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Fabrication of NanobiosensorsTom Fitzgerald, Nathan Howell, Brian Maloney

Oregon State University, Department of Chemical, Biological, and Environmental Engineering

Impact of Nanobiosensors

Meet the Team

Fabrication

Characterization Protein Binding

Accomplishments – Carbon Nanotube Growth

OPTIONALLOGO HERE

OPTIONALLOGO HERE

• 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

Project Components:• Catalyst deposition and aligned CNT growth• Photolithography• Non-specific protein binding

5 μm

-Growth using thermally evaporated iron catalyst

-Growth using sputtered iron

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

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

20 25 30 35 40 45 50 55 60 650

1

2

3

4

5

Sputter Time (sec)

CN

T L

inea

r D

ensi

ty

(CN

T/µ

m)

t = 32 s t = 45 s t = 60 s

1 - Start with step cut quartz 2 – Using photolithography, create lines on quartz running perpendicular

to steps

3 – Deposit catalyst on substrate

4 – Wash away photoresist, leaving lines of catalyst

5 – React with carbon gas in furnace to grow nanotubes

6 – Using evaporation, deposit chrome/gold electrodes and contact

pads

7 – Mask nanotubes between electrodes, and O2 plasma etch

excess tubes and any debris

8 - Final Product

Acknowledgements:- Dr. Milo Koretsky -Dr. Joe McGuire- Matt Leyden - Josh Kevek- Landon Prisbey -Shamon Walker- Canan Schuman -Eric Gunderson

Dr. Phil HardingLinus Pauling Chair, Dept. of CBEE

Dr. Ethan MinotProject Sponsor, Dept. of Physics

Brian MaloneyTeam lead

Protein adhesion

Tom Fitzgerald Photolithography

Nathan HowellCharacterization

An atomic force microscope is used to take “pictures’ at the nano-scale

• Continue investigation of catalyst deposition. -Sputter vs. evaporation

• Investigate metal catalyst.-Iron vs copper

• Complete first device before conclusion of project.

Heig

ht (p

m)

5

3

1

1.21.00.60.2

3

2

1

A flow cell is used to flow a small amount of current over the sensor.

An AFM works by tapping a surface and measuring the changes in amplitude.

When sputtering, an ion is propelled toward a metal target. This collision with the target releases metal atoms, which land on the substrate surface.

Aligned CNTs!!

White “specs” are iron catalyst particles

CNTs grown on striped substrate. Short, dense, non-aligned tubes were grown.

0 1 2 3 4 µm

4

3

2

1

0

µm

0 1 2 3 4 5 µm

3210

µm

Cancerresearchuk.org

Objective: Utilize aligned carbon nanotubes to construct a device capable of measuring changes in current while in solution

Why Nano?• Carbon nanotubes are an ideal semiconductor to detect small

changes in current• Surfaces of nanotubes provide a good area for protein adhesion

0 100 200 300 nm

0 100 200 300 nm

0 200 400 600 nm

Comparison of nanotube growth at three different sputter times are shown below with AFM images and nanotube cross sections.