Optical readout of a nanoparticle based sensor by cavity ring-down spectroscopy.

Highlights: [•] Cavity ring-down method was used for sensitive optical sensor readout. [•] Plasmonic nanoparticles immobilized within a microfluidic cuvette act as sensors. [•] Physical effect: plasmonic resonance shift of metallic nanoparticles in dependence on changes in refraction index. [•] Enables in situ sensitive optical readout in real-time. [•] DNA-sensing demonstrated as proof-of-principle. [Copyright &y& Elsevier]