Type I and Type II Photosensitized Oxidation Reactions: Guidelines and Mechanistic Pathways

Baptista, Maurício da Silva; Cadet, Jean; Mascio, Paolo Di; Ghogare, Ashwini A.; Greer, Alexander; Hamblin, Michael R.; Lorente, Carolina; Núñez, Silvia Cristina; Ribeiro, Martha S.; Thomas, Andrés H.; Vignoni, Mariana; Yoshimura, Tania Mateus

doi:10.1111/php.12716

Cited by 589 publications

(611 citation statements)

References 46 publications

(60 reference statements)

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“…These ROS (including hydroxyl radicals, hydrogen peroxide, and superoxide anion) were produced by what became known as the Type I photochemical mechanism [8]. It is thought that this initially involves a one-electron transfer from the photosensitizer (PS) triplet state to oxygen to form superoxide anion.…”

Section: Introductionmentioning

confidence: 99%

Potentiation of antimicrobial photodynamic inactivation by inorganic salts

Hamblin

2017

Expert Review of Anti-infective Therapy

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Introduction Antimicrobial photodynamic inactivation (aPDI) involves the use of non-toxic dyes excited with visible light to produce reactive oxygen species (ROS) that can destroy all classes of microorganisms including bacteria, fungi, parasites, and viruses. Selectivity of killing microbes over host mammalian cells allows this approach (antimicrobial photodynamic therapy, aPDT) to be used in vivo as an alternative therapeutic approach for localized infections especially those that are drug-resistant. Areas covered We have discovered that aPDI can be potentiated (up to 6 logs of extra killing) by the addition of simple inorganic salts. The most powerful and versatile salt is potassium iodide, but potassium bromide, sodium thiocyanate, sodium azide and sodium nitrite also show potentiation. The mechanism of potentiation with iodide is likely to be singlet oxygen addition to iodide to form iodine radicals, hydrogen peroxide and molecular iodine. Another mechanism involves two-electron oxidation of iodide/bromide to form hypohalites. A third mechanism involves a one-electron oxidation of azide anion to form azide radical. Expert commentary The addition of iodide has been shown to improve the performance of aPDT in several animal models of localized infection. KI is non-toxic and is an approved drug for antifungal therapy, so its transition to clinical use in aPDT should be straightforward.

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Section: Introductionmentioning

confidence: 99%

Potentiation of antimicrobial photodynamic inactivation by inorganic salts

Hamblin

2017

Expert Review of Anti-infective Therapy

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“…1 [18,19]. In the absence of light, most of the PS molecules lie in their state of least energy called ground state ( 1 PS, in general a singlet state) with two paired electrons in the outer molecular orbital.…”

Section: Basic Principles Of Pdtmentioning

confidence: 99%

Strategies for optimizing the delivery to tumors of macrocyclic photosensitizers used in photodynamic therapy (PDT)

Moret

Reddi

2017

J. Porphyrins Phthalocyanines

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This review briefly summaries the principles and mechanisms of action of photodynamic therapy (PDT) as concerns its application in the oncological field, highlighting its drawbacks and some of the strategies that have been or are being explored to overcome them. The major aim is to increase the efficiency and selectivity of the photosensitizer (PS) uptake in the cancer cells for optimizing the PDT effects on tumors while sparing normal cells. Some attempts to achieve this are based on the conjugation of the PS to biomolecules (small ligands, peptides) functioning as carriers with the ability to efficiently penetrate cells and/or specifically recognize and bind proteins/receptors overexpressed on the surface of cancer cells. Alternatively, the PS can be entrapped in nanocarriers derived from various types of materials that can target the tumor by exploiting the enhanced permeability and retention (EPR) effects. The use of nanocarriers is particularly attractive because it allows the simultaneous delivery of more than one drug with the possibility of combining PDT with other therapeutic modalities.

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“…Some fluorescent proteins participate in Type I and Type II photosensitization reactions 7. Predominant ROS generated by fluorescent proteins depends on the type of photosensitization reactions and the concentration of local molecular oxygen (i.e., electron acceptor).…”

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confidence: 99%

Green‐Light‐Activated Photoreaction via Genetic Hybridization of Far‐Red Fluorescent Protein and Silk

et al. 2018

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Fluorescent proteins often result in phototoxicity and cytotoxicity, in particular because some red fluorescent proteins produce and release reactive oxygen species (ROS). The photogeneration of ROS is considered as a detrimental side effect in cellular imaging or is proactively utilized for ablating cancerous tissue. As ancient textiles or biomaterials, silk produced by silkworms can directly be used as fabrics or be processed into materials and structures to host other functional nanomaterials. It is reported that transgenic fusion of far‐red fluorescent protein (mKate2) with silk provides a photosensitizer hybridization platform for photoinducible control of ROS. Taking advantage of green (visible) light activation, native and regenerated mKate2 silk can produce and release superoxide and singlet oxygen, in a comparable manner of visible light‐driven plasmonic photocatalysis. Thus, the genetic expression of mKate2 in silk offers immediately exploitable and scalable photocatalyst‐like biomaterials. It is further envisioned that mKate2 silk can potentially rule out hazardous concerns associated with foreign semiconductor photocatalytic nanomaterials.

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Type I and Type II Photosensitized Oxidation Reactions: Guidelines and Mechanistic Pathways

Cited by 589 publications

References 46 publications

Potentiation of antimicrobial photodynamic inactivation by inorganic salts

Potentiation of antimicrobial photodynamic inactivation by inorganic salts

Strategies for optimizing the delivery to tumors of macrocyclic photosensitizers used in photodynamic therapy (PDT)

Green‐Light‐Activated Photoreaction via Genetic Hybridization of Far‐Red Fluorescent Protein and Silk

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