title: Enhanced singlet oxygen production by photodynamic therapy and a novel method for its intracellular measurement.
abstract: 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.
authors.affiliation: 1 Department of Chemistry, University of Puerto Rico , Puerto Rico .
authors.forename: Sandra L
authors.initials: SL
authors.lastname: Pena Luengas
authors.forename: Gustavo Horacio
authors.initials: GH
authors.lastname: Marin
authors.forename: Kevin
authors.initials: K
authors.lastname: Aviles
authors.forename: Ricardo
authors.initials: R
authors.lastname: Cruz Acuña
authors.forename: Gustavo
authors.initials: G
authors.lastname: Roque
authors.forename: Felipe
authors.initials: F
authors.lastname: Rodríguez Nieto
authors.forename: Francisco
authors.initials: F
authors.lastname: Sanchez
authors.forename: Adrián
authors.initials: A
authors.lastname: Tarditi
authors.forename: Luis
authors.initials: L
authors.lastname: Rivera
authors.forename: Eduardo
authors.initials: E
authors.lastname: Mansilla
mesh_terms: D001402:B-Lymphocytes / Q000187:drug effects* / Q000378:metabolism*; D002478:Cells, Cultured; D006801:Humans; D008027:Light; D008345:Manganese / Q000008:administration & dosage; D053758:Nanoparticles / Q000008:administration & dosage; D010778:Photochemotherapy / Q000379:methods; D017319:Photosensitizing Agents / Q000008:administration & dosage; D045663:Quantum Dots / Q000008:administration & dosage; D026082:Singlet Oxygen / Q000378:metabolism*; D013440:Sulfides / Q000008:administration & dosage; D017967:Zinc Compounds / Q000008:administration & dosage; D015034:Zinc Oxide / Q000008:administration & dosage
chemical_list: D017319:Photosensitizing Agents; D013440:Sulfides; D017967:Zinc Compounds; D026082:Singlet Oxygen; D008345:Manganese; C031238:zinc sulfide; D015034:Zinc Oxide
keywords: B-CLL; chemotherapy; lymphoma; targeted therapy; treatment