Development of ZnO Nanoflake Type Structures Using Silk Fibres as Template for Water Pollutants Remediation.

We have fabricated ZnO nanoflake structures using degummed silk fibers as templates, via soaking and calcining the silk fibers bearing ZnO nanoparticles at 150 °C for 6 h. The obtained ZnO nanostructures were characterized using scanning electron microscopy (SEM), X-ray diffraction analysis (XRD), and UV-vis and fluorescence spectroscopic analysis. The size (~500-700 nm) in length and thicknesses (~60 nm) of ZnO nanoflakes were produced. The catalysis performances of ZnO nanoflakes on silk fibers (ZnSk) via photo-degradation of naphthalene (93% in 256 min), as well as Rose Bengal dye removal (~1.7 mM g-1) through adsorption from aqueous solution, were practically observed. Further, ZnSk displayed superb antibacterial activity against the tested model gram-negative Escherichia coli bacterium. The produced ZnSk has huge scope to be used for real-world water contaminants remediation applications.

Mixed Phytochemicals Mediated Synthesis of Multifunctional Ag-Au-Pd Nanoparticles for Glucose Oxidation and Antimicrobial Applications.

The growing awareness toward the environment is increasing commercial demand for nanoparticles by green route syntheses. In this study, alloy-like Ag-Au-Pd trimetallic nanoparticles have been prepared by two plants extracts Aegle marmelos leaf (LE) and Syzygium aromaticum bud extracts (CE). Compositionally different Ag-Au-Pd nanoparticles with an atomic ratio of 5.26:2.16:1.0 (by LE) and 11.36:13.14:1.0 (by LE + CE) of Ag:Au:Pd were easily synthesized within 10 min at ambient conditions by changing the composition of phytochemicals. The average diameters of the nanoparticles by LE and LE + CE are ∼8 and ∼11 nm. The catalytic activity of the trimetallic nanoparticles was studied, and they were found to be efficient catalysts for the glucose oxidation process. The prepared nanoparticles also exhibited efficient antibacterial activity against a model Gram-negative bacteria Escherichia coli. The catalytic and antimicrobial properties of these readymade trimetallic nanoparticles have high possibility to be utilized in diverse fields of applications such as health care to environmental.

A Force to Be Reckoned With: A Review of Synthetic Microswimmers Powered by Ultrasound.

Synthetic microswimmers are a class of artificial nano- or microscale particle capable of converting external energy into motion. They are similar to natural microswimmers such as bacteria in behavior and are, therefore, of great interest to the study of active matter. Additionally, microswimmers show promise in applications ranging from bioanalytics and environmental monitoring to particle separation and drug delivery. However, since their sizes are on the nano-/microscale and their speeds are in the µm s(-1) range, they fall into a low Reynolds number regime where viscosity dominates. Therefore, new propulsion schemes are needed for these microswimmers to be able to efficiently move. Furthermore, many of the hotly pursued applications call for innovations in the next phase of development of biocompatible microswimmers. In this review, the latest developments of microswimmers powered by ultrasound are presented. Ultrasound, especially at MHz frequencies, does little harm to biological samples and provides an advantageous and well-controlled means to efficiently power microswimmers. By critically reviewing the recent progress in this research field, an introduction of how ultrasound propels colloidal particles into autonomous motion is presented, as well as how this propulsion can be used to achieve preliminary but promising applications.

Solubilization of naphthalene in the presence of plant-synthetic mixed surfactant systems.

Solubilization efficiencies of naphthalene by micellar solution of a plant-based surfactant extracted from fruit of Sapindus mukorossi (reetha) and the synthetic surfactants like nonionic (Triton X-100 or TX-100), cationic (cetyltrimethylammonium bromide or CTAB), and anionic (sodium dodecylbenzenesulfonate or SDBS; dioctyl sodium sulfosuccinate or AOT; sodium octanesulfonate or SOS) in their single and as well as binary mixed (plant-synthetic) systems were measured and compared. The solubilization efficiency of single surfactants shows that reetha is less effective than TX-100, similar to SDBS, and more than AOT and SOS. The mixed surfactant systems show negative deviation in molar solubilization ratio (MSR) from ideality. The ascending order of percent change in MSR (Delta(MSR)) is TX-100-reetha < CTAB-reetha < SDBS-reetha < AOT-reetha < SOS-reetha. The mixed micellar solution for a particular combination also shows that Delta(MSR) is more negative when the interaction parameter for the mixed micelle (beta) is more negative. The results of this study may be useful for the applications of natural or natural-synthetic mixed surfactants in surfactant-enhanced remediation or detergency.