NER: Electron Beam Emitter SPR for Biosensor Applications Nanoscale Exploratory Research

Georgia Tech Research Corporation, Atlanta GA

Investigators

Abstract

In this project, we propose to investigate the feasibility of developing biosensor nano-microarrays based on a novel type of surface plasmon resonance device. In our approach, U.S. provisional patent 601,283,051 "Field Emission Electron Beam Biosensor", nanoscale field emission electrodes will be used as electron sources to excite surface plasmons in a thin metal film. Antibodies will be immobilized onto the opposing side of the metal film and data on molecular binding events will be extracted obtained via the collection of spectral data associated with the surface plasmon resonance. We will refer to the device as the eSPR for "electron-interrogated SPR." As the bias voltage on the field emission electrode of the vacuum nano-electronic device is swept through its range, the energy of the electron beam impinging on the metal film is also swept and the amplitude of the reflected current represents a spectral interrogation of the plasmon resonance. As is the case with commercial systems that utilize optical excitation sources, such as the Biacore 3000, the nature of the plasmon resonance is perturbed by the biomolecular interaction occurring in the vicinity of the metal film. The overarching goal of our efforts will be to produce small, portable or embedded biosensor micro-arrays with the capability to detect a multiplicity, of biochemical targets simultaneously. The objectives of our project will be as follows: Understand the physical principles of electron-beam induced surface plasmon resonance biosensors Develop design strategies and processing methods to transfer knowledge from the vacuum microelectronic domain to eSPR sensors that have nanoscale dimensions. Commercially available emitter arrays currently being developed for flat panel display devices will be reviewed and characterized to determine suitability for use in this eSPR application. Additional eSPR device characterization will be done with software model tools such as CFD- ACE from CFD Research Corporation. It has been known for approximately fifty years 1 that an electron beam can excite a surface plasmon resonance in a metal-dielectric structure. In practice the use of an electron beam to induce a surface plasmon resonance as a sensing device has remained largely an unexploited area because of the equipment needed and the complications of volatile organic materials in a vacuum. A review of the literature has revealed no studies of this type for eSPR. The reward is significant advancement in biosensing capabilities with the eSPR device. The development of micro-emitter arrays produced by standard microelectronics processing methods now brings the possibility of very small sizes, throw away costs and custom configurations which mitigate the vacuum-biological mixing problems. The advent of a low cost, high sensitivity, hand-held or smaller, multi-detector would undoubtedly find wide spread applications in both the consumer and industrial markets. The realization of such a biosensing device would be a significant advancement over current sensors which neither small in size nor inexpensive to produce and operate. The risk is due to the fact that the field of biosensing utilizing electron beam emitters is unexplored. Without relevant research having been previously conducted knowledge gained from optical SPR devices must be selectively transferred to an electron beam device. The very nature of a device that contains both vacuum microelectronics and biological material presents difficulties but contains large rewards in size and cost reduction if successfully combined.