PhD defence by Lars Iversen

Lars Iversen, BioNano Group, Nano-Science Center will give a public lecture on:
"Surface Patterning and Nanowire Biosensor Construction: Soft Lithographic Templated Protein Assembly Organic Monolayer Laser Pattering and Nanowire Biosensor Design."

Abstract
The work of this thesis concerns the preparation and characterization of three systems where surfaces of solid matter are interfaced with organic and biomolecular components, with the aim of creating (I) Patterned surfaces and (II) Functional nanowire sensor platforms for bio-nanotechnological applications.
I) We have combined micro-contact printing with a reactive SNAP-tag protein to establish a general platform for templated protein assembly, providing parallel patterning via gentle and oriented protein immobilization. Alternatively, we have used a highly focused laser beam to pattern a self-assembled monolayer on gold, forming a topologically ultra flat but chemically patterned surface, with submicron feature sizes, varying linearly in size with laser power and irradiation time
II) We have investigated the use of Indium Arsenide nanowires, incorporated in field effect transistor (FET) devices, as a sensitive platform for detection of charged analyte species binding to the wire surface. We propose to use proteins, which undergo large conformational changes, as capture agents. Using structure based protein charge prediction, we show how ligand induced changes in the conformation of a model protein can lead to changes in electrostatic potential predicted to be sufficient for nanowire sensing. In addition, the importance of protein orientation is highlighted. Finally we demonstrate how InAs nanowires can be biofunctionalized, integrated in FETs, and used to detect charged species, as demonstrated with H+ ions for pH sensing.

Evaluation Committee:

  • Prof. Horst Vogel, École Polytechnique Fédérale de Lausanne, Institut des Sciences et Ingéniere Chimiques, Lausanne, Switzerland
  • Prof. Anja Boisen, DTU Nanotech, Technical University of Denmark
  • Prof. Klaus Bechgaard (Chairman), Department of Chemistry and Nano-Science Center, University of Copenhagen

Supervisors:

  • Professor Thomas Bjørnholm, Nano-Science Center & Department of Chemistry, University of Copenhagen
  • Associate Professor Karen Martinez, Nano-Science Center, University of Copenhagen