Fabrication of Nanobiosensors Tom Fitzgerald, Nathan Howell, Brian Maloney

1. OPTIONALLOGO HERE Fabrication of Nanobiosensors Tom Fitzgerald, Nathan Howell, Brian Maloney Oregon State University, Department of Chemical, Biological, and Environmental Engineering OPTIONALLOGO HERE Fabrication Impact of Nanobiosensors Accomplishments – Carbon Nanotube Growth • Over 500,000 people die every year from cancer • Early detection of cancer biomarkers will increase patient survival rate • Early stage cancer biomarkers are present at 100 fM concentrations • Figure below depicts survival rate according to the years after diagnosis and stage of cancer -Growth using thermally evaporated iron catalyst 4 3 2 1 0 Aligned CNTs!! µm White “specs” are iron catalyst particles 2 – Using photolithography, create lines on quartz running perpendicular to steps 3 – Deposit catalyst on substrate 1 - Start with step cut quartz 0 1 2 3 4 µm 5 μm 3 2 1 0 CNTs grown on stripedsubstrate. Short, dense, non-aligned tubes were grown. µm 0 1 2 3 4 5 µm Cancerresearchuk.org 4 – Wash away photoresist, leaving lines of catalyst 8 - Final Product Objective: Utilize aligned carbon nanotubes to construct a device capable of measuring changes in current while in solution -Growth using sputtered iron When sputtering, an ion is propelled toward a metal target. This collision with the target releases metal atoms, which land on the substrate surface. • Why Nano? • Carbon nanotubes are an ideal semiconductor to detect small changes in current • Surfaces of nanotubes provide a good area for protein adhesion Comparison of nanotube growth at three different sputter times are shown below with AFM images and nanotube cross sections. • Project Components: • Catalyst deposition and aligned CNT growth • Photolithography • Non-specific protein binding t = 32 s t = 45 s t = 60 s 6 – Using evaporation, deposit chrome/gold electrodes and contact pads 7 – Mask nanotubes between electrodes, and O2 plasma etch excess tubes and any debris 5 – React with carbon gas in furnace to grow nanotubes Meet the Team Characterization Protein Binding 5 3 1 1.2 1.0 0.6 0.2 3 2 1 Height (pm) • Basic Protein Detection: • Bind entire nanotube surface with protein antibodies (green) • Expose nanotube to solution containing the protein of interest • Protein binding to antibodies will result in a detectable change of current through the nanotube 0 200 400 600 nm 0 100 200 300 nm 0 100 200 300 nm Nathan Howell Characterization Brian Maloney Team lead Protein adhesion Tom Fitzgerald Photolithography An atomic force microscope is used to take “pictures’ at the nano-scale An AFM works by tapping a surface and measuring the changes in amplitude. • Literature Results: • Figure to the right represents current vs. time for different concentrations of streptavidin • Higher concentrations of protein resulted in larger current Future Work Dr. Phil Harding Linus Pauling Chair, Dept. of CBEE Dr. Ethan Minot Project Sponsor, Dept. of Physics • Continue investigation of catalyst deposition. • Sputter vs. evaporation • Investigate metal catalyst. • Iron vs copper • Complete first device before conclusion of project. • Acknowledgements: • - Dr. Milo Koretsky -Dr. Joe McGuire • - Matt Leyden - Josh Kevek • Landon Prisbey -ShamonWalker • Canan Schuman -Eric Gunderson A flow cell is used to flow a small amount of current over the sensor.