| Title |
Optical Fiber Biosensor based on Heterodyne Demodulation for Pathogenic Bacteria Detection |
| Authors |
Seul-Lee Lee ; Youngjong Ko ; Jang Hyun Kim ; Hyun Wook Kang ; Yong Woo k Lee |
| DOI |
http://doi.org/10.5207/JIEIE.2020.34.11.023 |
| Keywords |
Optical fiber sensor; Optical biosensor; Fluorescence detection; Biofilms; LED light source |
| Abstract |
In this paper, we demonstrated an optical fiber biosensor based on heterodyne demodulation to detect five pathogenic bacteria species forming biofilms, such as Escherichia Coli, Vibrio Vulnificus, Pseudomonas Aeruginosa, Staphylococcus Aureus, and Streptococcus Iniae, with their fluorescence characteristics. The proposed sensor detects the fluorescence of the five bacteria species with the intrinsic fluorescence characteristics of amino acid tryptophan, whose excitation and emission wavelengths are 280 and 350 nm, respectively. The fabricated sensor consists of an UV light source for excitation of bacteria, a high sensitivity detector for detection of fluorescence signals emitted from the excited bacteria, and a lock-in amplifier for amplification of the detected fluorescence signals. The lock-in amplifier can remove various noise signals coupled with the desired fluorescence signals and amplify the magnitude of the desired signal through the heterodyne demodulation technique. This signal processing technique enables the detection of the weak picowatt (pW) fluorescence signals. Consequently, it is concluded that our sensor can successfully detect the intensity of the fluorescence signal emitted from five pathogenic bacteria species whose concentration lies within 102 to 107 CFU/ml. |