Label-Free and Highly Sensitive Optical Fiber Biosensor Based on Surface Plasmon Resonance for Rapid Detection of β2-MG

A novel optical fiber surface plasmon resonance (SPR) biosensor based on a hetero-core structure (multimode/non-core/multimode) and polydopamine modification is developed for the detection of beta-2-microglobulin (β2-MG) in urine. When β2-MG at different concentrations is captured by the antibody on the optical fiber probe, it leads to different changes in the local refractive index. Based on this SPR effect, the optimal conditions for various sensitive materials were explored and experimental characterization was done accordingly, and finally the proposed optical fiber biosensor was prepared. The β2-MG sensor showed a linear sensitivity of 0.96 nm/lg <italic xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">c</i> and a LOD of 4.22 ng/mL in the range of 0.01–1000 ng/mL. With no need for labeling, this biosensor has rapid response and low cost. In addition, it exhibited excellent specificity and stability. The proposed sensor provides excellent performance with simple fabrication and offers a bioanalytical platform with potential applications for clinical diagnosis of renal function diseases.