Localized and propagating surface plasmon resonance based fiber optic sensor for the detection of tetracycline using molecular imprinting

In the present study we report a novel approach for the fabrication of localized and propagating surface plasmon resonance based fiber optic sensor for the detection of tetracycline using molecular imprinting (MIP) technique. The sensor is fabricated by coating layers of silver film, silver nanoparticles and MIP film prepared using tetracycline molecule as template over an unclad core of the multimode optical fiber. Nanoparticles of sizes in the range 10-30 nmare synthesized by hydrothermal process. A polychromatic light source is used to launch the light from one end of the fiber and the absorption spectrum for a given concentration of the tetracycline solution around the probe is measured at the other end of the fiber using a spectrometer interfaced with a computer. The absorption spectra are recorded for the concentration range of tetracycline from 10^-8M to 10^-5 M. A shift of 102 nmin peak absorbance wavelength is obtained for this concentration range. The sensor works in the promising concentration range of tetracycline found in foods etc. The sensor has various advantages such as high sensitivity, low cost, fast response and capability of online monitoring and remote sensing. Further, the sensitivity of the sensor is about double the sensor based on localized surface plasmon resonance and molecular imprinting.