Trace Doxycycline Detection via Molecular Imprinting Combined With Fiber Surface Plasmon Resonance

Doxycycline (DOX) is one of the most widely used veterinary antibiotics in animal husbandry, and its residues may affect the health of humans and animals due to the in-creased bacterial resistance. Here we developed a trace DOX detection means based on molecular imprinting technology with tilted fiber Bragg grating surface plasmon resonance (TFBG-SPR). Sputtering a 50 nm thick gold film on the surface of TFBG to excite surface plasmon resonance, and coating a layer of molecularly imprinted polymers (MIPs) on the surface of the gold film to capture DOX. Experimental results show that the proposed sensor shows a detection sensitivity of 1.89 dB/(μg/mL) for DOX in the concentration range of 0.1-1 μg/mL, with a detection time of about 5 minutes and a detection limit (LOD) of about 0.0323 μg/mL (0.0672 μM). The obtained LOD is half of that of the current similar DOX sensor. The proposed sensor is expected to provide technical support for real-time trace monitoring of DOX concentration in the environment and food.