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Proceedings Paper

Optical sensor for rapid microbial detection
Author(s): Mustafa Al-Adhami; Dagmawi Tilahun; Govind Rao; Yordan Kostov
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Paper Abstract

In biotechnology, the ability to instantly detect contaminants is key to running a reliable bioprocess. Bioprocesses are prone to be contaminated by cells that are abundant in our environment; detection and quantification of these cells would aid in the preservation of the bioprocess product. This paper discusses the design and development of a portable kinetics fluorometer which acts as a single-excitation, single-emission photometer that continuously measures fluorescence intensity of an indicator dye, and plots it. Resazurin is used as an indicator dye since the viable contaminant cells reduce Resazurin toResorufin, the latter being strongly fluorescent. A photodiode detects fluorescence change by generating current proportional to the intensity of the light that reached it, and a trans-impedance differential op-amp ensures amplification of the photodiodes’ signal. A microfluidic chip was designed specifically for the device. It acts as a fully enclosed cuvette, which enhances the Resazurin reduction rate. E. coli in LB media, along with Resazurin were injected into the microfluidic chip. The optical sensor detected the presence of E. coli in the media based on the fluorescence change that occurred in the indicator dye in concentrations as low as 10 CFU/ml. A method was devised to detect and determine an approximate amount of contamination with this device. This paper discusses application of this method to detect and estimate sample contamination. This device provides fast, accurate, and inexpensive means to optically detect the presence of viable cells.

Paper Details

Date Published: 17 May 2016
PDF: 6 pages
Proc. SPIE 9862, Advanced Environmental, Chemical, and Biological Sensing Technologies XIII, 986207 (17 May 2016); doi: 10.1117/12.2224132
Show Author Affiliations
Mustafa Al-Adhami, Ctr. for Advanced Sensor Technology (United States)
Dagmawi Tilahun, Ctr. for Advanced Sensor Technology (United States)
Govind Rao, Ctr. for Advanced Sensor Technology (United States)
Yordan Kostov, Ctr. for Advanced Sensor Technology (United States)

Published in SPIE Proceedings Vol. 9862:
Advanced Environmental, Chemical, and Biological Sensing Technologies XIII
Tuan Vo-Dinh; Robert A. Lieberman; Günter G. Gauglitz, Editor(s)

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