Capillary electrokinetic chromatography for studying interactions between ß-blockers and Intralipid emulsion.

Toxicity of ß-blockers is one of the most common causes of poison-induced cardiogenic shock throughout the world. Therefore, methodologies for in vivo removal of the drugs from the body have been under investigation. Intralipid emulsion (ILE) is a common commercial lipid emulsion used for parenteral nutrition, but it has also been administered to patients suffering from drug toxicities. In this work, a set of ß-blockers of different hydrophobicity's (log KD values ranging from 0.16 to 3.8) were investigated. The relative strength of the interactions between these compounds and the ILE was quantitatively assessed by means of binding constants and adsorption constants of the formed ß-blocker-ILE complexes. The binding constants were determined by capillary electrokinetic chromatography and the adsorption constants were calculated based on different adsorption isotherms. Expectedly, the binding constants were strongly related to the log KD values of the ß-blockers. The binding and adsorption constants also show that less hydrophobic ß-blockers interact with ILE, suggesting that this emulsion could be useful for capturing such compounds in cases of their overdoses. Thus, the use of ILE for treatment of toxicities caused by a larger range of ß-blockers is worth further investigation.

Nonspecific enzymatic hydrolysis of a highly ordered chitopolysaccharide substrate.

Chitin and chitosan can undergo nonspecific enzymatic hydrolysis by several different hydrolases. This susceptibility to nonspecific enzymes opens up many opportunities for producing chitooligosaccharides and low molecular weight chitopolysaccharides, since specific chitinases and chitosanases are rare and not commercially available. In this study, chitosan and chitin were hydrolyzed using several commercially available hydrolases. Among them, cellulases with the highest specific activity demonstrated the best activity, as indicated by the rapid decrease in viscosity of a chitosan solution. The hydrolysis of chitosan by nonspecific enzymes generated a sugar release that corresponded to the decrease in the degree of polymerization. This decrease reached a maximum of 3.3-fold upon hydrolysis of 10% of the sample. Cellulases were better than lysozyme or amylases at hydrolyzing chitosan and chitin. Analysis of 13C CP-MAS NMR and FTIR spectra of chitin after cellulase treatment revealed changes in the chitin crystal structure related to rearrangement of inter- and intramolecular H-bonds. The structural changes and decreases in crystallinity allowed dissolution of chitin molecules of high molecular weight and enhanced the solubility of chitin in alkali by 10-12% compared to untreated chitin.

The conformation of bovine serum albumin adsorbed to the surface of single all-dielectric nanoparticles following light-induced heating.

Interaction between nanoparticles and biomolecules leads to the formation of biocompatible or bioadverse complexes. Despite the rapid development of nanotechnologies for biology and medicine, relatively little is known about the structure of such complexes. Here, we report on the changes in conformation of a blood protein (bovine serum albumin) adsorbed on the surface of single all-dielectric nanoparticles (silicon and germanium) following light-induced heating to 640 K. This protein is considerably more resistant to heat when adsorbed on the nanoparticle than when in solution or in the solid state. Intriguingly, with germanium nanoparticles this heat resistance is more pronounced than with silicon. These observations will facilitate biocompatible usage of all-dielectric nanoparticles.