Publication Date

5-2014

Date of Final Oral Examination (Defense)

3-26-2014

Type of Culminating Activity

Thesis

Degree Title

Master of Science in Materials Science and Engineering

Department

Materials Science and Engineering

Major Advisor

Jeunghoon Lee, Ph.D.

Advisor

William L. Hughes, Ph.D.

Advisor

Bernard Yurke, Ph.D.

Abstract

This study focuses on the use of gold nanoparticles with DNA-based signal amplification as a detection method for low concentrations of DNA bio-markers. Biotechnology is a rapidly evolving field with primarily medical applications. Early detection is a challenging process for some cancers and other diseases yet is so critical to successful treatment. Increasingly sensitive detection techniques are being developed, but the current gold standard for detecting nucleotide biomarkers at low concentrations is polymerase chain reaction. While this technique is sensitive, it requires the use of active enzymes, a thermocycler, and trained personnel working in a clean environment, and is thus not very feasible for diagnosing diseases in remote locations or third world epidemic scenarios. Gold nanoparticles with complimentary DNA probes provide an easy, colorimetric method for detecting a DNA target, but are not very sensitive to sub-nanomolar concentrations without post-hybridization enhancement or sensitive instruments. To overcome this limitation, we employ enzyme-free, DNA-based amplification networks that use cascading hybridization reactions to produce multiple nanoparticle binding events per molecule of target DNA. Our data show that the DNA-based amplification does increase sensitivity of our colorimetric gold nanoparticles without sacrificing their ease of use. We also expand this detection method to other biomolecule of interest, by using an aptamer sequence to bind a small biomolecule and then trigger the DNA-based amplification network.

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