Indocyanine green: Intracellular uptake and phototherapeutic effects in vitro

Fickweiler, Sonja; Szeimies, Rolf‐Markus; Bäumler, Wolfgang; Steinbach, Pia; Karrer, Sigrid; Goetz, Alwin E.; Abels, Christoph; Hofstädter, Ferdinand

doi:10.1016/s1011-1344(96)07453-2

Cited by 161 publications

(127 citation statements)

References 16 publications

Supporting

Mentioning

121

Contrasting

Unclassified

Order By: Relevance

“…Irradiation with a low energy density (30 J cm -2 ) significantly decreased the cell viability. Other experiments in vitro using different sensitizers and a different setup, yielded a similar cell toxicity (Ma et al, 1994;Jori, 1996;Rossi et al, 1996;Fickweiler et al, 1997). However, ICG concentrations up to 500 µM did not exhibit a dark toxicity.…”

Section: Discussionmentioning

confidence: 63%

See 1 more Smart Citation

Photo-oxidative killing of human colonic cancer cells using indocyanine green and infrared light

et al. 1999

View full text Add to dashboard Cite

Summary Despite of the approval of Photofrin® in various countries, chemically defined sensitizers for photodynamic therapy (PDT) are still needed for the absorption of light in the infrared spectrum, which provides a maximal penetration of light into tissue. Therefore, both the efficacy and the mechanism of action of the clinically approved dye indocyanine green (ICG) and laser irradiation were investigated in vitro. For the investigation of phototoxic effects, HT-29 cells were incubated 24 h prior to irradiation by using different concentrations of ICG (10-500 µM). In each experiment, cells were irradiated using a continuous wave (cw)-diode laser (λ ex = 805 nm, 30 J cm -2 , 40 mW cm -2 ). After laser irradiation, cell viability of dark control and of cells incubated with 500 µM ICG was 1.27 ± 0.11 or 0.28 ± 0.05 respectively. Using 100 µM ICG and D 2 O, cell viability was further decreased from 0.46 ± 0.03 (H 2 O) to 0.11 ± 0.01 (D 2 O). Using D 2 O and 100 µM ICG, the concentration of malondialdehyde, a marker of lipid peroxidation, increased from 0.89 ± 0.10 nmol 10 -6 cells to 11.14 ± 0.11 nmol 10 -6 cells. Using 100 µM ICG and laser irradiation sodium azide or histidine (50 mM), quenchers of singlet oxygen reduced the cell killing significantly. In contrast, when using mannitol, a quencher of superoxide anion and hydroxyl radical, cell killing was not inhibited. According to the present results, photoactivated ICG seems to kill colonic cancer cells due to the generation of singlet oxygen and the subsequent formation of lipid peroxides. Therefore, ICG might present a promising photosensitizer for PDT; first clinical results confirm these findings.

show abstract

Section: Discussionmentioning

confidence: 63%

“…First, in vitro experiments using ICG and normal keratinocytes (Fickweiler et al, 1997) showed phototoxic effects. However, the mechanism of action -photo-oxidative versus photothermal cell killing -remained unclear and was investigated again using carcinoma cells (colon cancer, HT-29).…”

mentioning

confidence: 99%

Photo-oxidative killing of human colonic cancer cells using indocyanine green and infrared light

et al. 1999

View full text Add to dashboard Cite

show abstract

“…The uptake of cell-bound Photofrin, after three washing steps, was estimated by spectroscopic analysis (49). Suspensions of S. aureus or E. coli were incubated in the dark for 90 min with 50, 100, 200, 400, and 800 g/ml Photofrin at 37°C, centrifuged (200 ϫ g, 10 min), and then washed triply with PBS.…”

Section: Methodsmentioning

confidence: 99%

The role of singlet oxygen and oxygen concentration in photodynamic inactivation of bacteria

Maisch¹,

Baier²,

Franz³

et al. 2007

Proc. Natl. Acad. Sci. U.S.A.

Self Cite

375

289

View full text Add to dashboard Cite

New antibacterial strategies are required in view of the increasing resistance of bacteria to antibiotics. One promising technique involves the photodynamic inactivation of bacteria. Upon exposure to light, a photosensitizer in bacteria can generate singlet oxygen, which oxidizes proteins or lipids, leading to bacteria death. To elucidate the oxidative processes that occur during killing of bacteria, Staphylococcus aureus was incubated with a standard photosensitizer, and the generation and decay of singlet oxygen was detected directly by its luminescence at 1,270 nm. At low bacterial concentrations, the time-resolved luminescence of singlet oxygen showed a decay time of 6 ؎ 2 s, which is an intermediate time for singlet oxygen decay in phospholipids of membranes (14 ؎ 2 s) and in the surrounding water (3.5 ؎ 0.5 s). Obviously, at low bacterial concentrations, singlet oxygen had sufficient access to water outside of S. aureus by diffusion. Thus, singlet oxygen seems to be generated in the outer cell wall areas or in adjacent cytoplasmic membranes of S. aureus. In addition, the detection of singlet oxygen luminescence can be used as a sensor of intracellular oxygen concentration. When singlet oxygen luminescence was measured at higher bacterial concentrations, the decay time increased significantly, up to Ϸ40 s, because of oxygen depletion at these concentrations. This observation is an important indicator that oxygen supply is a crucial factor in the efficacy of photodynamic inactivation of bacteria, and will be of particular significance should this approach be used against multiresistant bacteria.luminescence ͉ oxygen depletion ͉ Staphylococcus aureus

show abstract

“…As no significant differences in the uptake of the three PS-nanogels by macrophages were observed, these results are compatible with the known hierarchy of intrinsic photodynamic efficiencies of the three photosensitizers. It has to be noted that light doses of 1-15 J/cm 2 and up to 48 J/cm 2 are generally used in most photodynamic therapy protocols [33,34,[40][41][42][43].…”

Section: Discussionmentioning

confidence: 99%

Chitosan-based nanogels for selective delivery of photosensitizers to macrophages and improved retention in and therapy of articular joints

Schmitt

Lagopoulos

Käuper³

et al. 2010

Journal of Controlled Release

111

View full text Add to dashboard Cite

Macrophages play key roles in inflammatory disorders. Therefore, they are targets of treatments aiming at their local destruction in inflammation sites. However, injection of low molecular mass therapeutics, including photosensitizers, in inflamed joints results in their rapid efflux out of the joints, and poor therapeutic index. To improve selective uptake and increase retention of therapeutics in inflamed tissues, hydrophilic nanogels based on chitosan, of which surface was decorated with hyaluronate and which were loaded with one of three different anionic photosensitizers were developed. Optimal uptake of these functionalized nanogels by murine RAW 264.7 or human THP-1 macrophages as models was achieved after b 4 h incubation, whereas only negligible uptake by murine fibroblasts used as control cells was observed. The uptake by cells and the intracellular localization of the photosensitizers, of the fluorescein-tagged chitosan and of the rhodamine-tagged hyaluronate were confirmed by fluorescence microscopy. Photodynamic experiments revealed good cell photocytotoxicity of the photosensitizers entrapped in the nanogels. In a mouse model of rheumatoid arthritis, injection of free photosensitizers resulted in their rapid clearance from the joints, while nanogel-encapsulated photosensitizers were retained in the inflamed joints over a longer period of time. The photodynamic treatment of the inflamed joints resulted in a reduction of inflammation comparable to a standard corticoid treatment. Thus, hyaluronate-chitosan nanogels encapsulating therapeutic agents are promising materials for the targeted delivery to macrophages and long-term retention of therapeutics in leaky inflamed articular joints.

show abstract

Indocyanine green: Intracellular uptake and phototherapeutic effects in vitro

Cited by 161 publications

References 16 publications

Photo-oxidative killing of human colonic cancer cells using indocyanine green and infrared light

Photo-oxidative killing of human colonic cancer cells using indocyanine green and infrared light

The role of singlet oxygen and oxygen concentration in photodynamic inactivation of bacteria

Chitosan-based nanogels for selective delivery of photosensitizers to macrophages and improved retention in and therapy of articular joints

Contact Info

Product

Resources

About