Energy issues for construction of 10 nm sized electrostatic traps in saline

In addition to optical tweezers, magnetic tweezers and dielectrophoresis technique, trapping and manipulating micro or nano particles with electrostatic tweezers attracted attention in recent years. Here we present a simulation study on the contributions of electrostatic energy, change of entropy, as well as van der Waals interaction in the trapping performance of a 10 nm sized, pentagon shaped nano trap for a charged nanoparticle in saline. The results show that the system has a moderate trapping well of moderate depth; van der Waals interaction enhances the trapping capability, and the entropy term induced in distribution contributes significantly in the trapping capability. This work provides some valuable clues to the development of practical submicron devices of electrostatic tweezers working in a solution with ions.