The effect of multi-walled carbon nanotubes (MWCNT) coating in the presence of polyethyleneimine (PEI) of different molecular weights (MW) on the interfacial shear strength (IFSS) of carbon fiber/acrylonitrile–butadiene–styrene (ABS) and carbon fiber/epoxy composites was investigated. The IFSS between the carbon fiber and the polymer was evaluated by means of single fiber microbonding test. The results indicated that uses of the carbon fibers uncoated and coated with pristine, low MW PEI-treated, and high MW PEI-treated MWCNT significantly influenced the IFSS of both thermoplastic and thermosetting carbon fiber composites as well as the carbon fiber surface topography. The incorporation of low MW (about 1300) PEI into the carboxylated MWCNT was more effective not only to uniformly coat the carbon fiber with the MWCNT but also to improve the interfacial bonding strength between the carbon fiber and the polymer than that of high MW (about 25,000) PEI. In addition, carbon fiber/epoxy composite exhibited the IFSS much higher than carbon fiber/ABS composite due to the chemical interactions between the epoxy resin and amine groups existing in the PEI-treated MWCNT.

This study investigated the immune-enhancing effects of polysaccharides extracted from Gloiopeltis furcata (red seaweed) with different molecular weights. A crude polysaccharide mixture was hydrolyzed using acid treatment (0.1 N HCl) and three molecular weight fractions were generated and filtered using centrifugation: (≤10 kDa, 10 to 100 kDa, and 100 kDa. Nitric oxide (NO) production in RAW264.7 cells treated with 0.01-0.5 μg/mL polysaccharides ≥100 kDa was 12.28-19.05 μM. Treatment with polysaccharides ≥100 kDa increased cytokine levels, including TNF-α and IL-6 levels, in a dose-dependent manner. Polymerase chain reaction analysis also revealed marked increases in iNOS and COX-2 mRNA expression levels. These findings lead us to conclude that macrophage activation induced by polysaccharides ≥100 kDa was greater than that induced by polysaccharides ≤10 kDa or between 10 and 100 kDa. The polysaccharides ≥100 kDa extracted from Gloiopeltis furcata investigated herein are potentially useful as natural immune-enhancing agents. These findings provided further insights into the potential use of ≥100 kDa as immunopotentiator or new function food.

In this study, the physicochemical properties and anti-wrinkle effect of polysaccharides with different molecular weights from Gloiopeltis furcata were investigated. Crude polysaccharides were isolated by viscozyme treatment followed by ethanol precipitation and lyophilization. Crude polysaccharides were hydrolyzed by acid (0.1 N HCl) and the molecular weight fractions were generated by centrifugal filter (<10 kDa, 10 to 100 kDa, and 100 kDa>). The yield of polysaccharides with different molecular weight fractions was 8.4-39.6%. The major constituents in molecular weight fractions were total sugar (81.37-85.82%), uronic acid (27.89-32.85 g/100 g), sulfate (33.38-39.04%), and protein (0.35-3.16%) The L, a, and b value of the 100 kDa group were decreased, but viscosity increased. The oxygen radical absorbance capacity of the 100 kDa group at 180.07 μM was the highest among groups. The protective effects of 100 kDa group at 0.5 and 5 μg/mL against H2O2-induced cytotoxicity in L132 cell were 87.34% and 103.85%, respectively. The matrix metalloproteinase-1 activity of 100 kDa group decreased in a dose-dependent manner. The pro-collagen synthesis activity of 100 kDa group at 0.05-0.5 μg/mL was 64.91-77.80%. The polysaccharides with different molecular weights from Gloiopeltis furcata investigated herein are useful as a potential candidate for cosmedical materials.