If you are experiencing problems downloading PDF or HTML fulltext, our helpdesk recommend clearing your browser cache and trying again. If you need help in clearing your cache, please click here . Still need help? Email help@ingentaconnect.com

Fluorescence Microspectroscopy Technique for the Study of Intracellular Protoporphyrin IX Dynamics

$29.00 plus tax (Refund Policy)

Buy Article:

Abstract:

We describe a technique designed to monitor the fluorescence dynamics of photosensitizers used in photodynamic therapy (PDT) at micrometer-scale locations within individual formalin-fixed cells. The accumulation of protoporphyrin IX (PpIX) within keratinocytes and fibroblasts, following incubation with 5-aminolaevulinic acid (ALA), is shown to be dependent upon both incubation time and cell proliferation status. Also, the process of photobleaching within these cells is demonstrated via the depletion in PpIX fluorescence emission during exposure to 532 nm light. All spectra show a progressive reduction of the 634 nm PpIX peak, following a biexponential decay that is consistent with a singlet oxygen mediated process. The rate of photobleaching, when plotted as a function of light dose, increases with reduced incident laser power. The generation of the hydroxyaldehyde-chlorin photoproduct (photoprotoporphyrin), as monitored by the increase in fluorescence emission centered on 672 nm, is also greatest when the lowest laser power is applied. When light is delivered in two fractions, PpIX fluorescence recovers during the dark period and there is an increase in bleaching rate at the onset of the second exposure. These results are qualitatively consistent with measurements performed in vivo, which demonstrate that the photodynamic dose is dependent upon fluence rate and oxygen status.

Keywords: PDT; PHOTOBLEACHING; PHOTODYNAMIC THERAPY; PROTOPORPHYRIN IX

Document Type: Research Article

DOI: http://dx.doi.org/10.1366/000370203322005382

Publication date: June 1, 2003

More about this publication?
Related content

Tools

Favourites

Share Content

Access Key

Free Content
Free content
New Content
New content
Open Access Content
Open access content
Subscribed Content
Subscribed content
Free Trial Content
Free trial content
Cookie Policy
X
Cookie Policy
ingentaconnect website makes use of cookies so as to keep track of data that you have filled in. I am Happy with this Find out more