@article {Martin:September 2006:0003-7028:994, author = "Martin, V.S.", author = "Sullivan, B.A.", author = "Walker, K.", author = "Hawk, H.", author = "Sullivan, B.P.", author = "Noe, L.J.", title = "Surface Plasmon Resonance Investigations of Human Epidermal Growth Factor Receptor 2", journal = "Applied Spectroscopy", volume = "60", year = "September 2006", abstract = "This investigation utilizes surface plasmon resonance (SPR) spectroscopy to detect and quantify human epidermal growth factor receptor 2 (HER-2), an oncogene product that is over-expressed in some aggressive forms of breast cancer. Specifically, the HER-2 trans-membrane protein p185 and its extra cellular fragment p105 are analytes targeted in this work by using a gold-based biosensor slide on which an anti-HER-2 antibody has been immobilized by attachment to Protein G that is fixed to the gold film. A detection limit of ≥11 ng/mL for p185 resulted when trastuzumab was used as the anti-HER-2 antibody on the biosensor slide. Experiments with semi-purified p105 revealed that it binds weakly and reversibly to trastuzumab, therefore complicating its detection and quantification. Results of studies that reacted a 13-amino-acid peptide (PP13) from the HER-2 kinase domain with its specific antibody were critically different than p185 and p105 studies. Spectral analysis of the reflectivity at constant bulk buffer refractive index revealed a progressive negative SPR shift over time. A negative shift suggests that a loss of protein mass from the anti-PP13 antibody-Protein G biosensor is occurring. Several possibilities that may explain these negative SPR shifts are discussed.", pages = "994-1003(10)", url = "http://www.ingentaconnect.com/content/sas/sas/2006/00000060/00000009/art00013" doi = "doi:10.1366/000370206778397498" }