Nature of trapping forces in optically induced electrothermal vortex based tweezers

Abstract

Precise manipulation of micro and nanosized particles has enabled investigations into various applications ranging from mechanobiology of biomolecules and cells to self-assembly of two-dimensional colloids. This work is focussed on studying the nature of a noninvasive electrothermal vortex based micro-manipulation tool called rapid electrokinetic patterning (REP). Using the equipartition method, we show that a REP trap is Hookean in nature and has an ultralow trap stiffness on the order of femtonewtons/\ensuremath{\mu}m. The dynamic tunability of an optically induced REP trap makes it a versatile tool for various biophysical applications.