Recyclable heterogeneous palladium-catalyzed carbon–carbon coupling polycondensations toward highly purified conjugated polymers

A novel GO hoisted SnO2-BiOBr bifunctional catalyst for the remediation of organic dyes under illumination by visible light and electrocatalytic water splitting

It is imperative to develop affordable multi-functional catalysts based on transition metals for various applications, such as dye degradation or the production of green energy. For the first time, we propose a simple chemical bath method to create a SnO2-BiOBr-rGO heterojunction with remarkable photocatalytic and electrocatalytic activities. After introducing graphene oxide (GO) into the SnO2-BiOBr nanocomposite, the charge separation, electron mobility, surface area, and electrochemical properties were significantly improved. The X-ray diffraction results show the successful integration of GO into the SnO2-BiOBr nanocomposite. Systematic material characterization by scanning and transmission electron microscopy showed that the photocatalysts are composed of uniformly distributed SnO2 nanoparticles (∼11 nm) on the regular nanosheets of BiOBr (∼94 nm) and rGO. The SnO2-BiOBr-rGO photocatalyst has outstanding photocatalytic activity when it comes to reducing a variety of organic dyes like rhodamine B (RhB) and methylene blue (MB). Within 90 minutes of visible light illumination, degradation of a maximum of 99% for MB and 99.8% for RhB was noted. The oxygen evolution reaction (OER) and hydrogen evolution reaction (HER) performance was also tested for the ternary nanocomposite, and significantly lower overpotential values of 0.34 and -0.11 V (vs. RHE) at 10 mA cm-2 were observed for the OER and HER, respectively. Furthermore, the Tafel slope values are 34 and 39 mV dec-1 for the OER and HER, respectively. The catalytic degradation of dyes with visible light and efficient OER and HER performance offer this work a broad spectrum of potential applications.

UV filters and high refractive index materials based on carboxymethyl cellulose sodium and CuO@ZnO core/shell nanoparticles

Nanoparticles have substantially contributed to the field of skincare products with ultraviolet (UV) filters to preserve human skin from sun damage. Thus, the current study aims to develop new polymer nanocomposites for the efficient block of UV light that results from the stratospheric ozone layer loss. Co-precipitation method was used to successfully synthesis CuO@ZnO core/shell NPs with a well-crystalline monoclinic CuO core and wurzite ZnO shell. Using the casting method, core/shell NPs were successfully introduced to carboxymethyl cellulose sodium (CMC). The CMC nanocomposites displayed considerably broader optical response extending from near-ultraviolet to visible light, which was likely due to heterojunction between the p-CuO core and n-ZnO shell and defects originating from the synthetic process. The transmittance of pure CMC in the UV, visible, and near IR regions is significantly reduced with the addition of 2 and 4 wt% of CuO@ZnO core/shell NPs to CMC. 99% of UV light is absorbed when 4 wt% of CuO@ZnO core/shell NPs are added. The addition of different concentrations of CMC nanocomposite to one of the sunblock in Egyptian market were studied and showing the highest Sun Protection Factor of 22. Moreover, optical dispersion parameters and refractive index were improved strongly with core/shell NPs addition.

Review on descaling and anti-scaling technology of heat exchanger in high-salt wastewater thermal desalination

Thermal desalination evaporation of high-salt wastewater has been widely used in industry because of the proposed concept of 'zero liquid discharge'. However, due to the high content of Ca2+ and Mg2+ in high-salt wastewater, the heat exchanger, as the main treatment equipment, suffers from serious scaling problems. This review presents descaling and scale inhibition technologies of high-salt wastewater. The advantages and disadvantages of various technologies are summarized and analyzed to provide theoretical support for the research of descaling and anti-scaling of heat exchangers with high-salt wastewater. In future industrial development, the synergistic application of electromagnetic water treatment technology and scale inhibitors can significantly improve the anti-scaling effect, which can reach over 95% stably. Furthermore, the addition of a physical field can also expand the application range of scale inhibitors.

Acylhydrazone functionalized naphthalene-based self-assembled supramolecular gels for efficient fluorescence detection of Fe3

A new gel factor (named N) has been successfully designed and synthesized, which contains the conventional fluorophore naphthalene with the acylhydrazone bond as the self-assembly site. It can be self-assembled into stable organogels (named ON) in dimethyl sulfoxide (DMSO) and water mixed medium (V : V = 4 : 1) with a critical gel temperature and concentration (55 °C and 10 mg mL-1). Interestingly, under 365 nm UV light, the ON exhibits bright yellow Aggregation Induced Emission (AIE). The supramolecular organogel ON shows a fluorescent "OFF" response to the metal ions Fe3+, and the state of the gel ON remains constant before and after detection. Notably, the minimum detection limits (LODs) of the gel ON for Fe3+ are as low as 1.30 × 10-7 M. The binding mechanism of supramolecular organogels (ON) to ions has been investigated through a series of characterizations. Meanwhile, the organogel sensor ON can also be used as an ion-responsive membrane for the detection of Fe3+ in the aqueous phase.

Multi-Layered PLGA-PEI Nanoparticles Functionalized with TKD Peptide for Targeted Delivery of Pep5 to Breast Tumor Cells and Spheroids

PURPOSE

Peptide-based therapy is a promising strategy for cancer treatment because of its low drug resistance. However, the major challenge is their inability to target cancer cells specifically. So, a targeted nano-delivery system that could deliver therapeutic peptides selectively to cancer cells to stimulate their action is highly desirable. This study aims to deliver the antitumor peptide, Pep5, to breast tumor cells selectively using a targeting peptide functionalised multi-layered PLGA-PEI nanoparticles.

METHODS

In this study, Pep5 entrapped PLGA-PEI (Pep5-PPN) dual layered nanoparticles were developed. These nanoparticles were decorated with TKD (Pep5-TPPN) on their surface for site-specific delivery of Pep5 to breast tumor cells. The particles were then characterized using various instrumental analyses. In vitro cytotoxicity of the particles was evaluated in estrogen receptor positive (ER+ve) and triple negative breast cancer (TNBC) cells. An ex vivo tumor spheroid model was used to analyze the antitumor activity of the particles.

RESULTS

Uniformly round Pep5-TPPN particles were synthesized with an average diameter of 420.8 ± 14.72 nm. The conjugation of PEI over Pep5-PLGA nanoparticles shifted the zeta potential from -11.6 ± 2.16 mV to +20.01 ± 2.97 mV. In vitro cytotoxicity analysis proved that TKD conjugation to nanoparticles enhanced the antitumor activity of Pep5 in tested breast cancer cells. Pep5-TPPN induced cytoskeletal damage and apoptosis in the tested cells, which showed that the mechanism of action of Pep5 is conserved but potentiated. Active targeting of Pep5 suppressed the tumor growth in ex vivo spheroid models.

CONCLUSION

A multi-layered nanoparticle functionalized with dual peptide was fabricated for active tumor targeting, which stimulated Pep5 activity to reduce the tumor growth in vitro and ex vivo.

Synthesis of manganese molybdate/MWCNT nanostructure composite with a simple approach for supercapacitor applications

Recently, magnesium molybdate materials have attracted scientific attention for application in supercapacitor devices due to advantages like low synthesis cost and good redox reactions. Nevertheless, these materials endure low electrical conductivity leading to inferior electrochemical performance. To eliminate this drawback, we prepare a composite powder containing magnesium molybdate and functionalized carbon nanotubes (MMO/C) using a simple process to improve the supercapacitive properties. The results proved an electrostatic interaction between the two components of the composite powder, which contains 18-30 nm magnesium molybdate nanoparticles. A crystal model related to magnesium molybdate powder (MMO) was simulated, illustrating that MnO₆ octahedra are formed next to MoO₄ tetrahedra. The mesoporous structure of both powders was confirmed whereas the specific surface area of the MMO was enhanced by 69.9% to 36.86 m² g^-1 in the MMO/C powder with more electroactive sites. The higher electrical conductivity of the MMO/C electrode was proved using electrochemical impedance spectroscopy (EIS) results, with the MMO/C electrode achieving a specific capacitance of 571 F g^-1 at 1 A g^-1 current density, improved by more than 4.5 times that of the MMO. Furthermore, the rate performance and cycling stability of the MMO/C electrode reached 87% and 85.2%, respectively. Finally, a two-electrode energy storage device (MMO/C//AC) was assembled. It reveals a specific capacitance of 94.7 F g^-1, a maximum energy density of 29.6 W h kg^-1 at a power density of 660.1 W kg^-1, and cycling performance of 84.3% after 2000 cycles. As a result, the resulting data demonstrate that the MMO/C electroactive material has promising abilities in capacitive energy storage systems.

Preparation and optimization of a molecularly imprinted polymers - solid phase extraction system for the extraction of bioactive sesquiterpene lactones of Ambrosia maritima plant

A solid phase extraction (SPE) system for sesquiterpene lactones of damsissa was developed utilising molecularly imprinted polymers (MIPs). The prepared MIPs had a mesoporous structure and particle size of ≈2.65 µm with 3.99 nm pore size. Additionally, MIPs exhibited high thermal stability with degradation temperature between 209 and 459 °C. Optimized MIP-SPE protocol conditions were set at loading step: 1 mL ethanol; washing step: 1 mL water; eluting step: 4 mL methanol. Developed MIP-SPE system showed a binding capacity of 66.66 mg/g based on Langmuir isotherm which was selected as the best fitting model isotherm. Good selectivity coefficients were observed for neoambrosin of 2.37, 1.31 and 1.14 against umbelliferone, quercetin glucoside and p-coumaric acid, respectively. Furthermore, the proposed MIP-SPE protocol displayed some potential in the isolation of sesquiterpene lactones from damsissa plant extract and laid a foundation for the development of more selective MIPs to nonpolar natural products.

Gentiopicroside PLGA Nanospheres: Fabrication, in vitro Characterization, Antimicrobial Action, and in vivo Effect for Enhancing Wound Healing in Diabetic Rats

Purpose

Gentiopicroside (GPS), an adequate bioactive candidate, has a promising approach for enhancing wound healing due to its antioxidant and antimicrobial properties. Its poor aqueous solubility negatively affects oral absorption accompanied by low bioavailability due to intestinal/hepatic first-pass metabolism. Our aim in this study is to fabricate GPS into appropriate nanocarriers (PLGA nanospheres, NSs) to enhance its solubility and hence its oral absorption would be improved.

Methods

Normal and ODS silica gel together with Sephadex LH20 column used for isolation of GPS from Gentiana lutea roots. Crude GPS would be further processed for nanospheres fabrication using a single o/w emulsion solvent evaporation technique followed by in vitro optimization study to examine the effect of two formulation variables: polymer (PLGA) and stabilizer (PVA) concentrations on the physical characterizations of prepared NSs. Possible GPS-PLGA chemical and physical interactions have been analyzed using Fourier-transform infrared spectroscopy (FTIR) and differential scanning calorimetry (DSC). The optimum GPS-PLGA NSs have been chosen for antimicrobial study to investigate its inhibitory action on Staphylococcus aureus compared with unloaded GPS NSs. Also, a well-designed in vivo study on streptozotocin-induced diabetic rats has been performed to examine the wound healing effect of GPS-PLGA NSs followed by histological examination of wound incisions at different day intervals throughout the study.

Results

The optimum GPS PLGA NSs (F5) with well-controlled particle size (250.10±07.86 nm), relative high entrapment efficiency (83.35±5.71), and the highest % cumulative release (85.79±8.74) have increased the antimicrobial activity as it exhibited a higher inhibitory effect on bacterial growth than free GPS. F5 showed a greater enhancing impact on wound healing and a significant stimulating effect on the synthesis of collagen fibers compared with free GPS.

Conclusion

These findings demonstrate that loading GPS into PLGA NSs is considered a promising strategy ensuring optimum GPS delivery for potential management of wounds.

Microwave-Assisted Physically Cross-Linked Chitosan-Sodium Alginate Hydrogel Membrane Doped with Curcumin as a Novel Wound Healing Platform

This project purposes to develop chitosan and sodium alginate-based hydrogel membranes loaded with curcumin through microwave-based physical cross-linking technique and its evaluation for wound healing potential. For the purpose, curcumin-loaded chitosan and sodium alginate membranes were developed using microwave at fixed frequency of 2450 MHz, power 350 W for 60 s, and tested for their physicochemical attributes like swelling, erosion, surface morphology, drug content, and in vitro drug release. The membranes were also subjected to tensile strength and vibrational and thermal analysis followed by testing in vivo on animals. The results indicated that microwave treatment significantly enhanced the swelling ability, reduced the erosion, and ensured smooth surface texture with optimal drug content. The drug was released in a slow fashion releasing total of 41 ± 4.2% within 24-h period with a higher tensile strength of 16.4 ± 5.3 Mpa. The vibrational analysis results revealed significant fluidization of hydrophilic domains and defluidization of hydrophobic domains which translated into a significant rise in the melting temperature and corresponding enthalpy which were found to be 285.2 ± 3.2 °C and 4.89 ± 1.4 J/g. The in vivo testing revealed higher percent re-epithelialization (75 ± 2.3%) within 14 days of the treatment application in comparison to only gauze and other treatments applied, with higher extent of collagen deposition having well-defined epidermis and stratum corneum formation. The microwave-treated chitosan-sodium alginate hydrogel membranes loaded with curcumin may prove to be another alternative to treat skin injuries. Graphical Abstract.

Combining flow synthesis and heterogeneous catalysis for the preparation of conjugated polymers

We report the first successful synthesis of a conjugated polymer using a heterogeneous palladium catalyst in a flow system. The resulting polymer with an Mn of 13.6 kDa and high reproducibility shows the great potential of this system.

Highly efficient and rapid Pb(ii) removal from acidic wastewater using superhydrophilic polystyrene phosphate resin

Novel superhydrophilic polystyrene phosphate resin was synthesized for efficient and rapid Pb(ii) removal from acidic wastewater.

Self-Assembly of DNA molecules in magnetic Fields

In this work, a rich variety of self-assembled DNA patterns were obtained in the magnetic field. Herein, atomic force microscopy (AFM) was utilized to investigate the effects of the concentration of DNA solution, intensity and direction of magnetic field and modification of mica surface by different cations on the self-assembly of DNA molecules. It was found that owning to the change of the DNA concentration, even under the same magnetic field, the DNA self-assembly results were different. Thein situtest results showed that the DNA self-assembly in an magnetic field was more likely to occur in liquid phase than in gas phase. In addition, whether in a horizontal or vertical magnetic field, a single stretched dsDNA was obtained in a certain DNA concentration and magnetic field intensity. Besides, the modification of cations on the mica surface significantly increased the force between the DNA molecules and mica surface, and further changed the self-assembly of DNA molecules under the action of magnetic field.

Metal-organic frameworks (MOFs) as host materials for the enhanced delivery of biomacromolecular therapeutics

Biomacromolecular drugs have become an important class of therapeutic agents for the treatment of human diseases. Considering their high propensity for being degraded in the human body, the choice of an appropriate delivery system is key to ensure the therapeutic efficacy of biomacromolecular drugs in vivo. As an emerging class of supramolecular "host" materials, metal-organic frameworks (MOFs) exhibit advantages in terms of the tunability of pore size, encapsulation efficiency, controllable drug release, simplicity in surface functionalization and good biocompatibility. As a result, MOF-based host-guest systems have been extensively developed as a new class of flexible and powerful platform for the delivery of therapeutic biomacromolecules. In this review, we summarize current research progress in the synthesis of MOFs as delivery materials for a variety of biomacromolecules. Firstly, we briefly introduce the advances made in the use of biomacromolecular drugs for disease therapy and the types of commonly used clinical delivery systems. We then describe the advantages of using MOFs as delivery materials. Secondly, the strategies for the construction of MOF-encapsulated biomacromolecules (Biomacromolecules@MOFs) and the release mechanisms of the therapeutics are categorized. Thirdly, the application of MOFs to deliver different types of biomacromolecules (e.g., antigens/antibodies, enzymes, therapeutic proteins, DNA/RNA, polypeptides, and polysaccharides) for the treatment of various human diseases based on immunotherapy, gene therapy, starvation therapy and oxidation therapy is summarized. Finally, the remaining challenges and available opportunities for MOFs as drug delivery systems are outlined, which we anticipate will encourage additional research efforts directed towards developing Biomacromolecules@MOFs systems for biomedical applications.

A simple approach with scale-up potential towards intrinsically flame-retardant bio-based co-plasticizer for PVC artificial materials

Abstract

As an imitation of genuine leather, polyvinyl chloride (PVC) artificial materials are versatile, but suffers from being flammable due to the presence of large amounts of combustible plasticizers. Under such circumstance, intrinsically flame-retardant plasticizers displaying dual functions have been a subject of intensive research interest. However, previous strategies attempting to covalently attach flame-retardant moiety to plasticizers invariably required either expensive starting materials or laborious and tedious procedures, ultimately limiting their scale-up application in industry. In addition, driven by escalating demand of halogen-free flame retardants worldwide from an environmental health perspective, previously reported intrinsically flame-retardant plasticizers were mainly halogen-free, less attractive in PVC artificial material industry simply because PVC itself is a halogen-containing polymer. Here, we report an approach to introduce chlorine moieties into unsaturated fatty acid methyl ester by a simple addition reaction occurring on carbon-carbon double bonds, yielding a chlorine-containing, intrinsically flame-retardant bio-plasticizer. When combined with di-(2-ethylhexyl) phthalate (DOP) in PVC formulations, the chlorinated fatty acid methyl ester is qualified as a co-plasticizer while conferring flame retardancy upon the PVC coatings. This approach involves only a one-step procedure that employs renewable fatty acid methyl esters and cheap chlorine gas as raw materials, thus being of great potential to enable intrinsically flame-retardant bio-plasticizers on a large scale to manufacture functional PVC artificial materials for application in fire-prone scenarios.

Graphical abstract