Department: NanoEngineering
Research Institute Affiliation: Graduate Program in Materials Science and Engineering
Faculty Advisor(s): Jennifer Cha
Award(s): Honorable Mention

Primary Student
Name: Phyllis Xu
Email: phxu@ucsd.edu
Phone: 858-246-0983
Grad Year: 2014

Single molecule detection by surface-enhanced Raman scattering (SERS) have been widely studied using plasmonic nanostructures. By engineering a Raman reporter in very close vicinity to certain metal nanostructures, Raman signals of up to 1014 enhancement can be seen, allowing ultra-sensitive molecular detection. Compared to current fluorescent assays for molecular detection, Raman detection has the potential for even higher sensitivity at the single molecular level, as well as real-time and multiplexed detection. Current methods of single molecule detection via SERS involve immobilization of capture probes to substrates or complex fabrication methods for the detection probes. We present a probe design as a precursor for future SERS detection that is not only easy to fabricate but also has potential for detecting proteins in situ. Nanodumbbell gold nanoparticle (AuNP) dimers connected by DNA were created that will change in interparticle distance in the presence of an analyte. In its original state, the nanodumbbell is in an extended state, but after the addition of our analyte, the DNA connecting the AuNP will form a hairpin and thus causes a decrease in the interparticle distance. This decrease in interparticle distance between the AuNP is directly applicable to creating a SERS effect that can allow ultra-sensitive molecular detection.

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