Polydopamine Enhanced Interactions of Graphene Nanosheets to Fabricate Graphene/Polydopamine Aerogels with Effectively Clear Organic Pollutants.

Graphene/polydopamine aerogels (GPDXAG, where X represents the weight ratio of DA·HCl to GO) were prepared by the chemical reduction of graphene oxide (GO) using dopamine (DA) and l-ascorbic acid as reducing agents. During the gelation process, DA was polymerized to form polydopamine (PDA). The introduction of PDA in the gelation of aerogels led to a deeper reduction of GO and stronger interactions between graphene nanosheets forced by covalent cross-linking and noncovalent bonding including π-π stacking and hydrogen bonding. The weight ratio of DA·HCl to GO influencing the formation and morphology of GPDXAG was explored. With the increasing content of DA in gelation, the reduction of GO and the cross-linking degree of graphene nanosheets were enhanced, and the resulting GPDXAG had a more regular pore distribution. Additionally, introducing PDA into GPDXAG improved its hydrophobicity because of the adhesion of PDA to a network of aerogels. GPDXAG exhibited a higher removal efficiency for organic pollutants than the controlled graphene aerogels (GAG). Specifically, the adsorption capacity of GPDXAG for organic solvents was superior to that of GAG, and organic solvent was completely separated from the oil/water mixture by GPDXAG. The equilibrium adsorption capacity of GPDXAG for malachite green (MG) was measured to be 768.50 mg/g, which was higher than that for methyl orange (MO). In MG/MO mixed solutions, aerogels had obvious adsorption selectivity for the cationic dye. The adsorption mechanism of aerogels for MG was also discussed by simulating adsorption kinetic models and adsorption isothermal models.

Efficient delivery of Echinococcus multilocularis miRNAs using chitosan nanoparticles.

Alveolar echinococcosis caused by Echinococcus multilocularis is an important zoonotic disease, a great threat to human health due to limited interventions. microRNAs are a type of small non-coding RNA that plays a key role in many diseases and is considered as a potential therapeutic target for control of parasitic diseases. However, naked miRNAs are difficult to enter into cells and are easily degraded in both external and internal environments. Chitosan (CS) has recently been used as a promising vehicle for delivery of nucleic acids. Therefore, we prepared miRNA-bearing CS nanoparticles and investigated the physicochemical properties as well as the delivery efficiency. We found that CS nanoparticles was relatively stable, offered miRNA strong protection from degradation and had low cytotoxicity with no significant effects on cell proliferation and apoptosis. CS nanoparticles were shown to be easily absorbed by cells and have remarkable liver tropism. Furthermore, CS nanoparticles were used to efficiently deliver E. multilocularis miR-4989 in vitro and in vivo and caused a significant reduction in the expression of UBE2N in the liver, a potential target of emu-miR-4989, at both mRNA and protein levels. Our data demonstrate that CS nanoparticles can act as a vehicle for efficient liver-targeted delivery of miRNAs and for development of miRNA-based therapeutics against E. multilocularis infection.

Carbon Dioxide and Nitrogen-Modulated Shape Transformation of Chitosan-Based Composite Nanogels.

Chitosan/poly[N-(3-(dimethylamino)propyl)methacrylamide]/poly(acrylic acid) (CS/PDMAPMA/PAA) composite nanogels (CPACNGs) were fabricated in the solution of chitosan by surfactant-free emulsion polymerization. N-(3-(Dimethylamino)propyl)methacrylamide (DMAPMA) and acrylic acid (AA) were initiated by 2,2'-azobis-2-methyl-propanimidamide to graft from the backbone of chitosan. Nanogels were formed by noncovalent forces, including of hydrogen bonds, hydrophobic, and electrostatic interaction. Nanogels were characterized by transmission electron microscopy, scanning electron microscope dynamic light scattering, X-ray photoelectron spectroscopy, Fourier transform infrared spectrometer spectra, and 1H NMR. Spherical nanoparticles were observed in the latex system. Nanogels exhibited an excellent CO2 responsivity and CO2/N2 reversible response and switchability and had a faster response rate. The morphological shape transformation of nanogels was modulated by bubbling with CO2 and N2. The responsive mechanism was explored by determining the pH and electrical conductivity. In addition, nanogels were successfully emulsified by bubbling with CO2, and then a phase transition was achieved by bubbling with N2 in the organic solvent/water mixture.

Fabrication of Composite Hydrogels Based on Soy Protein Isolate and their Controlled Globular Protein Delivery.

Soy protein isolate (SPI) protein/polymer composite hydrogels (PPCGs) are fabricated in a urea solution of SPI using acrylic acid as monomer, ammonium persulphate (APS) as initiator, and N,N-methylenebisacrylamide (BIS) and glutaraldehyde (GA) as cross-linking agents. The scanning electron microscope (SEM) results show that SPI/polyacrylic (PAA) composite hydrogels formed network structure. In particular, in the absence of cross-linking agent (GA), the network structure of composite hydrogels is also formed by BIS cross-linking chains of PAA and the hydrophobic interactions between peptides from SPI and chain of PAA. In addition, composite hydrogels have good water absorption and present excellent pH sensitivity. Composite hydrogels adsorb bovine serum albumin (BSA) with higher adsorption capacity. BSA is the control released in pH 7.4 buffers and the accumulative release ratio achieved is 90%. It will be expected that these protein/polymer composite hydrogels could be applied for drug sustained release materials.