Improvement of the ON/OFF Switching Performance of a pH‐Activatable Porphyrin Derivative by the Introduction of Phosphorus(V)

Horiuchi, Hiroaki; Isogai, Masataka; Hirakawa, Kazuhiko; Okutsu, Tetsuo

doi:10.1002/cptc.201800248

Cited by 11 publications

(16 citation statements)

References 56 publications

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“…Electron transfer can be controlled by the surrounding environment. For example, pH is an important factor to control the photoinduced electron transfer [29,30,48,80,81]. Since it has been reported that cancer cells are slightly acidic (pH 6 ~ 7) against normal tissues (pH 7 ~ 7.4) [82][83][84][85], control of the electron transfer of the photosensitizer by pH can be applied for the development of cancer-selective PDT.…”

Section: Activity Control Based On the Electron Transfermentioning

confidence: 99%

“…In the cases of pH-dependent 1 O 2 photosensitizers, the redox control [30,[86][87][88], the structure change [89], and the control of intersystem crossing [90] by pH have been reported as the important concepts. Several types of pH-activatable-porphyrin photosensitizers [30,88], including a phosphorus(V) porphyrin [48,81], have been reported. In addition, a self-quenching of the photoexcited molecules can be also used to control the activity [47].…”

Section: Activity Control Based On the Electron Transfermentioning

confidence: 99%

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Electron Transfer-Supported Photodynamic Therapy

Hirakawa¹

2021

Photodynamic Therapy - From Basic Science to Clinical Research

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Photodynamic therapy (PDT) is a less-invasive treatment of cancer and precancerous lesions. Porphyrin derivatives have been used and studied as the photosensitizers for PDT. In general, the biomacromolecules oxidation by singlet oxygen, which is produced through energy transfer from the photoexcited photosensitizers to oxygen molecules, is an important mechanism of PDT. However, the traditional PDT effect may be restricted, because tumors are in a hypoxic condition and in certain cases, PDT enhances hypoxia via vascular damage. To solve this problem, the electron transfer-mediated oxidation of biomolecules has been proposed as the PDT mechanism. Specifically, porphyrin phosphorus(V) complexes demonstrate relatively strong photooxidative activity in protein damage through electron transfer. Furthermore, other photosensitizers, e.g., cationic free-base porphyrins, can oxidize biomolecules through electron transfer. The electron transfer-supported PDT may play the important roles in hypoxia cancer therapy. Furthermore, the electron transfer-supported mechanism may contribute to antimicrobial PDT. In this chapter, recent topics about the biomolecules photooxidation by electron transfer-supported mechanism are reviewed.

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Section: Activity Control Based On the Electron Transfermentioning

confidence: 99%

Section: Activity Control Based On the Electron Transfermentioning

confidence: 99%

Electron Transfer-Supported Photodynamic Therapy

Hirakawa¹

2021

Photodynamic Therapy - From Basic Science to Clinical Research

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“…Since tetrakis(p-alkoxyphenyl)porphyrin phosphorus(V) complexes can oxidize protein through electron transfer under the irradiation of relatively long-wavelength visible light (~650 nm) (3,16,17), these derivatives may improve the PDT effect. Another important characteristic of the porphyrin phosphorus(V) complex is its amphiphilic nature (3,(20)(21)(22). Its solubility in water and organic solvents can be modulated by the substituents (3,16,(20)(21)(22)(23).…”

Section: Introductionmentioning

confidence: 99%

Photosensitized Protein Damage by DiethyleneglycoxyP(V)tetrakis(p‐n‐butoxyphenyl)porphyrin Through Electron Transfer: Activity Control Through Self‐aggregation and Dissociation

Hirakawa

Yoshida

Hirano

et al. 2021

Photochem & Photobiology

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DiethyleneglycoxyP(V)tetrakis(p-n-butoxyphenyl)porphyrin (EGP(V)TBPP) forms a self-aggregation in an aqueous solution, and the photoexcited state of this molecule was effectively deactivated. Association with human serum albumin (HSA), a water-soluble protein, causes dissociation of the self-aggregation, resulting in recovery of the photosensitizer activity of EGP(V)TBPP. Under visible light irradiation, EGP(V)TBPP photosensitized HSA oxidation. The photosensitized singlet oxygen-generating activity of EGP(V)TBPP was confirmed by near-infrared emission measurement. A singlet oxygen quencher, sodium azide, partially inhibited the HSA photodamage; however, the quenching effect was estimated to be 57%. Another 43% of the HSA photodamage could be explained by the electron transfer mechanism. The redox potential of EGP(V)TBPP and the calculated Gibbs energy of electron transfer from tryptophan to photoexcited EGP(V)TBPP demonstrated the possibility of HSA oxidation through electron extraction. Fluorescence lifetime measurements of EGP(V)TBPP verified the electron transfer from HSA. The photosensitizer activity of EGP(V)TBPP can be controlled through an association with biomolecules, such as protein, and the electron transfer-mediated biomolecule photooxidation plays an important role in photodynamic therapy under hypoxia.

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“…Tetrakis( N -methyl- p -pyridinio)porphyrin (TMPyP) has been studied as the model compound for PDT. 17 , 29 Because the water-solubility of previously reported porphyrins was relatively low, 18 − 20 , 22 the use of TMPyP-based porphyrin may be advantageous for the application. To control the photosensitizing activity of TMPyP, meso -( N′ , N′ -dimethyl-4-aminophenyl)-tris( N -methyl- p -pyridinio)porphyrin (DMATMPyP, Figure 1 ) was designed and synthesized.…”

Section: Introductionmentioning

confidence: 99%

Photooxidation Activity Control of Dimethylaminophenyl-tris-(N-methyl-4-pridinio)porphyrin by pH

et al. 2020

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To control the activity of photodynamic agents by pH, an electron donor-connecting cationic porphyrin, meso -( N′ , N′ -dimethyl-4-aminophenyl)-tris( N -methyl- p -pyridinio)porphyrin (DMATMPyP), was designed and synthesized. The photoexcited state (singlet excited state) of DMATMPyP was deactivated through intramolecular electron transfer under a neutral condition. The p K a of the protonated DMATMPyP was 4.5, and the fluorescence intensity and singlet oxygen-generating activity increased under an acidic condition. Furthermore, the protonation of DMATMPyP enhanced the biomolecule photooxidative activity through electron extraction. Photodamage of human serum albumin (HSA) was observed under a neutral condition because a hydrophobic HSA environment can reverse the deactivation of photoexcited DMATMPyP. However, an HSA-damaging mechanism of DMATMPyP under a neutral condition was explained by singlet oxygen production. Therefore, it is indicated that the protein photodamaging activity of DMATMPyP goes into an OFF state under a neutral hypoxic condition. Under an acidic condition, the HSA photodamaging quantum yield by DMATMPyP through electron extraction could be preserved in the presence of a singlet oxygen quencher. Photooxidation of nicotinamide adenine dinucleotide by DMATMPyP was also enhanced under an acidic condition. This study demonstrated the concept of using pH to control photosensitizer activity via inhibition of the intramolecular electron transfer deactivation and enhancement of the oxidative activity through the electron extraction mechanism. Specifically, biomolecule oxidation through electron extraction may play an important role in photodynamic therapy to treat tumors under a hypoxic condition.

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Improvement of the ON/OFF Switching Performance of a pH‐Activatable Porphyrin Derivative by the Introduction of Phosphorus(V)

Cited by 11 publications

References 56 publications

Electron Transfer-Supported Photodynamic Therapy

Electron Transfer-Supported Photodynamic Therapy

Photosensitized Protein Damage by DiethyleneglycoxyP(V)tetrakis(p‐n‐butoxyphenyl)porphyrin Through Electron Transfer: Activity Control Through Self‐aggregation and Dissociation

Photooxidation Activity Control of Dimethylaminophenyl-tris-(N-methyl-4-pridinio)porphyrin by pH

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