Synergistic Effect of Redox Dual PdO x /MnO x Cocatalysts on the Enhanced H2 Production Potential of a SnS/α-Fe2O3 Heterojunction via Ethanol Photoreforming.

In the quest for optimal H2 evolution (HE) through ethanol photoreforming, a dual cocatalyst-modified heterocatalyst strategy is utilized. Tin(II) sulfide (SnS) was hybridized with α-Fe2O3 to form the heterocatalyst FeOSnS with a p-n heterojunction structure as confirmed by X-ray diffraction (XRD), Fourier transform infrared spectroscopy (FT-IR), UV-vis diffusive reflectance spectroscopy (UV-vis DRS), and Brunauer-Emmett-Teller (BET) techniques. PdO x and PdO x /MnO x cocatalysts were loaded onto the FeOSnS heterocatalyst through the impregnation method, as verified by high-resolution transform electron microscopy (HRTEM), X-ray photoelectron spectroscopy (XPS), and elemental mapping. Photocatalytic ethanol photoreforming resulted in the production of H2 as the main product with a selectivity of 99% and some trace amounts of CH4. The FeOSnS2-PdO x 2%/MnO x 1% photocatalyst achieved the highest HE rate of 1654 µmol/g, attributed to the synergistic redox contribution of the PdO x and MnO x species.

Iron Oxide Nanoparticles: Physicochemical Characteristics and Historical Developments to Commercialization for Potential Technological Applications.

Iron oxide nanoparticles (IONPs) have gained increasing attention in various biomedical and industrial sectors due to their physicochemical and magnetic properties. In the biomedical field, IONPs are being developed for enzyme/protein immobilization, magnetofection, cell labeling, DNA detection, and tissue engineering. However, in some established areas, such as magnetic resonance imaging (MRI), magnetic drug targeting (MDT), magnetic fluid hyperthermia (MFH), immunomagnetic separation (IMS), and magnetic particle imaging (MPI), IONPs have crossed from the research bench, received clinical approval, and have been commercialized. Additionally, in industrial sectors IONP-based fluids (ferrofluids) have been marketed in electronic and mechanical devices for some time. This review explores the historical evolution of IONPs to their current state in biomedical and industrial applications.

Improvements in the Organic-Phase Hydrothermal Synthesis of Monodisperse M x Fe3-x O4 (M = Fe, Mg, Zn) Spinel Nanoferrites for Magnetic Fluid Hyperthermia Application.

In the quest for optimal heat dissipaters for magnetic fluid hyperthermia applications, monodisperse M x Fe3-x O4 (M = Fe, Mg, Zn) spinel nanoferrites were successfully synthesized through a modified organic-phase hydrothermal route. The chemical composition effect on the size, crystallinity, saturation magnetization, magnetic anisotropy, and heating potential of prepared nanoferrites were assessed using transmission electron microscopy (TEM), dynamic light scattering, X-ray diffraction (XRD), thermogravimetric analysis (TGA), energy-dispersive X-ray spectroscopy (EDS), atomic absorption spectroscopy (AAS), X-ray photoelectron spectroscopy (XPS), and vibrating sample magnetometer (VSM) techniques. TEM revealed that a particle diameter between 6 and 14 nm could be controlled by varying the surfactant ratio and doping ions. EDS, AAS, XRD, and XPS confirmed the inclusion of Zn and Mg ions in the Fe3O4 structure. Magnetization studies via VSM revealed both the superparamagnetic nature of the nanoferrites and the dependence on substitution of the doped ions to the final magnetization. The broader zero-field cooling curve of Zn-doped Fe3O4 was related to their large size distribution. Finally, a maximum rising temperature (T max) of 66 °C was achieved for an aqueous ferrofluid of nondoped Fe3O4 nanoparticles after magnetic field activation for 12 min.

Model protein BSA adsorption onto novel magnetic chitosan/PVA/laponite RD hydrogel nanocomposite beads.

Chitosan-based magnetic beads were developed by solution-mixing method. Firstly, the Fe3O4 nanoparticles were in situ immobilized on laponite RD sheets. The magnetic laponite RD was then dispersed in PVA and mixed with chitosan solution. PVA was aimed to prevent the disintegration of chitosan under acidic media due to its ability to form hydrogel network through freezing-thawing method. The manufactured magnetic chitosan/PVA/laponite RD beads were utilized for adsorption study of a model protein, bovine serum albumin (BSA). The adsorption of BSA on beads was pH-dependent where smaller mass of protein was adsorbed at pH values lower than isoelectric point of BSA. Moreover, it was discovered that introduction of magnetic laponite RD can improve the adsorption capacity of magnetic beads for BSA in which hydrogel with the highest content of magnetic laponite RD demonstrated the maximum adsorption capacity for BSA (qm=240.5mg/g). Langmuir model described the isotherm data better than Freundlich model.

Investigation of pectin/starch hydrogel as a carrier for oral delivery of probiotic bacteria.

The present study highlights the fabrication of novel food-grade hydrogel particles based on pectin and starch for probiotic colon delivery. Lactobacillus plantarum ATCC:13643 (L. plantarum) cells were encapsulated in pectin/starch hydrogels by extrusion method. Four batches were formulated with different ratios of starch/pectin solutions. Optical and scanning electron microscopy obviously showed the random distribution of L. plantarum throughout the hydrogel network. The viability of encapsulated cells in simulated gastric fluid (SGF) and bile salt solution was significantly higher when compared to nonencapsulated cells. Results demonstrated that encapsulated cells in pectin/starch hydrogels were resistant against adverse conditions of the gastro-intestinal tract and bile salt solution compared to non-encapsulated cells. After sequential exposure to simulated gastric fluid (SGF) and simulated intestinal fluid (SIF) for 2h almost complete death of free cells was observed however the numbers of surviving cells were 5.15 and 6.67 Log CFU/g for pectin and pectin/starch hydrogel, respectively.

Development of novel carboxymethyl cellulose/k-carrageenan blends as an enteric delivery vehicle for probiotic bacteria.

This study reports a novel carrier based on blends of carboxymethyl cellulose (CMC) and k-carrageenan (k-Carr) for probiotic colon delivery. Lactobacillus plantarum ATCC:13643 (L. plantarum) cells were encapsulated in CMC/k-Carr blends by extrusion method. k-Carrageenan was used as a coating agent to improve encapsulation of L. plantarum cells in carboxymethyl cellulose biopolymer. K-Carrageenan and carboxymethyl cellulose were ionically cross-linked with K+ and Ca2+ ions, respectively. Optical and scanning electron microscopy obviously showed the random distribution of L. plantarum cells throughout the blend network. The viability of encapsulated cells in simulated gastric fluid (SGF) and bile salt solution were conducted. Results indicated that CMC/k-Carr blends could successfully protect L. plantarum cells against adverse conditions of the gastro-intestinal tract and bile salt solution. After sequential exposure to SGF for 2h almost complete death of free cells was observed. However, the number of surviving cells was 5.20 and 7.30 Log CFU/g for uncoated free CMC and CMC/k-Carr blends, respectively. Cumulatively the results of this research offer a suitable media to potentially deliver probiotics to colon site.

Magnetic/pH-responsive beads based on caboxymethyl chitosan and κ-carrageenan and controlled drug release.

This paper reports the synthesis of magnetic and pH-sensitive beads derived from κ-carrageenan and carboxymethyl chitosan for drug delivery. The magnetic Fe3O4 nanoparticles were synthesized inside a mixture of biopolymers by in situ method. The structural properties of hydrogel beads were characterized by TEM, SEM, XRD, and VSM techniques. The swelling ratio of beads indicated pH-dependent properties with maximum water absorbing at pH 7.4. Introducing magnetic nanoparticles caused a decrease in swelling capacity from 16.4 to 10 g/g. Drug loading and release efficiency were investigated using diclofenac sodium as a model system. The in vitro drug release studies exhibited significant behaviors on the subject of physiological simulated pHs and external alternative magnetic fields. The maximum cumulative release was around 82% at pH 7.4. The presence of magnetite nanoparticles certainly influenced the drug release patterns. The response of beads to external stimulus makes them as good candidates for novel drug delivery systems.

In situ synthesis of magnetic CaraPVA IPN nanocomposite hydrogels and controlled drug release.

In this work, the magnetic nanocomposite hydrogels that focused on targeted drug delivery were synthesized by incorporation of polyvinyl alcohol (PVA), kappa-carrageenan (Cara), and magnetite Fe3O4 nanoparticles. The magnetic nanoparticles were obtained in situ in the presence of a mixture of polyvinyl alcohol/kappa-carrageenan (CaraPVA). The produced magnetite-polymers were cross-linked with freezing-thawing technique and subsequent with K(+) solution. The synthesized hydrogels were thoroughly characterized by transmittance electron microscopy (TEM), scanning electron microscopy (SEM), X-ray diffraction (XRD), thermal gravimetric analysis (TGA), Fourier transform infrared spectroscopy (FT-IR), and vibrating sample magnetometer (VSM) techniques. The dynamic swelling kinetic models of hydrogels were analyzed according to the first- and second-order kinetic models and were found that the experimental kinetics data followed the second-order model well. Drug loading and release efficiency were evaluated by diclofenac sodium (DS) as the model drug. The in vitro drug release studies from hydrogels exhibited significant behaviors on the subject of physiological simulated pHs and external magnetic fields. Investigation on the antibacterial activity revealed the ability of drug-loaded hydrogels to inactivate the Gram-positive Staphylococcus aureus (S. aureus) bacteria. The mucoadhesive properties of the hydrogels were studied and the hydrogels containing kappa-carrageenan showed good mucoadhesiveness in both simulated gastric and intestinal conditions.

Synthesis of CarAlg/MMt nanocomposite hydrogels and adsorption of cationic crystal violet.

CarAlg/MMt nanocomposite hydrogels composed of kappa-carrageenan (Car) and sodium alginate (Alg) biopolymers were synthesized by incorporation of sodium montmorillonite (Na-MMt) nanoclay. Acrylamide (AAm), methylenebisacrylamide (MBA), and ammonium persulfate (APS) were used as monomer, crosslinker, and initiator, respectively. The structure and morphology of nanocomposites were characterized by XRD, SEM, and TEM techniques. The XRD results showed exfoliated MMt nanoclay and exfoliation of MMt was confirmed by TEM graph. The resulting nanocomposites were evaluated to remove cationic crystal violet (CV) dye from water. According to data, the adsorption capacity of nanocomposites was enhanced as the clay content was increased. The experimental data were analyzed according to both Langmuir and Freundlich models and experimental maximum adsorption capacity was obtained 88.8 mg g(-1). By studying the effect of pH on the dye adsorption capacity of nanocomposites, it was revealed that the adsorption capacity of nanocomposites was enhanced at acidic pHs as the Na-MMt nanoclay and kappa-carrageenan components were increased.