Localized Surface Plasmon Resonance (LSPR) Spectroscopy in Biosensing

Abstract

Methods based on localized surface plasmon resonance (LSPR) spectroscopy have been gaining popularity in recent years as promising transducers for label‐free biosensors. LSPR biosensing is based on the sensitivity of the localized plasmon absorbance of metal nanostructures to changes in the dielectric properties of the contacting medium. In the common scheme, a biological recognition interface is constructed on the metal nanostructure; specific binding of a bioanalyte is transduced into an optical signal, i.e., change in the plasmon absorbance (wavelength, intensity). A noted advantage of LSPR sensing is the relative simplicity of the experimental setup and measurements. In this chapter, different LSPR biosensing systems are reviewed in a comparative manner, with emphasis on basic characteristics such as system construction, refractive index sensitivity, distance sensitivity, measured parameters, and actual performance.

Highly Stable Localized Plasmon Transducers Obtained by Thermal Embedding of Gold Island Films on Glass

“…5f and inset photograph) is perfectly stable and shows high sensitivity to both the IgG antigen binding and the specific antibody-antigen interaction. [6] An experiment (not shown) similar to the latter but exposing the bound Rabbit IgG antigen to Mouse IgG antibody showed no change in the SP band, attesting to the high specificity and stability of the system. [37] In conclusion, Au island films evaporated directly on glass substrates and subjected to post-deposition annealing at a temperature T in the vicinity of the substrate glass transition T g (e.g., T !…”

“…Optical sensors based on LSPR spectroscopy have gained increasing interest in recent years as relatively simple and low-cost transducers for biological and chemical sensing (for a recent review, see ref. [6]). Au and Ag island films on transparent substrates (primarily glass) have been studied extensively as potential transducers for LSPR sensing in the transmission mode (T-LSPR spectroscopy).…”

“…[6] A major obstacle to sensing applications of metalisland-based LSPR transducers is the instability of such systems toward changes in the environmental conditions. This poor stability has been known for Ag island films [7][8][9][10][11][12][13] as well as for Au island films [6,[14][15][16] immersed in various solvents. Hicks et al [13] noted, concerning Ag island films on glass, that ''exposure to aqueous solutions (as is any biological milieu) significantly hinders their adhesion of metal to glass.''…”

“…[6] The stability of the morphology and optical response of Au island films evaporated on coverglass and annealed at high temperatures (partially embedded films) and its relevance to sensing applications, were evaluated and compared with non-embedded films. Both types of transducers were similarly subjected to a number of treatments representing common procedures in biosensing.…”

Metal island film-based structures for sensing using spectrophotometry and ellipsometry

“…SPR of isolated particles is highly sensitive to refractive index changes of the environment, enabling to detect presence of different analytes [1][2]. MIFs are attractive candidates for the production of performance-and cost-efficient sensors.…”