RESUMEN

Three bacterial glycogen branching enzymes (GBEs) having different branching characteristics were used to produce clustered amylopectin (CAP), and structure and functional properties of CAPs were intensively analyzed. Branch distributions of three CAPs varied from very short (DPn = 6.65) to medium (DPn = 14.1). Branch distribution showed profound correlation with hydrodynamic diameter, water solubility, digestibility, and effects on mice gut-microbiota. All the CAPs showed nearly no viscosity and retrogradation. The very short-branch CAP exhibited more than 100-fold water-solubility, 3.5-fold lower α-amylase catalytic efficiency, and 27% lower digestibility in small intestine-mimicking condition than amylopectin. Intriguingly, medium branch CAP had 1.8-fold larger hydrodynamic diameter than the very short one. Mice gut-microbiota composition statistically varied after 12-day feeding of the CAPs, but only the medium chain CAP brought clear positive changes on the gut-microbiota. Consequently, slowly digestible starch was successfully synthesized by the single GBE, but the CAP structure affects in vivo functions in complicated manner.

Asunto(s)

Enzima Ramificadora de 1,4-alfa-Glucano/metabolismo , Amilopectina/química , Amilopectina/metabolismo , Amilopectina/farmacología , Animales , Microbioma Gastrointestinal/efectos de los fármacos , Hidrodinámica , Hidrólisis , Masculino , Ratones , Ratones Endogámicos C57BL , Solubilidad , Viscosidad

RESUMEN

Polydimethyl-siloxane (PDMS) is often applied to fabricate cell chips. In this study, we fabricated an adipocyte microcell pattern chips using PDMS to analyze the inhibition activity of lipid droplets in mouse embryo fibroblast cells (3T3-L1) with anti-obesity agents. To form the PDMS based micropattern, we applied the micro-contact printing technique using PDMS micro-stamps that had been fabricated by conventional soft lithography. This PDMS micro-pattern enabled the selective growth of 3T3-L1 cells onto the specific region by preventing cell adhesion on the PDMS region. It then allowed growth of the 3T3-L1 cells in the chip for 10 days and confirmed that lipid droplets were formed in the 3T3-L1 cells. After treatment of orlistat and quercetin were treated in an adipocyte micro-cell pattern chip with 3T3-L1 cells for six days, we found that orlistat and quercetin exhibited fat inhibition capacities of 19.3% and 24.4% from 0.2 µM of lipid droplets in 3T3-L1 cells. In addition, we conducted a direct quantitative analysis of 3T3-L1 cell differentiation using Oil Red O staining. In conclusion, PDMS-based adipocyte micro-cell pattern chips may contribute to the development of novel bioactive compounds.

Asunto(s)

Adipocitos/efectos de los fármacos , Dispositivos Laboratorio en un Chip , Gotas Lipídicas/efectos de los fármacos , Células 3T3 , Animales , Fármacos Antiobesidad/farmacología , Dimetilpolisiloxanos/química , Gotas Lipídicas/metabolismo , Ratones , Orlistat/farmacología , Quercetina/farmacología

RESUMEN

This study demonstrates the possibility of controlling the directed self-assembly of microsized Janus cylinders by changing the solvent polarity of the assembly media. Experimental results are analyzed and theoretical calculations of the free energy of adhesion (ΔGad) are performed to elucidate the underlying basic principles and investigate the effects of the solvent on the self-assembled structures. This approach will pave a predictive route for controlling the structures of assembly depending on the solvent polarity. In particular, we find that a binary solvent system with precisely controlled polarity induces directional assembly of the microsized Janus cylinders. Thus, the formation of two-dimensional (2D) and three-dimensional (3D) assembled clusters can be reliably tuned by controlling the numbers of constituent Janus cylinders in a binary solvent system. Finally, this approach is expanded to stepwise assembly, which forms unique microstructures via secondary growth of primary seed clusters formed by the Janus cylinders. We envision that this investigation is highly promising for the construction of desired superstructures using a wide variety of polymeric Janus microparticles with chemical and physical multicompartments.

RESUMEN

Directed self-assembly can produce ordered or organized superstructures from pre-existing building blocks through pre-programmed interactions. Encoding desired information into building blocks with specific directionality and strength, however, poses a significant challenge for the development of self-assembled superstructures. Here, we demonstrate that controlling the shape and patchiness of particles trapped at the air-water interface can represent a powerful approach for forming ordered macroscopic complex structures through capillary interactions. We designed hexagram particles using a micromolding method that allowed for precise control over the shape and, more importantly, the chemical patchiness of the particles. The assembly behaviors of these hexagram particles at the air-water interface were strongly affected by chemical patchiness. In particular, two-dimensional millimeter-scale ordered structures could be formed by varying the patchiness of the hexagram particles, and we attribute this effect to the delicate balance between the attractive and repulsive interactions among the patchy hexagram particles. Our results provide important clues for encoding information into patchy particles to achieve macroscopic assemblies via a simple molding technique and potentially pave a new pathway for the programmable assembly of particles at the air-water interface.