Development of a multianalyte optical sol–gel biosensor for medical diagnostic

• Published in: Sensors and actuators. B, Chemical Chemical, 2015-12, Vol.221, p.96-103
• Main Authors: Oubaha, M., Gorin, A., McDonagh, C., Duffy, B., Copperwhite, R.
• Format: Article
• Language: English
• Subjects: Biosensors; Diagnostic; Diagnostic software; Excitation; Fluorescence; Hybrid sol–gel; Medical; Optical waveguides; Photonic; Photonics; Platforms; Sensors; Sol gel process
• ISSN: 0925-4005; 1873-3077
• DOI: 10.1016/j.snb.2015.06.012

•A waveguide-based biosensor platform is fabricated from hybrid sol–gel materials.•The waveguides and evanescent field intensity are designed by optical simulations.•The sensitivity is enhanced by increasing the intensity of the evanescent field.•A high refractive index material is used to improve the sensitivity.•The measured limit of detection is in the μg/ml order. This work describes the design and fabrication of a novel multianalyte biosensor platform for medical diagnostic applications. The sensor platform consists of a photonic waveguide-based optical circuit used to deliver excitation light to multiple sensor windows on the platform. The platform is fabricated by UV-photopatterning of photocurable hybrid organic–inorganic sol–gel materials. The sensing mechanism is based upon the detection of fluorescently labelled antibodies, in order to determine the concentration of specific analytes in a test solution. Fluorescence is excited by means of the evanescent wave in each sensor window. It is shown that the sensing properties of the platform can be dramatically enhanced by increasing the intensity of the evanescent field of the light propagating in the optical waveguide by a precise design of a high refractive index layer deposited at the waveguide surface. This work proved the concept of employing a waveguide-based photonic platform for the detection of fluorescently labelled antibodies, with μg/ml detection levels, and as such, we believe this system has immense potential for future applications as a medical diagnostic platform.