An Optical Fiber Optofluidic Laser Biosensor for Rapid Hemoglobin Detection Using Organic Dye

In this article, we reported an optical fiber optofluidic laser (FOFL) biosensor based on thin-walled hollow optical fiber (HOF). HOFs with wall thickness of several microns were fabricated, which integrated both whispering gallery mode (WGM) optical microcavity and microfluid channel for FOFL. Based on the fluorescence quenching caused by the interaction between rhodamine 6G (R6G) and hemoglobin (Hb), FOFL was used to amplify such quenching effect and an FOFL biosensor was constructed to detect Hb concentration. The experimental results showed that the limit of detection (LOD) of 0.7 nM and the dynamic range of three orders of magnitude were obtained within a short assay time on the order of seconds, which were both great improvements over fluorescence detection results. In addition, the designed sensor has the advantages of low-volume sample consumption, simple homogeneous and wash-free process, and reusability. This work may provide a new approach for Hb detection in blood and has the potential to be applied in the diagnosis of some related diseases.