&lt;title&gt;Photophysical properties of pheophorbide-a in different carrier-systems&lt;/title&gt;

Roeder, Beate; Hackbarth, St.; Korth, Olaf; Herter, Ralf; Hanke, Thomas; Hoehne, W.

doi:10.1117/12.230959

Cited by 7 publications

(6 citation statements)

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“…The calculated fluorescence lifetimes range between 6.5 and 6.9 ns using a single exponential to fit the data (Figure 4d and Table 2). These findings are also consistent with the Φ f value of Pyro reported by other authors (Φ f = 0.3 and in methanol) [16]. These results emphasize that the coupling of Pyro to the peptides and the grafting of the PP-PS conjugate to the AuNRs did not alter the fluorescence emission properties of Pyro.…”

Section: Photophysical Propertiessupporting

confidence: 93%

“…This issue leads to the aggregation of the PSs that, consequently, suppresses their photophysical properties especially the production of 1 O 2 [4,5,14,15]. To overcome this burden, and taking into account that it is hard to create a free PS with high selectivity, various nanoparticle (NP)-based carrier systems were developed [16][17][18][19][20]. These can facilitate the transportation of the dye and deliver the latter specifically to the targeted neoplastic cells due to their small size and especially their favored buildup in tumors thanks to the enhanced permeation and retention effect (EPR) [21].…”

Section: Introductionmentioning

confidence: 99%

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New Targeted Gold Nanorods for the Treatment of Glioblastoma by Photodynamic Therapy

Youssef

Yesmurzayeva

Larue

et al. 2019

JCM

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This study describes the employment of gold nanorods (AuNRs), known for their good reputation in hyperthermia-based cancer therapy, in a hybrid combination of photosensitizers (PS) and peptides (PP). We report here, the design and the synthesis of this nanosystem and its application as a vehicle for the selective drug delivery and the efficient photodynamic therapy (PDT). AuNRs were functionalized by polyethylene glycol, phototoxic pyropheophorbide-a (Pyro) PS, and a "KDKPPR" peptide moiety to target neuropilin-1 receptor (NRP-1). The physicochemical characteristics of AuNRs, the synthesized peptide and the intermediate PP-PS conjugates were investigated. The photophysical properties of the hybrid AuNRs revealed that upon conjugation, the AuNRs acquired the characteristic properties of Pyro concerning the extension of the absorption profile and the capability to fluoresce (Φ f = 0.3) and emit singlet oxygen (Φ ∆ = 0.4) when excited at 412 nm. Even after being conjugated onto the surface of the AuNRs, the molecular affinity of "KDKPPR" for NRP-1 was preserved. Under irradiation at 652 nm, in vitro assays were conducted on glioblastoma U87 cells incubated with different PS concentrations of free Pyro, intermediate PP-PS conjugate and hybrid AuNRs. The AuNRs showed no cytotoxicity in the absence of light even at high PS concentrations. However, they efficiently decreased the cell viability by 67% under light exposure. This nanosystem possesses good efficiency in PDT and an expected potential effect in a combined photodynamic/photothermal therapy guided by NIR fluorescence imaging of the tumors due to the presence of both the hyperthermic agent, AuNRs, and the fluorescent active phototoxic PS.

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Section: Photophysical Propertiessupporting

confidence: 93%

Section: Introductionmentioning

confidence: 99%

New Targeted Gold Nanorods for the Treatment of Glioblastoma by Photodynamic Therapy

Youssef

Yesmurzayeva

Larue

et al. 2019

JCM

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“…It is well known that both temperature and polarity of the surrounding solvent lead to changes in the photophysical properties of tetrapyrroles [1][2][3][4], i.e. ground state absorption, emission and lifetime of electronic excited states.…”

Section: Introductionmentioning

confidence: 99%

Observation of the phase transition in phospholipid liposomes taking advantage of the particular optical properties of octa-α-butyloxy-H₂phthalocyanines

Zeug

Paul

Röder

2001

J. Porphyrins Phthalocyanines

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ABSTRACT:In this work we report on the influence of the polarity of the environment on the optical properties of octa-a-butyloxy-H 2 phthalocyanine (H 2 PC(OBu) 8 ) in organic solvents and liposomes using steady-state absorption as well as time correlated single photon counting (TCSPC). A change was found in Q-band absorption in various solvents. Taking into account that the absorption properties of H 2 PC(OBu) 8 are modulated by the polarity of the direct surrounding, polarities inside micro-heterogeneous systems can be probed. This was demonstrated for liposomes of dipalmitoylphosphatidylcholine (DPPC), with regard to the behavior during the phase transition between the gel and liquid-crystal state. Absorption spectra of H 2 PC(OBu) 8 embedded in DPPC-liposomes have been recorded in the temperature range from 15 to 70°C, covering the phase transition region at about 36-39°C. The Q-band absorption at temperatures below and above the phase transition resembles those in polar and non-polar solvents, respectively. Measurements of fluorescence lifetime confirm this equivalence. We explain this behavior by a change of the localization of the dye molecules inside the membrane. For H 2 PC(OBu) 8 embedded in DPPC-liposomes we demonstrated by using optical methods that the position of the dye molecules strongly depends on the phase-state of the phospholipid. In addition, H 2 PC(OBu) 8 can be used as a probe for phase transition processes taking advantage of the specific behavior in surroundings with different polarity.

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“…However, many efficient photosensitizers are of hydrophobic nature and lose their efficacy when brought into the aqueous phase, due to the formation of photochemically inactive aggregates. Amphiphilic carriers, such as micelles 6 and liposomes 7 are currently used to bring insoluble or hardly soluble dyes into water and to avoid aggregation. In these systems, the photosensitizer is located in the hydrophobic core of the micro heterogeneous host.…”

Section: Introductionmentioning

confidence: 99%

“…For that reason, a suitable carrier system must be found which prevents Pheo from aggregation. So far, singlet oxygen photogeneration could be achieved for Pheo incorporated into micelles, liposomes, 6 and cyclodextrins 24 and attached to dendritic molecules. 22 In a previous work we investigated the photophysical properties of Pheo adsorbed onto microcrystalline cellulose particles.…”

Section: Introductionmentioning

confidence: 99%

Microcrystalline cellulose as a carrier for hydrophobic photosensitizers in water

Zeug

Zimmermann

Röder

et al. 2002

Photochem Photobiol Sci

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Samples of pheophorbide-a adsorbed on microcrystalline cellulose, which have been previously characterized in the solid state (M.G. Lagorio, E. San Roman, A. Zeug, J. Zimmermann and B. Röder, Phys. Chem. Chem. Phys., 2001, 3. 1524-1529), were washed with water, leading to stable suspensions of ultrafine particles (d < 2 microm) carrying photoactive, monomeric dye molecules. Detachment can be controlled through the particle size distribution. Suspensions are fluorescent and generate singlet molecular oxygen efficiently. A similar effect has been observed on washing samples containing hematoporphyrin IX adsorbed on the same support. Thus, using cellulose as a heterogeneous carrier, it is possible to introduce hydrophobic photosensitizers into the aqueous medium while avoiding aggregation, thus preserving their photophysical properties. At the same time, the spectroscopic properties of dyes attached to cellulose particles are compared with those in ethanol and ethanol-water mixtures and their differences are explained in terms of medium polarity and dye aggregation.

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<title>Photophysical properties of pheophorbide-a in different carrier-systems</title>

Cited by 7 publications

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New Targeted Gold Nanorods for the Treatment of Glioblastoma by Photodynamic Therapy

New Targeted Gold Nanorods for the Treatment of Glioblastoma by Photodynamic Therapy

Observation of the phase transition in phospholipid liposomes taking advantage of the particular optical properties of octa-α-butyloxy-H₂phthalocyanines

Microcrystalline cellulose as a carrier for hydrophobic photosensitizers in water

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<title>Photophysical properties of pheophorbide-a in different carrier-systems</title>

Cited by 7 publications

References 0 publications

New Targeted Gold Nanorods for the Treatment of Glioblastoma by Photodynamic Therapy

New Targeted Gold Nanorods for the Treatment of Glioblastoma by Photodynamic Therapy

Observation of the phase transition in phospholipid liposomes taking advantage of the particular optical properties of octa-α-butyloxy-H2phthalocyanines

Microcrystalline cellulose as a carrier for hydrophobic photosensitizers in water

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Observation of the phase transition in phospholipid liposomes taking advantage of the particular optical properties of octa-α-butyloxy-H₂phthalocyanines