  The ability of metallic nanostructures to confine light at the sub-wavelength
scale enables new perspectives and opportunities in the field of
nanotechnology. Making use of this unique advantage, nano-optical trapping
techniques have been developed to tackle new challenges in a wide range of
areas from biology to quantum optics. In this work, starting from basic
theories, we present a review of research progress in near-field optical
manipulation techniques based on metallic nanostructures, with an emphasis on
some of the most promising advances in molecular technology, such as the
precise control of single-biomolecules. We also provide an overview of possible
future research directions of nano-manipulation techniques.
