Dipartimento di Fisica - Tesi di Dottorato

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Questa collezione raccoglie le Tesi di Dottorato afferenti al Dipartimento di Fisica dell'Università della Calabria.

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Author: search.filters.author.Bartolino, Roberto

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    Active plasmonic nanostructures for biomedical applications
    (Università della Calabria, 2020-03-27) Chatterjee, Sharmistha; Bartolino, Roberto; Strangi, Giuseppe
    Real-time and label-free detection of protein molecules at ultralow concentration in their natural state is considered the “Holy-Grail” in biomedical research. Protein molecules pop up in the bodily fluids such as saliva, blood serum, at early stage of any infection or disease and circulate throughout the body. Therefore, the emergence of that particular infection or disease can be envisioned through the detection of the signature protein markers. The early detection of the disease would help to start the treatment early, and thus ensure therapeutic success which will eventually increase the survival rates and quality of life. The early detection of protein molecules is necessary for the diagnostics as well as for environmental monitoring, emergency response and homeland security. But the desired detection of protein molecules in the early stage is extremely challenging because of the ultralow concentration of the protein markers in the bodily fluid at the early stage and their acutely small size (< 3 nm). One way to overcome this hurdle is to use the extraordinary electromagnetic responses of noble metal nanoparticles (MNPs). Here stable gold nanostars (AuNS) have been synthesized to use their property for sensing. A surfactant-free, simple, one step wet-chemistry method was used to synthesize these spiky nanoparticles, which were stable in aqueous media for more than five months. Based on their characterization and the numerical analysis, it has been realized that these nanoantennas could be an efficient agent for the early detection of disease. Furthermore, for the marker detection, the heterodimeric nanogap, created between a nanostar antenna tip and a gold nanosphere, was seen to be more effective than those single nanostar antennas because of their higher intensity enhancement capability and also the optimum electric field map at the hot-spots which acts as the binding site for molecule. Both the AuNS antenna and the hybrid one could be easily converted to a biosensor, by anchoring suitable anti-bodies on the surface of the nanoantenna. Surprisingly, these gold nanostar antennas were seen to have both the non-edge breathing modes and the well-known edge dipolar mode. The optically active edge dipolar mode will be useful for the detection of protein molecules by using their localized surface plasmon resonance (LSPR) effect which is same as any conventional plasmonic biosensor. But the non-edge breathing modes of nanostar antenna will be helpful to determine the mass of adsorbed analyte based on the cantilever principle. The mass estimation (having the information about the polarizability and the size) of the markers is very crucial because it would provide the information about the number of amino acids present in that molecule which will help for better understanding of its molecular structure and thus will be useful for designing its anti-agent. This efficient acousto-plasmonic nanoantenna therefore could become a key element at a point of care. To go one step forward in this research area, Fano-lineshape based sensing was thought to be a promising idea. Here the reported Fano line-shape arises from the coupling of the gold nanorods dipped in thermo-responsive polymer matrix and a silver thin film. The Fano system was seen to respond to both the change in external temperature and the refractive index. This kind of Fano system will be helpful for the label-free detection of the foreign protein molecule with high efficiency and also for identifying the marker’s thermodynamic state and reactions of the molecule which is crucial for protein engineering. All these constitute the base of the discussion of part I of the thesis which is about the light harvesting plasmonic nanoantennas. In the 2nd part of the thesis, AZO metasurfaces and their optical activities are discussed. Aluminium doped Zinc Oxide (AZO) is a low-loss material and popular as an alternate plasmonic material. The highly ordered AZO nanotubes array system has seen to have gas sensing capability. The reported H2 gas detection within a very short time can make this system suitable for industrial application. The detection of H2 gas of lower concentration with the help of these nanostructures is also useful to detect the presence of bacteria by tasting their exhaled H2 gas. On the other hand, the AZO solid nanopillars arrays are seen to have generalized Brewster angle phenomena which can be useful for many applications including the optical switching. Lastly, some additional works have been described in a brief way. In this section, photonic nanojet related theoretical study, asymmetric sound transmission behaviour shown in 3D printed acoustics metamaterials, focal-length tunability of metalens and plasmon assisted cancer therapy has been reported. As per my belief and understanding, all these studies reported in this thesis will enrich the related research areas.
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    Combined use of X-ray Fluorescence Microscopy, X-ray Phase Contrast Imaging, Atomic Force Microscopy and X-ray Nanotomography for high resolution quantitative Fe mapping in inflamed cells.
    (2017-07-17) Gramaccioni, Chiara; Carbone, Vincenzo; Lagomarsino, Stefano; Bartolino, Roberto
    The PhD project is based on the applications of several x-ray microscopy techniques for compositional and morphological studies at nanoscale spatial resolution to a biological problem, i.e. the quantitative determination of morphological and compositional properties of epithelial cells. Three x-ray microscopy techniques were exploited in this work: X-ray fluorescence microscopy, X-ray phase contrast imaging and nanotomography, which were made at the ID16NI beamline of the European Synchrotron Radiation Facility in Grenoble, France. In addition to synchrotron-based techniques, also Atomic Force Microscopy was performed. The latter was used for morphology characterization, and forcalibration and comparison purpose. The main aim of this study was to quantitatively determine the map of iron concentration at nanoscale spatial resolution of epithelial cells infected by bacterial pathogens in the presence or absence of lactoferrin (Lf), an iron-chelating glycoprotein of natural immunity. Two experiments have been carried out at ESRF, one on freeze dried cells, and one on frozen hydrated cells this last using the cryo stage foreseen in the Id16 NI beamline, in order to examine cells as close as possible to their native state, and to avoid radiation damage. The measurement and data analysis protocols have been carefully studied for optimal combination of all the techniques, to give quantitative results. Iron concentration and mass fraction maps have been obtained, which give an insight about the modification of iron spatial distribution under the influence of lactoferrin. Moreover, for the first time it has been demonstrated the possibility to obtain quantitative element concentration in cells through the combination of x-ray nanotomography in phase contrast and x-ray fluorescence microscopy.
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    Interaction of waves and particles with inhomogeneous structures in heliospheric plasmas
    (2015-12-18) Pucci, Francesco; Bartolino, Roberto; Malara, Francesco
    In questo lavoro vengono affrontati alcuni problemi ancora non risolti che riguardano la fisica dell’eliosfera. Nell’introduzione vengono esposti i risultati finora raggiunti nella ricerca in questo campo e presentate le tematiche, ancora oggetto di dibattito scientifico, che vengono affrontate nel lavoro. Il primo capitolo riguarda la messa a punto di un codice numerico per la risoluzione delle equazioni della magnetoidrodinamica (MHD) in configurazione 2.5 dimensionale; in particolare, sono state implementate delle condizioni al contorno che simulano l’ingresso di onde mediante moti trasversali, oppure bordi aperti, in entrambi i casi utilizzando un metodo basato sulle caratteristiche proiettate. Tale codice `e stato usato per modellizzare l’interazione tra onde e strutture di equilibrio disomogenee alla base dei “buchi coronali”, ossia quelle regioni dell’atmosfera solare da cui si origina il vento solare. Il modello ha mostrato la formazione precoce di uno spettro, con formazione di piccole scale localizzate lungo le separatrici magnetiche oppure in vicinanza dei punti neutri ad X, ove ha luogo un fenomeno di riconnessione magnetica alternata. Il secondo capitolo `e dedicato allo studio della generazione di Kinetic Alfv´en Waves a seguito della propagazione di onde di Alfv´en in mezzi disomogenei. Tale lavoro `e stato svolto sia tramite l’impiego di simulazioni Hall-MHD, sia di simulazioni cinetiche di tipo Vlasov-ibrido; queste ultime hanno permesso di evidenziare la formazione di strutture non-termiche nella funzione di distribuzione degli ioni, come anisotropie di temperatura e fasci di particelle accelerate. Nel terzo capitolo viene affrontato il problema della accelerazione di particelle in turbolenza. Attraverso simulazioni di tipo “test particle” viene studiato il processo di accelerazione di particelle in una turbolenza 3D ottenuta in approssimazione di MHD ridotta. I risultati prelimanari mostrano una prevalenza di accelerazione nella direzione del campo magnetico medio e una dipendenza dell’accelerazione dal numero di Reynolds del sistema fisico considerato. Il quarto capitolo rigurda il problema del trasporto di particelle in turbolenza MHD. Utilizzando un modello di turbolenza sintetica, `e stato condotto uno studio parametrico che ha evidenziato come i coefficienti di difdiffusione parallelo e perpendicolare al campo magnetico medio dipendono da parametri quali la lunghezza dello spettro, l’ampiezza delle fluttuazioni e il livello di intermittenza. I risultati ottenuti trovano applicazione a numerosi problemi riguardanti la diffusione di particelle energetiche nell’eliosfera. Infine, nelle conclusioni vengono riassunti brevemente i risultati ottenuti e presentati i possibili sviluppi delle ricerche effettuate.
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    Advanced Materials (Ceramics in particular) for Structural Applications
    (2015-12-15) Koduru, Hari Krishna; Bartolino, Roberto; Versace, Carlo; Scaramuzza, Nicola
    The study of ‘Intrinsic and Metal nano particles doped polymer thin films for soft matter applications and nanostructured Hyperbolic metamaterials’ is an challenging and dynamic field of research with significant implications in the development of novel technologies, like gas sensors, bio-medical application and engineering of spontaneous emission of florescent molecules. In the present investigation, we presented research work in two directions. We prepared Polymer thin films by homemade Cold Plasma Polymerization technique and studied their Microstructural, Optical and dielectric responses as a function of thin film growth parameters, in view of gas sensor applications. In other direction, we fabricated lamellar structured Hyperbolic Metamaterials by employing physical and chemical vapour thin film deposition techniques and employed them as effective substrates to engineer the life time of florescent dye molecules. The first part of this thesis is devoted to preparing Polypyrrole (PPy) thin films of nano sized thickness, by Cold plasma polymerization technique and analyzing the influence of Plasma power on Microstructural, Optical, wetting and dielectric properties of grown PPy films. Fabricating layered structures of “PVA/AgNPs/PVA” thin films to investigate the influence of rate of distribution of AgNPs on dielectric responses of PVA matrix to employ them as a gas sensor applications, whose study is still open and is getting substantial interest in industrial and academic environments. Enhancement of spontaneous emission is a dynamic and challenging fundamental quantum phenomenon in optics and in nutshell it opens new avenues for spectrum of futuristic applications. Metamaterials are artificially designed nanocomposite materials, in which bulk electromagnetic properties arise due to underlying structural resonances and near field coupling between the designed sub-wavelength building blocks. Metamaterials promise to alleviate the classical limitations of optics and led to exotic applications such as negative refraction, sub-wavelength resolution imaging, invisibility devices and perfect absorbers. In the second part of this thesis, we fabricated Hyperbolic metamaterials and proposed new grating coupled hyperbolic metamaterial (GCHMM) configuration for the enhancement of spontaneous emission rate of dye molecules by exploiting the unique property of a hypergrating to outcouple and extract the non-radiative plasmonic modes.
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    Soft matter for active plasmonics and applications
    (2015-12-15) Palermo, Giovanna; Bartolino, Roberto; Umeton, Cesare Paolo
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    Nanomechanics and nanotribology of protein films
    (2015-12-15) Patil, Navinkumar Jayvant; Bartolino, Roberto; Zappone, Bruno
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    Self-assembly of structural defects and nano-objects in liquid crystal films
    (2015-12-21) Gryn, Iryna; Bartolino, Roberto; Zappone, Bruno
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    Across Scales Approach Based on Exciton-Plasmon Coupling for Low Loss Optical Metamaterials
    (2015-12-15) Dhama, Rakesh; Bartolino, Roberto; Versace, Carlo; De Luca, Antonio
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    <> study wind behavior from the micro to the mesoscale of different temporal and spatial horizons: turbulent regime, mean and climate
    (2014-11-13) Tiriolo, Luca; Bartolino, Roberto; Sempreviva, Anna Maria; Carbone, Vincenzo