title: Lithographically defined uniform worm-shaped polymeric nanoparticles.
abstract: We report a nanoimprint lithography method combined with photolithography on a bi-layer polymer setup to define nano-worms laterally in nano-gratings and produce uniform worm-shaped polymeric nanoparticles in aqueous solution by dissolving water soluble sacrificial layer poly(vinyl alcohol) (PVA). Process control of the thin residue layer, SU-8 curing using broadband UV source, and warm development to remove any residue are necessary to ensure success of this technique. The use of water soluble PVA as a releasing layer and elimination of an invasive plasma etching for the releasing process makes this protocol highly compatible with biomaterials. Direct release and suspension of fluorescent worm-shaped nanoparticles (length to width ratio up to 75) in aqueous solution were demonstrated. Compared to the worm-shaped nanoparticles made by self-assembly, these lithographically defined nano-worms have much better controllability and uniformity on the shape, size, and aspect ratio. The availability of these precisely defined non-spherical particles would be important to develop a comprehensive understanding of the shape effects of nanoparticles on their efficacy in nanomedicine applications.
authors.affiliation: Department of Electrical Engineering, University of Texas at Dallas, Richardson, TX 75080, USA.
authors.forename: L
authors.initials: L
authors.lastname: Tao
authors.forename: X M
authors.initials: XM
authors.lastname: Zhao
authors.forename: J M
authors.initials: JM
authors.lastname: Gao
authors.forename: W
authors.initials: W
authors.lastname: Hu