Nucleic acid detection with surface plasmon resonance using cationic latex

An affinity sensor based on Surface Plasmon Resonance (SPR) was used to detect nucleic acids. SPR is an optical technique that is able to detect small changes in the refractive index of the immediate vicinity of a metal surface. After a specific amplification of DNA, achieved using the polymerase chain reaction (PCR), detection was accomplished through the application of latex particle intermediates. The assay was based on the inhibition of latex particle adsorption to a metal surface by DNA. The amount of latex present determined the sensitivity of the inhibition assay. The adsorption behaviour of latex particles at a gold surface was investigated using SPR. The parameters that played an important role in this adsorption were ionic strength and pH