Synthesis and Characterization of Mitochondria-Targeted Triphenylphosphonium Bolaamphiphiles.

In this chapter we describe: (1) the procedure for the synthesis of four single chain bolaamphiphiles, displaying chains of 12, 16, 20 and 30 methylene units and triphenylphosphonium moieties as headgroups (TPP1-TPP4); (2) the methods used to characterize TPP1-TPP4 spontaneous aggregation in aqueous solution. We illustrate the determination of Krafft point and cac by conductivity measurements and the procedures used to investigate dimensions, morphology, and stability by dynamic and dielectrophoretic laser light scattering, dialysis, transmission electron microscopy, and Raman spectroscopy measurements.

Experimental Evidence of Single-Stranded DNA Adsorption on Multiwalled Carbon Nanotubes.

Noncovalent DNA functionalization is one of the most used routes for the easy dispersion of carbon nanotubes (CNTs) yielding DNA-CNTs complexes with promising applications. Definition of the structure of adsorbed DNA is crucial, but the organization of polymer at the carbon interface is far from being understood. In comparison to single-walled nanotubes, not much effort has been devoted to assessing the structure of the adsorbed DNA on multiwalled carbon nanotubes (MWCNTs), where their metallic nature, large size, and polydispersity represent serious obstacles for both experimental and theoretical studies.

Aggregation behaviour of triphenylphosphonium bolaamphiphiles.

Hypothesis: Bolaamphiphiles are characterized by wide polymorphism of their aggregates, due to the connection of the headgroups that renders their investigation very intriguing in several technological applications. Some bolaamphiphiles displaying the triphenylphosphonium motif (TPP-bolaamphiphiles) were previously explored for their ability in crossing the mitochondrial membranes but their colloidal features, which are crucial for the potential development of an effective drug delivery system, were never investigated.

Experiments: Single chain TPP-bolaamphiphiles, featuring chains of 12, 16, 20 and 30 methylene units, were synthesized and their aggregation features (Krafft point, cac, dimensions, morphology, stability) were investigated by conductivity, dialysis, transmission electron microscopy, Raman spectroscopy, dynamic and dielectrophoretic laser light scattering measurements.

Overcharging and reentrant condensation of thermoresponsive ionic microgels.

We investigated the complexation of thermoresponsive anionic poly(N-isopropylacrylamide) (PNiPAM) microgels and cationic ε-polylysine (ε-PLL) chains. By combining electrophoresis, light scattering, transmission electron microscopy (TEM) and dielectric spectroscopy (DS) we studied the adsorption of ε-PLL onto microgel networks and its effect on the stability of suspensions. We show that the volume phase transition (VPT) of microgels triggers a large polyion adsorption.