Poly(acrylic acid) brushes pattern as a 3D functional biosensor surface for microchips

► The convenient method of microcontact printing(μCP) was used for fabricating 3D PAA brushes pattern surface. ► Protein immobilization enhancement based on 3D PAA brushes pattern surface was found in model protein immunoassay. ► HBsAg concentration array chip based on 3D PAA brushes pattern surface was developed for label-free assaying of HBsAb. ► The linearity range for HBsAb assay is wider than that of conventional ELISA method.