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Proceedings Paper

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

Bacterial adhesion is a primary cause of failure in implanted medical devices. Bacteria commonly found in device-related infections, such as S. aureus, have multiple cell surface adhesins which mediate specific adhesion to molecules found in extracellular matrix and blood plasma. Adhesins recognizing fibrinogen, fibronectin, collagen, and elastin molecules have been isolated in S. aureus. We have used optical tweezers to measure the adhesive force between a single bacterium and a protein-coated surface. Various concentrations of fibronectin, fibrinogen, or whole plasma were immobilized onto 10-micrometers diameter polystyrene microspheres. We optically trapped a bacterium with a titanium-sapphire laser tuned to 830 nm and contacted the cell with a coated bead. We determined the minimum force necessary to separate the cell and bead. For beads coated with fibronectin and fibrinogen, detachment force values occurred as approximate integer multiples of an estimated single bond detachment force. With plasma-coated beads, only cells lacking the fibrinogen adhesin could be detached; therefore, we believe that either this adhesin is prevalent on wilde-type cells, or it is preferentially adsorbed onto the beads. Additionally, the whole plasma detachment forces appeared random; therefore, we believe that many adhesins participate in boding to plasma.

Paper Details

Date Published: 28 May 2002
PDF: 8 pages
Proc. SPIE 4622, Optical Diagnostics of Living Cells V, (28 May 2002); doi: 10.1117/12.468335
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. 4622:
Optical Diagnostics of Living Cells V
Robert C. Leif; Daniel L. Farkas; Robert C. Leif, Editor(s)

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