Redox-responsive maltoheptaose-b-polystyrene nanoparticles containing zinc phthalocyanine: Formulation, photophysical properties, release kinetic and toxicity

International audienceSugar-based nanoparticles with redox responsive properties are an emerging class of nanovehicles designed to boost photodynamic therapy (PDT) in the treatment of neoplastic and non-neoplastic diseases. In this paper, it was synthesized a maltoheptaose-b-polystyrene [MH1.2k-b-PS5k)] block copolymer using metal-free click reaction, containing a redox-cleavable linker. The glyconanoparticles, loaded with photosensitizer zinc phthalocyanine (ZnPc) were produced by block copolymer self-assembly in an appropriate solvent mixture. The hydrodynamic radius of the nanoparticles (MH1.2k-b-PS5k@ZnPc) was dependent on copolymer concentration and method of nanoprecipitation (standard or reverse). The polymeric micelles displayed a spherical morphology, suitable values of efficiency encapsulation and kinetics profile showed a burst release at first stage, followed by a sustained release controlled by diffusion. The nanocarriers were able to produce cytotoxic singlet oxygen (1O2) and displayed appropriate values of singlet oxygen quantum yields (). The MH1.2k-b-PS5k@ZnPc nanoparticles were non-toxic towards Caernohabditis elegans and do not induced delay on larval development on dark conditions. The redox-responsive cleavage of block copolymer by N-bromosuccinimide (NBS) and MH1.2k-b-PS5k@ZnPc nanoparticles by NBS or reduced glutathion (GSH) was evidenced through by several techniques. These outcomes highlight that glyconanoparticles are stimuli-responsive and can contribute to the development of third-generation photosensitizers for use in PDT

Synthesis, structure and SOD activity of Mn complexes with symmetric Schiff base ligands derived from pyridoxal

This study describes the synthesis, crystal structure and antioxidant activity of manganese(III) complexes with Schiff-base ligands obtained from condensation of pyridoxal with alkyl diamines: [Mn(pyr2en) (H2O)2]Cl 4H2O, [Mn(pyr2en)(H2O)(CH3OH)]Cl, [Mn(pyr2pn)(H2O)2]ClO4 and [Mn2(pyr2bn)3] 4H2O, where H2pyr2en = 1,2-bis(pyridoxylidenamino)ethane, H2pyr2pn = 1,3-bis(pyridoxylidenamino)propane and H2pyr2bn = 1,4-bis(pyridoxylidenamino)butane. The four complexes catalyze the dismutation of superoxide efficiently with IC50 values in the range of 1.22?2.15 lM, evaluated through the nitro blue tetrazolium photoreduction inhibition superoxide dismutase assay, in aqueous solution of pH 7.8. The length of the alkyl spacer in the diamine fragment plays a key role in the antioxidant activity of these complexes, with [Mn(pyr2pn)(H2O)2]ClO4 showing the lowest IC50 value.Fil: Signorella, Sandra Rosanna. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Rosario. Instituto de Química Rosario; ArgentinaFil: Daier, Veronica Andrea. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Rosario. Instituto de Química Rosario; ArgentinaFil: Ledesma, Gabriela Nanci. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Rosario. Instituto de Química Rosario; ArgentinaFil: Palopoli, Claudia Marcela. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Rosario. Instituto de Química Rosario; ArgentinaFil: Back, Davi Fernando. Universidade Federal de Santa Maria. Departamento de Química. Laboratório de Materiais Inorgânicos; BrasilFil: Lang, Ernesto S.. Universidade Federal de Santa Maria. Departamento de Química. Laboratório de Materiais Inorgânicos; BrasilFil: Rossini Kopp, Cristiéli. Universidade Federal de Santa Maria. Departamento de Química. Laboratório de Materiais Inorgânicos; BrasilFil: Ebani, Patrícia. Universidade Federal de Santa Maria. Departamento de Química. Laboratório de Materiais Inorgânicos; BrasilFil: Brum Pereira, Mateus. Universidade Federal de Santa Maria. Departamento de Química. Laboratório de Materiais Inorgânicos; BrasilFil: Giacomelli, Cristiano. Universidade Federal de Santa Maria. Departamento de Química. Laboratório de Polímeros e Colóides; BrasilFil: Piquini, Paulo Cesar. Universidade Federal de Santa Maria. Departamento de Física; Brasi