Noboru Hioka | Universidade Estadual de Maringa (original) (raw)

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Papers by Noboru Hioka

Spectrochimica Acta Part A: Molecular and Biomolecular Spectroscopy, 2017

The spectrophotometric properties of chlorophylls' derivatives (Chls) formulated in the P... more The spectrophotometric properties of chlorophylls' derivatives (Chls) formulated in the Pluronics® F-127 and P-123 were evaluated and the results have shown that the Chls were efficiently solubilized in these drug delivery systems as monomers. The relative location of the Chls in the Pluronics® was estimated from the Stokes shift and micropolarity of the micellar environment. Chls with phytyl chain were located in the micellar core, where the micropolarity is similar to ethanol, while phorbides' derivatives (without phytyl chain) were located in the outer shell of the micelle, i.e., more polar environment. In addition, the thermal stability of the micellar formulations was evaluated through electronic absorption, fluorescence emission and resonance light scattering with lowering the temperature. The Chls promote the stability of the micelles at temperatures below the Critical Micellar Temperature (CMT) of these surfactants. For F-127 formulations, the water molecules drive through inside the nano-structure at temperatures below the CMT, which increased the polarity of this microenvironment and directly affected the spectrophotometric properties of the Chls with phytyl chain. The properties of the micellar microenvironment of P-123, with more hydrophobic core due to the small PEO/PPO fraction, were less affected by lowering the temperature than for F-127. These results enable us to better understand the Chls behavior in micellar copolymers and allowed us to design new drug delivery system that maintains the photosensitizer's properties for photodynamic applications.

Abstract The singlet oxygen (1 O 2) is one of the reactive species responsible for the destructio... more Abstract The singlet oxygen (1 O 2) is one of the reactive species responsible for the destruction of target cells in Photodynamic Therapy (PDT). However, the quantification of 1 O 2 yields (?? ??) involves lifetime measurements with very expensive equipment. An ...

Anais da Academia Brasileira de Ciências, 2013

The development of drugs for photodynamic therapy (PDT) is an important area of research due to t... more The development of drugs for photodynamic therapy (PDT) is an important area of research due to their growing use in medical applications. Therefore, it is important to develop new bioassay methods for PDT photosensitizers that are inexpensive, easy to handle and highly sensitive to environmental conditions. Xanthene dyes (fluorescein, rose bengal B, erythrosine B and eosin Y) with LED light sources were investigated using Artemia salina as a bioindicator of photodynamic activity. In this study, three factors were investigated: (i) photosensitizers concentration, (ii) the LED irradiation time and (iii) the waiting time between the addition of the photosensitizers and the beginning of the irradiation. To analyze the photo-killing of A. salina, it was employed a 2³ full factorial design. The death of A. salina was related to dye structure and the interaction between the irradiation time and the photosensitizers concentration. About 60% of crustaceans death was obtained using rose beng...

Photochemistry and Photobiology, 2003

Quimica Nova, 2002

solvent has a high cryoscopic constant and is miscible with both polar and non-polar compounds. T... more solvent has a high cryoscopic constant and is miscible with both polar and non-polar compounds. The molar masses of acetone, water, chloroform, dichloro-methane, ethanol, hexane, carbon tetrachloride and toluene were determined. The results were good except for water. Even though there are reliable techniques of molar mass determination nowadays, this method is still frequent ly taught in undergraduate courses.

Journal of Molecular Liquids, 2000

The parallel (k║) and perpendicular (k┴) absorption coefficients are determined along the entire ... more The parallel (k║) and perpendicular (k┴) absorption coefficients are determined along the entire range of a calamitic nematic phase (NC) and near the NC - reentrant isotropic (IRE) and NC - isotropic (I) phase transitions. We have made these measurements in a lyotropic mixture of potassium laurate, decanol and D2O in the spectral range from 400 to 700nm using a

Journal of Porphyrins and Phthalocyanines, 2005

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