Fig. 1: Schematic illustration of the digital immunoassay workflow with nanopore electrical detection.
From: Digital immunoassay for biomarker concentration quantification using solid-state nanopores
a Paramagnetic beads (PMBs) conjugated with antibodies efficiently capture specific target protein in serum sample. b PMBs are pelleted and immobilized with a magnet and supernatant is removed to eliminate unbound molecules. c PMBs are resuspended and incubated with secondary antibody conjugated with streptavidin. d Following a wash, the immuno-sandwich structure is incubated with biotinylated ssDNA junction strand. e Following another wash, the solution is exposed to UV light to release the junction strand. f PMBs are pelleted and immobilized with a magnet and the supernatant containing the junction strand is recovered with a pipette. g Shooting star-like DNA probes are added to the solution containing recovered junction strand leading to assembly of a dumbbell-like DNA nanostructure. h Digital nanopore sensing to determine the fraction of probes to dumbbells.
