TiC MXene/GNRs for synergistically highly enhanced sensitivity of optical fiber SPR acetylcholine biosensors via an electrostatic layer-by-layer assembly method.

Improving the sensitivity of biosensor has always the major challenge to measure lower detection concentration of biological samples. In this paper, a novel optical fiber surface plasmon resonance (SPR) biosensor based on TiC MXene/GNRs synergistically highly enhanced sensitivity was proposed. The TiC MXene and GNRs were coated on the optical fiber sensing probe by the electrostatic layer-by-layer (ELBL) assembly method. The sensitivity of this optical fiber sensor was significantly improvement by 217.73% which largely benefited from the synergistic interaction between the increases of depth of evanescent wave and enhancement local electromagnetic field. The biosensors were successfully used to the high sensitivity detection of acetylcholine by immobilizing AchE as specific biorecognition molecules on the probe surface with PDA as the enzyme immobilization carrier. The sensitivity and LOD of the proposed biosensor for acetylcholine were 0.04521 nm/μM and 4.42 μM, respectively. The recovery rate of the biosensor in the actual samples detection were between 96 and 106%, and the response time was 220s. The proposed biosensor will provide a promising rapidly and accurately method for the detection of neurotransmitters in the clinic diagnosis.