help button home button Biophys. J.
HOME HELP FEEDBACK SUBSCRIPTIONS ARCHIVE SEARCH TABLE OF CONTENTS

Biophysical Journal 60: 1128-1131 (1991)
© 1991 the Biophysical Society

This Article
Right arrow Full Text (PDF)
Right arrow Alert me when this article is cited
Right arrow Alert me if a correction is posted
Services
Right arrow Similar articles in this journal
Right arrow Alert me to new issues of the journal
Right arrow Download to citation manager
Right arrow reprints & permissions
Citing Articles
Right arrow Citing Articles via Google Scholar
Google Scholar
Right arrow Articles by Bjarneson, D. W.
Right arrow Articles by Petersen, N. O.
Right arrow Search for Related Content
PubMed
Right arrow Articles by Bjarneson, D. W.
Right arrow Articles by Petersen, N. O.

Effects of second order photobleaching on recovered diffusion parameters from fluorescence photobleaching recovery

D. W. Bjarneson and N. O. Petersen

Department of Chemistry, The University of Western Ontario, London, Ontario, N6A 5B7, Canada

ABSTRACT

In the original theoretical development of fluorescence photobleaching recovery with circular or Gaussian laser intensity profiles (Axelrod et al., 1976, Biophys. J.) the bleaching process is assumed to obey first order kinetics in the fluorescent probe. While this is reasonable in most cases where oxygen participates in the photolysis reaction, some processes may obey second order kinetics in the fluorophore concentration due to dimerization. Accordingly, we present here an analysis of the fluorescence recovery when the photobleaching process is taken to be second order in the probe. Analytical solutions for small bleaching levels indicate that the fluorescence recovery curve is very similar to that measured following a bleaching process first order in the probe. Numerical solutions for moderate bleaching levels show that the recovery is qualitatively similar, but quantitatively different. Because the shape of the recovery curve provides no evidence as to the order of photobleaching, we recommend continued use of the previous theoretical analysis. However, it must be borne in mind that the diffusion coefficient is increasingly underestimated as the extent of photobleaching is increased. The true diffusion coefficient is obtained in the limit of small levels of photobleaching. Estimates of the fractional recovery are not affected by this approach.






HOME HELP FEEDBACK SUBSCRIPTIONS ARCHIVE SEARCH TABLE OF CONTENTS
Copyright © 1991 by the Biophysical Society.