Scientific Highlights

Nanoscale magnetic materials play a central role in many areas of science and technology, such as high density data storage, development of advanced materials, and biomedical devices for cancer hyperthermia therapy, drug delivery and rapid cell sorting. At reduced size, magnetic properties of individual particles are  affected by surface states due to the high surface to volume ratio, and  the particle shape becomes important. Therefore, magnetic nanoparticles assemblies have to be investigated by means of techniques capable to record magnetic and topography texture simultaneously at both high magnetic sensitivity and nanometer spatial resolution. Magnetic Force Microscopy (MFM) can match both requirements, since it provides the nanometer resolution typical of dynamic atomic force microscopy (AFM), making single particle studies possible.

Supported lipid membranes (SLM) are widely used models to investigate the action of pathogenic agents on cell membranes. The study of their nanomechanical properties by means of advanced AFM Force Spectroscopy, in conjunction with structural characterizations, has provided new insights on the effect of medically relevant peptides on cell membranes. Beta-amyloid peptides (Aß) are trigger agents in Alzheimer’s disease, but their mechanism of action at the molecular level is unknown and their interaction with the neural membrane is crucial to elucidate the onset of the disease. We have investigated the interaction of water soluble forms of beta-amyloid Aß(1-42) with lipid bilayers supported by polymer cushion.

We developed the fabrication process of nanocomposite coatings of organic capped colloidal TiO² nanorods dispersed into a poly(methyl methacrylate) matrix, with rising value of refractive index from the bottom to the top layers, and UV-induced surface wettability alteration, in a reversible manner. This behaviour is attributable to preferential dispersion of the TiO² nanoparticles towards the superficial layers of the coatings. Above a critical TiO² loading, the nanorods at the surface form aggregates deteriorating the optical and the surface properties of the nanocomposites. We developed a new technique based on UV pulsed laser irradiation of acrylate polymers-based solutions, that generates in a single step the separation of the initial clusters of colloidal TiO² nanorods (NRs) into single, clearly separated units.

In the last years far-field optical super–resolution and nanoscopy methods with a theoretically unlimited resolution, which exploit the photophysical characteristics of labeling molecules, showed their huge potential in materials science applications and in particular in biological sciences. We have embarked on a research program aiming to improve ultra-high resolution methods and, more specifically, to make them applicable to thick scattering samples. In fact, an open challenge is still represented by the development of new approaches for 3D super-resolution imaging in depth, allowing the widening of super-resolution applications to thick samples (>15 μm). Within this scenario, we implemented light sheet and two-photon excitation approaches. We demonstrated three-dimensional super-resolution live cell imaging through thick biological specimen (>50 μm), by coupling far-field individual molecule localization (IML) and selective plane illumination microscopy (SPIM): this brand new set up is called IML-SPIM. This technique allowed to image cellular spheroids with < 35 nm lateral precision and sub-diffraction resolution in depth.