Increasing antibiotic resistance in bacteria is a critical issue that often leads to infections or other morbidities. Mechanical properties of the bacterial cell wall, such as thickness or elastic modulus, may contribute to the ability of a bacterial cell to resist antibiotics. Techniques like atomic force microscopy (AFM) are used to quantify bacterial cell mechanical properties and image cell structures at nanoscale resolutions. An additional benefit of AFM is the ability to probe samples submerged in liquids, meaning that live bacteria can be imaged or evaluated in environments that more accurately simulate in vivo conditions as compared to other methods like electron microscopy. However, because AFM measurements are highly sensitive to small perturbations in the deflection of the tip of a sensor probe brought into contact with the specimen, immobilization of bacteria prior to measurement is essential for accurate measurements. Traditional chemical fixatives crosslink the molecules within the bacterial cell wall, which prevent the bacteria from locomotion. While effective for imaging, chemical crosslinkers are known to affect the measured stiffness of eukaryotic cells and also may affect the measured stiffness of the bacterial cell wall. Alternative immobilization methods include Cell-Tak™, an adhesive derived from marine mussels that does not interact with the bacterial wall and filters with known pore sizes which entrap bacteria. Previous studies have examined the effect of these immobilization methods on successful imaging of bacteria but have not addressed differences in measured modulus. This study compares the effects of immobilization methods including chemical fixatives, mechanical entrapment in filters, and Cell-Tak™ on the stiffness of the bacterial cell wall as measured by force spectroscopy.
|Title of host publication||Challenges in Mechanics of Time-Dependent Materials and Mechanics of Biological Systems and Materials, Volume 2 - Proceedings of the 2022 Annual Conference on Experimental and Applied Mechanics|
|Editors||Alireza Amirkhizi, Jevan Furmanski, Christian Franck, Karen Kasza, Aaron Forster, Jon Estrada|
|Number of pages||4|
|State||Published - 2023|
|Event||SEM Annual Conference and Exposition on Experimental and Applied Mechanics, 2022 - Pittsburgh, United States|
Duration: Jun 13 2022 → Jun 16 2022
|Name||Conference Proceedings of the Society for Experimental Mechanics Series|
|Conference||SEM Annual Conference and Exposition on Experimental and Applied Mechanics, 2022|
|Period||6/13/22 → 6/16/22|
Bibliographical noteFunding Information:
Funding This material is based upon work supported by the National Science Foundation CAREER Award grant number 2045853. Any opinions, findings, and conclusions or recommendations expressed in this material are those of the authors and do not necessarily reflect the views of the National Science Foundation.
We gratefully acknowledge NIH Center of Biomedical Research Excellence (COBRE) in Pharmaceutical Research and Innovation (CPRI, P20GM130456) and NIH NIDCR funding (R03DE029547) for completion of these experiments. AFM was performed in the Light Microscopy Core at the University of Kentucky. Funding This material is based upon work supported by the National Science Foundation CAREER Award grant number 2045853. Any opinions, findings, and conclusions or recommendations expressed in this material are those of the authors and do not necessarily reflect the views of the National Science Foundation.
© 2023, The Society for Experimental Mechanics, Inc.
- Atomic force microscopy
- Live cell immobilization
ASJC Scopus subject areas
- Engineering (all)
- Computational Mechanics
- Mechanical Engineering