Cortisol AuPd plasmonic unclad POF biosensor

Biotechnology Reports

Ana R. Almeida¹  Arnaldo Leal-Junior²  C. Marques³  João L. Pinto³  Cátia Leitão³  Sónia O. Pereira³  Florinda M. Costa³ 

[1] Mechanical Engineering Department, Federal University of Espirito Santo, Vitória, 29075-910, Brazil;;Graduate Program of Electrical Engineering &i3N, Department of Physics, University of Aveiro, Campus Universitário de Santiago, 3810-193, Aveiro, Portugal;

关键词: Plastic optical fiber;    Unclad POF;    Biosensor;    SPR;    Stress monitoring;    Well-being monitoring;   

DOI  :  

来源: DOAJ

【 摘 要 】

This paper presents the development and feasibility tests of a cortisol immunosensor. The sensor is based on surface plasmon resonance (SPR) using an unclad plastic optical fiber (POF) in which the SPR is used as sensitivity enhancer, promoted by a gold/palladium (AuPd) alloy coating. The AuPd coated fibers were functionalized with an anti-cortisol antibody and passivated with bovine serum albumin (BSA) to be tested in the presence of cortisol as target analyte. The antibody-antigen binding reaction caused a variation of the refractive index on the surface of the AuPd coating, which leads to a shift of the SPR signature wavelength. The sensor was tested for different cortisol concentrations, ranging from 0.005 to 10 ng/mL. The reported biosensor presented a total wavelength shift of 15 nm for the testing range, putting in evidence a high sensitivity. Control tests for selectivity assessment were also performed. Concentrations as high as 10 ng/mL of cortisol, in a sensor functionalized with anti-hCG antibodies, only resulted in 1 nm variation of the resonance wavelength, 15 times lower than the one functionalized with the anti-cortisol antibodies, which indicates a high selectivity for the proposed approach. For this sensing approach the limit of detection (LOD) was determined to be 1 pg/mL. The proposed SPR based POF sensor has a low-cost interrogation method, high sensitivity and low LOD, straightforward signal processing and find important applications in different biological fields.

【 授权许可】

Unknown