Investigations on photolon-and porphyrin-doped sol-gel fiberoptic coatings for laser-assisted applications in medicine

Autor: Uwe Bindig, Halina Podbielska, Gerhard Müller, Marta Kopaczyńska, A. Ulatowska-Jarża
Rok vydání: 2008
Předmět:
Zdroj: Laser Physics. 18:63-72
ISSN: 1555-6611
1054-660X
DOI: 10.1134/s1054660x08010118
Popis: In view of laser-assisted medical applications, the construction of silica-based sol-gel fiberoptic sensors based on photolon (Ph) and protoporphyrin IX (PP IX) is discussed. Electron microscopy and AFM were used to characterize the silica sol-gel coatings. AFM measurements indicate a change in the surface porosity. The PP IX-based sensors were constructed as a one-layer optode as well as a multilayered structure. An additional hybrid sensor made up of alternate layers of PP IX-and Ph-doped sol-gel was also constructed and examined. Sol-gel matrices were prepared from silicate precursor tetraethylorthosilicate (TEOS) mixed with ethanol in acid-catalyzed hydrolysis. The carrier matrices of photosensitive dyes were produced with factor R = 20, where R denotes the ratio of solvent moles (ethanol) to the number of TEOS moles. A multilayered coating was built up using the reverse-dipping technique. The overall coating thickness was determined by electron microscopy. Doped sol-gels with different PP IX concentrations were used to produce fiberoptic coatings. The film optodes with a different number of layers were examined by fluorescence spectroscopy. It was found that photolon and protoporphyrin IX entrapped in sol-gel preserve their chemical reactivity and have contact with the external environment. The hybrid sensor demonstrated clear fluorescence and a reversible behavior in gaseous environments.
Databáze: OpenAIRE
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