Enhanced surface plasmon resonance with the modified catalytic growth of Au nanoparticles

The catalytic growth of Au nanoparticles (AuNPs) has been employed in several analytical methods for improving the detection sensitivity, or integrated with the enzyme reactions for the quantitative detection of the respective substrates. However, the catalytic growth of Au nanoparticles do not work in some situations, such as surface plasmon resonance (SPR), electrochemistry, where metal matrices were used, because metal matrices used in these techniques, e.g. Au, are susceptible to metal deposition, which increased the background seriously. In this work, a SiO2 layer was vapor-deposited on the gold film. The inhibition of metal deposition by this SiO2 layer was investigated by SPR sensor. The results showed that the SiO2 layer could avoid the deposition of metal on Au film. With the low background achieved by SiO2-coated Au films, sensitive detection of DNA hybridization using the catalytic growth of Au nanoparticles enhanced SPR was demonstrated. The work described here maybe helpful for the development of sensitive bioanalytical methods.