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. Author manuscript; available in PMC: 2012 Jan 1.
Published in final edited form as: Acta Biomater. 2010 Jul 23;7(1):96–105. doi: 10.1016/j.actbio.2010.07.021

Figure 5. The Effects of AFM Measurements on the Fibroblast-Derived Matrix.

Figure 5

A fibroblast-derived matrix was labeled with Alexa Fluor 488 and visualized with a 40x objective with the fluorescent microscope attached to the AFM (A). The matrix is shown before (top left), during (top right), and after (bottom left) indentation. Scale bar is 20 μm. The sphere attached to the AFM cantilever was centered in the field of view and its location is indicated in the top right image. The matrix structure appeared similar in all 3 images. The lack of matrix alteration by contact with the sphere is demonstrated in the overlay of the matrix images before (green) and after (red) contact (bottom right image). Yellow represents colocalization of the two images. Additionally, one location of fibroblast-derived matrix was repeatedly indented 16 times in order to assess mechanical changes in the matrix from repeated measurements. The Young’s modulus was calculated for all 16 curves and is displayed in B. The y axis is the Young’s modulus and the x axis is the number of indentations. The line represents the average of all 16 Young’s modulus measurements, 156±5 Pa. The consistency in Young’s modulus values suggested that the repeated measurements caused little alteration in matrix mechanical properties, and linear regression analysis corroborated this interpretation.