title: Quantitative biomolecular sensing station based on magnetoresistive patterned arrays.
abstract: The combination of magnetoresistive sensors and magnetic labeling of bioanalytes, which are selectively captured by their complementary antibody in the proximity of the sensor is a powerful method in order to attain truly quantitative immunological assays. In this paper we present a technical solution to exploit the existing spin valve technology to readout magnetic signals of bio-functionalized magnetic nanoparticles. The method is simple and reliable, and it is based on a discrete scan of lateral flow strips with a precise control of the contact force between sensor and sample. It is shown that the signal of the sensor is proportional to the local magnetization produced by the nanoparticles in a wide range of concentrations, and the sensitivity thresholds in both calibration samples and real immunorecognition assays of human chorionic gonadotropin hormone are well below the visual inspection limit (5.5 ng/ml). Furthermore the sample scanning approach and the reduced dimensions of the sensors provide unprecedented spatial resolution of the nanoparticle distribution across the supporting nitrocellulose strip, therefore enabling on-stick control references and multi-analyte capability.
authors.affiliation: Instituto de Nanociencia de Aragón (INA), Universidad de Zaragoza, C/Mariano Esquillor s/n, 50018, Zaragoza, Spain; Dpto. Física de Materia Condensada, Universidad de Zaragoza, C/Pedro Cerbuna 12, 50009 Zaragoza, Spain. Electronic address: serrate@unizar.es.
authors.forename: D
authors.initials: D
authors.lastname: Serrate
authors.affiliation: Dpto. Física de Materia Condensada, Universidad de Zaragoza, C/Pedro Cerbuna 12, 50009 Zaragoza, Spain; Instituto de Ciencia de Materiales de Aragón (ICMA), CSIC - Universidad de Zaragoza, C/Pedro Cerbuna, 50009 Zaragoza, Spain.
authors.forename: J M
authors.initials: JM
authors.lastname: De Teresa
authors.affiliation: Dpto. Física de Materia Condensada, Universidad de Zaragoza, C/Pedro Cerbuna 12, 50009 Zaragoza, Spain; Instituto de Ciencia de Materiales de Aragón (ICMA), CSIC - Universidad de Zaragoza, C/Pedro Cerbuna, 50009 Zaragoza, Spain.
authors.forename: C
authors.initials: C
authors.lastname: Marquina
authors.affiliation: Instituto de Ciencia de Materiales de Aragón (ICMA), CSIC - Universidad de Zaragoza, C/Pedro Cerbuna, 50009 Zaragoza, Spain.
authors.forename: J
authors.initials: J
authors.lastname: Marzo
authors.affiliation: Instituto de Nanociencia de Aragón (INA), Universidad de Zaragoza, C/Mariano Esquillor s/n, 50018, Zaragoza, Spain.
authors.forename: D
authors.initials: D
authors.lastname: Saurel
authors.affiliation: INESC Microsistemas e Nanotecnologias (INESC MN), Rua Alves Redol 9, 1000-029 Lisbon, Portugal.
authors.forename: F A
authors.initials: FA
authors.lastname: Cardoso
authors.affiliation: INESC Microsistemas e Nanotecnologias (INESC MN), Rua Alves Redol 9, 1000-029 Lisbon, Portugal.
authors.forename: S
authors.initials: S
authors.lastname: Cardoso
authors.affiliation: INESC Microsistemas e Nanotecnologias (INESC MN), Rua Alves Redol 9, 1000-029 Lisbon, Portugal.
authors.forename: P P
authors.initials: PP
authors.lastname: Freitas
authors.affiliation: Instituto de Nanociencia de Aragón (INA), Universidad de Zaragoza, C/Mariano Esquillor s/n, 50018, Zaragoza, Spain; Dpto. Física de Materia Condensada, Universidad de Zaragoza, C/Pedro Cerbuna 12, 50009 Zaragoza, Spain.
authors.forename: M R
authors.initials: MR
authors.lastname: Ibarra
mesh_terms: D015374:Biosensing Techniques / Q000295:instrumentation* / Q000706:statistics & numerical data; D006063:Chorionic Gonadotropin / Q000032:analysis; D004867:Equipment Design; D006801:Humans; D057230:Limit of Detection; D008280:Magnetics; D058185:Magnetite Nanoparticles
chemical_list: D006063:Chorionic Gonadotropin; D058185:Magnetite Nanoparticles