A hybrid material with excellent mechanical and biological properties is produced by electrospinning a co-solution of PET and collagen. The fibers are mapped using SEM, confocal Raman microscopy and collagenase digestion assays. Fibers of different compositions and morphologies are intermingled within the same membrane, resulting in a heterogeneous scaffold. The collagen distribution and exposure are found to depend on the PET/collagen ratio. The materials are chemically and mechanically characterized and biologically tested with fibroblasts (3T3-L1) and a HUVEC culture in vitro. All of the hybrid scaffolds show better cell attachment and proliferation than PET. These materials are potential candidates to be used as vascular grafts.

A teoria de espalhamento de luz dinâmico (Dinamic Light Scattering-DLS) é uma técnica utilizada para medir o tamanho de partículas na faixa de nanômetros ou mesmo de microns. O conceito usa a idéia que pequenas

A dicarboxybipyridine‐trimercaptotriazine ruthenium complex, primarily designed for dye solar cells, has been successfully employed for generating electrostatically stabilized gold colloids, because of its high negative charge and capability of binding to gold nanoparticles via the sulfur groups. Surprisingly, a strong surface‐enhanced Raman scattering enhancement has been observed for the isolated nanoparticles, exceeding those recorded after inducing agglomeration. Such unusual response has been ascribed to the predominant contribution of the charge‐transfer and resonance Raman mechanisms, more than compensating for the lack of the local hot spots, in relation to the agglomerated systems. Copyright © 2014 John Wiley & Sons, Ltd.

The substitution kinetics and specific binding modes of the dithiooxamide (dto) ligand at the metal surface have been investigated and interpreted on the light of theoretical and experimental Raman studies. By monitoring the vibrational properties of this ligand, it was shown that gold nanoparticles employed as surface‐enhanced effects (SERS) probes are strongly dependent on the coordination chemistry of the ligands at the metal interface. The binding of dto to the gold nanoparticles led to linkage isomers, and at low concentrations, the bidentate form, corresponding to bis‐thione‐Au bond in cis configuration {Au‐S(NH2)CC(NH2)S‐Au}, was the predominating species. Even at high concentrations, the cis‐configuration was observed first; but as the ligand competition dynamics proceeded, the binding mode gradually changed into a monodentate thione‐Au mode {AuS(NH2)CCS(NH2)}. In this mode, the dto ligand adopts a thermodynamically favorable trans‐conformation geometry, producing dramatic changes in the SERS spectra. Such dynamic behavior of the ligand at the metal plasmonic surface is of crucial importance, as one of the possible factors associated with lack of reproducibility of the SERS spectra frequently reported in the literature.

Prussian blue analogues (PBAs) have been constructed in chiral nematic mesoporous organosilica and silica templates. By functionalizing the surface of the mesoporous hosts with bipyridinium ligands, it was possible to construct PBAs in their interiors through hard templating. The optical properties of the composites were studied and the relationship between the circular dichroism (CD) signals and the UV-Vis absorption spectra was found through mathematical modeling. Efforts to remove the hard templates to give free-standing PBA films with high surface area and pore volume were met with limited success, but it was possible in the case of zinc/iron PBAs to obtain a highly porous PBA sponge that retained the overall morphology of the template. This work demonstrates the potential for hard templating of coordination polymers in mesoporous materials.

Mesoporous resins with chiral nematic order were used as scaffolds to construct novel iridescent metal-polymer composites. Gold, silver and palladium nanoparticles were formed by an in situ reduction reaction. We have investigated the effects of concentration and time on the deposition. As a proof-of-concept, we demonstrate that this process can be extended to patterning photonic resins by inkjet printing.

The bis(4-thienylterpyridine)iron(II) complex was employed, in comparison with the 4-phenylterpyridine analogue, as a molecular probe for monitoring the surface plasmon interactions with gold nanoparticles. The two complexes exhibited distinct SERS responses, confirming the binding of the thienyl group to the gold nanoparticles. Their inclusion into β-cyclodextrin anchored on TiO2 surfaces provided a useful system for applications in UV dosimetry, based on the gradual bleaching of the violet-blue color under sunlight and air.

Agradeço aos alunos de iniciação científica que trabalharam ao meu lado e que foram os primeiros que pude incentivar a gostarem de pesquisa: Amanda, Caio, Shaina, Mikhael, Flavia e em especial, o Daniel Grasseschi, que hoje é aluno de doutorado do laboratório e trabalha ao meu lado. Desejo todo sucesso do mundo a ele, espero ter sido uma peça importante em seu aprendizado e que possamos trabalhar juntos por muitos anos, ainda.