On-chip transporting arresting and characterizing individual nano-objects in biological ionic liquids

Abstract

Understanding and controlling the individual behavior of nanoscopic matter in liquids, the environment in which many such entities are functioning, is both inherently challenging and important to many natural and man-made applications. Here, we transport individual nano-objects, from an assembly in a biological ionic solution, through a nanochannel network and confine them in electrokinetic nanovalves, created by the collaborative effect of an applied ac electric field and a rationally engineered nanotopography, locally amplifying this field. The motion of so-confined fluorescent nano-objects is tracked, and its kinetics provides important information, enabling the determination of their particle diffusion coefficient, hydrodynamic radius, and electrical conductivity, which are elucidated for artificial polystyrene nanospheres and subsequently for sub–100-nm conjugated polymer nanoparticles and adenoviruses. The on-chip, individual nano-object resolution method presented here is a powerful approach to aid research and development in broad application areas such as medicine, chemistry, and biology.

Long-range transport and directed assembly of charged colloids under aperiodic electrodiffusiophoresis

“…By inducing large potential wells under aperiodic EDP, the simple parallelplate devices in this work essentially function as electrokinetic tweezers or traps. 60,61 Therefore, the methods developed here could facilitate the trapping at the limit of a single nanoparticle, which can enable analysis at femtomolar concentrations. The potential landscapes under aperiodic EDP confine and concentrate particles in small regions.…”