Sensitivity and Limit of Detection of biosensors based on ring resonators

Abstract

In this work, we present a study of the Sensitivity (S) and Limit of Detection (LOD) of microring based photonic biosensors as a function of the waveguide composition and dimensions. The target is aflatoxin, which is a toxin of major concern for south Europe diary industry. The sensing device is based on an array of multiple SiON microring resonators, fiber-coupled to both an 850 nm VCSEL and a silicon photodetectors, packaged with a microfluidic circuit. Volumetric sensing with glucose-water solutions of various concentrations yields a best sensitivity of 112 nm/RIU. To link these results to the limit of detection of the sensors, we also measured the noise of our experimental readout system and then calculated the LOD of our sensors. We found a best value of LOD of 1.6x10 -6 RIU (referred to volumetric sensing). Finally, we detected aflatoxin in solutions of various concentrations (down to 1.58 nM) by functionalized sensors. The functionalization is based on a wet silanization and specific DNA-aptamer binding on the chip. Reproducibility and reusability of the sensor are investigated by several chemical treatments. Optimum procedure allows multiple sequential measurements with a good endurance.

Aptasensors Based on Whispering Gallery Mode Resonators

“…Figure 7 shows the sensorgrams for the three concentrations of AFM1, demonstrating the reproducibility and reusability of the sensor for AFM1. The binding effect was observed down to a minimum concentration of 1.58 nM [ 25 ].…”

“…In order to create the sensors, the cladding layer was opened through a BHF wet etching. This allows the functionalization of the rings as well as the sensing measurements through their exposure to the ambient and to the molecules to be analyzed [ 25 ]. Figure 3 shows a sketch of the sensor configuration that was coupled to a PDMS microfluidic flow cell, with a chamber of about 0.5 μL of volume, connected to a VICI M6 liquid handling pump.…”

Chemical Sensors and Biosensors in Italy: A Review of the 2015 Literature

“…The M1 form of aflatoxin, a toxin of major concern for the southern Europe dairy industry, was the target of the study of Guider at al. They used a newly developed optical label-free detector consisting in an array of multiple SiON microring resonators, fiber-coupled to both an 850 nm VCSEL and a silicon photodetector, packaged with a microfluidic circuit [65]. Multiple sequential measurements were possible after chemical regeneration of the sensing surface.…”

Sensitivity optimization in whispering gallery mode optical cylindrical biosensors

“…In this work, we propose the use of cylindrical micro-resonators with optimized structural parameters for optical biosensing. This kind of optical biosensor detects changes in the surrounding refractive index through the electromagnetic (EM) field evanescent depth of WGMs, travelling outside the cylindrical resonator boundary, providing label-free sensing ability [8,9,10]. WGM resonances in these structures can have two degrees or orders of freedom i and l or ν, where i is radial order and l or ν is the angular order of a WGM.…”