Download Optical methods for studying cell mechanics

School of Electrical, Computer and Energy Engineering
PhD Final Oral Defense
Optical Methods for Studying Cell Mechanics
by
Yunze Yang
March 29, 2016
1:00 pm
ERC 490
Committee:
Dr. Nongjian Tao (chair)
Dr. Shaopeng Wang
Dr. Michael Goryll
Dr. Jennie Si
Abstract
Mechanical properties of cells are important in maintaining physiological
functions of biological systems. Quantitative measurement and analysis of mechanical
properties can help understand cellular mechanics and its functional relevance and
discover physical biomarkers for diseases monitoring and therapeutics.
This dissertation presents a work to develop optical methods for studying cell
mechanics which encompasses four applications. Surface plasmon resonance microscopy
based optical method has been applied to image intracellular motions and cell mechanical
motion. This label-free technique enables ultrafast imaging with extremely high
sensitivity in detecting cell deformation. The technique was first applied to study
intracellular transportation. Organelle transportation process and displacement steps of
motor protein can be tracked using this method. The second application is to study
heterogeneous subcellular membrane displacement induced by membrane potential
(de)polarization. The application can map the amplitude and direction of cell
deformation. The electromechanical coupling of mammalian cells was also observed. The
third application is for imaging electrical activity in single cells with sub-millisecond
resolution. This technique can fast record actions potentials and also resolve the fast
initiation and propagation of electromechanical signals within single neurons. Brightfield optical imaging approach has been applied to the mechanical wave visualization that
associated with action potential in the fourth application. Neuron-to-neuron viability of
membrane displacement was revealed and heterogeneous subcellular response was
observed.
All these works shed light on the possibility of using optical approaches to study
millisecond-scale and sub-nanometer-scale mechanical motions. These studies revealed
ultrafast and ultra-small mechanical motions at the cellular level, including motor
protein-driven motions and electromechanical coupled motions. The observations will
help understand cell mechanics and its biological functions. These optical approaches
will also become powerful tools for elucidating the interplay between biological and
physical functions.