title: Site-directed antibody immobilization using a protein A-gold binding domain fusion protein for enhanced SPR immunosensing.
abstract: We have implemented a novel strategy for the oriented immobilization of antibodies onto a gold surface based on the use of a fusion protein, the protein A-gold binding domain (PAG). PAG consists of a gold binding peptide (GBP) coupled to the immunoglobulin-binding domains of staphylococcal protein A. This fusion protein provides an easy and fast oriented immobilization of antibodies preserving its native structure, while leaving the antigen binding sites (Fab) freely exposed. Using this immobilization strategy, we have demonstrated the performance of the immunosensing of the human Growth Hormone by SPR. A limit of detection of 90 ng mL(-1) was obtained with an inter-chip variability lower than 7%. The comparison of this method with other strategies for the direct immobilization of antibodies over gold surfaces has showed the enhanced sensitivity provided by the PAG approach.
authors: Nanobiosensors and Bioanalytical Applications Group, Research Center on Nanoscience and Nanotechnology (CSIC) & CIBER-BBN, 08193 Bellaterra, Barcelona, Spain.
authors: Elena
authors: E
authors: de Juan-Franco
authors: Antonio
authors: A
authors: Caruz
authors: J R
authors: JR
authors: Pedrajas
authors: Laura M
authors: LM
authors: Lechuga
mesh_terms: D000595:Amino Acid Sequence; D055910:Antibodies, Immobilized; D015374:Biosensing Techniques / Q000379:methods*; D006046:Gold / Q000737:chemistry* / Q000276:immunology; D019382:Human Growth Hormone / Q000032:analysis / Q000276:immunology; D006801:Humans; D011993:Recombinant Fusion Proteins / Q000737:chemistry; D013205:Staphylococcal Protein A / Q000276:immunology*; D020349:Surface Plasmon Resonance / Q000379:methods
chemical_list: D055910:Antibodies, Immobilized; D011993:Recombinant Fusion Proteins; D013205:Staphylococcal Protein A; D019382:Human Growth Hormone; D006046:Gold