Document Detail


Optical method for monitoring the concentration of general anesthetics and other small organic molecules. An example of phase transition sensing.
MedLine Citation:
PMID:  2096736     Owner:  NLM     Status:  MEDLINE    
Abstract/OtherAbstract:
As an example of chemical sensing based on perturbations of thermal phase transitions, we have shown that phospholipids labeled with a fluorescent dye may be used to measure the concentration of general anesthetics and other small organic molecules. The emission maximum of the hydrophobic fluorescent probe Laurdan in phospholipid bilayers shifts from a wavelength of 445 nm below the main phase transition of the lipid to 480 nm above it, with an isosbestic point at approximately 475 nm. The greatest changes in intensity at the transition occur at 440 and 500 nm, so the ratio of the intensities at these two points was used as an "order parameter". The effects of variation of the liposomal preparation method on the order parameter were explored, and it was found that in mixed lipids the parameter varied nearly linearly over the physiological temperature range. Fluorometry detected changes in the order of bilayers caused by solubilization of the anesthetic isoflurane (Forane) and of ethanol. At a defined temperature, the intensity ratio measured in the presence of anesthetic decreases in a concentration-dependent manner. Immobilizing the liposomes in a hydrogel did not perturb the response of the system. This work demonstrates the potential for using lipid phase transitions in an optical sensor for monitoring anesthetics and other small nonpolar molecules.
Authors:
S Merlo; P Yager
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Publication Detail:
Type:  Journal Article; Research Support, Non-U.S. Gov't; Research Support, U.S. Gov't, P.H.S.    
Journal Detail:
Title:  Analytical chemistry     Volume:  62     ISSN:  0003-2700     ISO Abbreviation:  Anal. Chem.     Publication Date:  1990 Dec 
Date Detail:
Created Date:  1991-07-17     Completed Date:  1991-07-17     Revised Date:  2007-11-14    
Medline Journal Info:
Nlm Unique ID:  0370536     Medline TA:  Anal Chem     Country:  UNITED STATES    
Other Details:
Languages:  eng     Pagination:  2728-35     Citation Subset:  IM    
Affiliation:
Center for Bioengineering, University of Washington, Seattle 98195.
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MeSH Terms
Descriptor/Qualifier:
Anesthetics / analysis*
Liposomes / analysis
Phospholipids / analysis
Spectrometry, Fluorescence
Spectrophotometry, Ultraviolet
Grant Support
ID/Acronym/Agency:
RR-07096/RR/NCRR NIH HHS
Chemical
Reg. No./Substance:
0/Anesthetics; 0/Liposomes; 0/Phospholipids

From MEDLINE®/PubMed®, a database of the U.S. National Library of Medicine


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