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A novel bi-layered multiphasic scaffold (BLS) have been fabricated for the first time by combining melt mixing, compression molding and particulate leaching. One layer has been composed by polylactic acid (PLA) presenting pore size in the range of 90–110 µm while the other layer has been made of polycaprolactone (PCL) with pores ranging from 5 to 40 µm. The different chemo-physical properties of the two biopolymers combined with the tunable pore architecture permitted to realize monolithic functionally graded scaffolds engineered to be potentially used for interface tissues regenerations. BLS have been characterized from a morphological and a mechanical point of view. In particular, mechanical tests have been carried out both in air and immersing the specimens in phosphate buffered saline (PBS) solution at 37 °C, in order to evaluate the elastic modulus and the interlayer adhesion strength. Fibroblasts and osteoblasts have been cultured and co-cultured in order to investigate the cells permeation trough the different layers. The results indicate that the presented method is appropriate for the preparation of multiphasic porous scaffolds with tunable morphological and mechanical characteristics. Furthermore, the cells seeded were found to grow with a different trend trough the different layers thus demonstrating that the presented device has good potential to be used in interface tissue regeneration applications. [ABSTRACT FROM AUTHOR]

Interface tissue engineering (ITE) is used to repair or regenerate interface living tissue such as for instance bone and cartilage. This kind of tissues present natural different properties from a biological and mechanical point of view. With the aim to imitating the natural gradient occurring in the bone–cartilage tissue, several technologies and methods have been proposed over recent years in order to develop polymeric functionally graded scaffolds (FGS). In this study three-layered scaffolds with a pore size gradient were developed by melt mixing polylactic acid (PLA) and two water-soluble porogen agents: sodium chloride (NaCl) and polyethylene glycol (PEG). Pore dimensions were controlled by NaCl granulometry while PEG solvation created a micropores network within the devices. Scaffolds were characterized from a morphological and mechanical point of view in order to find a correlation between the preparation method, the pore architecture and compressive mechanical behavior. Biological tests were also performed in order to study the effect of pore size gradient on the permeation of different cell lines in co-culture. To imitate the physiological work condition, compressive tests were also performed in phosphate buffered saline (PBS) solution at 37 °C. The presented preparation method permitted to prepare three-layered scaffolds with high control of porosity and pore size distribution. Furthermore mechanical behaviors were found to be strongly affected by pore architecture of tested devices as well as the permeation of osteoblast and fibroblast in-vitro . [ABSTRACT FROM AUTHOR]

The solidification of microstructure of hypereutectic Al-20%Si alloy obtained by mixing high-temperature Al-30%Si alloy melt and low-temperature Al-10%Si alloy melt in a mixing ratio of 1 : 1 was investigated by optical microscopy. A certain amount of AlTi5BRE10 inter alloy was added into high-temperature Al-30%Si alloy melt before mixing. The results showed that the primary Si crystals were refined and passivated by the melt mixing process and a certain amount of AlTi5BRE10 inter alloy further refined the primary silicon and α-Al phase. The coarse plates, petals and irregular triangular-shaped primary Si crystals turned into fine block shapes, and the α-Al phases were spherical. After the melt mixing treatment, the microstructure of the hypereutectic Al-20%Si alloy was composed of a primary α-Al phase, eutectic (α + Si) phase, and the primary silicon, which caused the hypereutectic Al-20%Si alloy to exhibit typical hypoeutectic and hypereutectic characteristics. [ABSTRACT FROM AUTHOR]

To improve the properties of dynamically cross-linked olefinic thermoplastic elastomer (TPV), we prepared composites of TPV and liquid crystal polymer (LCP) under melt mixing. The composites had good damping properties. In the case of the composites without any compatibilizer, LCP particles were dispersed in volumes the size of several dozen micrometers in the composites. However, in the case of the composites prepared by the addition of polypropylene modified with maleic anhydride as a compatibilizer, LCP particles were dispersed in volumes the size of several micrometers in the composites. The tensile strength and stress of the composites were increased with increasing the content of LCP. In the case of the composites which were injection-molded, LCP particles were dispersed in filaments in the composites and were oriented along the machine direction. In this case, the composites had an unisotropy and showed high tensile strength and modulus in the machine direction. The damping properties of the composites were increased with increasing the content of LCP. [ABSTRACT FROM AUTHOR]

This section presents abstracts of articles included in the volume 62, number 5 issue of the Kobunshi Ronbunshu (Japanese Journal of Polymer Science and Technology), including Extraction of Protein From Human Nails and Preparation of Nail Protein Films by Toshihiro Fujii.