Plasmonic optical trapping in biologically relevant media.
We present plasmonic optical trapping of micron-sized particles in biologically relevant buffer media with varying ionic strength. The media consist of 3 cell-growth solutions and 2 buffers and are specifically chosen due to their widespread use and applicability to breast-cancer and angiogenesis studies. High-precision rheological measurements on the buffer media reveal that, in all cases excluding the 8.0 pH Stain medium, the fluids exhibit Newtonian behavior, thereby enabling straightforward measurements of optical trap stiffness from power-spectral particle displacement data. Using stiffness as a trapping performance metric, we find that for all media under consideration the plasmonic nanotweezers generate optical forces 3-4x a conventional optical trap. Further, plasmonic trap stiffness values are comparable to those of an identical water-only system, indicating that the performance of a plasmonic nanotweezer is not degraded by the biological media. These results pave the way for future biological applications utilizing plasmonic optical traps.
Department of Electrical and Computer Engineering, University of Illinois at Urbana-Champaign, Urbana, Illinois, United States of America.
Brian J
BJ
Roxworthy
Department of Mechanical Science and Engineering, University of Illinois at Urbana-Champaign, Urbana, Illinois, United States of America.
Michael T
MT
Johnston
Department of Bioengineering, University of Illinois at Urbana-Champaign, Urbana, Illinois, United States of America.
Felipe T
FT
Lee-Montiel
Department of Mechanical Science and Engineering, University of Illinois at Urbana-Champaign, Urbana, Illinois, United States of America.
Randy H
RH
Ewoldt
Department of Bioengineering, University of Illinois at Urbana-Champaign, Urbana, Illinois, United States of America.
Princess I
PI
Imoukhuede
Department of Mechanical Science and Engineering, University of Illinois at Urbana-Champaign, Urbana, Illinois, United States of America.
Kimani C
KC
Toussaint
D003470:Culture Media; D036103:Nanotechnology / Q000379:methods*; D052898:Optical Tweezers
D003470:Culture Media