Optical Tweezers at The National Institute of Standards and Technology and Davidson College Research performed by: Rachel Patton McCord
Dec 23, 2015
Optical Tweezers
at
The National Institute of Standards and Technology and
Davidson College
Research performed by:
Rachel Patton McCord
Background: Optical Tweezers Physics • Balancing Forces:
• Scattering Force- “Radiation Pressure”• Gradient Force- Restoring force analogy to spring
Figure from: Svoboda and Block, 1994.
Physics, cont.• Tight focus = largest gradient force
• obtained with microscope objective
Images from: http://www.olympusmicro.com/primer/java/nuaperture/index.html
Basic Components
Objective LensL2 L3L1
f1 + f2 f3 16 cm
Image created from Physlet at http://webphysics.davidson.edu/Course_Material/Py230L/optics/lenses.htm Physlet by Dr. Wolfgang Christian and Mike Lee
Laser
NIST Alignment
• Gained experience with alignment by working on a two-laser trap setup.
Results
Single Trap
Both Traps Together
NIST Optical Tweezers Applications
• Liposomes• Stretching/Nanotubes• Microreaction Vesicles
• Single Mitochondria Isolation and Sorting• Available for PCR and genetic analysis
• Antigen/Antibody Binding• Quantum Dots in Polymersomes• Fluorescence Resonance Energy Transfer and
single molecule imaging
Davidson Setup
Results• Trapping microspheres in 3D
• 10 mW minimum power from laser (about 2 mW at the slide)
• Trapping single celled chlamydomonas
Image from: http://www.ucmp.berkeley.edu/greenalgae/chlorophyceae.html
Future Plans
• Force calibration• Measuring the swimming force of
chlamydomonas• Flagellar mutantsFurther in the future:• Physics Applications
• Stretching- elasticity, determining shear moduli
• Biology Applications• More chlamy- phototaxis• Virus adhesion
Acknowledgments• Dr. Kris Helmerson, Jeff Wells, Lara Crigger, Rani Kishore, Joe
Reiner at NIST
• Dr. John Yukich and Dr. Karen Bernd