Documento senza titolo

2019 University of Rome Tor Vergata

"Beyond Borders 2019"

SRRS: Slot Ring Resonator for biochemical Sensor project

A hybrid-waveguide ring resonator sensor is proposed for the fabrication of the device, goal of the present project. It combines a high sensitive slot-waveguide with a low loss and strongly guiding strip waveguide in a single ring. The innovative aspect we present in this paper is twofold. First, we propose the hybrid-waveguide ring resonator concept as photonic sensor for optical sensing and present an approach to optimize this ring resonator for homogeneous sensing. Second, we provide a proof of concept of homogeneous sensing with the optimized ring structure and show an increased overall sensitivity compared to most traditional slot- and strip-waveguide ring resonators. The overall sensitivity is quantified by a figure of merit that takes into account the optical losses and the ring resonator sensitivity. The project is aimed to functionalize the hybrid ring resonator by means of functionalized nanodiamonds embedded in porous polymer matrix. The use of nanodiamond, a material with high refractive index, could improve sensitivity of the sensor and are the perfect platform for chemical functionalization. Nanodiamond will be functionalized using some enzyme sensitive to ROS such as superoxide dismutase (SOD), catalase (CAT) and Glutathione peroxidase (GPx) in order to sensitize the device to ROS.

2017 University of Rome Tor Vergata

"Mission Sustainability"

GHOST: GrapHene Oxide quantum dots in Sol-gel maTerials for environmental sensing applications

In the last 3 years the international community expressed an increasing interest in the study of Graphene Oxide Quantum Dots (GOQDs), especially in liquid solutions, since they present a characteristic photoluminescence emission sensible to the external environment (presence of heavy metal ions such as Hg2+, Cu2+, Pb2+ and Cr3+). This important property can be exploited for sensing application in the field of safe environment, water quality and human health.
The GHOST project proposes to insert luminescent GOQDs in semi-permeable solid matrices synthesized by sol-gel techniques. These offer many advantages such as extensive manageability, reduction of possible dispersion of GOQDs in the external environment, compactness and great versatility. Moreover, the material porosity, that can be modified during the synthesis, will allow the modulation of the sensor response thanks to the different permeabilities of the analytes and will favor a better sensibility and selectivity to the dangerous ions. We propose to synthesize and characterize sol-gel materials doped with GOQDS as bulks, thin films and coatings of the active part (core) of an optical fiber in order to have heavy metal ions sensors of different geometries, suitable for being tested in different environments.
The final goal of the research will be the development of solid-state sensors based on GOQDs able to detect dangerous ionssuch as Hg, Cd, Co, Ni, Pb and As in aqueous, semi-aqueous and semi-solid environments.

2015 University of Rome Tor Vergata

"Consolidate Foundations"

BILLY: GaAs_(1-x)Bi_x aLLoY: a potential candidate for Future Photonic Devices

The mission of this project is to develop GaAsBi alloys on a GaAs substrate that offer the potential of engineering optimized band structures for covering the entire band for high-speed optical-fiber telecommunications. The development of fundamental knowledge on GaAsBi alloys, as established for other III-V compounds, is envisioned as the base for the success of such devices. However, they suffer from problems related to epitaxial growth, which have slowed down their development up to now. The large size, low electronegativity and poor miscibility of the Bi atoms in GaAs make it difficult to incorporate the required high concentration of Bi atoms while preserving good crystalline quality of the material. Based on our long-term experience with III-V semiconductor heterostructures growth, we propose in this project to grow by Molecular Beam Epitaxy (MBE) and investigate GaAsBi alloys. Our aim is to improve Bi incorporation in the material in order to achieve Bi concentration greater than 10-12% (required to suppress Auger recombination) and to obtain optimal optical emission at room temperature in the operating window at 1.55 micron. To this end, we will investigate the role of the elastic strain on Bi incorporation, until now unexplored for this material system. We will perform combined optical, structural and spectroscopic investigations, this being facilitated by the long-term expertise of local and international groups collaborating in this research.

2014 University of Rome Tor Vergata

"Uncovering Excellence"

Nanodiamond: a bright shuttle for molecules in the cell space

KEYWORDS: Nanodiamonds, drug delivery, photoluminescence, bioactivity

New scenarios in the design of systems for biomedical applications are now been opened by the availability of multifunctional nanomaterials that can be used to image or label biomolecules and to assist in drug delivery, making possible to define new reliable and effective strategies for theranostic approaches. Detonation nanodiamonds (DND) are carbon sp3 nanoparticles sized from 2 to 8 nm. This material not only bares the well-known bulk diamond proprieties like hardness, mechanical resistance, stiffness but also possess several unique capacities due to nanosized dimensions like: high surface area (up to 300 m2/g) and the possibility to easily manipulate the chemical groups on the surface. The peculiar surface chemistry and higher biocompatibility distinguish DND from all other carbon nanostructure. Nanodiamonds were identified as the less toxic among nanocarbons (i.e. carbon blacks, fullerenes, carbon nanotubes) in a wide variety of cell lines: they generally induced neither significant oxidative stress nor apoptosis during cell treatments (Horie et al., 2012). DND are readily internalized by the cells presumably via endocytosis and do not interfere with cells viability even at high concentrations. These promising results open the possibility to use DND as an ideal drug- shuttle for cells The coupling of DND with natural substances and their combined use in cancer therapy is proposed. To preserve biological activity of natural substances the carriers have to interact with the antioxidant preventing chemical alterations and release efficiently the active molecules into target cells. Understanding chemical interactions between drugs and DND surface is a keystone to enhance drug loading and comprehend meds releasing mechanisms in cells. The investigation of the electronic interactions between the chemical species involved (molecules, functional groups and ND) which represent a key point to understand the biological activity of such adducts, is one object of this research project.

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2014 University of Rome Tor Vergata

"Uncovering Excellence"

PHANTOM - PHotonic ApplicatioN in diaTOM frustules

KEYWORDS: Diatoms,Frustules,Photoluminescence,Dyes,Random laser,Biophotonic application

Diatoms are unicellular aquatic microalgae possessing amazing self-assembled ordered micro- and nano-porous hierarchical silica cell walls called frustules. The quasi periodic and highly regular pore patterns on the diatom surface are very attractive for applications based on optical and photonic properties of materials. Our proposed pioneering research aims to explore the multiple scattering and localization of light shown by diatom frustules in order to amplify their photoluminescence in a random laser (RL), as this technology is highly attractive for environmental monitoring, medical diagnostics and advanced packaging inspection. RL is a special type of laser in which the optical feedback is due to light scattering in an amplifying medium instead of a conventional optical cavity. The major aim will be to study a set of selected frustules with different shapes and pore patterns, obtained from diatom cultivation in large scale photobioreactors, for comparative analysis of their random lasing effect doping the bioscaffold with organic dyes having luminescence in the visible range. A multidisciplinary approach combining expertise from biology, physics and materials sciences, relying on high-resolution instrumentation and advanced algal cultivation equipment, is necessary. This will allow to go beyond our past research on RL effect in commercial diatomite and natural diatom samples and is highly prospect to inspire novel developments in photonics and materials sciences.