Carbon dot-functionalized interferometric optical fiber sensor for detection of ferric ions in biological samples

• Main Authors: Yap, Stephanie Hui Kit, Chan, Kok Ken, Zhang, Gong, Tjin, Swee Chuan, Yong, Ken-Tye
• Other Authors: School of Electrical and Electronic Engineering
• Format: Article
• Language: English
• Published: 2020
• Subjects: Engineering::Electrical and electronic engineering; Carbon Dots; Heavy Metal Ion
• Online Access: https://hdl.handle.net/10356/138312
• Institution: Nanyang Technological University

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.