Fabrication of Needle-Like Silicon Nanowires by Using a Nanoparticles-Assisted Bosch Process for Both High Hydrophobicity and Anti-Reflection

In this work, a modified Bosch etching process is developed to create silicon nanowires. Au nanoparticles (NPs) formed by magnetron sputtering film deposition and thermal annealing were employed as the hard mask to achieve controllable density and high aspect ratios. Such silicon nanowire exhibits the excellent anti-reflection ability of a reflectance value of below 2% within a broad light wave range between 220 and 1100 nm. In addition, Au NPs-induced surface plasmons significantly enhance the near-unity anti-reflection characteristics, achieving a reflectance below 3% within the wavelength range of 220 to 2600 nm. Furthermore, the nanowire array exhibits super-hydrophobic behavior with a contact angle over ~165.6° without enforcing any hydrophobic chemical treatment. Such behavior yields in water droplets bouncing off the surface many times. These properties render this silicon nanowire attractive for applications such as photothermal, photocatalysis, supercapacitor, and microfluidics.

Bioremediation of PAH-Contaminated Soils: Process Enhancement through Composting/Compost

Bioremediation of contaminated soils has gained increasing interest in recent years as a low-cost and environmentally friendly technology to clean soils polluted with anthropogenic contaminants. However, some organic pollutants in soil have a low biodegradability or are not bioavailable, which hampers the use of bioremediation for their removal. This is the case of polycyclic aromatic hydrocarbons (PAHs), which normally are stable and hydrophobic chemical structures. In this review, several approaches for the decontamination of PAH-polluted soil are presented and discussed in detail. The use of compost as biostimulation- and bioaugmentation-coupled technologies are described in detail, and some parameters, such as the stability of compost, deserve special attention to obtain better results. Composting as an ex situ technology, with the use of some specific products like surfactants, is also discussed. In summary, the use of compost and composting are promising technologies (in all the approaches presented) for the bioremediation of PAH-contaminated soils.

Multicompartmental Mesoporous Silica/Polymer Nanostructured Hybrids: Design Capabilities by Integrating Linear and Star-Shaped Block Copolymers

Poly(2-vinyl pyridine)-b-poly(ethylene oxide) (P2VP-b-PEO) linear diblock copolymer and polystyrene–poly(ethylene oxide) (PS10PEO10) heteroarm star copolymer were used as building elements to prepare organic–inorganic hybrids. By using the layer-by-layer (LbL) methodology, these elements were integrated on mesoporous silica through non-covalent interactions, namely, ionic and H-bonding. For the latter, tannic acid (TA) was used as an intermediate layer. The deposition of the various layers was monitored by thermogravimetric analysis (TGA), electrophoretic measurements, and confocal microscopy. The final silica hybrid, bearing alternating P2VP-b-PEO and PS10PEO10 star layers was capable of carrying one hydrophilic and two hydrophobic chemical species in distinct compartments. These multicompartmental organic–inorganic hybrids could be used as nanostructured carriers for pH-responsive multiple drug delivery and potential theranostic applications.

Development of a Multi-Compartment Micro-Cell Culture Device as a Future On-Chip Human: Fabrication of a Three-Compartment Device and Immobilization of Mature Rat Adipocytes for the Evaluation of Chemical Distributions

Absorption, distribution, metabolism and excretion (ADME) are important in estimating the influence of chemicals on health. Distribution among internal organs is difficult to estimate without animal experiments. In vitro development targets the perfusion culturing of multiple cells derived from organs such as the liver, stomach, small intestines, and kidney. Using cheep, easily molded polydimethylsiloxane (PDMS), we produced a cell-culture microdevice having three compartments to determine the kinetic distribution of hydrophobic chemicals imaged by fluorescent imaging based on the presence of mature rat adipocytes. The disposable device uses liquid feeding using a magnetic stirrer. Separate and complete perfusion modes are easily changed by a valve after nurturing organ-derived cells in the device under separate conditions, enabling kinetic evaluation. To stabilize, disperse, and fix mature adipocytes whose specific gravity is lower than the culture solution, nonwoven fabric is used as a three-dimensional scaffold. When fluoranthene, a fluorescent hydrophobic chemical, is added during perfusion culturing, fluoranthene selectively accumulates in a fat compartment after six hours in a device to which adipocytes are added, enabling in vitro determination of hydrophobic chemical accumulation determining the distribution of chemicals in adipocytes. By introducing cells of target organs and metabolic organs in to other compartments, the device is extremely effective in experimentally determining the ADME of chemicals and the development of toxicity in vitro.