Nano-plasmonic biosensors: A review

Abstract

In this paper, first the fundamental concept of nano-optical biosensing is studied. Since Raman scattered signal is very weak to be recognized by current measuring equipments, the signal must be amplified. SPR and LSPR are utilized to enhance the incident field of the target molecules, to improve the sensitivity of the sensor. The paper focuses on the use of LSPR to enhance Raman signal in SERS technology. Different structures of nano-particles in LSPR to improve enhancement of the SERS signal are reviewed and compared.

Rapid prototyping techniques for the fabrication of biosensors

“…used a piezoelectric non-contact Scienion S3 Flexarrayer (BioDot, Irvine, CA) to multiplex an array of resonant photonic ring biosensors to study the interaction of various proteins and carbohydrates on the biosensor surfaces. Resonant photonic biosensors are extremely sensitive and operate on the basis of an evanescent fi eld interacting with molecules on the surface of the resonator in a manner somewhat similar to surface plasmon resonant biosensors (Bl ä ttler et al ., 2009;Mortazavi et al ., 2011). Shifts in resonant frequency are measured and correlate with the intensity of interaction of an analyte with the resonant ring or biomolecules at its surface.…”

Developing LSPR Design Guidelines

“…Accordingly, the resulting field outside the sphere, E out , can then be written as [15][16][17][18], E out (x,y,z) =E 0ẑ −αE 0 ẑ r 3 − 3z r 3 (xx+yŷ+zẑ) (1) where the first term is the applied field, and the second one is the induced dipole that results from polarization of the sphere electron density; also, x, y, and z are the usual Cartesian coordinates; r is the radial distance;x,ŷ, andẑ are the Cartesian unit vectors; and α is the metal dipole polarizability expressed as,…”

“…Since the scattered wave is very weak for detection, the incident field must be first enhanced in a process called surface enhanced Raman scattering (SERS) [1]. The SERS method was initially discovered by Fleischmann et al [2] in 1974.…”

Evolution Towards a New LSPR Particle: Nano-Sinusoid

“…Once the incident field is locally increased, it is beamed toward the target molecules. This process, which is called surface enhanced Raman scattering (SERS), enhances the amplitude of the Raman scattered wave from the target molecules [3]. When the collective resonance of valence electrons in the noble metal is equal to the frequency of the incident light, dipolar localized surface plasmon resonance (LSPR) is generated [4,5], where the incident wave may excite dipolar LSPRs on the surface of the noble metal NPs.…”