Microbubbles methods

Ishikawa H, Shimoda M, Tamaya K, Yonekura A, Kawano T, Osajima Y. Inactiviation of Bacillus spores by the supercritical carbon dioxide microbubble method. Biosci Biotechnol Biochem 1997 61 1022-1023. 

In addition to acoustical methods, which take advantage of the fact that gas nuclei (i.e., stable microbubbles) are elastic bodies and thus absorb sound energy (ref. 4,5,9,25,26,31,32,50), another class of methods for detecting these gas microbubbles that has been employed repeatedly is based on their optical behavior. Specifically, most of these optical methods involve detection of these long-lived microbubbles in water from the light scattered by them (ref. 5,26,59,60,127). 

Subsequent experimental work in this laboratory was aimed at the systematic development of an efficient method for isolating the proteinaceous surfactants, which help stabilize natural microbubbles, from both commercial agarose powder and from forest soil samples collected locally. Successful isolation of this glycopeptide fraction was eventually achieved (ref. 322), and the results obtained from an extended program of chemical analysis, to further characterize and compare chemically these proteinaceous surfactants from both natural substances, are described below. 

The isolation of the microbubble surfactant mixture from forest soil has been described in detail in preceding chapters. Quantitative examination of the surface properties of mono-molecular films of the isolated microbubble surfactant complex, at an air/water interface, were carried out using a modified Langmuir trough apparatus incorporating the surface tension method of Padday et al. (ref. 380). 

J.S. D Arrigo, Method for the production of medical-grade lipid-coated microbubbles, paramagnetic labeling of such microbubbles and therapeutic uses of microbubbles, United States Patent No. 5,215,680 (issued 1993). 

The delivery of macromolecules into the central nervous system (CNS) via the blood stream is seriously limited by the blood-brain barrier (BBB). Noninvasive, transient, and local image-guided blood-brain barrier disruption (BBBD) can be accomplished using focused ultrasound exposure with intravascular injection of pre-formed microbubbles. A detailed description of the method for MRI-guided focal BBBD in animals will be described in this chapter. The method may open a new era in CNS macromolecular drug delivery. 

Alternatively, protein particles can be produced using a supercritical or near critical C02-assisted aero-solization and bubble drying process. This method utilizes the high solubility of CO2 in water, coupled with expansion of the solution through a nozzle to aerosolize aqueous solutions of drugs. When the microbubbles formed are dried, solid (such as lactose and albuterol sulfate, with size between 0.5 pm and... 

For the extraction of hydrocarbons in carbonate minerals and microbubbles, the method widely used is acid treatment under vacuum, for which most laboratories in China use the apparatus shown in Fig. 6-5. The soil sample is heated to 40"C in the flask, then 1 6 HCl is added until its reaction with the warm sample ceases. The mixture of gases evolved is filtered through NaOH solution to remove COt (which makes up the bulk of the evolved gases) and the remaining gases are injected into a gas chromatograph. 

A selective method to flush out microbubbles is hydrogen stripping. This was first proposed by Schaefer et al. (1978) and has been developed by Ruan and Cheng (1991). Soil samples are kept in a natural wet state and an aliquot of saturated NaCI solution is added to make a slurry, through which Hi is passed. The gases stripped from the sample are condensed in a liquid N2 cold trap, which is then used as the gas sample loop in the carrier gas line to a gas chromatograph (Fig. 6-6). 

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