Document Detail


An improved strip FRAP method for estimating diffusion coefficients: correcting for the degree of photobleaching.
MedLine Citation:
PMID:  20579262     Owner:  NLM     Status:  MEDLINE    
Abstract/OtherAbstract:
Fluorescence recovery after photobleaching is a widely established method for the estimation of diffusion coefficients, strip bleaching with an associated recovery curve analysis being one of the simplest techniques. However, its implementation requires near 100% bleaching in the region of interest with negligible fluorescence loss outside, both constraints being hard to achieve concomitantly for fast diffusing molecules. We demonstrate that when these requirements are not met there is an error in the estimation of the diffusion coefficient D, either an under- or overestimation depending on which assumption is violated the most. We propose a simple modification to the recovery curve analysis incorporating the concept of the relative bleached mass m giving a revised recovery time parametrization tau=m(2)w(2)/4piD for a strip of width w. This modified model removes the requirement of 100% bleaching in the region of interest and allows for limited diffusion of the fluorophore during bleaching. We validate our method by estimating the (volume) diffusion coefficient of FITC-labelled IgG in 60% glycerol solution, D= 4.09 +/- 0.21 microm(2) s(-1), and the (surface) diffusion coefficient of a green-fluorescent protein-tagged class I MHC protein expressed at the surface of a human B cell line, D= 0.32 +/- 0.03 microm(2) s(-1) for a population of cells.
Authors:
J Yang; K Köhler; D M Davis; N J Burroughs
Publication Detail:
Type:  Journal Article; Research Support, Non-U.S. Gov't    
Journal Detail:
Title:  Journal of microscopy     Volume:  238     ISSN:  1365-2818     ISO Abbreviation:  J Microsc     Publication Date:  2010 Jun 
Date Detail:
Created Date:  2010-06-28     Completed Date:  2010-09-23     Revised Date:  -    
Medline Journal Info:
Nlm Unique ID:  0204522     Medline TA:  J Microsc     Country:  England    
Other Details:
Languages:  eng     Pagination:  240-53     Citation Subset:  IM    
Affiliation:
Qingdao Institute of Bioenergy and Bioprocess Technology, Chinese Academy of Sciences, Qingdao, China.
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MeSH Terms
Descriptor/Qualifier:
Cell Line
Cell Membrane / chemistry*
Diffusion*
Green Fluorescent Proteins / analysis,  genetics
HLA-C Antigens / analysis*,  genetics
Humans
Microscopy, Fluorescence / methods*
Models, Theoretical
Photobleaching
Recombinant Fusion Proteins / analysis,  genetics
Grant Support
ID/Acronym/Agency:
BB/D011663/1//Biotechnology and Biological Sciences Research Council; GO500563//Medical Research Council; GR/S29256/01//Biotechnology and Biological Sciences Research Council
Chemical
Reg. No./Substance:
0/HLA-C Antigens; 0/HLA-Cw6; 0/Recombinant Fusion Proteins; 147336-22-9/Green Fluorescent Proteins

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


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