nn7b05902_si_004.pdf (1.6 MB)
Three-Dimensional Super-resolution Imaging of Single Nanoparticles Delivered by Pipettes
journal contribution
posted on 2017-10-02, 00:00 authored by Yun Yu, Vignesh Sundaresan, Sabyasachi Bandyopadhyay, Yulun Zhang, Martin A. Edwards, Kim McKelvey, Henry S. White, Katherine A. WilletsControlled three-dimensional
positioning of nanoparticles is achieved
by delivering single fluorescent nanoparticles from a nanopipette
and capturing them at well-defined regions of an electrified substrate.
To control the position of single nanoparticles, the force of the
pressure-driven flow from the pipette is balanced by the attractive
electrostatic force at the substrate, providing a strategy by which
nanoparticle trajectories can be manipulated in real time. To visualize
nanoparticle motion, a resistive-pulse electrochemical setup is coupled
with an optical microscope, and nanoparticle trajectories are tracked
in three dimensions using super-resolution fluorescence imaging to
obtain positional information with precision in the tens of nanometers.
As the particles approach the substrate, the diffusion kinetics are
analyzed and reveal either subdiffusive (hindered) or superdiffusive
(directed) motion depending on the electric field at the substrate
and the pressure-driven flow from the pipette. By balancing the effects
of the forces exerted on the particle by the pressure and electric
fields, controlled, real-time manipulation of single nanoparticle
trajectories is achieved. The developed approach has implications
for a variety of applications such as surface patterning and drug
delivery using colloidal nanoparticles.