Mechanical unzipping of DNA molecules in parallel using nanophotonic tweezers

Optical trapping is a valuable technique widely used in biological and materials sciences, covering size scales ranging from the single molecule to the cellular level, and force scales from sub piconewton (pN) to tens of pN. In the past decades, the rapid development of nano techniques has bolstered the emergence of nanophotonic tweezers. The ability of nanostructures to direct and confine light beyond the diffraction limit enables miniaturized, on-chip devices with abilities beyond microscope-based optical traps. Our lab has developed and implemented such an on-chip device - the nanophotonic standing-wave array trap (nSWAT) [1,2]. The nSWAT is based on Si or Si₃N₄ waveguides and allows for controlled and precise manipulation of trapped single biomolecule (such as DNA) arrays via microparticle handles. Here, we present an nSWAT that achieves manipulation forces large enough to mechanically unzip an array of DNA molecules at room temperature. This benchmark achievement is another step closer to the full realization of nanophotonic tweezers’ capabilities, promising increased accessibility and expansion of these platforms to a wide range of biological and biomedical research topics.
[1] M. Soltani et al., Nature Nanotech. 9, 448 (2014).
[2] F. Ye et al., Nano Lett. 16, 6661 (2016).