Sensitivity enhancement of WS2-coated SPR-based optical fiber biosensor for detecting glucose concentration
Yun Cai(蔡云)1,4, Wei Li(李卫)1,2,3,4, †, Ye Feng(冯烨)1,4, Jian-Sheng Zhao(赵建胜)1,4, Gang Bai(白刚)1,4, Jie Xu(许杰)1,4, and Jin-Ze Li(李金泽)1,4$
1 College of Electronic and Optical Engineering & College of Microelectronics, Nanjing University of Posts and Telecommunications, Nanjing 210023, China 2 State Key Laboratory of Millimeter Waves, Southeast University, Nanjing 210093, China 3 State Key Laboratory of Luminescent Materials and Devices, South China University of Technology, Guangzhou 510641, China 4 Research Center of Optical Communications Engineering & Technology, Nanjing 210023, China
In this paper, we propose a theoretical model of the surface plasmon resonance-based optical fiber biosensor for detecting glucose concentration. The Au/ZnO/WS2 multilayer film is coated around optical fiber. Compared with the conventional surface plasmon resonance sensor, WS2 material can increase the sensitivity of the biosensor. The absorption capacity of WS2 is used to load glucose oxidase by forming a sensitive area to recognize glucose. Refractive index of the solution is calculated and then the concentration of the glucose can be obtained by the correspondence between refractive index and glucose concentration. The highest sensitivity of the SPR biosensor with a structure of 40-nm Au/5-nm ZnO/14 layers of WS2 is 4310 nm/RIU. The proposed WS2-based SPR fiber biosensor has a unique effect on the detection of glucose concentration. It is expected to have potential applications in future medical blood glucose concentration detection.
Received: 17 April 2020
Revised: 08 July 2020
Accepted manuscript online: 15 July 2020
Fund: the Natural Science Foundation of Jiangsu Province, China (Grant No. BK20171442), the China Postdoctoral Science Foundation (Grant No. 2018T110480), the Open Foundation of State Key Laboratory of Millimeter Waves, China (Grant No. K202003), the Open Foundation of State Key Laboratory of Luminescent Materials and Devices, China (Grant No. 2020-skllmd-03), and the Fund from the Research Center of Optical Communications Engineering & Technology, Jiangsu Province, China (Grant No. ZXF201904).
Yun Cai(蔡云), Wei Li(李卫), Ye Feng(冯烨), Jian-Sheng Zhao(赵建胜), Gang Bai(白刚), Jie Xu(许杰), and Jin-Ze Li(李金泽)$ Sensitivity enhancement of WS2-coated SPR-based optical fiber biosensor for detecting glucose concentration 2020 Chin. Phys. B 29 110701
Fig. 1.
Schematic diagram of SPR fiber biosensor.
Fig. 2.
Transmission spectra of SPR biosensors with different coating materials: (a) Au, (b) Au/ZnO, and (c) Au/ZnO/WS2.
Fig. 3.
Variations of tranmission with resonance wavelength for different values of Au film thickness.
Fig. 4.
(a) SPR transmission spectra of proposed fiber-optic biosensor at different RI values of the analyte, and (b) variation of sensitivity with the number of WS2 layers, with inset showing the linear fits between the resonance wavelength and the RI of the analyte for various numbers of WS2 sensing layers.
Thickness of ZnO layer/nm
Sensitivity/(nm/RIU) Number of WS2 layer
2
4
6
8
10
12
14
16
18
5
3750
3870
3980
4100
4180
4230
4310
4310
4290
10
3680
3710
3760
3760
3740
3680
3640
3600
3500
15
3560
3540
3490
3450
3340
3230
3150
3090
2970
20
3410
3340
3250
3160
3000
2860
2780
2720
2590
Table 1.
Sensitivities of fiber-optic SPR biosensor with various thickness values of ZnO and WS2.
Fig. 5.
(a) Mode field distribution of Au, Au/ZnO, and proposed Au/ZnO/WS2 SPR biosensor at sensing medium RI of 1.33, respectively, and (b) mode field distribution of proposed biosensor at the analyte RI from1.33 to 1.37 (in steps of 0.01), respectively.
Fig. 6.
Comparison of normalized electric field versus distance curve between (a) SPR sensor with Au/ZnO structure and (b) that with Au/ZnO/WS2 structure.
Structure
RI range
Sensitivity/(nm/RIU)
Reference
Ag/graphene
1.46–1.49
300
[40]
Au/ZnO
1.30–1.37
3161
[33]
Au/TiO2
1.333–1.403
1015.15
[41]
Au/WS2
1.333–1.360
2459.3
[30]
Au/ZnO/WS2
1.33–1.37
4310
this work
Table 2.
Comparison of performance between proposed sensor and other sensors.
Glucose
Refraction
Resonance wavelength/nm
concentration/(g/l)
index/(RIU)
Au/ZnO
Au/ZnO/WS2
1.33
603
1047
65
1.34
631
1080
149
1.35
664
1119
233
1.36
703
1165
317
1.37
750
1220
Table 3.
Correspondence among glucose concentration, refractive index, and resonance wavelength.
Fig. 7.
Comparison of measurement of glucose concentration between two structures.
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