| Title |
Study on SARS-CoV-2 Spike Protein Detection Using Multi-mode Interference Based on Tapered No-Core Fiber |
| Authors |
Minchan Bae ; Yong Wook Lee |
| DOI |
http://doi.org/10.5207/JIEIE.2022.36.10.021 |
| Keywords |
Multi-mode interference; No-core fiber; Refractive index; SARS-CoV-2; Spike protein; Tapering |
| Abstract |
In this paper, we demonstrated the detection of SARS-CoV-2 spike protein using a fiber-optic biosensor composed of tapered no-core fiber (NCF), which leads to multi-mode interference (MMI) when its both ends are spliced with standard single-mode fiber (SMF). For the fabrication of the tapered NCF as a bare sensor head, we utilized a commercial arc fusion splicer (AFS) and optimized the tapering condition by adjusting a pull speed, an arc duration, and a pull length of the AFS, resulting in a tapered core diameter of ∼105μm. To check if the bare sensor head is feasible for the SARS-CoV spike protein detection, the response of the tapered NCF (whose both ends are connected with SMF) to the external refractive index (RI) was investigated using an sucrose solution. It was confirmed from the RI examination that two loss dips selected from the MMI spectrum of the bare sensor head, designated as Dip A and Dip B, showed the RI sensitivities of ∼65.60 and ∼73.01nm/RIU, respectively. Then, we immobilized human ACE2 protein on the fiber surface of the bare sensor head to increase the binding efficiency of the sensor head with SARS-CoV-2 spike protein. Finally, we experimentally demonstrated that the proposed sensor could detect SARS-CoV-2 spike protein with the sensitivities of 54.42 and 79.55pm/(μg/ml) for Dip A and Dip B, respectively. |