Fluorescence dynamics of ALA-induced PpIX in normal and malignant skin cells

Caroline D. Sudworth; Mark R Stringer; Janet E Cruse-Sawyer; Stanley B Brown

doi:10.1117/12.500636

16 October 2003 Fluorescence dynamics of ALA-induced PpIX in normal and malignant skin cells

Caroline D. Sudworth, Mark R Stringer, Janet E Cruse-Sawyer, Stanley B Brown

Proceedings Volume 5142, Therapeutic Laser Applications and Laser-Tissue Interactions; (2003) https://doi.org/10.1117/12.500636
Event: European Conferences on Biomedical Optics 2003, 2003, Munich, Germany

Abstract

We have applied a spectroscopic system capable of monitoring the fluorescence dynamics of photosensitiser at micron-scale locations within individual cells. This report shows that the accumulation of protoporphyrin IX (PpIX) within the nucleus of formalin-fixed keratinocytes, fibroblasts, and a metastatic squamous carcinoma cell line, following incubation with 5-aminolaevulinic acid (ALA), is dependent upon both incubation time and cell proliferation status. We demonstrate that the process of photobleaching can be monitored via the depletion in PpIX fluorescence emission during exposure to 532 nm laser light. All spectra show a progressive reduction of the 634 nm PpIX peak - following a bi-exponential decay which 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, as monitored by the increase in fluorescence emission centred on 672 nm, is also greatest when the lowest laser power is applied. When light is delivered in two fractions, there is evidence of PpIX fluorescence recovery during the dark period, and an increase in bleaching rate at the onset of the second exposure. These results are in qualitative agreement with measurements performed in vivo which demonstrate that the photodynamic dose is dependent upon fluence-rate and oxygen status.

Citation Download Citation

Caroline D. Sudworth, Mark R Stringer, Janet E Cruse-Sawyer, and Stanley B Brown "Fluorescence dynamics of ALA-induced PpIX in normal and malignant skin cells", Proc. SPIE 5142, Therapeutic Laser Applications and Laser-Tissue Interactions, (16 October 2003); https://doi.org/10.1117/12.500636

ACCESS THE FULL ARTICLE

INSTITUTIONAL
Select your institution to access the SPIE Digital Library.

SELECT YOUR INSTITUTION

PERSONAL
Sign in with your SPIE account to access your personal subscriptions or to use specific features such as save to my library, sign up for alerts, save searches, etc.

PERSONAL SIGN IN

No SPIE Account? Create one

PURCHASE THIS CONTENT

SUBSCRIBE TO DIGITAL LIBRARY

50 downloads per 1-year subscription

Members: $195

Non-members: $335 ADD TO CART

25 downloads per 1 - year subscription

Members: $145

Non-members: $250 ADD TO CART

PURCHASE SINGLE ARTICLE

Includes PDF, HTML & Video, when available

Members: $17.00

Non-members: $21.00 ADD TO CART

PROCEEDINGS
12 PAGES

DOWNLOAD PAPER SAVE TO MY LIBRARY

GET CITATION

RIGHTS & PERMISSIONS

Get copyright permission Get copyright permission on Copyright Marketplace

KEYWORDS

Luminescence

Oxygen

Photodynamic therapy

Skin

In vivo imaging

In vitro testing

Microscopes

Show All Keywords

Keywords/Phrases

Search In:

Publication Years