Small size nanoparticles—Co3O4 based lateral flow immunoassay biosensor for highly sensitive and rapid detection of furazolidone

Lateral flow immunoassay (LFIA) biosensor is a paper-based tool and widely utilized in various fields. Here, we developed a novel LFIA biosensor by introducing Co 3 O 4 nanoparticles (NPs) as signal labels for highly sensitive detection of 3-amino-2-oxazolidinone (AOZ), a metabolite of furazolidone . The characteristic brown color of Co 3 O 4 NPs enabled AOZ to be visually detected by the LFIA. Significantly, the size of Co 3 O 4 NPs is relatively small compared with most of other signal labels, which could remarkably reduce steric hindrance , increase immunoreaction probability and shorten the analysis time. Under optimal conditions, the novel Co 3 O 4 NPs-LFIA could possess high sensitivity for the detection of AOZ with a detection limit of 0.4 ng mL −1  by naked eyes, which was at least 3-fold improved than that of the conventional gold nanoparticles (GNPs) based LFIA. Moreover, the detection could be achieved within 6 min and without cross-reactions with other analogue small molecules. Taking merits of convenience, rapid and sensitivity, the proposed Co 3 O 4 NPs-LFIA may be readily adapted for the detection of other small molecules.