Chiara Battocchio

Self-assembled nanoparticles of functional copolymers for photonic applications

A modified emulsion copolymerization of phenylacetylene (PA) with hydrophilic monomers having different functions, i.e., acrylic acid (AA) and N,N-dimethylpropargylamine (DMPA) respectively, yields functionalized polymeric P(PA-co-AA) and P(PA-co-DMPA) nanoparticles. The systematic investigation on the experimental parameters affecting size, surface charge and polydispersity of the copolymers (initiator concentration, reaction time, cosolvent and PA/comonomer ratios) allows to modulate the nanoparticle physico-chemical properties. Spherical shaped particles with diameters in the range 80-500 nm, low polydispersity (PI values in the range 1.11-1.30) and different surface charge densities, between 0.44 and 2.87 microC/cm(2), have been consistently obtained and characterized by means of Dynamic Light Scattering (DLS), laser Doppler electrophoretic and Scanning Electron Microscopy (SEM) studies. XPS measurements have provided information on the nanoparticles chemical surface structure and suggest that AA and DMPA units are preferentially distributed on the surface of the spheres. The nanospheres self-assemble giving large domains (9.5 x 14.5 microm). Photonic analysis of the self-assembled copolymeric nanoparticles has been performed by means of Spectroscopic Ellipsometry (SE) and Bragg reflection spectroscopy, both of them demonstrating a three-dimensional photonic crystal property of these systems.

Study of chemical structure and conjugation length in organometallic Pt(II) oligomers and polymers containing 1,4-diethynylbenzene derivatives as bridging units

Abstract The synthesis of platinum containing organometallic rigid rod oligomers and polymers, of general formula—[PtL 2 (ue5f8Cue606Cue5f8 p C 6 H 4 (2,5-R) 2 ue5f8Cue606Cue5f8)] n , where L=PPh 3 , PBu 3; R=H, OC 4 H 9 or OC 16 H 33 , has been carried out. The multinuclear macromolecules have been prepared by the Stille coupling in the extended one pot version. Oligomers of different chain lengths were obtained and fully characterised by means of spectroscopic techniques. Different organic spacers and precursor metal complexes have been employed in order to study and compare the reaction products. Well-defined oligomers were isolated and X-ray photoelectron spectroscopy technique provided information about the chain length and the nature of the end-groups. Luminescence and absorption studies of the newly synthesised Pt based poly-ynes are also reported. A correlation between the chain length, the nature of ligand phosphines and organic spacers with the optical properties was rationalised. The Pt metal centre played an important role in the conjugation, showing a red shift of absorption maxima upon increasing the number of repeating units. Band gaps of about 2.8–3.0 eV were found, corresponding to blue-light emission with a quantum efficiency up to about 3% for measurements performed in solution.

Nanostructured functional co-polymers bioconjugate integrin inhibitors

Synthesis and properties of bioconjugates based on functionalized polymeric nanoparticles (PNs) and monoclonal anti-Integrin αV CD51 (aI) antibody were investigated. Polymeric and co-polymeric colloidal nanoparticles with different functionalities, i.e., acid, amine, or thiol, namely poly(methylmethacrylate-co-acrylic acid) [P(MMA-co-AA)], poly(methylmethacrylate-co-dimethylpropargylamine) [P(MMA-co-DMPA)], poly(methylmethacrylate-co-allil mercaptane) [P(MMA-co-AM)], were obtained by tailoring emulsion synthesis and fully characterized by means of spectroscopic techniques and scanning electron microscopy (SEM). Bioconjugates (PN/aI) based on P(MMA) or P(MMA-co-AA) were obtained by loading the polymeric nanoparticles with the antibody anti-Integrin with a simple and straightforward immobilization strategy. Bioconjugates qualitative and quantitative loading analyses were carried out by means of polyacrylamide gel electrophoresis 1D-PAGE, MALDI-TOF, and LC/ESI-MS/MS investigations. The biological efficacy of bioconjugates was confirmed by the reduced migration potential of PN/aI-treated human kidney cells (HEK293). The easy immobilization procedure and high immobilization capacity of polymeric nanoparticles together with tuneable chemical functionalities and dimension of the polymeric nanoparticles open applicative perspectives for targeted delivery.

Functional and Nanostructured Materials Investigated by XPS and NEXAFS Spectroscopies

Surface properties of materials play an important role in a number of applications of technologically relevant materials. In the framework of the interest to the soft matter nanostructured systems it emerges the relevance of the task by surface and interfaces, providing the effectiveness of adhesion, presence of molecular organization at nanoscale and surface active sites. In this chapter the information gained about surface study of functional and nanostructured materials have been reviewed as concerning two main investigation methodologies: NEXAFS (Near Edge X-ray Absorption Fine Structure) and XPS (X-ray Photoelectron Spectroscopy). A rather extensive, even if not exhaustive, description of the fundamental basis of the two selected spectroscopies has been illustrated, developing all concepts from an elementary level. Special attention, concerning the investigation methods, has been dedicated to the use of synchrotron plants as sources of radiation with all the peculiarity deriving from this. Several selected, state-of-the-art, significant investigations have been taken as major examples and the achievable information have been discussed, ranging from simple to complex molecular systems.