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Biomedical Engineering and Bioengineering Commons

Open Access. Powered by Scholars. Published by Universities.®

Physical Sciences and Mathematics

Nancy A. Burnham

2006

Articles 1 - 2 of 2

Full-Text Articles in Biomedical Engineering and Bioengineering

Precision And Accuracy Of Thermal Calibration Of Atomic Force Microscopy Cantilevers, Nancy Burnham, G Matei, E Thoreson, J Pratt, D Newell Jul 2006

Precision And Accuracy Of Thermal Calibration Of Atomic Force Microscopy Cantilevers, Nancy Burnham, G Matei, E Thoreson, J Pratt, D Newell

Nancy A. Burnham

To have confidence in force measurements made with atomic force microscopes(AFMs), the spring constant of the AFM cantilevers should be known with good precision and accuracy, a topic not yet thoroughly treated in the literature. In this study, we compared the stiffnesses of uncoated tipless uniform rectangular silicon cantilevers among thermal, loading, and geometric calibration methods; loading was done against an artifact from the National Institute of Standards and Technology (NIST). The artifact was calibrated at NIST using forces that were traceable to the International System of units. The precision and accuracy of the thermal method were found to ...


Substrate Rigidity Regulates The Formation And Maintenance Of Tissues, Nancy Burnham, Wei-Hui Guo, Margo Frey, Yu-Li Wang Mar 2006

Substrate Rigidity Regulates The Formation And Maintenance Of Tissues, Nancy Burnham, Wei-Hui Guo, Margo Frey, Yu-Li Wang

Nancy A. Burnham

The ability of cells to form tissues represents one of the most fundamental issues in biology. However, it is unclear what triggers cells to adhere to one another in tissues and to migrate once a piece of tissue is planted on culture surfaces. Using substrates of identical chemical composition but different flexibility, we show that this process is controlled by substrate rigidity: on stiff substrates, cells migrate away from one another and spread on surfaces, whereas on soft substrates they merge to form tissue-like structures. Similar behavior was observed not only with fibroblastic and epithelial cell lines but also explants ...