Open AccessOptical multi-channel interrogation instrument for bacterial colony characterization
Author(s) -
IyllJoon Doh,
Huisung Kim,
Jennifer Sturgis,
Bartek Rajwa,
J. Paul Robinson,
Euiwon Bae
Publication year - 2021
Publication title -
plos one
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.99
H-Index - 332
ISSN - 1932-6203
DOI - 10.1371/journal.pone.0247721
Subject(s) - optics , microscope , laser , materials science , confocal , microscopy , confocal microscopy , detector , channel (broadcasting) , photodiode , optoelectronics , physics , computer science , telecommunications
A single instrument that includes multiple optical channels was developed to simultaneously measure various optical and associated biophysical characteristics of a bacterial colony. The multi-channel device can provide five distinct optical features without the need to transfer the sample to multiple locations or instruments. The available measurement channels are bright-field light microscopy, 3-D colony-morphology map, 2-D spatial optical-density distribution, spectral forward-scattering pattern, and spectral optical density. The series of multiple morphological interrogations is beneficial in understanding the bio-optical features of a bacterial colony and the correlations among them, resulting in an enhanced power of phenotypic bacterial discrimination. To enable a one-shot interrogation, a confocal laser scanning module was built as an add-on to an upright microscope. Three different-wavelength diode lasers were used for the spectral analysis, and high-speed pin photodiodes and CMOS sensors were utilized as detectors to measure the spectral OD and light-scatter pattern. The proposed instrument and algorithms were evaluated with four bacterial genera, Escherichia coli , Listeria innocua , Salmonella Typhimurium, and Staphylococcus aureus ; their resulting data provided a more complete picture of the optical characterization of bacterial colonies.