"Light microrobotics in biophysics" by Pal Ormos (Institute of Biophysics, Biological Research Centre, Hungarian Academy of Sciences)

Thursday, February 16, 2017 - 4:00pm to 5:00pm
Physics and Astronomy Colloquium

Thursdays, 4:00-5:00 pm

1-434 Physics and Astronomy (map)
Reception from 3:30-4:00 p.m.
(unless otherwise posted)


Guest Speaker: Pal Ormos (Institute of Biophysics, Biological Research Centre, Hungarian Academy of Sciences)

Talk Title:  “Light microrobotics in biophysics”


In the basic scheme of optical micromanipulation a focussed Gaussian light beam traps a spherical object defining its position. Since typically objects of micrometer size are grabbed by pN forces, the method is extremely useful in the study of biological objects. The possibilities can be vastly extended if the trapping light is structured and the object has appropriate non trivial shape. Key components of the procedure are the generation of structured trapping light field and the fabrication of complex shaped microparticles and the generation of structured trapping light field.

Beam shaping is achieved by the use of Spatial Light Modulators (SLM), freely configurable optical traps actuated in real time are generated by this system. Two-photon excitation induced photopolymerization is the method to produce particles with shapes of unlimited complexity, generating micrometer sized objects to be manipulated: microtools, models of biological objects etc. By the combination of these technologies complex manipulation schemes can be realized, creating a new field of light robotics.  I will show characteristic examples to illustrate the possibilities.

The grabbed objects can be oriented, rotated, creating an optical wrench that enables the measurement of the torsional properties of biological micromolecules. With the help of the light actuated microtools one can determine local mechanical properties of biological objects, local fluorescence or Raman excitation with submicrometer resolution can be achieved using plasmonic excitation mediated by appropriate microtools. The indirect optical manipulation of live cells with the help of the manipulators enables the separation of the trapping light from the trapped object, thus preventing light damage of the cells, so that a prolonged investigation becomes possible. 

Optically manipulated microparticles also offer excellent model systems to study biological motion in a well-controlled manner, in detail not possible on native systems. Two examples will be discussed: Hydrodynamic synchronization and quasi-autonomous moving robots driven by light.

For more information, contact Jay Hauser

We thank the following people for their contributions to the wine fund for the post-colloquium reception:
Prof. Dolores Bozovic, Prof. Mike Cornwall, Prof. Bob Cousins, Prof. Andrea Ghez, Prof. Karoly Holczer, Prof. Eric Hudson, Robert Huff, Prof. Alex Kusenko, Prof. Myank Mehta, Prof. John Miao, Prof. Roberto Peccei, Prof. Claudio Pellegrini, Prof. David Saltzberg, Prof. Jean Turner and Prof. Ben Zuckerman.

1-434 PAB