Quartz Crystal Microbalance Immunoassay of Hepatitis B Surface Antigen Using Magnetic CoFe2O4/Cu2O Composite Nanoparticles as Immunosensing Probe

This study describes a new strategy toward the development of advanced immunosensors based on chemically functionalized magnetic-core/porous-shell CoFe2O4/Cu2O composite nanoparticles, and the preparation, characterization, and measurement of relevant properties of the immunosensor useful for the detection of hepatitis B surface antigen (HBsAg) in clinical immunoassay. The immunosensor based on the combination of a magnetic nanocore and a Cu2O shell shows good adsorption properties for the attachment of hepatitis B surface antibody (HBsAb) selective to HBsAg. The core-shell nanostructure presents good magnetic properties to facilitate and modulate the way while it was integrated into a magnetic interface. Under optimal conditions, the resulting composite presents good frequency response for the detection of HBsAg, and allows detection of HBsAg at concentration as low as 0.5 ng/mL. Importantly, the proposed methodology could be extended to the detection of other antigens or biocompounds.