Integrated label-free erbium-doped fiber laser biosensing system for detection of single cell Staphylococcus aureus

Jiandong Liu, Bin Liu*, Juan Liu, Xing-Dao He, Jinhui Yuan, Zabih Ghassemlooy, Hamdi Torun, Yong-Qing Fu, Xuewu Dai, Wai Pang Ng, Richard Binns, Qiang Wu*

*Corresponding author for this work

Research output: Contribution to journalArticlepeer-review

5 Citations (Scopus)
36 Downloads (Pure)


A critical challenge to realize ultra-high sensitivity with optical fiber interferometers for label free biosensing is to achieve high quality factors (Q-factor) in liquid. In this work a high Q-factor of 105, which significantly improves the detection resolution is described based on a structure of single mode -core-only -single mode fiber (SCS) with its multimode (or Mach-Zehnder) interference effect as a filter that is integrated into an erbium-doped fiber laser (EDFL) system for excitation. In the case study, the section of core-only fiber is functionalized with porcine immunoglobulin G (IgG) antibodies, which could selectively bind to bacterial pathogen of Staphylococcus aureus (S. aureus). The developed microfiber-based biosensing platform called SCS-based EDFL biosensors can effectively detect concentrations of S. aureus from 10 to 105 CFU/mL, with a responsivity of 42.6 p.m./(CFU/mL) for the wavelength shift of the measured spectrum. The limit of detection (LoD) is estimated as 7.3 CFU/mL based on the measurement of S. aureus with minimum concentration of 10 CFU/mL. In addition, when a lower concentration of 1 CFU/mL is applied to the biosensor, a wavelength shift of 0.12 nm is observed in 10% of samples (1/10), indicating actual LoD of 1 CFU/mL for the proposed biosensor. Attributed to its good sensitivity, stability, reproducibility and specificity, the proposed EDFL based biosensing platform has great potentials for diagnostics.
Original languageEnglish
Article number124385
Number of pages8
Early online date18 Feb 2023
Publication statusPublished - 15 May 2023


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