Ultrasensitive biosensor based on magnetic microspheres enhanced microfiber interferometer

• Published in: Biosensors & bioelectronics 2019-12, Vol.145, p.111563-111563, Article 111563
• Main Authors: Kumar, Rahul, Leng, Yuankui, Liu, Bin, Zhou, Jun, Shao, Liyang, Yuan, Jinhui, Fan, Xinyu, Wan, Shengpeng, Wu, Tao, Liu, Juan, Binns, Richard, Fu, Yong Qing, Ng, Wai Pang, Farrell, Gerald, Semenova, Yuliya, Xu, Hengyi, Xiong, Yonghua, He, Xingdao, Wu, Qiang
• Format: Article
• Language: English
• Subjects: Biosensing Techniques; Biosensor; Chorionic Gonadotropin - chemistry; Chorionic Gonadotropin - isolation & purification; Human chorionic gonadotropin (hCG); Humans; Interferometry; Limit of Detection; Magnetics; Microspheres; Optical fiber interferometer; Optical fiber sensor
• ISSN: 0956-5663; 1873-4235
• DOI: 10.1016/j.bios.2019.111563

A critical barrier for the successful development of fiber sensors for bio-chemical processes is their limitedly improved sensitivity, restricted by the sensor structural design. To solve this, in this paper, a novel concept was proposed using functionalised modified magnetic microspheres (MMSs) to “amplify” the effect of target bio-chemical analytes to significantly improve the fiber sensor's sensitivity, which has been demonstrated using human chorionic gonadotropin (hCG) as an example. Two types of antibody hCG, (β and α, both can specifically bind with hCG), were adhered on the surface of fibre sensor and MMSs respectively. Both hCG and MMSs will be specifically captured by the fibre sensor, where MMSs act as an “amplifier” to improve the sensor sensitivity. Experimentally immunomagnetic detection limit of 0.0001 mIU/mL has been achieved, which is the highest reported so far. This newly developed methodology opens a new direction for sensitivity improvement and could be further explored to applications require ultrahigh sensitivity detections such as earlier medical diagnostics. •Use surface modified magnetic microspheres (MMSs) to “amplify” the signal of target analyte.•Provide “additional” sensitivity improvement for the fabricated sensor.•Demonstrated limit of detection of human chorionic gonadotropin as low as 0.0001 mIU/mL, the best value reported so far.•The concept will be pivotal for applications require ultra-high sensitivity detection such as early medical diagnostics..