IngentaConnect Surface Plasmon Resonance Investigations of Human Epidermal Growt...

Authors: Martin, V.S.¹; Sullivan, B.A.²; Walker, K.²; Hawk, H.²; Sullivan, B.P.¹; Noe, L.J.¹

Source: Applied Spectroscopy, Volume 60, Issue 9, Pages 220A-236A and 951-1095 (September 2006) , pp. 994-1003(10)

Publisher: Society for Applied Spectroscopy

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.

Keywords: HUMAN EPIDERMAL GROWTH FACTOR RECEPTOR-2; HER-2; PROTEIN G BASED BIOSENSOR SLIDE; SURFACE PLASMON RESONANCE; SPR; SPECTROSCOPY

Document Type: Research article

DOI: 10.1366/000370206778397498

Affiliations: 1: Department of Chemistry, University of Wyoming, Laramie, Wyoming 82071 2: School of Pharmacy, University of Wyoming, Laramie, Wyoming 82071

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Surface Plasmon Resonance Investigations of Human Epidermal Growth Factor Receptor 2