Singlet Oxygen Generation Enhanced by Silver-Pectin Nanoparticles

Melo, Letícia Santos Alves de; Gomes, Anderson S. L.; Saska, Sybele; Nigoghossian, Karina; Messaddeq, Younès; Ribeiro, Sidney José Lima; Araujo, Renato E. de

doi:10.1007/s10895-012-1107-4

Cited by 45 publications

(37 citation statements)

References 42 publications

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“…This same electromagnetic fi eld can also modify the spin-orbit coupling (a quantum mechanical process that is responsible for intersystem crossing) in the fl uorophore [ 30 ] leading to the increase in its triplet formation and thus the yield of 1 O 2 . Such contrasting behavior, i.e., the enhancement of both the fl uorescence emission and the yield of 1 O 2 , has also been recently reported by de Melo et al [ 31 ] in case of silver-pectin nanoparticles.…”

Section: Communicationsupporting

confidence: 72%

Nanosilver Could Usher in Next‐Generation Photoprotective Agents for Magnesium Porphyrins

Bekale

Barazzouk

Hotchandani

2014

Part & Part Syst Charact

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A novel strategy, based on silver nanoparticles (AgNPs), has been developed for simultaneously improving: 1) photostability, 2) fluorescence emission, and 3) singlet oxygen generation ability of natural porphyrin (i.e., chlorophyll (Chl) molecules). The benefit of AgNPs as photoprotector of Chl is that they spontaneously bind with the nitrogen atoms of Chl as soon as they are mixed together, even in the dark prior to the illumination, inhibiting thus the binding of reactive oxygen species (ROS) at nitrogen sites, known to cause the photodegradation of porphyrins.

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Section: Communicationsupporting

confidence: 72%

Nanosilver Could Usher in Next‐Generation Photoprotective Agents for Magnesium Porphyrins

Bekale

Barazzouk

Hotchandani

2014

Part & Part Syst Charact

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“…3 We have reviewed current methods for generating SO 4 and have found that the proper amounts of light, photosensitizer (PS), and/or oxygen influence the SO generation efficiency. 5 The photosensitizing capacity of any compound is dependent on its SO yield (Q D ), 6,7 as well as on the so-called triplet-state yield (F t ); that is, the probability that a PS, after absorption of a quantum of light, will be converted to the T1 state or first excited triplet state of PS. 8 Triplet-state energy (DE t ) reflects the difference between the energies of the S0 and T1 states of the PS.…”

Section: Introductionmentioning

confidence: 99%

Enhanced Singlet Oxygen Production by Photodynamic Therapy and a Novel Method for Its Intracellular Measurement

Luengas

Marín²,

Aviles

et al. 2014

Cancer Biotherapy and Radiopharmaceuticals

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The generation of singlet oxygen (SO) in the presence of specific photosensitizers (PSs) or semiconductor quantum dots (QDs) and its application in photodynamic therapy (PDT) is of great interest to develop cancer therapies with no need of surgery, chemotherapy, and/or radiotherapy. This work was focused on the identification of the main factors leading to the enhancement of SO production using Rose Bengal (RB), and Methylene Blue (MB) as PS species in organic and aqueous mediums. Subsequently, the capacity of zinc oxide (ZnO), zinc sulfide (ZnS), and ZnO/ZnS core-shell QDs as well as manganese (Mn(+2)) doped ZnO and ZnS nanoparticles (NPs) as potential PS was also investigated. Many variable parameters such as type of quencher, PSs, NPs, as well as its different concentrations, light source, excitation wavelength, reaction time, distance from light source, and nature of solvent were used. The degradation kinetics of the quenchers generated by SO species and the corresponding quantum yields were determined by monitoring the photo-oxidation of the chemical quencher and measuring its disappearance by fluorometry and spectrophotometry in the presence of NPs. Small intracellular changes of SO induced by these metal Zn (zinc) NPs and PDT could execute and accelerate deadly programs in these leukemic cells, providing in this way an innovative modality of treatment. In order to perform further more specific in vitro cytotoxic studies on B-chronic lymphocytic leukemia cells exposed to Zn NPs and PDT, we needed first to measure and ascertain those possible intracellular SO variations generated by this type of treatment; for this purpose, we have also developed and tested a novel method first described by us.

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“…Several different properties can be envisaged and in a previous contribution, singlet oxygen generation in riboflavin water solutions was observed to be enhanced by pectin stabilized silver nanoparticles. 42 …”

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confidence: 99%

Orange pectin mediated growth and stability of aqueous gold and silver nanocolloids

Nigoghossian

Santos

Barud

et al. 2015

Applied Surface Science

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The role of orange based pectin in the nucleation and growth of silver and gold nanoparticles is addressed. Pectin is a complex polysaccharide found in fruits such as oranges, lemons, passion fruits or apples. It displays smooth and hairy chain regions containing hydroxyl-, ester-, carboxylate-and eventually amine groups that can act as surface ligands interacting under various pH conditions more or less efficiently with growing nanometals. Here, a high methoxy pectin (> 50% esterified) was used as a stabilizer/reducing agent in the preparation of gold, silver and silver-gold nanoparticles. Commercial pectin (CP) and pectin extracted from orange bagasse (OP) were used. Optionally, trisodium citrate or oxalic acid we used to reduce AgNO 3 and HAuCl 4 in aqueous environment. Characterization methods included UV-VIS absorption spectroscopy, transmission electron microscopy, electron diffraction and energy-dispersive x-ray spectroscopy. The results show that under different pH conditions, pectin and reducing agents allow producing various nanostructures shapes (triangles, spheres, rods, octahedrons and decahedrons) often with high polydispersity and sizes ranging between 5 nm and 30 nm. In addition, depending on Ag/Au-ratio and pH, the surface plasmon bands can be continuously shifted between 410 nm and 600 nm. Finally, pectin seems to be a highly efficient stabilizer of the colloidal systems that show a remarkable stability and unchanged optical spectral response even after five years.

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Singlet Oxygen Generation Enhanced by Silver-Pectin Nanoparticles

Cited by 45 publications

References 42 publications

Nanosilver Could Usher in Next‐Generation Photoprotective Agents for Magnesium Porphyrins

Nanosilver Could Usher in Next‐Generation Photoprotective Agents for Magnesium Porphyrins

Enhanced Singlet Oxygen Production by Photodynamic Therapy and a Novel Method for Its Intracellular Measurement

Orange pectin mediated growth and stability of aqueous gold and silver nanocolloids

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