A role for ultrasound in the fabrication of carbohydrate-supported nanomaterials

Ultrasound-assisted air-jet spinning of silk fibroin-soy protein nanofiber composite biomaterials

Ultrasound utilizes a non-radiation technology that can meet modern standards to gain access to cheap, reliable and sustainable modern energy. Ultrasound technology can be implemented in the field of biomaterials for its exceptional potential in controlling the shape of nanomaterials. This study presents the first example of the production of soy and silk fibroin protein composite nanofibers in various ratios via combining ultrasonic technology with air-spray spinning. Characterization of ultrasonic spun nanofibers was performed by scanning electron microscopy (SEM), Fourier-transform infrared spectroscopy (FTIR), X-ray powder diffraction (XRD), differential scanning calorimetry (DSC), thermogravimetric (TG) analysis, water contact angle, water retention, enzymatic degradation, and cytotoxicity assays. The effects that adjustments on the ultrasonic time have on the surface morphology, structures, thermal properties, hydrophilicity, water-uptake, bio-enzyme degradability, mechanical properties, and cytocompatibility of the material were examined. It was discovered that as the sonication time increased from 0 to 180 min, the beading phenomenon disappeared, forming nanofibers with uniform diameter and porosity; while the content of β-sheet crystals in the composites and their thermal stability gradually increased, the materials glass transition temperature decreased, and preferred mechanical properties were obtained. Additional studies show that the hydrophilicity, water retention capacity and enzymatic degradation rate were also enhanced by ultrasound, providing a favorable environment for cell attachment and proliferation. This study highlights the experimental and theoretical methods for ultrasound assisted air-jet spinning of biopolymer nanofibrous materials with tunable properties and high biocompatibility, which provide a wide range of applications in wound dressings and drug-carrying systems. This work shows great potential for a direct road to sustainable development of protein based fibers in the industry, thus promoting economic growth, and improving the health of the general population and well-being of wounded patients worldwide.

Tunable Aryl Alkyl Ionic Liquid Supported Synthesis of Platinum Nanoparticles and Their Catalytic Activity in the Hydrogen Evolution Reaction and in Hydrosilylation

Tunable aryl alkyl ionic liquids (TAAILs) are ionic liquids (ILs) with a 1-aryl-3-alkylimidazolium cation having differently substituted aryl groups. Herein, nine TAAILs with the bis(trifluoromethylsulfonyl)imide anion are utilized in combination with and without ethylene glycol (EG) as reaction media for the rapid microwave synthesis of platinum nanoparticles (Pt-NPs). TAAILs allow the synthesis of small NPs and are efficient solvents for microwave absorption. Transmission electron microscopy (TEM) shows that small primary NPs with sizes of 2 nm to 5 nm are obtained in TAAILs and EG/TAAIL mixtures. The Pt-NPs feature excellent activity as electrocatalysts in the hydrogen evolution reaction (HER) under acidic conditions, with an overpotential at a current density of 10 mA cm^-2 as low as 32 mV vs the reversible hydrogen electrode (RHE), which is significantly lower than the standard Pt/C 20% with 42 mV. Pt-NPs obtained in TAAILs also achieved quantitative conversion in the hydrosilylation reaction of phenylacetylene with triethylsilane after just 5 min at 200 °C.

Sweet, Sugar-Coated Hierarchical Platinum Nanostructures for Easy Support, Heterogenization and Separation

Metal nanoparticles are increasingly gaining interest in the field of heterogeneous catalysis. Here, we present a novel strategy for synthesizing sugar-coated platinum nanostructures (SC-Pt-NS) from the carbohydrates sucrose and D(-)-fructose. In the synthesis from a mixture of H2PtCl6·6H2O, the carbohydrate in an ionic liquid (IL) yielded primary particles of a homogeneous average size of ~10 nm, which were aggregated to hierarchical Pt nanostructures of ~40–65 nm and surrounded or supported by the carbohydrate. These sugar-coated platinum nanostructures present a facile way to support and heterogenize nanoparticles, avoid leaching and enable easier separation and handling. The catalytic activity of the SC-Pt-NS was shown in the hydrosilylation test reaction of phenylacetylene with triethylsilane, where very high turnover frequency (TOF) values of up to 87,200 h−1 could be achieved, while the platinum metal leaching into the product was very low.

Pharmaceutical applications of starch nanoparticles: A scoping review

Starch nanoparticles (SNPs) have been applied to different areas of material sciences, especially in pharmaceuticals due to their characteristics such as small particle size, high surface ratio-volume, and biological compatibility. However, in pharmaceutical sciences, there are no records of a scoping review that had extensively mapped all available information about SNPs. A scoping review was performed here by searching electronic databases (Pubmed and Science Direct) to identify studies published previous to June 2020. From 699 total records, 37 matched the criteria for inclusion. The findings showed that SNPs have been used, not only for the development of different active pharmaceutical ingredient delivery systems, but also as an enzyme inhibitor, adsorption, and DNA precipitation agent. In conclusion, by combining different starch sources and methods SNPs show a remarkable diversity in pharmaceutical applications. Future studies should explore SNPs safety and provide information about variables that may affect important properties for this kind of application.

Polyurethane-functionalized starch nanocrystals as anti-tuberculosis drug carrier

Studies related to loading ability and delivery of clinically used first-line anti-tuberculosis drugs (ATDs) such as isoniazid, rifampicin, pyrazinamide and streptomycin on the surface of starch-derived bulk and nanopolyurethanes (SBPUs and SNPUs) as drug delivery systems (DDS) have been focused to minimise or remove the drug-associated adverse effects. The efficiencies of nanopolyurethanes obtained from the differently substituted cyclic aliphatic and aromatic isocyanates have been studied for drug loading and release purposes. Different advanced instrumental techniques analysed the structural and morphological properties, thermal stability and crystallinity of the starch nanopolyurethans. Average particle sizes ranging from 27.35–42.38 nm to 126.89–218.60 nm for starch nanopolyurethans, SNPU3i and SNPU4i, respectively, were determined by high-resolution transmission electron microscopy. Similarly, the loading efficiency of ATDs to the surfaces of SNPUs and SBPUs was observed in the range of 60–97% while ATDs-loaded SNPUs showed a sustainable release profile for all ATDs except for streptomycin. However, most SBPUs provided burst-release for all the above-mentioned ATDs in pH-dependent studies. The anti-tuberculosis assay against the Mycobacterium tuberculosis H37Rv strain revealed that streptomycin-loaded SNPU4i and isoniazid-loaded SNPU7i are approximately 42 and 7 times more active than the native streptomycin and isoniazid, respectively.