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Proceedings Paper

Fluorescence lifetime imaging of oxygen in dental biofilm
Author(s): Hans C. Gerritsen; Cees J. de Grauw
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Paper Abstract

Dental biofilm consists of micro-colonies of bacteria embedded in a matrix of polysaccharides and salivary proteins. pH and oxygen concentration are of great importance in dental biofilm. Both can be measured using fluorescence techniques. The imaging of dental biofilm is complicated by the thickness of the biofilms that can be up to several hundred micrometers thick. Here, we employed a combination of two-photon excitation microscopy with fluorescence lifetime imaging to quantify the oxygen concentration in dental biofilm. Collisional quenching of fluorescent probes by molecular oxygen leads to a reduction of the fluorescence lifetime of the probe. We employed this mechanism to measure the oxygen concentration distribution in dental biofilm by means of fluorescence lifetime imaging. Here, TRIS Ruthenium chloride hydrate was used as an oxygen probe. A calibration procedure on buffers was use to measure the lifetime response of this Ruthenium probe. The results are in agreement with the Stern-Volmer equation. A linear relation was found between the ratio of the unquenched and the quenched lifetime and the oxygen concentration. The biofilm fluorescence lifetime imaging results show a strong oxygen gradient at the buffer - biofilm interface and the average oxygen concentration in the biofilm amounted to 50 μM.

Paper Details

Date Published: 18 December 2000
PDF: 9 pages
Proc. SPIE 4164, Laser Microscopy, (18 December 2000); doi: 10.1117/12.410635
Show Author Affiliations
Hans C. Gerritsen, Utrecht Univ. (Netherlands)
Cees J. de Grauw, Utrecht Univ. (Netherlands)


Published in SPIE Proceedings Vol. 4164:
Laser Microscopy
Karsten Koenig; Hans J. Tanke; Herbert Schneckenburger, Editor(s)

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