Field Optical Forces Research Articles

Photothermal forces enhanced by nanoneedle array for nanoparticle manipulation

Plasmonic nanostructures provide strong electromagnetic fields enhancement and confinement for nanoparticle trapping. Here, we study the thermal and optical nanoparticle trapping effects using plasmonic nanoneedles array. Results show that the photo-thermal force outside the nanostructure can affect movements of nanoparticles in the far field as a result of heat transfer. The thermal force is decreased about one order of magnitude for nanoparticle at about 6μm away from the nanostructure where the optical force is no longer effective. Plasmonic nanoneedles with high aspect ratio provides more trapping positions in three dimensions. The thermal force together with the near field optical force make plasmonic nanoneedles array a flexible and wide working range manipulation strategy for nanoparticles.

Molecular Nanotweezers; True Nano-Manipulation of Macromolecules and Other Bioparticles

The Molecular NanoTweezer is a new system capable of optically trapping the smallest objects yet including individual proteins, quantum dots, lambda DNA, polystyrene microspheres and viruses. The key to this technology is in producing incredibly small “spots” of light (using near field photonics) which reach out and grab nearby particles like a tractor beam. Till now, the only direct way of altering or manipulating these objects was with chemistry. Traditional optical tweezers are unable to stably trap bioparticles smaller than 100 nm in characteristic size due to the diffraction limit of light. Optofluidics' Molecular NanoTweezer technology is able to bypass this limitation by exploiting near field optical forces in custom photonic chips. In this talk, we will discuss the current achievements of the Molecular NanoTweezer, as well as present a brief overview of its envisioned future applications. These future applications include (1) localizing individual proteins in 3D space for single molecule researchers, (2) nanoparticle size measurements and the ability to do label-free size-based assays, (3) producing custom-made protein agglomerates to be used as ultra-high binding capacity beads and (4) straight-forward single particle AFM tip functionalization.View Large Image | View Hi-Res Image | Download PowerPoint Slide