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Optical Manipulation - OM Lab
Research
Research Projects (short description, chronologic order beginning with the newest projects):- Cell mechanics to define/characterize metastasis prone cells
- Photonic force microscopy and optical manipulation of neurites during neuronal differentiation
- Development of a optical tweezers for sample manipulation in X-ray diffraction with Synchrotron light
- Development of optical tweezers setup for precise positioning and manipulation of ultrasound contrast agent microbubbles
- Design and use of diffractive optical elements for micro particles manipulation by means of laser tweezers
Cell mechanics to define/characterize metastasis prone cells
This activity is part of an interdisciplinary project in collaboration with Prof. Giorgio Stanta and Dr. Serena Bonin from the University of Trieste, Department of Clinical, Morphological and Technological Sciences and the Hospital Cattinara, Trieste. The project initiated in 2008 (November) is national (funded by MIUR – the Italian Ministry of Education, University and Research) and the grant allowed the funding of a PhD student in Nanotechnology to work on this activity. The goal of the activity is to measure the viscoelastic properties of different types of tumor cell lines with different aggressiveness by optical tweezers microscopy and correlate these measurements with specific molecular patterns of cell polarization, cell membrane protein expression and cytoskeleton modification. The main approaches to be used are: viscoleastic measurements from the thermal fluctuations of the cells using dynamic light scattering microscopy, elastic modulus/stiffness measurements by opto-mechanical stressing the cells, analysis of the dynamic cell response to force gradients..:. top
Photonic force microscopy and optical manipulation of neurites during neuronal differentiation
This activity is part of the FP7 EU project (NanoScale) started in 2008 which has 6 partners from 4 countries. OM Lab is responsible of a workpackage in which, beside the development of the force spectroscopy technique the goals are to manipulate directly and indirectly the neurites by means of optical tweezers and to deliver with sub-micron spatial resolution very small (femtoliter) volumes of drugs incorporated in lipid vesicles to precised locations of the cell membrane. The activity is a result of a previous collaboration project since 2005 with the Neurobiology Sector of the International School for Advanced Studies (SISSA) Trieste (Prof. Vincent Torre ). A quantitative characterization of forces exerted by neurons during neuronal differentiation and regeneration is necessary for understanding the precise role of molecular motors. Therefore we used optical tweezers to measure for the first time the force exerted by neurites during neuronal differentiation. The force exerted by a single thin filopodium does not exceed 2 pN. In contrast, the force exerted by larger neurites such as lamellopodia ranged up to 10 pN. The measurement setup is based on back focal plane interferometry and video tracking of a trapped silica microbead interacting with the differentiating neurite. The experimental data, high temporal and spatial resolution observation of the fillopodia and lamellipodia, are analysed to understand how the neuron interprets the information received from the surrounding ambient and understand biological mechanisms as for instance the polimerization and depolimerizatin of the actin filaments in the presence of these external signals..:. top
Development of a optical tweezers for sample manipulation in X-ray diffraction with Synchrotron light
The project has been developed since 2003 in collaboration with the Austrian beam-line SAXS at Elettra (Dr. Heinz Amenitsch) and since 2005 also with the Micro-focus ID13 beam line at ESRF Grenoble (Dr. Christian Riekel). The goal of this project is to analyse by SAXS technique single particles or pairs of different particles which are set into contact. To achieve this we built a custom optical tweezers microscope that allow trapping and manipulation of colloidal particles in capillaries and their alignment with the X-ray beam. The microscope has been successfully tested on the experimental platform existent at ESRF Grenoble. The development of a more complex fluidic device for circulating the particles under investigation and the improvement of the optical system is on progress within a collaboration contract signed by ESRF, INFM and IBN. The usefulness of optical and magnetic tweezers will be studied within a workpackage of a recently approved design study EU project (NFFA)..:. top
Development of optical tweezers setup for precise positioning and manipulation of ultrasound contrast agent microbubbles
This project has been developed since 2004 until 2007 in collaboration with Bracco Research (Milan and Geneva Laboratories) and the Physics of Fluids Department from the University of Twente (prof. Michel Versluis). The goal of the project has been to study the dynamics of individual microbubbles under different conditions, in the vicinity or separated of interfaces and other micobubbles. The manipulation of the microbubbles has been achieved using Laguerre Gauss beams and implemented on the experimental platform including the ultrasound transducer and the ultra-fast imaging camera Brandaris existent at the Univeristy of Twente. The experiments showing the influence of the wall interface and the neighboring bubbles allow a quantitative understanding of changes in the bubble dynamics with prescribed boundaries and represents a strong potential for applications in targeted molecular imaging..:. top
Design and use of diffractive optical elements for micro particles manipulation by means of laser tweezers
This project has been developed since 2002 at the LILIT group and is focused on the design and implementation of diffractive optical elements (DOEs) for micro particles trapping and micromanipulation using laser tweezers. I developed techniques to calculate DOEs for multiple trapping in arrays organized in plane and in volume as well and for the transfer of the orbital angular momentum of light to particles. The DOEs were implemented on Liquid Crystal Spatial Light Modulators and micro manipulation was achieved using dynamically computer generated DOEs. Trapping and micro manipulation were tested for dielectric particles (silica and latex micro spheres) and preliminary results were also obtained with biological particles (liposomes, red blood cells, E.Colli bacteria). Trapping and micro manipulation combined with fluorescence microscopy experiments have been used to mimic multipoint mechanical stress of the cell membranes with pN forces, in collaboration with the Institute Jacques Monod, Paris, within a bilateral Italian - French collaboration (Leonardo program) in 2004 and 2005..:. top