We demonstrate that in situ optical surface plasmon resonance spectroscopy can be used to monitor hybridization kinetics for unlabeled DNA in tethered monolayer nucleic acid films on gold in the presence of an applied electrostatic field. The dc field can enhance or retard hybridization and can also denature surface-immobilized DNA duplexes. Discrimination between matched and mismatched hybrids is achieved by simple adjustment of the electrode potential. Although the electric field at the interface is extremely large, the tethered single-stranded DNA thiol probes remain bound and can be reused for subsequent hybridization reactions without loss of efficiency. Only capacitive charging currents are drawn; redox reactions are avoided by maintaining the gold electrode potential within the ideally polarizable region. Because of potential-induced changes in the shape of the surface plasmon resonance curve, we account for the full curve rather than simply the shift in the resonance minimum.

https://www.pnas.org/content/pnas/98/7/3701.full.pdf

Electrostatic surface plasmon resonance: direct electric field-induced hybridization and denaturation in monolayer nucleic acid films and label-free discrimination of base mismatches.

Surface plasmon resonance spectroscopy as a tool for investigating the biochemical and biophysical properties of membrane protein systems. I: Theoretical principles.

Surface plasmons as a probe of the electrochemical interface

Surface plasmon resonance spectroscopy as a tool for investigating the biochemical and biophysical properties of membrane protein systems. II: Applications to biological systems.

Surface plasmon resonance (SPR) interferometry is reported as a novel technique for biological and chemical sensing, which employs not only the amplitude of a resonantly reflected light wave, but its phase as well. In this connection, the phase behavior under SPR has been comprehensively described by theoretical analysis, numerical simulations, and a number of experiments. Near optimum SPR conditions, a resonant phase dependence is step-like, the ‘step’ being at the reflectivity minimum. For SPR-based sensors, the slope of the ‘step’ can always be made by several orders steeper than that of the resonant reflectivity contour. The ‘step’ has been imaged by the fringe of a 2-dimensional interference pattern where one coordinate was the incidence angle, and the other was the phase. The inversion of the ‘step’ has been observed for the first time during antigen–antibody binding, when the system passes through the optimum SPR conditions. Monitoring the inversion provides for ultra-high sensitivity to an analyte while recording angular position of the ‘step’, does for dynamic range as wide as that of traditional SPR sensors. The SPR interferometry technique has confirmed theoretical findings and opened up new possibilities for (bio)chemical sensing.

F. Abelès

Papers

Investigation of the metal-electrolyte interface using surface plasma waves with ellipsometric detection

Étude de l'oxydation et de la réduction électrochimiques de l'or par ellipsométrie avec excitation de plasmons de surfaces (SEW)

Simultaneous determination of the scattering parameter and the mean free path of conduction electrons in thin films

Study of the electrochemical oxidation and reduction of gold by ellipsometry with surface plasmon excitation