathogen that causes major yield losses in many economically important crops. Spray-induced gene silencing has recently been shown to be a promising alternative method for controlling plant diseases. Based on our prior research, we focused on developing a spray-induced gene silencing approach to control white mold by silencing S. sclerotiorum argonaute 2 (SsAgo2), a crucial part of the fungal small RNA pathway. We compared the lesion size as a result of targeting each ∼500-bp segment of SsAgo2 from the 5' to the 3' end and found that targeting the PIWI/RNaseH domain of SsAgo2 is most effective. External application of double-stranded RNA (dsRNA)-suppressed white mold infection using either in vitro or in vivo transcripts was determined at the rate of 800 ng/0.2 cm2 area with a downregulation of SsAgo2 from infected leaf tissue confirmed by RT-qPCR. Furthermore, magnesium/iron-layered double hydroxide nanosheets loaded with in vitro- and in vivo-transcribed dsRNA segments significantly reduced the rate of S. sclerotiorum lesion expansion. In vivo-produced dsRNA targeting the PIWI/RNaseH domain of the SsAgo2 transcript showed increased efficacy in reducing the white mold symptoms of S. sclerotiorum when combined with layered double hydroxide nanosheets. This approach is promising to produce a large scale of dsRNA that can be deployed as an environmentally friendly fungicide to manage white mold infections in the field.

Silver nanoparticles coated cellulose-based flexible membrane with excellent UV resistance, high infrared reflection and water resistance for personal thermal management

Designing of a green and multifunctionally integrated cellulose-based flexible wearable material with personal thermoregulation, water and ultraviolet (UV) resistance is essential for the development of personal thermal management and smart textiles. Herein, a hydrophobic silver nanoparticles cellulose-based membrane (H-AgNPs/CEPCM) was prepared through simple solution blending, spin-coating process and chemical vapor modification. The prepared membrane exhibited excellent UV resistance due to the synergistic effect of carbon quantum dots (CQDs) as well as UV-absorbing functional groups. The spin-coated AgNPs layer with high infrared reflectivity has great radiant insulation, and temperature was reduced by 3.4 °C compared with H-CEPCM in indoor environment. Furthermore, the mechanical properties of H-AgNPs/CEPCM were significantly improved by the introduction of amide and ether bonds, as well as a large number of hydrogen bonds. This led to a tensile strength of 23.21 MPa and an elongation at break of 16.57 %, while also providing water resistance. Additionally, the H-AgNPs/CEPCM exhibited outstanding thermal stability and hydrophobicity. This work may provide a feasible and promising strategy for the construction of multifunctional integrated cellulose membrane materials for radiant insulation, outdoor textiles and novel UV protection applications.

Removal of Isolan Dark Blue 2SGL-01 from aqueous solutions onto calcined and uncalcined (Mg-Zn)/(Al-Fe)-(CO3)/Cl layered double hydroxides

The adsorption process of the industrialized dye Isolan Dark Blue 2SGL-01 (IDB) onto (Mg-Zn)/(Al-Fe)-(CO3)/Cl layered double hydroxides (LDHs) coded LDH21 and LDH22 and its calcined products CLDHs (CLDH21 and CLDH22), respectively, was investigated. The characterization of LDHs and CLDHs before and after loading with IDB by Fourier transform infrared, scanning electron microscope and surface area measurements showed a typical hydrotalcite structure and confirmed the loading of IDB. The adsorption parameters; initial pH, shaking time, adsorbent dose, initial concentration of IDB dye and temperature were studied. The optimum conditions for IDB adsorption were pH 4.3 and shaking time 3 h. A complete removal of IDB (> 99%) was achieved using a dosage of 2.0 g L− 1 CLDHs or LDH22, and 3.0 g L− 1 of LDH21. The adsorption processes were suggested to be best described by the pseudo-second order kinetics and Langmuir-type adsorption isotherm with monolayer capacities of 75, 91, 427 and 530 mg g− 1, onto LDH21, LDH22, CLDH21 and CLDH22, respectively. The loaded IDB was recovered from LDHs and CLDHs adsorbent using Na2CO3. CLDH22 showed best adsorption capacity of 530 mg g− 1. Its adsorption thermodynamic parameters ∆Gadsorption, ∆Hadsorption and ∆Sadsorption indicated that the adsorption processes were spontaneous and endothermic in nature. CLDH22 was successfully applied for the removal of IDB from simulated dyeing process with removal efficiency 97%.

Preparation of Ag Nanoclusters-Modified Non-Sintered Silica Ceramic-Like Nanosheet for Removing Dyes and Bacteria from Water

PURPOSE

Worldwide water contamination treatment and water security are essential for all living organisms. Among various water contaminants, dye, and bacteria pollution needs to be solved urgently.

METHODS AND RESULTS

In this work, a ceramic sheet from monodisperse, porous silica nanospheres (SiO2 NSs) with an average diameter of 220 was prepared. The prepared SiO2 ceramic sheets were investigated as a "filtration" material in removing dyes (alcian blue, AB; and methylene blue, MB) and bacteria (E. coli and S. aureus). The obtained sheets had efficient adsorption efficiency of 98.72% (for AB) and 97.35% (for MB), and a high adsorption capacity for AB is 220 (mg/g), for MB is 176 (mg/g). Furthermore, these SiO2 ceramic sheets had a high recycling capability for removing dyes by calcination. Being modified by Ag nanoclusters, the ceramic sheets present a strong bactericidal function.

CONCLUSION

Our results demonstrated that the obtained SiO2 non-sintered ceramic sheets is rapid and efficient in the filtration of dyes and bacteria from polluted water.

Semi-interpenetrating Network Membrane from Polyethyleneimine-Epoxy Resin and Polybenzimidazole for HT-PEM Fuel Cells

In the present work, a semi-interpenetrating network (semi-IPN) high-temperature proton exchange membrane based on polyethyleneimine (PEI), epoxy resin (ER), and polybenzimidazole (PBI) was prepared and characterized, aiming at their future application in fuel cell devices. The physical properties of the semi-IPN membrane are characterized by thermogravimetric analysis (TGA) and tensile strength test. The results indicate that the as-prepared PEI-ER/PBI semi-IPN membranes possess excellent thermal stability and mechanical strength. After phosphoric acid (PA) doping treatment, the semi-IPN membranes show high proton conductivities. PA doping level and volume swelling ratio as well as proton conductivities of the semi-IPN membranes are found to be positively related to the PEI content. High proton conductivities of $3.9\backsim 7.8\times {10}^{-2}\text{S}\text{c}{\text{m}}^{-1}$ are achieved at 160°C for these PA-doped PEI-ER/PBI series membranes. H2/O2 fuel cell assembled with PA-doped PEI-ER(1 : 2)/PBI membrane delivered a peak power density of 170 mW cm-2 at 160°C under anhydrous conditions.

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 20.0 mg adsorbent was used to extract the mycotoxins from 50.0 mL loading solution. The maximum adsorption capacities of the adsorbent toward the mycotoxins ranged from 4.9 to 10.2 mg/g. Adsorption and desorption were completed within 3.0 and 2.0 min, 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 0.442 μg/kg. The proposed adsorbent has great potential in the routine analysis of mycotoxins in ordinary analytical chemistry laboratory.

Highly dispersed layered double oxide hollow spheres with sufficient active sites for adsorption of methyl blue

The adsorption of dyes in contaminated water is an effective approach to solving the environmental crisis. Layered double hydroxide (LDH) and its calcinated product layered double oxide (LDO) show great potential as adsorbents. However, the conventional preparation of LDH or LDO typically suffers from aggregation and blocked active sites, hampering the adsorption efficiency of the adsorbent. Herein, three-dimensional, hollow MgFe-LDO spheres were constructed through the sacrifice of a carbon template. The hollow structure and the monodisperse state provided MgFe-LDO with sufficient microchannels and abundant active sites for adsorption. Through the memory effect of LDO, the anion methyl blue (MB) can be effectively adsorbed with a high uptake capacity of 398 mg g^-1. Isotherm simulations demonstrated the monolayer adsorption of MB and the heterogeneous surfaces of the reconstructed LDHs. Moreover, the adsorbents can be recycled and reutilized at least five times through magnetic separation followed by calcination. Our proposed strategy is expected to provide new possibilities for the construction of adsorbents with well-controlled architecture and abundant active sites to deal with anionic pollutants.

MAPLE Assembled Acetylcholinesterase⁻Polyethylenimine Hybrid and Multilayered Interfaces for Toxic Gases Detection

Developing a controlled method for obtaining hybrid enzymatic-based interfaces for sensing application require the use of a multiuse, reusable sensor. By controlling the interface characteristics in terms of the surface chemistry, thickness, and roughness, a tailored response toward various toxic compounds can be obtained, regarding both materials used as active surfaces and fabrication methods. Herein, we report a preliminary study on using a laser-based method (i.e., matrix-assisted pulsed laser evaporation, or MAPLE) for obtaining active polymeric⁻enzymatic interfaces as hybrid or layered coatings for detecting toxic vapors. The MAPLE fabrication consisted of the simultaneous alternating evaporation of layers of polyethylenimine (PEI) and acetylcholinesterase (AchE) in order to obtain active surfaces as both hybrid PEI-AchE and a PEI/AchE layered coating, respectively. The deposition processes of the polymer and enzyme were carried out using a double-target system and a Nd:YAG pulsed laser, operating at 0.45 J/cm² fluences with a wavelength of 266 nm and a repetition rate of 10 Hz. Fourier transform infrared spectroscopy revealed no significant changes in the functional groups of both hybrid and layered coatings compared with the initial material. The thickness and roughness, as well as the morphologies of the coatings revealed by atomic force microscopy and scanning electron microscopy showed coatings thicker than two μm that had smooth surfaces and average roughness values below six nm. The sensors were tested with simulants for nerve gases and pesticides containing phosphonate ester groups, namely dimethyl methylphosphonate (DMMP) and diisopropyl methylphosphonate (DIMP), and a different sensitivity was shown to the selected chemical agents for each of the sensors. The best sensitivities for DMMP and DIMP obtained by using a PEI-AchE coated sensor are 65 kHz and 200 kHz, respectively, whereas the best sensitivity when using multilayered interfaces is 30 kHz and 10 KHz for DIMP and DMMP, respectively.

Optimization of Formulations Consisting of Layered Double Hydroxide Nanoparticles and Small Interfering RNA for Efficient Knockdown of the Target Gene

Layered double hydroxide (LDH) nanoparticles (NPs) are safe and effective vectors for small interfering RNA (siRNA) delivery. However, it is unclear whether there are optimal parameters for the efficient delivery of functional siRNA using LDH NPs. In this research, we comprehensively examined the effect of parameters, such as the mixing method and LDH/siRNA mass ratio on siRNA silencing capability. We first noted that the best way for loading gene segments (25 bp dsDNA and siRNA) is to add gene molecules to 100 nm LDH and then diluting in Dulbecco's modified Eagle's medium. Very interestingly, the optimal LDH/gene mass ratio is around 20:1 in terms of cellular uptake amount of gene segments, whereas this ratio is shifted to around 5:1 in terms of target gene silencing efficacy, which has been reasonably explained. The optimization for LDH NP-based gene delivery system may provide the guidance for more efficient in vitro and in vivo siRNA delivery using the optimal parameters.

Absorption of sulfur dioxide from simulated flue gas by polyethyleneimine-phosphoric acid solution

Clean fuel technologies have been widely developed in current society because fuel combustion can directly bring about the emission of hazardous gasses such as SO2. Flue gas desulfurization by polyethyleneimine (PEI)-phosphoric acid solution is an efficient desulfurization method. In this research, the PEI and the additive H3PO4 were used as absorption solution. SO2 was absorbed by the system and desorbed from the loaded solution. The cycle operation was also analyzed. Some technology conditions such as the concentration of PEI, the temperature, the gas flow rate, the concentration of SO2 and the pH value were experimentally researched. With the optimized process, the absorption efficiency of this system could reach 98% and the desorption efficiency was over 60%, showing good absorption/desorption capability. With this efficient approach, the present study may open a new window for developing high-performance absorbents which can make SO2 be well desorbed from the loaded solution and better reused in the flue gas desulfurization.