Optical fiber sensor for glycoprotein detection based on localized surface plasmon resonance of discontinuous Ag-deposited nanostructure

A combination of the optical fiber technology and the art of material miniaturization provides a label-free glycoprotein sensor with an excellent range of detection. This study examines the fabrication of a novel glycoprotein sensor based on partially-unclad optical fiber and discontinuous Ag nanostructure deposition via electroless mechanism. The performance of the sensor is assessed by exposing the sensing part of the fiber to a starch eliminated ipomoea batatas (sweet potato) solution. Interaction of evanescent light with localized surface plasmon wave and interference of core-cladding mode are responsible for wavelength shift and amplitude modulation. Increasing the glycoprotein concentration reduces the contact angle between Ag and analyte due to the hydrophobicity nature of these two materials, which boosts their interaction and develops the sensitivity. The high sensitivity of 30.76 nm/ppm and 19.31 dB/ppm for wavelength and intensity was achieved, respectively, for a sensor with 2 cm active length. The detection range and response time of the sensor are 1.625 x 10(-4) ppm and 574.16 s/ppm, respectively.