University of Ljubljana Faculty of Mathematics and Physics. Microrheology with optical tweezers. Biljana Stojković Mentor: Prof. Dr Igor Poberaj. Ljubljana, December 4th, 2012. Outline. Introduction Microrheology Optical tweezers. Passive Microrheology Active Microrheology
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Faculty of Mathematics and Physics
Microrheology with optical tweezers
Mentor: Prof. Dr Igor Poberaj
Ljubljana, December 4th, 2012
Rheology is the study of the deformation and flow of a material in response to applied force.
Resultant shear stress:
“rheology on the micrometer length scale”
How we could describe the trapping of dielectric bead?
Linear response theory:
Oscillations of trap:
The response of the bead is:
The equation of motion:
The viscoelastic moduli are calculated as:
Mutual response functions:
Single particle response functions:
Complex viscoelastic modulus:
Bacteria – single cell organisms
Free-floating organisms attach to a surface
Colonies of bacteria embedded in an extracellular matrix (EPS)
The production and assembly of cells, polymer, cross-links and surfactants result in a structure that is heterogeneous and dynamic.
We will use optical tweezers to study viscoelastic properties of different biological samples;