2018 IEEE SENSORS
JOAQUIN ASCORBE; JESÚS M. CORRES; FRANCISCO J. ARREGUI; IGNACIO R. MATÍAS
An optical fiber immunosensor based on long period gratings (LPGs) made by periodic laser ablation is presented in this work. In order to be able to modify the effective index of the fundamental and the cladding modes, a cladding-etched SMF (CE-SMF) was coated with tin dioxide and after that the grating was created by periodic ablation of the overlay. Type G immunoglobulins (IgGs) were attached to (3-glycidyloxypropyl) trimethoxysilane (GPTMS) overlay. Samples with anti-IgGs concentrations ranging from 1 mg/L to 100 mg/L have been studied and a maximum sensitivity of 1.2 nm/(mg/L) was obtained. There is still room for the improvement of this optical platform.
Link to source: https://ieeexplore.ieee.org/abstract/document/8589678
Fabrication of the Long Period Grating
… Afterwards, the CE-SMF was coated with 50 nm of tin dioxide (ZhongNuo Advanced Material Technology Co), according to the QCM included in the pulsed DC sputtering system (Nadetech, Inc.). Tin dioxide was sputtered at Sx10–2 mbar and 180 mA.
Keywords: Biosensors; Optical fibers; Optical fiber sensors; Gratings; Sensitivity; Fiber gratings; Long period gratings; Laser ablation; Immunosensor; GPTMS; Chemical etching; Vacuum evaporation