Nanoparticle trapping is considered to be more challenging than trapping micron-sized objects because of the diffraction
limit of light and the severe Brownian motion of the nanoparticles. We introduce a nanoparticle trapping approach based
on plasmonic nanostructures, which consist of nanopillars with high aspect ratio. The plasmonic nanopillars behave as
plasmonic resonators that rely on paired nano-pillars supporting gap plasmon modes. The localized surface plasmon
resonance effect provides strong electromagnetic field enhancement and enables confinement of nanoparticles in three
dimensional space. Numerical simulations indicate that the plasmonic structure provides stronger optical forces for
trapping nanoparticles. The study of thermal effect of the plasmonic structure shows that the impact of the thermal force
is significant, which may determine the outcome of the nanoparticle trapping.