<p><a>The quick, reliable, and sensitive detection of bacterial contamination
is desired in areas such as counter bioterrorism, medicine, and food/water
safety as pathogens such as<i> E. coli</i> can cause harmful effects with the
presence of just a few cells. However, standard high sensitivity techniques
require laboratories and trained technicians, requiring significant time and
expense. More desirable would be a sensitive point-of-care device that could
detect an array of pathogens without sample pre-treatment, or a continuous
monitoring device operating without the need for frequent operator
intervention.<br>
<br>
Optical microring resonators in silicon photonic platforms are particularly
promising as scalable, multiplexed refractive index sensors for an integrated
biosensing array. However, no systematic effort has been made to optimize the
sensitivity of microrings for the detection of relatively large discrete
analytes such as bacteria, which differs from the commonly considered cases of
fluid or molecular sensitivity. This work demonstrates the feasibility of using
high finesse microrings to detect whole bacterial cells with single cell
resolution over a full range of potential analyte-to-sensor binding scenarios. Sensitivity
parameters describing the case of discrete analyte detection are derived and
used to guide computational optimization of microrings and their constituent
waveguides, after considering a range of parameters such as waveguide
dimension, material, modal polarization, and ring radius. The sensitivity of
the optimized 2.5 µm radius silicon TM O-band ring is experimentally
demonstrated with photoresist cellular simulants. A multiplexed optimized ring
array is then shown to detect <i>E. Coli</i>
cells in an experimental proof of concept.</a></p>
| Identifer | oai:union.ndltd.org:purdue.edu/oai:figshare.com:article/9914492 |
| Date | 17 October 2019 |
| Creators | Justin C. Wirth (5930402) |
| Source Sets | Purdue University |
| Detected Language | English |
| Type | Text, Thesis |
| Rights | CC BY-NC-SA 4.0 |
| Relation | https://figshare.com/articles/Engineering_Sensitivity_An_Optical_Optimization_of_Ring_Resonator_Arrays_for_Label-Free_Whole_Bacterial_Sensing/9914492 |
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