Mass Measurements of Focal Adhesions in Single Cells Using High Resolution Surface Plasmon Resonance Microscopy

Published

February 22, 2018

Author(s)

Alexander Peterson, Alessandro Tona, Michael Halter, Anne Plant, John Elliott

Abstract

Surface plasmon resonance microscopy (SPRM) is a powerful label-free imaging technique with spatial resolution approaching the optical diffraction limit. The high sensitivity of SPRM to small changes in index of refraction at an interface allows imaging of dynamic protein structures within a cell. Visualization of subcellular features, such as focal adhesions (FAs), can be performed on live cells using a high numerical aperture objective lens with a digital light projector to precisely position the incident angle of the excitation light. Within the cell-substrate region of the SPRM image, punctate regions of high contrast are putatively identified as the cellular FAs. Optical parameter analysis is achieved by application of the Fresnel model to the SPRM data and resulting refractive index measurements are used to calculate protein mass. FAs are known to be regions of high protein density that reside at the cell-substratum interface. Comparing SPRM with fluorescence images of antibody stained for vinculin, a component in FAs, reveals similar measurements of FA size. In addition, a positive correlation between FA size and protein density is revealed by SPRM. Comparing SPRM images for two cell types reveals a distinct difference in the protein density and mass of their respective FAs. Application of SPRM to quantify mass can greatly aid monitoring basic processes that control FA mass and growth and contribute to accurate models that describe cell- extracellular interactions.

Proceedings Title

Proceedings of SPIE

Volume

10509

Conference Dates

January 27-February 1, 2018

Conference Location

San Francisco, CA, US

Conference Title

SPIE Photonics West BIOS: Plasmonics in Biology and Medicine XV

Pub Type

Conferences

Download Paper

https://doi.org/10.1117/12.2290776

Local Download

Keywords

Surface plasmon, SPRM, focal adhesions, mass, density, cells, proteins, microscope

Citation

Peterson, A. , Tona, A. , Halter, M. , Plant, A. and Elliott, J. (2018), Mass Measurements of Focal Adhesions in Single Cells Using High Resolution Surface Plasmon Resonance Microscopy, Proceedings of SPIE, San Francisco, CA, US, [online], https://doi.org/10.1117/12.2290776, https://tsapps.nist.gov/publication/get_pdf.cfm?pub_id=925257 (Accessed March 14, 2025)