A novel luminescent polyhedral oligomeric silsesquioxane (POSS) containing in the structure a fluorescein derivative molecule and a carboxylic functionality, suitable to anchor different organic compounds (dyes, markers, drugs, contrast agents, …), was successfully synthesized and characterized in this manuscript by a multidisciplinary approach. An emission enhancement of the dye of ca. four times was found after reaction with POSS, rendering this new hybrid compound a promising contrast agent for optical imaging. In vitro tests on tumoral HeLa cells demonstrated that the luminescent POSS (namely POSS_F), here described, is able to be taken up in the cell cytosol by an efficient and selective process. Its high chemical versatility and peculiar properties could render this novel bifunctional POSS a molecular platform for biomedical applications.

A novel hybrid organic/inorganic clay prepared by intercalation of a luminescent polyhedral oligomeric silsesquioxane (POSS) in a nanosized synthetic saponite clay was synthesized and characterized by a multidisciplinary approach including XRD, HRTEM, TGA and UV-Vis and photoluminescence spectroscopies. The luminescent POSS was obtained by linking a cyanine (IRIS3COOH) on the POSS cage functionalized with two amino groups (sample named IRIS3-POSS-NH 2 ). One of the amino groups served for the inclusion in the saponite interlayer space. The final hybrid material (IRIS3-POSS-NH 3 /SAP), characterized by high quantum efficiency and improved thermal and photochemical stability with respect to the pure luminescent POSS and dye, was successfully tested as the luminescent layer in a hybrid light emitting diode (HLED) device.

A new hybrid photostable saponite clay with embedded donor-acceptor dyes was prepared and characterized in this work. The saponite is intercalated with a luminescent polyhedral oligomeric silsesquioxane, which transfers the photoexcitation energy directly to an acceptor dye (rhodamine B). The obtained composite material was characterized by means of XRD, TEM microscopy, and UV/Vis and photoluminescence spectroscopy. A physicochemical study showed that the system behaved as an efficient Förster resonance energy transfer pair, owing to the very good spectral overlap of donor emission (λem =510-540 nm) and acceptor absorption in the λ=530-570 nm range. The hybrid material represents the first example of a photonic antenna based on a synthetic saponite clay and can be considered a step forward in the search for new, efficient, and stable materials suitable for light-harvesting applications.

Polymer light-emitting diodes (PLEDs) have attracted growing interest in recent years for their potential use in displays and lighting fields. Nevertheless, PLED devices have some disadvantages in terms of low optoelectronic efficiency, high cost, short lifetimes and low thermal stability, which limit their final applications. Huge efforts have been made recently to improve the performances of these devices. The addition of inorganic or hybrid organic-inorganic nanoparticles to the light-emitting polymers, for example, allows their thermal stability and electroluminescent efficiency to be increased. Following this approach, novel PLED devices based on composite films of PPV-derivative copolymer (commercial name Super Yellow, SY) and octaisobutil POSS, were developed in this study. The device containing Super Yellow loaded with 1 wt% of POSS showed higher efficiency (ca. +30%) and improved lifetime in comparison to PLED prepared with the pure electroluminescent polymer. The PLED devices developed in this study are suitable candidates for automotive dashboards and, in general, for lighting applications.

Nanoparticles (NPs) entering the human body are immediately confronted with the innate part of human immune system. In particular, monocyte and neutrophil granulocytes readily clear particles by phagocytosis, even if in the case of NPs the uptake mechanism may be classified as macropinocytosis. Among engineered nanoparticles, in the last years, siliceous materials have emerged as promising materials for several applications ranging from catalysis to biomedical. The polyhedral oligomeric silsesquioxanes (POSS) are nanodimensional, easily synthesizable molecular compounds and POSS-based systems are promising carriers for biological molecules. In this work, the ability of human granulocytes to uptake positively and negatively charged POSS was measured using a simple flow cytometry analysis based on cell size modifications. The data obtained showed that after a 30 min exposure only positive NPs were uptaken by human granulocyte using both macropinocytosis and clathrin-mediated mechanisms as demonstrated by uptake inhibition mediated by amiloride and chlorpromazine.