title: Aptamer-based fiber sensor for thrombin detection.
abstract: The detection of thrombin based on aptamer binding is studied using two different optical fiber-based configurations: long period gratings coated with a thin layer of titanium dioxide and surface plasmon resonance devices in optical fibers coated with a multilayer of gold and titanium dioxide. These structures are functionalized and the performance to detect thrombin in the range 10 to 100 nM is compared in transmission mode. The sensitivity to the surrounding refractive index (RI) of the plasmonic device is higher than 3100  nm RIU−1 in the RI range 1.335 to 1.355, a factor of 20 greater than the sensitivity of the coated grating. The detection of 10 nM of thrombin was accomplished with a wavelength shift of 3.5 nm and a resolution of 0.54 nM.
authors.affiliation: University of Porto, CAP/INESC TEC-Technology and Science and FCUP-Faculty of Sciences, Rua do Campo Alegre, 4150-179 Porto, Portugal.
authors.forename: Luís
authors.initials: L
authors.lastname: Coelho
authors.affiliation: University of Porto, CAP/INESC TEC-Technology and Science and FCUP-Faculty of Sciences, Rua do Campo Alegre, 4150-179 Porto, PortugalbUniversidade de Trás-os-Montes e Alto Douro, Department of Physics, School of Sciences and Technology, Apartado 1013, 5001-801 Vila Real, Portugal.
authors.forename: José Manuel
authors.initials: JM
authors.lastname: Marques Martins de Almeida
authors.affiliation: University of Porto, CAP/INESC TEC-Technology and Science and FCUP-Faculty of Sciences, Rua do Campo Alegre, 4150-179 Porto, Portugal.
authors.forename: José Luís
authors.initials: JL
authors.lastname: Santos
authors.affiliation: University of Porto, CAP/INESC TEC-Technology and Science and FCUP-Faculty of Sciences, Rua do Campo Alegre, 4150-179 Porto, Portugal.
authors.forename: Pedro Alberto
authors.initials: PA
authors.lastname: da Silva Jorge
authors.affiliation: Universidade do Porto, i3S-Instituto de Investigação e Inovação em Saúde, PortugaldUniversidade do Porto, INEB-Instituto de Engenharia Biomédica, Rua Alfredo Allen, 208, 4200-135 Porto, PortugaleUniversidade do Porto, ICBAS-Instituto de Ciências Biomédicas Abel Salazar, Rua de Jorge Viterbo Ferreira 228, 4050-313 Porto, Portugal.
authors.forename: Maria Cristina L
authors.initials: MC
authors.lastname: Martins
authors.affiliation: Universidade do Porto, INEB-Instituto de Engenharia Biomédica, Rua Alfredo Allen, 208, 4200-135 Porto, Portugal.
authors.forename: Diana
authors.initials: D
authors.lastname: Viegas
authors.affiliation: INL-International Iberian Nanotechnology, Avenida Mestre José Veiga s/n, 4715-330 Braga, Portugal.
authors.forename: Raquel B
authors.initials: RB
authors.lastname: Queirós
mesh_terms: D052158:Aptamers, Peptide / Q000378:metabolism; D006046:Gold / Q000737:chemistry; D057230:Limit of Detection; D055100:Optical Fibers; D012031:Refractometry; D020349:Surface Plasmon Resonance; D013917:Thrombin / Q000032:analysis*; D014025:Titanium / Q000737:chemistry
chemical_list: D052158:Aptamers, Peptide; C009495:titanium dioxide; D006046:Gold; D014025:Titanium; D013917:Thrombin