Optofluidic microcapillary biosensor for label-free, low glucose concentration detection

Hongdan Wan; Jijing Chen; Cheng Wan; Quan Zhou; Jie Wang; Zuxing Zhang

doi:10.1364/BOE.10.003929

Optofluidic microcapillary biosensor for label-free, low glucose concentration detection

Biomed Opt Express. 2019 Jul 12;10(8):3929-3937. doi: 10.1364/BOE.10.003929. eCollection 2019 Aug 1.

Authors

Hongdan Wan^{1

2}, Jijing Chen¹, Cheng Wan³, Quan Zhou¹, Jie Wang¹, Zuxing Zhang^{1

4}

Affiliations

¹ Nanjing University of Posts and Telecommunications, Nanjing 210023, China.
² hdwan@njupt.edu.cn.
³ Department of Biomedical Engineering, College of Engineering of Peking University, Beijing, China.
⁴ zxzhang@njupt.edu.cn.

Abstract

We demonstrate label-free detection of low glucose concentration based on whispery gallery mode resonance in an optofluidic microcapillary (OFMC) biosensor. The wall surface of the OFMC is bio-chemically functionalized to detect cellular-level glucose concentration as low as 2.78 mM. The measured sensitivity is 0.966 pm/mM. The fabricated microcapillary has a thin wall thickness of 2 μm and a Q factor of 1.3 × 10⁶, corresponding to a bulk refractive index sensitivity of 23.36 nm/RIU. The OFMC biosensor has advantages such as high resistance to environmental perturbation, small sample volume down to 90 nL and cost-effectiveness. Theoretical analysis shows the sensor sensitivity depends on the microcapillary wall thickness and liquid core refractive index.