AVS 51st International Symposium
    Biomaterial Interfaces Tuesday Sessions
       Session BI+NS-TuM

Paper BI+NS-TuM10
Lifetime of Biomolecules in Hybrid Nanodevices: The Aging Process of Motor Protein-based Molecular Shuttles

Tuesday, November 16, 2004, 11:20 am, Room 210D

Session: The Nano-Bio Interface
Presenter: V. Vogel, University of Washington and ETH Zurich, Switzerland
Authors: H. Hess, University of Washington
C. Brunner, ETH Zurich, Switzerland
K.-H. Ernst, EMPA Duebendorf, Switzerland
V. Vogel, University of Washington and ETH Zurich, Switzerland
Correspondent: Click to Email
Prolonging the lifetime of biomolecules in their functional states is critical for applications where biomolecules are integrated into synthetic materials or nanodevices. A simplified molecular shuttle system, which consists of fluorescently labeled microtubules propelled by kinesin motor proteins bound to the surface of a flow cell, served here as a model system for such a hybrid device. In this system, the functional decay can easily be assayed by utilizing optical microscopy to detect motility and disintegration of microtubules (MTs). We found that the lifetimes of these hybrid systems were mainly limited by the stability of MTs, rather than of kinesin. To determine the biocompatibility of polymers widely used in microfabrication, we assembled flow cells with glass bottom surfaces and covers fabricated from glass, poly(urethane) (PU), poly(methyl-metacrylate) (PMMA), poly(dimethylsiloxane) (PDMS), and ethylene-vinyl alcohol copolymer (EVOH). Without illumination, only PU had a substantial negative impact on MT stability, while PMMA, PDMS and EVOH showed stabilities comparable to glass. Under the influence of light, however, the MTs degraded rapidly on PDMS or PMMA. A similar effect was observed on glass if oxygen scavengers were not added to the medium. Strong bleaching of the fluorophores was again only found on the polymer substrates and photobleaching coincided with an accelerated depolymerization of the MTs. The presented data provide a benchmark for the lifetime of motor protein-based bionanodevices which utilize glass as the primary synthetic material, and test the impact of a variety of polymer materials on the longevity of microtubules, the most fragile biological structure in the device. This study demonstrates that our definition of biocompatibility evolves, as we progress towards architectures engineered on a molecular level, which integrate multimeric proteins and protein assemblies.