Limits...
Monitoring photosensitizer uptake using two photon fluorescence lifetime imaging microscopy.

Yeh SC, Diamond KR, Patterson MS, Nie Z, Hayward JE, Fang Q - Theranostics (2012)

Bottom Line: Fluorescence emission in PDT may be used to monitor the uptake process but fluorescence intensity is subject to variability due to scattering and absorption; the addition of fluorescence lifetime may be beneficial to probe site-specific drug-molecular interactions and cell damage.The fluorescence decays were analyzed using a bi-exponential model, followed by segmentation analysis of lifetime parameters.When Photofrin(®) was localized at the cell membrane, the slow lifetime component was found to be significantly shorter (4.3 ± 0.5 ns) compared to those at other locations (cytoplasm: 7.3 ± 0.3 ns; mitochondria: 7.0 ± 0.2 ns, p < 0.05).

View Article: PubMed Central - PubMed

Affiliation: 1. School of Biomedical Engineering, McMaster University, 1280 Main Street West, Hamilton, Ontario, L8S 4K1, Canada;

ABSTRACT
Photodynamic Therapy (PDT) provides an opportunity for treatment of various invasive tumors by the use of a cancer targeting photosensitizing agent and light of specific wavelengths. However, real-time monitoring of drug localization is desirable because the induction of the phototoxic effect relies on interplay between the dosage of localized drug and light. Fluorescence emission in PDT may be used to monitor the uptake process but fluorescence intensity is subject to variability due to scattering and absorption; the addition of fluorescence lifetime may be beneficial to probe site-specific drug-molecular interactions and cell damage. We investigated the fluorescence lifetime changes of Photofrin(®) at various intracellular components in the Mat-LyLu (MLL) cell line. The fluorescence decays were analyzed using a bi-exponential model, followed by segmentation analysis of lifetime parameters. When Photofrin(®) was localized at the cell membrane, the slow lifetime component was found to be significantly shorter (4.3 ± 0.5 ns) compared to those at other locations (cytoplasm: 7.3 ± 0.3 ns; mitochondria: 7.0 ± 0.2 ns, p < 0.05).

No MeSH data available.


Related in: MedlinePlus

Distribution of τ1 as a function of different incubation times. All values of τ1 are less than 1.0 ns and at 0.5 ± 0.1 ns when Photofrin® localized at the mitochondrial region.
© Copyright Policy
Related In: Results  -  Collection


getmorefigures.php?uid=PMC3475212&req=5

Figure 5: Distribution of τ1 as a function of different incubation times. All values of τ1 are less than 1.0 ns and at 0.5 ± 0.1 ns when Photofrin® localized at the mitochondrial region.

Mentions: The time-lapse τ1 (short lifetime component) of Photofrin® was plotted in Figure 5. It should be noted that all values of τ1 are less than 1.0 ns and mostly at 0.5 ± 0.1 ns when Photofrin® localized at the mitochondrial region. Although τ1 was found to be significantly shorter when comparing data at 1 hour and 3 hours of incubation (p < 0.01), it was also observed that the lifetime values in the cytoplasm group fluctuated more than other groups. The relatively small variations of short lifetime components over incubation time suggested that τ1 may not be a good option for monitoring cellular uptake of Photofrin®.


Monitoring photosensitizer uptake using two photon fluorescence lifetime imaging microscopy.

Yeh SC, Diamond KR, Patterson MS, Nie Z, Hayward JE, Fang Q - Theranostics (2012)

Distribution of τ1 as a function of different incubation times. All values of τ1 are less than 1.0 ns and at 0.5 ± 0.1 ns when Photofrin® localized at the mitochondrial region.
© Copyright Policy
Related In: Results  -  Collection

Show All Figures
getmorefigures.php?uid=PMC3475212&req=5

Figure 5: Distribution of τ1 as a function of different incubation times. All values of τ1 are less than 1.0 ns and at 0.5 ± 0.1 ns when Photofrin® localized at the mitochondrial region.
Mentions: The time-lapse τ1 (short lifetime component) of Photofrin® was plotted in Figure 5. It should be noted that all values of τ1 are less than 1.0 ns and mostly at 0.5 ± 0.1 ns when Photofrin® localized at the mitochondrial region. Although τ1 was found to be significantly shorter when comparing data at 1 hour and 3 hours of incubation (p < 0.01), it was also observed that the lifetime values in the cytoplasm group fluctuated more than other groups. The relatively small variations of short lifetime components over incubation time suggested that τ1 may not be a good option for monitoring cellular uptake of Photofrin®.

Bottom Line: Fluorescence emission in PDT may be used to monitor the uptake process but fluorescence intensity is subject to variability due to scattering and absorption; the addition of fluorescence lifetime may be beneficial to probe site-specific drug-molecular interactions and cell damage.The fluorescence decays were analyzed using a bi-exponential model, followed by segmentation analysis of lifetime parameters.When Photofrin(®) was localized at the cell membrane, the slow lifetime component was found to be significantly shorter (4.3 ± 0.5 ns) compared to those at other locations (cytoplasm: 7.3 ± 0.3 ns; mitochondria: 7.0 ± 0.2 ns, p < 0.05).

View Article: PubMed Central - PubMed

Affiliation: 1. School of Biomedical Engineering, McMaster University, 1280 Main Street West, Hamilton, Ontario, L8S 4K1, Canada;

ABSTRACT
Photodynamic Therapy (PDT) provides an opportunity for treatment of various invasive tumors by the use of a cancer targeting photosensitizing agent and light of specific wavelengths. However, real-time monitoring of drug localization is desirable because the induction of the phototoxic effect relies on interplay between the dosage of localized drug and light. Fluorescence emission in PDT may be used to monitor the uptake process but fluorescence intensity is subject to variability due to scattering and absorption; the addition of fluorescence lifetime may be beneficial to probe site-specific drug-molecular interactions and cell damage. We investigated the fluorescence lifetime changes of Photofrin(®) at various intracellular components in the Mat-LyLu (MLL) cell line. The fluorescence decays were analyzed using a bi-exponential model, followed by segmentation analysis of lifetime parameters. When Photofrin(®) was localized at the cell membrane, the slow lifetime component was found to be significantly shorter (4.3 ± 0.5 ns) compared to those at other locations (cytoplasm: 7.3 ± 0.3 ns; mitochondria: 7.0 ± 0.2 ns, p < 0.05).

No MeSH data available.


Related in: MedlinePlus