Encapsulation of gold nanoparticles with PHB based on coffee ring effect

The hydrodynamic process of ring formation has been utilized to encapsulate gold nanoparticles in the matrix of PHB using an ink jet printing technique. The coffee ring phenomenon on the polymer substrate was elucidated by geometrical evaluation, mathematical formulations and FESEM images.

Recent advances in chloroplast and mitochondrial division

Stomatin, originally identified as a major protein of the human erythrocyte membrane, is widely expressed in various tissues. Orthologues are found in vertebrates, invertebrates, plants, and microorganisms. Related proteins exhibit a common core structure, termed the prohibitin (PHB) domain, with varying extensions. Stomatin has an unusual topology, similar to caveolin-1, with a hydrophobic domain embedded at the cytoplasmic side of the membrane. Additional anchoring is provided by palmitoylation and the membrane affinity of the PHB domain. Stomatin associates with cholesterol-rich microdomains (lipid rafts), forms oligomers, and thereby displays a scaffolding function by generating large protein-lipid complexes. It regulates the activity of various membrane proteins by reversibly recruiting them to lipid rafts. This mechanism of regulation has been shown for GLUT-1 and may also apply for ion channels. Stomatin is located at the plasma membrane, particularly in microvilli, in endocytic and exocytic vesicles, and cytoplasmic granules. Stomatin-carrying endosomes are highly dynamic and interact with lipid droplets suggesting a role in intracellular lipid transport. This subcellular distribution and the caveolin-like protein structure suggest important membrane organizing functions for stomatin. A general picture emerges now that cell membranes contain cholesterol-rich domains that are generated and regulated by scaffolding proteins like caveolins, stomatins, and flotillin/reggie proteins.

Transesterification induced mechanical properties enhancement of PLLA/PHBV bio-alloy

In order to improve the miscibility and mechanical properties of poly(l-lactic acid) (PLLA) and poly(3-hydroxybutyrate-co-3-hydroxyvalerate) (PHBV) bio-alloy, small amount of transesterification catalyst, zinc acetate was added in the melt blending process. We show that the PLLA-PHBV copolymer generated during the melt blending significantly improves the miscibility and therefore enhances the mechanical properties of the product. Dynamic mechanical analysis (DMA), scanning electron microscopy (SEM), and tensile tests were performed to study the miscibility and mechanical properties of the blends. Fourier transform infrared spectroscopy (FTIR) and gel permeation chromatography (GPC) were used to reveal the molecular structural, and molecular weight changes of PLLA and PHBV after melt mixing with zinc acetate. SEM and FTIR results have clearly shown that the PLLA-PHBV copolymer generated from transesterification reaction acted as a compatibilizer and therefore resulted in an improved interfacial miscibility and ductility of PLLA/PHBV blend. In our mechanistic study, a competition between the PLLA/PHBV transesterification reaction and the thermal decomposition of PHBV was identified for the first time. On the basis of these observations, a new mechanism of transesterification reaction was proposed.