Polyglycerol based coatings to reduce non-specific protein adsorption in sample vials and on SPR sensors

Tobias Becherer; Christian Grunewald; Vivienne Engelschalt; Gerhard Multhaup; Thomas Risse; Rainer Haag

doi:10.1016/j.aca.2015.01.048

Polyglycerol based coatings to reduce non-specific protein adsorption in sample vials and on SPR sensors

Anal Chim Acta. 2015 Mar 31:867:47-55. doi: 10.1016/j.aca.2015.01.048. Epub 2015 Feb 10.

Authors

Tobias Becherer¹, Christian Grunewald², Vivienne Engelschalt², Gerhard Multhaup³, Thomas Risse², Rainer Haag²

Affiliations

¹ Freie Universität Berlin, Institute of Chemistry and Biochemistry, Takustr. 3, 14195 Berlin, Germany. Electronic address: tobias.becherer@fu-berlin.de.
² Freie Universität Berlin, Institute of Chemistry and Biochemistry, Takustr. 3, 14195 Berlin, Germany.
³ McGill University, Department of Pharmacology & Therapeutics, Faculty of Medicine, 3655 Promenade Sir-William-Osler, H3G 0B1 Montréal, QC, Canada.

PMID: 25813027
DOI: 10.1016/j.aca.2015.01.048

Abstract

Coatings based on dendritic polyglycerol (dPG) were investigated for their use to control nonspecific protein adsorption in an assay targeted to analyze concentrations of a specific protein. We demonstrate that coating of the sample vial with dPG can significantly increase the recovery of an antibody after incubation. First, we determine the concentration dependent loss of an antibody due to nonspecific adsorption to glass via quartz crystal microbalance (QCM). Complementary to the QCM measurements, we applied the same antibody as analyte in an surface plasmon resonance (SPR) assay to determine the loss of analyte due to nonspecific adsorption to the sample vial. For this purpose, we used two different coatings based on dPG. For the first coating, which served as a matrix for the SPR sensor, carboxyl groups were incorporated into dPG as well as a dithiolane moiety enabling covalent immobilization to the gold sensor surface. This SPR-matrix exhibited excellent protein resistant properties and allowed the immobilization of amyloid peptides via amide bond formation. The second coating which was intended to prevent nonspecific adsorption to glass vials comprised a silyl moiety that allowed covalent grafting to glass. For demonstrating the impact of the vial coating on the accuracy of an SPR assay, we immobilized amyloid beta (Aβ) 1-40 and used an anti-Aβ 1-40 antibody as analyte. Alternate injection of analyte into the flow cell of the SPR device from uncoated and coated vials, respectively gave us the relative signal loss (1-RUuncoated/RUcoated) caused by the nonspecific adsorption. We found that the relative signal loss increases with decreasing analyte concentration. The SPR data correlate well with concentration dependent non-specific adsorption experiments of the analyte to glass surfaces performed with QCM. Our measurements show that rendering both the sample vial and the sensor surface is crucial for accurate results in protein assays.

Keywords: Biosensor; Molecular diagnostics; Nonspecific protein adsorption; QCM; SPR.

Publication types

Research Support, Non-U.S. Gov't

MeSH terms

Amyloid beta-Peptides / analysis*
Amyloid beta-Peptides / chemistry*
Amyloid beta-Peptides / immunology
Antibodies, Monoclonal / immunology
Glass / chemistry
Glycerol / chemistry*
Peptide Fragments / analysis*
Peptide Fragments / chemistry*
Peptide Fragments / immunology
Polymers / chemistry*
Surface Plasmon Resonance / methods*

Substances

Amyloid beta-Peptides
Antibodies, Monoclonal
Peptide Fragments
Polymers
amyloid beta-protein (1-40)
polyglycerol
Glycerol