AVS 60th International Symposium and Exhibition
    Biomaterial Interfaces Thursday Sessions
       Session BI+NL+NS+SS-ThM

Paper BI+NL+NS+SS-ThM5
Ultrathin Poly(ethylene glycol) Films as Flexible Platform for Plasmonics and Lithography and as Precursors for Free-Standing Nanomembranes

Thursday, October 31, 2013, 9:20 am, Room 201 B

Session: Bio/Nano Interfaces
Presenter: N. Meyerbröker, University of Heidelberg, Germany
Authors: N. Meyerbröker, University of Heidelberg, Germany
M. Zharnikov, University of Heidelberg, Germany
Correspondent: Click to Email
We present a novel approach to prepare ultrathin, biocompatible films based on cross-linking of multi-functionalized, star-branched poly(ethylene glycols) (STAR-PEGs) with tunable film thicknesses of 4 – 200 nm. A two-component mixture of amine- and epoxy-terminated four-arm STAR-PEGs was spin-coated on a flat substrate and cross-linked chemically by gentle heating, resulting in a stable, hydrogel-like film with a density close to that of bulk PEG material. The films revealed pronounced swelling behavior, which was fully reversible and could be precisely controlled. Additionally, they provided a high affinity to citrate-stabilized gold nanoparticles (AuNP) that could be adsorbed with high densities into the PEG matrix from an aqueous solution. These novel PEG/AuNP composite films offer interesting and potentially useful optical properties. Controlling the accessibility, swelling behavior, and biorepulsive properties of the PEG films lithographically, we prepared nanocomposite patterns of metal nanoparticles and fluorophores imbedded into the PEG matrix as well as protein-affinity patterns in protein-repelling background. Further, using electron beam lithography, we succeeded to fabricate wettability patterns and to sculpture complex 3D microstructures on the PEG basis. Finally, we demonstrated that the PEG films can be separated from the substrate and exist as ultrathin, biocompatible, free-standing membranes. These membranes possess high stability and exceptional elasticity. They can be used in transmission electron microscopy experiments on sensitive biological targets and as a new type of support for the characterization of nanoparticles.