Optical sensor based on periodic array of resonant nanopillars for real time monitoring

Authors: Fátima Fernándeza , Paula Ciaurriz, Iñaki Cornago, R. Casquel, Ana L. Hernandez, F.J. Sanza, M.F. Laguna, M. Holgado


Here we present the real time response of a recently reported optical transducer, a periodic array of resonant nanopillars (R-NP). The signal of the sensor was obtained with a common spectrophotometer by measuring light transmission through the R-NP surface. A flow-cell, connected to a peristaltic pump, was employed to load different refractive index (RI) solutions in order to assess R-NP bulk sensitivity and resolution (limit of detection, LoD). Besides spectra, real time sensograms at constant wavelength were recorded. Excellent resolution and fluidic behavior were found, indicating the suitability of the R-NP system for real time biosensing applications.

The results were also compared with other optical sensor (LSPR, localized surface plasmon resonance). Both sensors were assayed with the same optical and fluidic setup, in order to evaluate the differences between transducers in the same conditions. Bulk sensitivity and resolution parameters resulted 4 and 5 times better respectively for R-NP compared to LSPR.

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