ssDNA-Functionalized Optical Fiber SPR Sensor for Trace Dopamine Detection

Dopamine, as a neurotransmitter, is essential for maintaining the function of the extrapyramidal nervous system. This article introduces an optical fiber sensor based on surface plasmon resonance (SPR) for detecting trace dopamine. The SPR effect is induced by an Au film coated on a plastic-cladding optical fiber. The specificity for dopamine is achieved through an aptamer, while graphene serves as a mediator between the gold-coated optical fibers and adapters. The sensor shows a linear sensitivity of 0.853 nm/log(M) over a dopamine concentration range of 10⁻¹¹ to 10⁻⁴ M, with a detection limit of 1 × 10⁻¹¹ M. Compared with existing dopamine detection methods, the proposed sensor exhibits a lower detection limit, a sufficiently wide linear range, and broad application prospects in biosensing.