Probing mass-transport and binding inhomogeneity in macromolecular interactions by molecular interferometric imaging

Ming Zhao, Xuefeng Wang, David Nolte

Research output: Chapter in Book/Report/Conference proceedingConference contribution

Abstract

In solid-support immunoassays, the transport of target analyte in sample solution to capture molecules on the sensor surface controls the detected binding signal. Depletion of the target analyte in the sample solution adjacent to the sensor surface leads to deviations from ideal association, and causes inhomogeneity of surface binding as analyte concentration varies spatially across the sensor surface. In the field of label-free optical biosensing, studies of mass-transport-limited reaction kinetics have focused on the average response on the sensor surface, but have not addressed binding inhomogeneities caused by mass-transport limitations. In this paper, we employ Molecular Interferometric Imaging (MI2) to study mass-transport-induced inhomogeneity of analyte binding within a single protein spot. Rabbit IgG binding to immobilized protein A/G was imaged at various concentrations and under different flow rates. In the mass-transport-limited regime, enhanced binding at the edges of the protein spots was caused by depletion of analyte towards the center of the protein spots. The magnitude of the inhomogeneous response was a function of analyte reaction rate and sample flow rate.

Original languageEnglish (US)
Title of host publicationProgress in Biomedical Optics and Imaging - Proceedings of SPIE
Volume7188
DOIs
Publication statusPublished - 2009
Externally publishedYes
EventNanoscale Imaging, Sensing, and Actuation for Biomedical Applications VI - San Jose, CA, United States
Duration: Jan 27 2009Jan 28 2009

Other

OtherNanoscale Imaging, Sensing, and Actuation for Biomedical Applications VI
CountryUnited States
CitySan Jose, CA
Period1/27/091/28/09

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ASJC Scopus subject areas

  • Atomic and Molecular Physics, and Optics
  • Electronic, Optical and Magnetic Materials
  • Biomaterials
  • Radiology Nuclear Medicine and imaging

Cite this

Zhao, M., Wang, X., & Nolte, D. (2009). Probing mass-transport and binding inhomogeneity in macromolecular interactions by molecular interferometric imaging. In Progress in Biomedical Optics and Imaging - Proceedings of SPIE (Vol. 7188). [71880O] https://doi.org/10.1117/12.809500