High-Sensitivity Optical Fiber Photothermal Sensor for Antibiotic Detection With PDMS/Ti3CN MXene Composite Coating

Oxacillin sodium (OXS) is a typical antibiotic contaminant in water and belongs to the semi-synthetic penicillin category. OXS is toxic to human cells and may damage the immune system when it enters the human body. In this study, we propose an optical fiber sensor to detect antibiotic pollutants in water based on the photothermal effect of OXS with a polydimethylsiloxane (PDMS)/Ti3CN MXene composite-coated microfiber. The interaction between the evanescent field and OXS can be enhanced by the coated microfiber, which improves the sensor performance. Moreover, the coated microfiber can enhance the detection sensitivity owing to the high-thermo-optic coefficient of PDMS and the strong molecular adsorption of Ti3CN MXene. The results show that using the PDMS/Ti3CN MXene composite-coated microfiber, detection in the linear range of 0.02–0.1 mg/mL with a sensitivity of −761.39 nm/(mg/mL), and a detection limit of 26 ng/mL are achieved. Compared to that of an uncoated microfiber, the sensitivity of the composited-coated microfiber is improved by a factor of 6. The proposed sensor does not require solvent extraction or complex antibody preparation; therefore, it is easy to operate and exhibits high sensitivity. Furthermore, the sensor has potential applications in food safety and environmental pollutant detection.