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Proceedings Paper

Optical measurements of dynamic adhesive forces between bacteria and protein-coated surfaces
Author(s): Kathryn H. Simpson; Gabriela Bowden; Magnus Hook; Bahman Anvari
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Paper Abstract

Bacterial adhesion to host tissue is an initial step in the infectious process. Staphylococcus aureus, a major human pathogen, has covalently anchored cell surface adhesins called microbial surface components recognizing adhesive matrix molecules (MSCRAMMs) which mediate specific adhesion to extracellular matrix (ECM) molecules. Understanding MSCRAMM binding is potentially useful in developing effective antibacterial drugs. In this study, optical tweezers were used in conjunction with a quadrant photodetector to measure adhesive forces between MSCRAMMs and surfaces coated with the ECM molecule fibronectin. Using a piezoelectrically driven stage, a fibronectin-coated microsphere adherent to a coverslip was brought into contact with a cell optically trapped at 830 nm. The microsphere was subsequently moved away from the cell, and a quadrant photodiode monitored the cell displacement from the trap center during the detachment process. The photodetector voltage signals were subsequently converted into the adhesive forces between MSCRAMMs and fibronectin based on a calibration using Stoke’s law for viscous drag. Optical detection of the trapped bead displacement allowed us to study both the dynamics of the detachment process and observe the effects of various loading rates. This technique can be extended to identify the contributions of various MSCRAMM domains to adhesion in order to develop new methods of treating infections.

Paper Details

Date Published: 19 June 2003
PDF: 8 pages
Proc. SPIE 4962, Manipulation and Analysis of Biomolecules, Cells, and Tissues, (19 June 2003); doi: 10.1117/12.477870
Show Author Affiliations
Kathryn H. Simpson, Rice Univ. (United States)
Gabriela Bowden, Texas A&M Univ. System Health Science Ctr. (United States)
Magnus Hook, Texas A&M Univ. System Health Science Ctr. (United States)
Bahman Anvari, Rice Univ. (United States)

Published in SPIE Proceedings Vol. 4962:
Manipulation and Analysis of Biomolecules, Cells, and Tissues
Dan V. Nicolau; Joerg Enderlein; Robert C. Leif; Daniel L. Farkas, Editor(s)

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