LM FOTOCHIMICA E MATERIALI MOLECOLARI Titolare: Prof. Pierluigi Reschiglian CORSO OPZIONALE LM FOTOCHIMICA E MATERIALI MOLECOLARI Formazione di Provenienza Studenti: Triennale Chimica Triennale Chimica dei Materiali Crediti Formativi: - 4 lezioni frontali (32 ore)

Contenuti Sistemi dispersi: definizioni e cenni storici, l'importanza dei sistemi dispersi in natura. Principi di chimica-fisica dei sistemi dispersi: stabilità delle dispersioni, interazioni di superficie e intraparticellari, forze elettrostatiche e chimica superficiale, proprietà cinetiche e moto browniano. L'analisi di distribuzione dimensionale e morfologica di campioni dispersi. Principi delle tecniche analitiche e relativi metodi per la loro applicazione all’ analisi di campioni dispersi. Microscopia, Metodi ottici, Coulter counter, Tecniche separative.

Analisi di Nano e Micro Sistemi Dispersi I Sistemi Colloidali: Proprietà e Caratteristiche di Nano e Micro Sistemi Dispersi Spuma Latte Sangue FACOLTA’ DI SCIENZE FF MM NN – ANALISI DI NANO E MICROSISTEMI DISPERSI Vernici Nebbia

What is light scattering? In nature… red sunset blue sky and white clouds Son is very good, indeed! Theoreticals first described by Lord Rayleigh 1871 Notes: Simple questions about our everyday world, such as “Why is the sky blue?”, “How can we see clouds?”, or “Why are sunsets red?” have interesting answers that depend upon light scattering. In fact, it was the question of the blue sky and the polarization of skylight that lead Lord Rayleigh to develop a theoretical description of light scattering in 1871. When light passes through matter, most of the light continues in its original direction. However, some of the light is scattered into new directions. A careful analysis of the scattered light can yield detailed information about the scattering system.

MALS photodiodes Incident light Transmitted light Using MALS we then measure the intensity of the light scattered as a function of the scattered angle. To have real-time, multiangle readings, the detector system has multiple photodiodes around the cell. Incident light photodiodes Transmitted light

Analisi di Nano e Micro Sistemi Dispersi Metodi d’analisi per la determinazione della distribuzione dimensionale e morfologica di campioni dispersi FACOLTA’ DI SCIENZE FF MM NN – ANALISI DI NANO E MICROSISTEMI DISPERSI ESZ Microscopio Elettronico

Size/shape characterization by F4-MALS MALS  rg or RMS – mass average (root mean square) distance of each point in a molecule from the molecule center of gravity. lower limit 10nm F4  rh or Hydrodynamic radius – radius of a sphere with the same diffusion coefficient of the sample. lower limit 1nm F4 and MALS makes a perfectly combined method for the separation and biophysical characterization of biosamples. This is because: --The RMS value, that is the mass-average distance of each point of the particle from the center of gravity of the particle, it is measured by multi angle light scattering without assumptions on molecular shape or conformation. -- The hydrodynamic radius Rh, that is the radius of a sphere with same diffusion coefficient of the analyte, is directly measured from F4 retention.

Analisi di Nano e Micro Sistemi Dispersi Legame covalente del fluoroforo via SiOEt3 Nanoparticelle quali 3D scaffold per il fluoroforo Energy transfer tra le unità di fluoroforo Nanosensori FRET FACOLTA’ DI SCIENZE FF MM NN – ANALISI DI NANO E MICROSISTEMI DISPERSI Purificazione dal fluoroforo non legato Fluoroforo è legato alla matrice Size sorting

Analisi di Nano e Micro Sistemi Dispersi H 3 + diametro=20-30nm 10 20 30 40 -0.05 0.00 0.05 0.10 0.15 0.20 0.25 H G F E C D B Segnale UV a 230 nm (AU) tempo di eluizione (min) Cicloaddizione 1,3-dipolare di azometina illide sul sistema p FACOLTA’ DI SCIENZE FF MM NN – ANALISI DI NANO E MICROSISTEMI DISPERSI

Amyloid-like aggregates: fungal hydrophobins Hydrophobins are small proteins produced by fungi They self-assemble at any hydrophilic-hydrophobic interface Hydrophobins constitute amphipatic membranes Hydrophobins are interesting for medical and technical applications Hydropathy patterns can be used to divide them into classes I and II. The proteins in the two classes differ in the solubility of the aggregates that they form. Class I members form aggregates with similarities to amyloid fibrils. These properties make them a suitable “model” for studying self-assembling proteins. To reach the full potential of these proteins a better understanding of hydrophobin self-assembly process as well as of their behaviour in solution is needed.