Carbon Dot-functionalized Interferometric Optical Fiber Sensor for Detection of Ferric Ions in Biological Samples

• Published in: ACS applied materials & interfaces 2019-08, Vol.11 (31), p.28546-28553
• Main Authors: Yap, Stephanie Hui Kit, Chan, Kok Ken, Zhang, Gong, Tjin, Swee Chuan, Yong, Ken-Tye
• Format: Article
• Language: English
• Subjects: Carbon - chemistry; Ferric Compounds - analysis; Ferric Compounds - chemistry; Fluorescence; Interferometry; Light; Limit of Detection; Optical Fibers; Quantum Dots - chemistry
• ISSN: 1944-8244; 1944-8252
• DOI: 10.1021/acsami.9b08934

This work reports an interferometric optical microfiber sensor functionalized with nitrogen- and sulfur-codoped carbon dots (CDs) for the detection of ferric ions (Fe3+). Compared to other CD-based ferric ion sensors, the sensing mechanism of this presented sensor is dependent on the refractive index modulations due to selective Fe3+ adsorption onto the CD binding sites at the tapered region. This is the first study in which CD-based sensing was performed at the solid phase as a chelator, which does not rely on its fluorescence properties. The detection performance of the proposed sensor is not only comparable to a conventional fluorescence-based CD nanoprobe sensor but also capable of delivering quantitative analysis results and ease of translation to a sensor device for on-site detection. The presented sensor exhibits Fe3+ detection sensitivity of 0.0061 nm/(μg/L) in the linear detection range between 0 and 300 μg/L and a detection limit of 0.77 μg/L based on the Langmuir isotherm model. Finally, the potential use of the CD-functionalized optical microfiber sensor in the real environmental and biological Fe3+ monitoring applications has also been validated in this work.