Microfluidics-based nanobiosensors and devices

A method of microfluidic detection of a target analyte in a biological sample collected from a subject, the method comprising:

• providing a microfluidic device, said device comprising:
• a planar substrate comprising a sample inlet well positioned above a sample chamber in or on the substrate and a detection chamber in fluid communication with the sample chamber via a microfluidic channel extending from the sample chamber to the detection chamber;
• and a washing chamber positioned along the microfluidic channel intermediate to the sample chamber and the detection chamber;
• and
• a magnet positioned external and adjacent to said microfluidic channel, wherein said magnet is translatable along a plane parallel and to the plane of said microfluidic channel;
• incubating said biological sample with a first nanobiosensor in said sample chamber, wherein said first nanobiosensor comprises a magnetic nanoparticle releasably attached to a plurality of reporter molecules;
• transferring said incubated sample and said first nanobiosensor to said wash chamber;
• introducing a wash fluid into said wash chamber to yield a first washed nanobiosensor;
• magnetically transferring said first washed nanobiosensor to said detection chamber by translating said magnet along a plane parallel to said microfluidic channel from a position adjacent said wash chamber to a position adjacent said detection chamber;
• separating said nanoparticle and said reporter molecules to yield separated reporter molecules and a delinked nanoparticle,
• magnetically removing said delinked nanoparticle from said detection chamber by translating said magnet along a plane parallel to said microfluidic channel away from said detection chamber;
• detecting said separated reporter molecules in said detection chamber by microfluidic Isoelectric Focusing of said separated reporter molecules and detecting locations of said separated reporter molecules in said detection chamber, wherein said reporter molecules are indicative of interaction of said target analyte with said reporter molecules.