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. 2015 Jul 16;15(7):17300-12.
doi: 10.3390/s150717300.

Design and Optimization of SiON Ring Resonator-Based Biosensors for Aflatoxin M1 Detection

Romain Guider  1 , Davide Gandolfi  2 , Tatevik Chalyan  3 , Laura Pasquardini  4 , Alina Samusenko  5   6 , Georg Pucker  6 , Cecilia Pederzolli  7 , Lorenzo Pavesi  8
Affiliations

Design and Optimization of SiON Ring Resonator-Based Biosensors for Aflatoxin M1 Detection

Romain Guider et al. Sensors (Basel). .

Abstract

In this article, we designed and studied silicon oxynitride (SiON) microring-based photonic structures for biosensing applications. We designed waveguides, directional couplers, and racetrack resonators in order to measure refractive index changes smaller than 10-6 refractive index units (RIU). We tested various samples with different SiON refractive indexes as well as the waveguide dimensions for selecting the sensor with the best performance. Propagation losses and bending losses have been measured on test structures, along with a complete characterization of the resonator's performances. Sensitivities and limit of detection (LOD) were also measured using glucose-water solutions and compared with expected results from simulations. Finally, we functionalized the resonator and performed sensing experiments with Aflatoxin M1 (AFM1). We were able to detect the binding of aflatoxin for concentrations as low as 12.5 nm. The results open up the path for designing cost-effective biosensors for a fast and reliable sensitive analysis of AFM1 in milk.

Keywords: Whispering Gallery Mode; aflatoxin; biosensor; label-free; limit of detection; ring resonator; sensitivity; waveguide.

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Figures

Figure 1
Figure 1
(Left) Quality factors in function of the waveguide thickness simulated for nSiON = 1.66 and 1.8 for both transverse electric (TE) and transverse magnetic (TM) polarizations; (Right) Bulk sensitivity in function of the waveguide thickness simulated for nSiON = 1.66 and 1.8 for both TE and TM polarizations.
Figure 2
Figure 2
Sketch and microscope picture of the ring resonators sample. In the microscope image, we can clearly observe the etching windows around the resonators that allow the functionalization of the sensors.
Figure 3
Figure 3
(Left) Bending losses of sample L2; (Right) Bending losses of sample L5.
Figure 4
Figure 4
(Left) Propagation losses of sample L2; (Right) Propagation losses of sample L5.
Figure 5
Figure 5
Optical characterization of the directional coupler for L2 and L5 samples. The optical output ratio represents the optical power at the output waveguide (Pa) versus the sum of the optical power of both output waveguides (Pa + Pb). (inset) Scheme of a directional coupler.
Figure 6
Figure 6
(Left) Extinction ratio analysis for the L2 sample; (Right) Quality factor analysis for the L2 sample.
Figure 7
Figure 7
(Left) Extinction ratio analysis for the L5 sample; (Right) Quality factor analysis for the L5 sample.
Figure 8
Figure 8
(Left) Sensitivity of the L2 sample; (Right) Sensitivity of the L5 sample.
Figure 9
Figure 9
(Left) Sensorgram recorded using a sample from the L2 wafer in TM polarization. The high step-like response is due to the refractive index mismatch produced by the small content of Dimethyl sulfoxide (DMSO) in the solution. This solvent is needed to dissolve the AFM1 in the buffer solution; (Right) Specific binding sensorgrams obtained from the curves in (Left) by subtracting the bulk shift induced by the DMSO content. The dashed curves are exponential fittings for the evaluation of the rate constants and of the initial slopes [4].
See this image and copyright information in PMC

References

    1. Ciminelli C., Campanella C.M., Dell’Olio F., Campanella C.E., Armenise M.N. Label-free optical resonant sensors for biochemical applications. Prog. Quantum Electron. 2013;37:51–107. doi: 10.1016/j.pquantelec.2013.02.001. - DOI
    1. Vollmer F., Yang L. Label-free detection with high-Q microcavities: A review of biosensing mechanisms for integrated devices. Nanophotonics. 2012;1:267–291. doi: 10.1515/nanoph-2012-0021. - DOI - PMC - PubMed
    1. Bogaerts W., de Heyn P., van Vaerenbergh T., de Vos K., Kumar Selvaraja S., Claes T., Dumon P., Bienstman P., van Tourhout D., Baets R. Silicon microring resonators. Laser Photonics Rev. 2012;6:47–73. doi: 10.1002/lpor.201100017. - DOI
    1. Iqbal M., Gleeson M.A., Spaugh B., Tybor F., Gunn W.G., Hochberg M., Baehr-Jones T., Bailey R.C., Gunn L.C. Label-free biosensor arrays based on silicon ring resonators and high-speed optical scanning instrumentation. IEEE J. Sel. Top. Quantum Electron. 2010;16:654–661. doi: 10.1109/JSTQE.2009.2032510. - DOI
    1. Symphony Project Official Website. [(accessed on 31 May 2015)]. Available online: http://www.symphony-project.eu/

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