Mild sonication

Artificial membrane systems can be prepared by appropriate techniques. These systems generally consist of mixtures of one or more phospholipids of natural or synthetic origin that can be treated (eg, by using mild sonication) to form spherical vesicles in which the lipids form a bilayer. Such vesicles, surrounded by a lipid bilayer, are termed liposomes. 

Vesicles composed of DOPE/16, or DOPC/16 in either a 2/1 or 3/1 molar ratio were prepared by a variety of methods, including mild sonication of... 

A number of factors for DOTAP-cholesterol/DNA complex preparation including the DNA/liposome ratio, mild sonication, heating, and extrusion were found to be crucial for improved systemic delivery maximal gene expression was obtained when a homogeneous population of DNA/liposome complexes (200-450 nm) was used. Cryoelectron microscopy showed that the DNA was condensed on the interior of liposomes between two lipid bilayers in these formulations, a factor that was thought to be responsible for the high transfection efficiency in vivo and for the broad tissue distribution (150). 

Electron Microscopy. A JEOL 100 CX electron microscope, operated at 100 kV, was used throughout this work. To prepare thin specimens, fibers immersed in water were repeatedly peeled into small fragments with the aid of sharp needles. The fibrillar fragments were then directly picked up on carbon coated grids. In some cases, the suspension was mildly sonicated to aid in dispersal of the fragments. 

Raw nanotubes having a mean diameter of 1.41 nm containing about 30 wt% metal catalysts, such as Ni and Co, were purified by oxidation with acidic KMn04 solution and then washed with HCl and water. The purified tubes were dried at 100°C and dispersed in DMSO by mild sonication. 

Formation of stable, unilamellar vesicles for phospholipids 1-3 was produced with mild sonication at 50 °C for 1 h and was optimized for unilamellar vesicle formation at a pH of 9.3. A clean, almost translucent dispersion was easily obtained under the previously described conditions 23), Monitoring the dispersion using UV-vis at 400 nm for turbidity resulted in an... 

Shear the DNA by a mild-sonication step (five pulses of 5 s at 10% intensity) see Note 7)... 

Jackson and co-workers (1988) used mild sonication conditions (20 s at 55 °C) to disrupt swollen starch granules. This treatment increased the solubility of starch in water without extensive depolymerization and allowed starch samples to be characterized by HPLC-SEC without the use of DMSO or alkaline aqueous solvent systems. Sonication for longer than 80s substantially altered the HPLC-SEC profile. 

Water-soluble poly(diallyl-dimethylammonium chloride) (PDDA)/MWNTs aggregates have been also obtained by mild sonication [78]. In these composites, it has been suggested that the interaction between PDDA and MWNTs is not electrostatic in nature but, instead, the presence of unsaturated impurities in the PDDA chain drives tr-tt interactions. Thus, NTs coated with PDDA function as positively charged polyelectrolytes that exhibit electrostatic repulsion between NTs/PDDA, thereby guaranteeing the NTs hydrophUicity. 

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