Fluorescence detection and photodynamic activity of endogenous protoporphyrin in human skin

Koenig, Karsten; Rueck, Angelika C.; Schneckenburger, Herbert

doi:10.1117/12.57700

Cited by 40 publications

(18 citation statements)

References 8 publications

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“…Porphyrins Erythrocytes 400/650-670 nm (König et al, 1992;Schneckenburger et al, 1993;Ricchelli, 1995). 800/590 nm (König, 2000a;Mathai et al, 2007).…”

Section: Flavoproteinmentioning

confidence: 99%

Two‐photon microscopy of deep intravital tissues and its merits in clinical research

Wang

König

2010

Journal of Microscopy

178

131

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SummaryMultiphoton excitation laser scanning microscopy, relying on the simultaneous absorption of two or more photons by a molecule, is one of the most exciting recent developments in biomedical imaging. Thanks to its superior imaging capability of deeper tissue penetration and efficient light detection, this system becomes more and more an inspiring tool for intravital bulk tissue imaging. Two-photon excitation microscopy including 2-photon fluorescence and second harmonic generated signal microscopy is the most common multiphoton microscopic application. In the present review we take diverse ocular tissues as intravital samples to demonstrate the advantages of this approach. Experiments with registration of intracellular 2-photon fluorescence and extracellular collagen second harmonic generated signal microscopy in native ocular tissues are focused. Data show that the in-tandem combination of 2-photon fluorescence and second harmonic generated signal microscopy as two-modality microscopy allows for in situ co-localization imaging of various microstructural components in the whole-mount deep intravital tissues. New applications and recent developments of this high technology in clinical studies such as 2-photon-controlled drug release, in vivo drug screening and administration in skin and kidney, as well as its uses in tumourous tissues such as melanoma and glioma, in diseased lung, brain and heart are additionally reviewed. Intrinsic emission two-modal 2-photon microscopy/tomography, acting as an efficient and sensitive non-injurious imaging approach featured by high contrast and subcellular spatial resolution, has been proved to be a promising tool for intravital deep tissue imaging and clinical studies. Given the level of its performance, we believe Correspondence to B.-G. Wang. Tel: +49 3641 938496; fax: +49 3641 938552; e-mail: Baogui.Wang@mti.uni-jena.de that the non-linear optical imaging technique has tremendous potentials to find more applications in biomedical fundamental and clinical research in the near future.

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“…Porphyrins Erythrocytes 400/650-670 nm (König et al, 1992;Schneckenburger et al, 1993;Ricchelli, 1995). 800/590 nm (König, 2000a;Mathai et al, 2007).…”

Section: Flavoproteinmentioning

confidence: 99%

Two‐photon microscopy of deep intravital tissues and its merits in clinical research

Wang

König

2010

Journal of Microscopy

178

131

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“…We carried out fluorescence imaging and spectral analysis of different skin areas (face, back) of 30 test patients with and without acne vulgaris [65]. For that purpose we used the in vivo fluorescence spectrometer depicted in Fig.…”

Section: In Vivo Detection Of Bacteria In Human Skinmentioning

confidence: 99%

Laser-induced autofluorescence for medical diagnosis

1994

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The naturally occurring autofluorescence of cells and tissues is based on biomolecules containing intrinsic fluorophores, such as porphyrins, the amino acids tryptophan and tyrosine, and the coenzymes NADH, NADPH, and flavins. Coenzymes fluoresce in the blue/green spectral region (fluorecence lifetimes: 0.5-6 ns) and are highly sensitive indicators of metabolic function. Steadystate and time-resolved blue-green autofluorescence is, therefore, an appropriate measure of the function of the respiratory chain as well as of cellular and tissue damage. Autofluorescence in the yellow/red spectral region is based mainly on endogenous porphyrins and metalloporphyrins, such as coproporphyrin, protoporphyrin (fluorescence lifetime of porphyrin monomers: >10 ns), and Zn-protoporphyrin (2 ns). Various pathological microorganisms such asPropionibacterium acnes, Pseudomonas aeruginosa, Actinomyces odontolyticus, Bacteroides intermedius, andSaccharomyces cerevisiae are able to synthesize large amounts of these fluorophores and can therefore be located. This permits fluorescence-based detection of a variety of diseases, including early-stage dental caries, dental plaque, acne vulgaris, otitis externa, and squamous cell carcinoma. The sensitivity of noninvasive autofluorescence diagnostics can be enhanced by time-gated fluorescence measurements using an appropriate time delay between ultrashort laser excitation and detection. For example, videocameras with ultrafast shutters, in the nanosecond region, can be used to create "caries images" of the teeth. Alternatively, autofluorescence can be enhanced by stimulating protoporphyrin biosynthesis with the exogenously administered porphyrin precursor 5-aminolevulinic acid (ALA). The fluorophore protoporphyrin IX (PP IX) is photolabile and photodynamically active. Irradiation of PP IX-containing tissue results in cytotoxic reactions which correlate with modifications in fluorescence due to photobleaching and singlet oxygen-dependent photoproduct formation. Therefore, on-line autofluorescence measurements during the phototreatment can yield information on the efficiency of ALA-based photodynamic therapy.

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“…P.acnes makes porphyrins, which are present in the follicle, in proportion to its population. Once the porphyrin is exposed to visible light, it becomes chemically active and transfers to an excited state, resulting in the formation of singlet oxygen, which combines with cell membranes to destroy the P. acnes [1,2,10]. This process is depended on the rate of production of excited porphyrin molecules, which is influenced by the concentration of porphyrins, the concentration of photons, the temperature and the wavelength of photons [8].…”

Section: Figurementioning

confidence: 99%