Selective Photooxidation of Valencene and Thymol with Nano-TiO2 and O2 as Oxidant.

The selective photocatalytic oxidation with O2 as oxidant of valencene and thymol was evaluated using nanostructured TiO2 under UV-Vis radiation at atmospheric conditions. The effect of the morphology and optical properties of TiO2 nanotubes and aminate nanoparticles was studied. Different scavengers were used to detect the presence of positive holes (h+), electrons (e-), hydroxyl radicals (•OH), and the superoxide radical anion (O2-) during the photooxidation reaction. Superoxide anion radical is the main oxidizing specie formed, which is responsible for the selective formation of nootkatone and thymoquinone using aminated TiO2 nanoparticles under 400 nm radiation.

Laser photo-thermal therapy of epithelial carcinoma using pterin-6-carboxylic acid conjugated gold nanoparticles.

Gold nanoparticles functionalized with folic acid toward the internalization into cancer cells have received considerable attention recently. Folic acid is recognized by folate receptors, which are overexpressed in several cancer cells; it is limited in normal cells. In this work, pterin-6-carboxylic acid is proposed as an agonist of folic acid since the pterin-6-carboxylic acid structure has a pterin moiety, the same as folic acid that is recognized by the folate receptor. Here a simple photochemical synthesis of gold nanoparticles functionalized with pterin-6-carboxylic acid is studied. These conjugates were used to cause photothermal damage of HeLa cells irradiating with a diode laser of 808 nm. Pterin-6-carboxylic acid-conjugated gold nanoparticles caused the death of the cell after near-infrared irradiation, dose-dependently. These results indicate a possible internalization of AuNPs via folate receptor-mediated endocytosis due to the recognition or interaction between the folate receptors of HeLa cells and pterin, P6CA.

Nanotubo de carbono-chitosan en células HOS y THP-1 / Carbon nanotubes-chitosan in HOS and TPH-1 cells

Introducción: Los nanotubos de carbono (NTC) son estructuras nanométricas utilizadas en el tratamiento de enfermedades, principalmente en la entrega de fármacos para terapias en cáncer. Objetivo: Estudiar la internalización de NTC acoplado a quitosan (NTC-Q) en células de osteosarcoma humano (HOS) y monocitos humanos de leucemia aguda (THP-1). Materiales y métodos: Los NTC solubilizados con quitosan 30% fueron caracterizados espectroscópicamente por UV-Vis, fluorescencia y Raman. Las células HOS y THP-1 fueron tratadas con NTC-Q y se evaluó la internalización por tinción de Giemsa en microscopio de luz y la citotóxicidad utilizando la prueba fluorométrica de Azul de Alamar. Resultados: Los espectros Raman y de fluorescencia mostraron la funcionalización de los NTC con quitosan. Los NTC fueron internalizados por las líneas celulares después de 24 h mostrando una ubicación citoplasmática sin presentar citotóxicidad en ninguna de las células evaluadas. Discusión: Las características presentadas por los NTC-Q les brinda la posibilidad de ser utilizados como transportadores de fármacos.

Introduction: Carbon nanotubes (CNT) are nanometer-sized structures used in medicine in the treatment of diseases, mainly in drug delivery in therapies against cancer. Objective: Study the internalization of carbon nanotubes modified with chitosan (CNT-CH) in human osteosarcom cells (HOS) and human monocytes of acute leukemia (THP1). Materials and methods: The CNTs solubilized in chitosan 30% were characterized spectroscopically by UV-Vis, fluorescence and Raman. HOS cells and THP-1 were treated with CNT-CH, the internalization was evaluated by Giemsa staining with light microscopy, and cytotoxicity was determined using Alamar Blue assay. Results: Raman and fluorescence spectra showed the functionalization of the CNT with chitosan. After 24 h the NTC were internalized in the cell lines showing a cytoplasmic location and were not cytotoxic in any of both cell lines types. Discussion: The properties of CNT-CH on cells allowing it to be potentially used as drug carrier.

Study of the stabilization of zinc phthalocyanine in sol-gel TiO2 for photodynamic therapy applications.

Photodynamic therapy (PDT) has emerged as an alternative and promising noninvasive treatment for cancer. It is a two-step procedure that uses a combination of molecular oxygen, visible light, and photosensitizer (PS) agents; phthalocyanine (Pc) was supported over titanium oxide but has not yet been used for cell inactivation. Zinc phthalocyanine (ZnPc) molecules were incorporated into the porous network of titanium dioxide (TiO(2)) using the sol-gel method. It was prepared from stock solutions of ZnPc and TiO(2). ZnPc-TiO(2) was tested with four cancer cell lines. The characterization of supported ZnPc showed that phthalocyanine is linked by the N-pyrrole to the support and is stable up to 250°C, leading to testing for PDT. The preferential localization in target organelles such as mitochondria or lysosomes could determine the cell death mechanism after PDT. The results suggest that nanoparticulated TiO(2) sensitized with ZnPc is an excellent candidate as sensitizer in PDT against cancer and infectious diseases.