A developed Christmas-tree derived immunosensor based on a gold label silver stain (GLSS) technique was fabricated for a highly sensitive analysis of Vibrio parahaemolyticu (VP). In this strategy, captured VP antibody (cAb) was immobilized on a solid substrate; then, the VPs were sequentially tagged with a signal probe by incubating the assay with a detection VP antibody (dAb) conjugated gold nanoparticles (AuNPs)-labeled graphite-like carbon nitride (g-C3N4). Finally, the attached signal probe could harvest a visible signal by the silver meal deposition, and then followed by homebrew Matlab 6.0 as a grey value acquisition. In addition, the overall design of the biosensor was established in abundant AuNPs and g-C3N4 with a two-dimensional structure, affording a bulb-decorated Christmas-tree model. Moreover, with the optimized conditions, the detection limit of the as-proposed biosensor is as low as 102 CFU (Colony-Forming Units) mL-1, exhibiting an increase of two orders of magnitude compared with the traditional immune-gold method. Additionally, the developed visible immunosensor was also successfully applied to the analysis of complicated samples.
Keywords: AuNPs@g-C3N4; Immunosensor; Vibrio parahaemolyticus; gold label silver stain technology.