Diagnosing Cancer Plasmonically

Based on the collaborative work at Sylvester Comprehensive Cancer Center at the University of Miami Miller School of Medicine and the College of Engineering, Dr. Sung Jin Kim, an assistant professor in the Department of Electrical and Computer Engineering, was recently awarded a grant from the National Science Foundation (NSF) for his research titled “Plasmonic Sensing Platform for Cancer Diagnosis.” The award consists of $324,832 distributed over three years.

Recent advances in nanotechnology have made subwavelength nanostructures a reality, allowing various nanomaterials, fabrication techniques and characterization methods to successfully demonstrate plasmonic effects in a myriad of applications. The plasmon is the oscillation of electrons in the nanostructure, and it can be created when the nanostructure interacts with a specific energy of light.

One of the key functions for the use of the plasmonic effect is an efficient conversion of plasmon energy to an electrical signal or vice versa. A metal semiconductor-junction structure enables plasmonic energy detection as a form of electrical current. Photons absorbed in a metal nanostructure generate hot electrons; the electrons can cross by thermionic diffusion at the boundary between metal and semiconductor, resulting in photocurrent or increased conductivity of the semiconductors.

Dr. Kim’s research focuses on the design of a bio-sensing platform using hot electron energy transfer generated by localized surface plasmon resonance (LSPR). The biosensor will utilize a LSPR-based hybrid plasmon device consisting of both metallic nanoparticles and a field effect transistor (FET), thereby engendering highly sensitive, label-free detection of biomolecular interactions. The related works have been published in high impact journals such as Nano Letters (DOI: 10.1021/acs.nanolett.5b03625) and Nanoscale (DOI: 10.1039/C6NR05544C). And a related US utility patent has been issued by the United States Patent and Trademark Office (USPTO).

Plasmon FET does not require bulky optical readout instrumentation, while taking advantage of plasmon-based sensing. Unique characteristics (such as electrically isolated plasmonic sensing surface, on-chip optical-to-electrical conversion, and two-color lock-in amplifier-based sensing) will ensure robust sensing, an excellent signal-to-noise ratio and real-time detection of molecular interaction. Moreover, this sensing platform offers whole blood based sensing, which is a very challenging capability for the optical sensing technology.

This sensor design allows for the reduction of sensing area size beyond the diffraction limit of light. Thus, it has the potential to lower cost and allows for highly sensitive and rapid detection of disease biomarkers, specifically cancer. The sensor can also be modified for measuring other biological entities and can potentially have broad impact in medical diagnostics, environmental measurements and food safety.

Dr. Kim ultimately aims to develop a multiplexed microchip-based sensing technology for a point-of-care device and a lab-on-a-chip-based sensor assay. The project will develop innovative materials with a focus on nanotechnology in general and nanophotonics and LSPR in particular, promoting interdisciplinary research (engineering, biochemistry and clinical research) for graduate students, and providing research opportunities for undergraduate students.

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