Surface-specific nonlinear optical spectroscopy presents multiple useful methods for monitoring processes at buried solid-liquid interfaces.  For example, resonantly enhanced second harmonic generation (SHG) can be used to monitor binding processes when binding leads to the ordering of SHG-active molecules at the interface. We have been able to monitor the association and dissociation of DNA in solution with DNA immobilized on a glass substrate using resonantly enhanced SHG.  The DNA is functionalized with a commercially available SHG-active modified nucleotide bearing a 3-nitropyrrole, so that the surface coverage of hybridized DNA can be readily assessed from the change in SHG signal. Unlike previous methods that employed electrochemical techniques, surface-specific nonlinear optical methods can be used to explore the behavior of DNA immobilized on insulating surfaces like silica.  Thus, our work provides key insights for optimizing assays based on DNA chips and microarrays that are performed on glass substrates.

Quantifying the influence of confinement on the behavior of DNA immobilized at the silica-water interface using second harmonic generation

244th National Meeting (2012)

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