Single-cell force spectroscopy of bacteria enabled by naturally derived proteins

Langmuir. 2014 Apr 15;30(14):4019-25. doi: 10.1021/la404673q. Epub 2014 Apr 2.

Abstract

Bringing the study of bacterial adhesion down to a single-cell level is critical for understanding the molecular mechanisms involved in initial bacterial attachment. We have developed a simple and versatile method for making single-cell bacterial probes to study the adhesion of single bacterial cells by atomic force microscopy (AFM). A single-cell probe was made by picking up a bacterial cell from a glass surface using a tipless AFM cantilever coated with a commercial cell adhesive Cell-Tak. The method was applied to four different bacterial strains, and single-cell adhesion was measured on three surfaces (fresh glass, hydrophilic glass, and mica). Attachment to the cantilever was stable during the AFM force measurements that were conducted for 2 h, and viability was confirmed by Live/Dead fluorescence staining at the end of each experiment. The adhesion force and final rupture length were dependent on bacterial strains, surfaces properties, and contact time. The single-cell probe offers control of cell immobilization and thus holds advantages over the commonly used multicell probes with which random immobilization is obtained by submerging the cantilever in a bacterial suspension. The reported method provides a general platform for investigating single-cell interactions of bacteria with different surfaces and other cells by AFM force spectroscopy, thus improving our understanding of the mechanisms of bacterial attachment.

Publication types

  • Research Support, Non-U.S. Gov't

MeSH terms

  • Bacterial Proteins / chemistry*
  • Cell Adhesion
  • Escherichia coli / cytology*
  • Escherichia coli / growth & development
  • Microscopy, Atomic Force*
  • Pseudomonas fluorescens / cytology*
  • Pseudomonas fluorescens / growth & development
  • Single-Cell Analysis*
  • Staphylococcus / cytology*
  • Staphylococcus / growth & development

Substances

  • Bacterial Proteins