US 11,698,381 B2
Opto-magnetophoretic method for the detection of biological and chemical substance
Maria Benelmekki Erretby, Sant Privat d'en Bas (ES); Sergi Gassó Pons, Sant Privat d'en Bas (ES); and Lluís Miquel Martínez García, Cerdanyola del Vallès (ES)
Assigned to SEPMAG SYSTEMS, S.L., Barcelona (ES)
Appl. No. 16/613,401
Filed by SEPMAG SYSTEMS, S.L., Barcelona (ES)
PCT Filed May 30, 2018, PCT No. PCT/ES2018/070392
§ 371(c)(1), (2) Date Nov. 13, 2019,
PCT Pub. No. WO2019/229276, PCT Pub. Date Dec. 5, 2019.
Prior Publication US 2021/0333296 A1, Oct. 28, 2021
Int. Cl. G01N 21/59 (2006.01); B03C 1/32 (2006.01); B03C 1/30 (2006.01); B82Y 5/00 (2011.01); G01N 35/00 (2006.01); B03C 1/033 (2006.01); B82Y 25/00 (2011.01); B82Y 35/00 (2011.01)
CPC G01N 35/0098 (2013.01) [B03C 1/0332 (2013.01); B03C 1/30 (2013.01); B03C 1/32 (2013.01); G01N 21/59 (2013.01); B03C 2201/18 (2013.01); B03C 2201/22 (2013.01); B03C 2201/26 (2013.01); B82Y 5/00 (2013.01); B82Y 25/00 (2013.01); B82Y 35/00 (2013.01)] 12 Claims
 
1. A method for detecting the presence or absence of a biological or chemical substance in a particular sample mixed with a suspension with functionalized magnetic particles, the particles having a diameter between 10 and 1000 nm and a saturation magnetization such that their magnetic separation time is different in the absence or presence of the biological or chemical substance, by monitoring the optical properties of the suspension, the method comprising the steps of:
providing a light source and detector;
providing a constant magnetic force perpendicular to the light's propagation direction by applying a constant magnetic field gradient, and with an absolute value of the magnetic field which is higher than 0.1 T;
measuring the change of the magnetic particle's suspension transparency versus time; and
comparing the variation along time of the magnetic particle's suspension transparency in the presence and in the absence of the biological or chemical substance of interest,
wherein the magnetic force is provided by a magnetic force generator comprising at least four permanent magnets following the Halbach progression for a quadrupole in a cylindrical support.