Optical method for detecting a target molecule by means of the amplification in the interference response, resulting from the refractive index and dispersion

• Main Authors: Maria Garrido Arandia, Miguel Holgado Bolanos, Araceli Diaz Perales, Beatriz Santamaria Fernandez, Yolanda Ramirez Alonso, Maria Fe Laguna Heras, Luis Fernandez Pacios, Francisco Javier Sanza Gutierrez, Alejandro Romero Sahagun, Rocio Lopez Espinosa
• Format: Patent
• Language: English
• Published: 07.12.2022
• Subjects: INVESTIGATING OR ANALYSING MATERIALS BY DETERMINING THEIRCHEMICAL OR PHYSICAL PROPERTIES; MEASURING; PHYSICS; TESTING

The invention relates to an optical method for detecting at least one target molecule (TM) contained in a sample at a determined concentration, which comprises: (a) bringing a sample containing the TM into contact, in a liquid medium, with a solution containing nanoparticles (NPs), the surface of the NPs having been coated or functionalised with at least one type of specific bioreceptor (BR) of the target molecule to be detected (NP-BR), such that the BRs specifically recognise the TM, thus forming conjugates of the NP-BRs with the TMs (NP-BR-TMs); (b) separating the nanoparticles conjugates (NP-BR-TMs and/or NP-BRs) formed in the previous step; (c) bringing the nanoparticles conjugates (NP-BR-TMs and/or NP-BRs) into contact with a sensor surface of an optical transducer that operates by means of reflection and/or transmission, the response of which is based on optical interference, the sensor surface being functionalised by immobilising thereon: (i) the target molecule (TM) or (ii) at least one specific bioreceptor of the target molecule, which may be of the same type (BR) or of another type (BR1); and (d) determining the optical reading on the sensor surface by means of change in the interference response of the optical transducer, caused by change in the real part of the refractive index as a result of the NP conjugates recognised on the sensor surface, and/or by means of change in intensity in the interference response, caused by variation in intensity as a result of dispersion or as a result of variation in the complex part of the refractive index of the NP conjugates, or by means of a combination of both effects.