Chapter 2. Properties of Singlet Oxygen

Boix-Garriga, Ester; Rodríguez-Amigo, Beatriz; Planas, Oriol; Nonell, Santi

doi:10.1039/9781782622208-00023

Cited by 33 publications

(27 citation statements)

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“…Indeed, a charge-transfer interaction mechanism was proposed by Foley et al [60]. Nevertheless, the increase in the quenching activity was probably due to the contribution of nanoparticles themselves, as observed by other authors [61,62], mainly as a result of (i) quenching by amino groups on the nanoparticle surface, (ii) quenching by hydrogen-bonded water and silanol groups in the mesopores, and (iii) enhancement of these processes by the increased wall-collision frequency in the silica mesoporous channels [63]. Singlet oxygen deactivation by ACSSNs was determined as a control.…”

Section: Resultsmentioning

confidence: 72%

Antioxidant Nanomaterial Based on Core–Shell Silica Nanospheres with Surface-Bound Caffeic Acid: A Promising Vehicle for Oxidation-Sensitive Drugs

et al. 2019

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The design of efficient, biocompatible, and easily prepared vehicles for drug delivery is a subject of great interest for medicine and pharmaceutical sciences. To achieve the above goals, surface functionalization is critical. Here, we report a hybrid nanocarrier consisting of core–shell silica nanospheres and the antioxidant caffeic acid linked to the surface, to evaluate their in vitro antioxidant capacity, their capability to protect oxidation-sensitive compounds incorporated in nanoparticles, and to study the interaction with bovine serum albumin protein. The results show that the radical-scavenging activity of immobilized caffeic acid is attenuated in the silica nanospheres; however, other antioxidant properties such as Fe2+-chelating activity and singlet oxygen quenching are enhanced. In addition, caffeic acid is protected from binding to proteins by the nanoparticle, suggesting that this nanosystem is more likely to maintain the antioxidant activity of caffeic acid in biological media. Finally, the natural antioxidant barrier on the nanocarrier is able to delay the degradation of a compound incorporated into this nanovehicle. Considering all findings, this work proposes a suitable tool for pharmaceutical and cosmetic industries as an antioxidant nanocarrier for oxidation-sensitive drugs.

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Section: Resultsmentioning

confidence: 72%

Antioxidant Nanomaterial Based on Core–Shell Silica Nanospheres with Surface-Bound Caffeic Acid: A Promising Vehicle for Oxidation-Sensitive Drugs

et al. 2019

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“…In addition, this is evidenced by a change of color from orange-red to intense purple, a characteristic color change when a violet tri-anionic molecule appears [75]. Another explanation could be the quenching effect of the silica matrix [76]; nevertheless, previously we reported that the effect in this nanosystem was not significant [42]. These results display a suitable antioxidant agent, the k T value of this nanomaterial is similar or even greater than the value reported for a few recognized antioxidants such as quercetin or morin [77,78].…”

Section: Antioxidant Capacity: Singlet Oxygen Quenching By Acssnps-camentioning

confidence: 99%

Carminic Acid Linked to Silica Nanoparticles as Pigment/Antioxidant Bifunctional Excipient for Pharmaceutical Emulsions

et al. 2020

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The incorporation of pigments and natural polyphenols into inorganic matrices, resulting in a hybrid material that improves the resistance and chemical stability of the pigments and the antioxidant capacity of the materials, has been of great interest to the pharmaceutical, chemical and food industries. The aim of this work was to prepare and characterize a bifunctional pigment–antioxidant nanomaterial-based carminic acid-decorated solid core-mesoporous shell silica nanoparticles, evaluating its properties as a pigment, its antioxidant capacity and its properties as a chemical stabilizer of emulsions. The chemical stability of oil-in-water (O/W) Pickering emulsions was evaluated determining the stability of vitamin E solubilized in the oil phase. Carminic acid was attached through the action of coupling ethylcarbodiimide hydrochloride (EDC)/N-hydroxysuccinimide (NHS) agents, and the resulting spherical and homogeneous nanoparticles showed a diameter close to 175 nm. A notorious change of emulsion color was observed by the addition of the nanomaterial. Emulsions showed an attractive pink color, and when the pH was adjusted to pH 3 and pH 9, a change in color was observed, analogous to carminic acid in solution. The nanomaterial incorporation also improved chemical stability, decreasing vitamin E consumption to 9.26% of the initial value, demonstrating an important antioxidant effect of the developed nanomaterial.

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“…O 2 ( 1 Δ g ) has energy ( E ) of 0.98 eV ( E Δ ) and its second (higher energy) singlet excited state O 2 ( 1 Σ g + ) is 1.63 eV ( E Δ + E Σ ) above the triplet ground state (i.e. 3 O 2 ) [ 35 – 37 ]. O 2 ( 1 Σ g + ) decays extremely fast (~ picoseconds) to the first excited state 1 O 2 especially in aqueous media by its electronic-to-vibrational energy-transfer process [ 36 – 38 ].…”

Section: Basic Mechanisms Of Plasmonic Photocatalysis and Photosensitmentioning

confidence: 99%

“…b Electronic configuration of the triplet ground state molecular oxygen O 2 ( 3 Σ g − ), its first (i.e. lowest-energy) singlet excited state O 2 ( 1 Δ g ), and its second (higher energy) singlet excited state O 2 ( 1 Σ g + ) [ 36 , 37 ], where the superscripts 3 and 1 indicate triplet and singlet states, respectively. The energy gaps between the ground state and the two singlet excited states are shown in eV, including the corresponding luminescent wavelengths …”

Section: Basic Mechanisms Of Plasmonic Photocatalysis and Photosensitmentioning

confidence: 99%

Plasmonic photocatalyst-like fluorescent proteins for generating reactive oxygen species

et al. 2018

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The recent advances in photocatalysis have opened a variety of new possibilities for energy and biomedical applications. In particular, plasmonic photocatalysis using hybridization of semiconductor materials and metal nanoparticles has recently facilitated the rapid progress in enhancing photocatalytic efficiency under visible or solar light. One critical underlying aspect of photocatalysis is that it generates and releases reactive oxygen species (ROS) as intermediate or final products upon light excitation or activation. Although plasmonic photocatalysis overcomes the limitation of UV irradiation, synthesized metal/semiconductor nanomaterial photocatalysts often bring up biohazardous and environmental issues. In this respect, this review article is centered in identifying natural photosensitizing organic materials that can generate similar types of ROS as those of plasmonic photocatalysis. In particular, we propose the idea of plasmonic photocatalyst-like fluorescent proteins for ROS generation under visible light irradiation. We recapitulate fluorescent proteins that have Type I and Type II photosensitization properties in a comparable manner to plasmonic photocatalysis. Plasmonic photocatalysis and protein photosensitization have not yet been compared systemically in terms of ROS photogeneration under visible light, although the phototoxicity and cytotoxicity of some fluorescent proteins are well recognized. A comprehensive understanding of plasmonic photocatalyst-like fluorescent proteins and their potential advantages will lead us to explore new environmental, biomedical, and defense applications.

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Chapter 2. Properties of Singlet Oxygen

Cited by 33 publications

References 0 publications

Antioxidant Nanomaterial Based on Core–Shell Silica Nanospheres with Surface-Bound Caffeic Acid: A Promising Vehicle for Oxidation-Sensitive Drugs

Antioxidant Nanomaterial Based on Core–Shell Silica Nanospheres with Surface-Bound Caffeic Acid: A Promising Vehicle for Oxidation-Sensitive Drugs

Carminic Acid Linked to Silica Nanoparticles as Pigment/Antioxidant Bifunctional Excipient for Pharmaceutical Emulsions

Plasmonic photocatalyst-like fluorescent proteins for generating reactive oxygen species

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