Label-free detection of Escherichia coli bacteria by cascaded Chirped Long Period Gratings immunosensor

Nilima, * (2019) Label-free detection of Escherichia coli bacteria by cascaded Chirped Long Period Gratings immunosensor. Review of Scientific Instruments, 90 (2). pp. 1-20. ISSN 0034-6748

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An optical fiber based immunosensing platform formed by two identical chirped long period gratings (CLPG) for sensitive and label-free detection of Escherichia coli (E. coli) is presented. The proposed immunosensor having two CLPG with an inter-grating space (IGS) work like a Mach-Zehnder interferometer (MZI). The important feature of this sensor is that changing the refractive index (RI) induced phase at IGS region, a corresponding shift in resonance wavelength can be realized without affecting the actual grating region. Additionally, the confining bandwidth of the interference fringes romotes greater resolution in the resonance wavelength analysis of the transmission spectrum. The main aim of this study was the specific and rapid detection of the E. coli bacteria in PBS buffer (detection range: 10 cfu/mL to 60 cfu/mL) by using the bio-functionalized IGS region as a sensing probe of the dual CLPG structure. The observed detection limit was 7 cfu/mL.For specificity analysis, Salmonella typhimurium and Staphylococcus aureus were tested and no significant shift in resonance wavelength was observed. In addition, the proposed immunosensor has the ability to selectively detect E. coli in real samples including lake water. The high specificity, good sensitivity to ambient refractive index and robustness of the developed sensing platform will open a new avenue in optical immunosensing technology and cascaded long CLPG sensors can contribute significantly for the detection of pathogenic bacteria in water and food samples.

Item Type: Article
Subjects: Departments at MU > Statistics
Depositing User: KMC Library
Date Deposited: 11 Apr 2019 06:29
Last Modified: 11 Apr 2019 06:29

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