Protein adsorption/desorption and antibody binding stoichiometry on silicon interferometric biosensors examined with TOF-SIMS

Gajos, Katarzyna; Budkowski, Andrzej; Petrou, Panagiota; Pagkali, Varvara; Awsiuk, Kamil; Rysz, Jakub; Bernasik, Andrzej; Misiakos, Konstantinos; Raptis, Ioannis; Kakabakos, Sotirios

Protein adsorption/desorption and antibody binding stoichiometry on silicon interferometric biosensors examined with TOF-SIMS

Files

1-s2.0-S0169433218306895-main.pdf (1.88 MB)

1-s2.0-S0169433218306895-fx1.jpg (35.52 KB)

Type

Article

Authors

Gajos, Katarzyna
Budkowski, Andrzej
Petrou, Panagiota
Pagkali, Varvara
Awsiuk, Kamil
Rysz, Jakub
Bernasik, Andrzej
Misiakos, Konstantinos
Raptis, Ioannis
Kakabakos, Sotirios

KAUST Department

Patterning

Online Publication Date

2018-03-05

Print Publication Date

2018-06

Date

2018-03-05

Abstract

Time-of-flight secondary ion mass spectrometry has been employed to examine, with biomolecular discrimination, sensing arm areas (20 μm x 600 μm) of integrated onto silicon chips Mach-Zehnder interferometers aiming to optimize their biofunctionalization with regard to indirect immunochemical (competitive) detection of ochratoxin A. Sensing areas are examined after: modification with (3-aminopropyl)triethoxysilane, spotting of OTA-ovalbumin conjugate (probe) from solutions with different concentration, blocking with bovine serum albumin, reaction with OTA-specific mouse monoclonal antibody followed by goat anti-mouse IgG secondary antibody. Component mass loadings of all proteins involved in immunodetection are determined from TOF-SIMS micro-analysis combined with ellipsometry of planar surfaces. These data show that partial desorption of surface-bound probe and blocking protein takes place upon primary immunoreaction to a degree that depends on probe concentration in spotting solution. Taking into account this desorption, apparent binding stoichiometry of both antibodies in immune complexes formed onto chip surface is determined more accurately than the respective evaluation based on real-time sensor response. In addition, mass loadings for probe and secondary antibody is observed to saturate for optimum probe concentrations. Also, principal component analysis of TOF-SIMS data could resolve both immunoreactions and biofunctionalization and discriminate surfaces prepared with optimum probe concentrations from those prepared using suboptimum ones.

Citation

Gajos K, Budkowski A, Petrou P, Pagkali V, Awsiuk K, et al. (2018) Protein adsorption/desorption and antibody binding stoichiometry on silicon interferometric biosensors examined with TOF-SIMS. Applied Surface Science. Available: http://dx.doi.org/10.1016/j.apsusc.2018.03.029.

Acknowledgements

This work was supported by the EU funded project “FOODSNIFFER” (FP7-ICT8-318319). Data analysis was partially financed by Polish National Science Center (NCN) under Grant 2016/21/N/ST5/00880. The equipment used was purchased thanks to the financial support of the European Regional Development Fund (POIG.02.01.00-12-023/08).