Imaging and chemical surface analysis of biomolecular functionalization of monolithically integrated on silicon Mach-Zehnder interferometric immunosensors

Katarzyna Gajos*, Michailia Angelopoulou, Panagiota Petrou, Kamil Awsiuk, Sotirios Kakabakos, Willem Haasnoot, Andrzej Bernasik, Jakub Rysz, Mateusz M. Marzec, Konstantinos Misiakos, Ioannis Raptis, Andrzej Budkowski

*Corresponding author for this work

Research output: Contribution to journalArticleAcademicpeer-review

12 Citations (Scopus)

Abstract

Time-of-flight secondary ion mass spectrometry (imaging, micro-analysis) has been employed to evaluate biofunctionalization of the sensing arm areas of Mach-Zehnder interferometers monolithically integrated on silicon chips for the immunochemical (competitive) detection of bovine κ-casein in goat milk. Biosensor surfaces are examined after: modification with (3-aminopropyl)triethoxysilane, application of multiple overlapping spots of κ-casein solutions, blocking with 100-times diluted goat milk, and reaction with monoclonal mouse anti-κ-casein antibodies in blocking solution. The areas spotted with κ-casein solutions of different concentrations are examined and optimum concentration providing homogeneous coverage is determined. Coverage of biosensor surfaces with biomolecules after each of the sequential steps employed in immunodetection is also evaluated with TOF-SIMS, supplemented by Atomic force microscopy and X-ray photoelectron spectroscopy. Uniform molecular distributions are observed on the sensing arm areas after spotting with optimum κ-casein concentration, blocking and immunoreaction. The corresponding biomolecular compositions are determined with a Principal Component Analysis that distinguished between protein amino acids and milk glycerides, as well as between amino acids characteristic for Mabs and κ-casein, respectively. Use of the optimum conditions (κ-casein concentration) for functionalization of chips with arrays of ten Mach-Zehnder interferometers provided on-chips assays with dramatically improved both intra-chip response repeatability and assay detection sensitivity.

Original languageEnglish
Pages (from-to)529-542
JournalApplied Surface Science
Volume385
DOIs
Publication statusPublished - 2016

Keywords

  • Atomic force microscopy
  • Biosensor functionalization
  • Multi-molecular coverage
  • On-chip immunoassay
  • Time-of-flight secondary ion mass spectrometry
  • X-ray photoelectron spectroscopy

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    Gajos, K., Angelopoulou, M., Petrou, P., Awsiuk, K., Kakabakos, S., Haasnoot, W., Bernasik, A., Rysz, J., Marzec, M. M., Misiakos, K., Raptis, I., & Budkowski, A. (2016). Imaging and chemical surface analysis of biomolecular functionalization of monolithically integrated on silicon Mach-Zehnder interferometric immunosensors. Applied Surface Science, 385, 529-542. https://doi.org/10.1016/j.apsusc.2016.05.131