Dataset Information

Force scanning: a rapid, high-resolution approach for spatial mechanical property mapping.

ABSTRACT: Atomic force microscopy (AFM) can be used to co-localize mechanical properties and topographical features through property mapping techniques. The most common approach for testing biological materials at the microscale and nanoscale is force mapping, which involves taking individual force curves at discrete sites across a region of interest. The limitations of force mapping include long testing times and low resolution. While newer AFM methodologies, like modulated scanning and torsional oscillation, circumvent this problem, their adoption for biological materials has been limited. This could be due to their need for specialized software algorithms and/or hardware. The objective of this study is to develop a novel force scanning technique using AFM to rapidly capture high-resolution topographical images of soft biological materials while simultaneously quantifying their mechanical properties. Force scanning is a straightforward methodology applicable to a wide range of materials and testing environments, requiring no special modification to standard AFMs. Essentially, if a contact-mode image can be acquired, then force scanning can be used to produce a spatial modulus map. The current study first validates this technique using agarose gels, comparing results to ones achieved by the standard force mapping approach. Biologically relevant demonstrations are then presented for high-resolution modulus mapping of individual cells, cell-cell interfaces, and articular cartilage tissue.

SUBMITTER: Darling EM

PROVIDER: S-EPMC3150532 | biostudies-literature | 2011 Apr

REPOSITORIES: biostudies-literature

ACCESS DATA

Publications

Force scanning: a rapid, high-resolution approach for spatial mechanical property mapping.

Darling E M EM

Nanotechnology 20110316 17

Atomic force microscopy (AFM) can be used to co-localize mechanical properties and topographical features through property mapping techniques. The most common approach for testing biological materials at the microscale and nanoscale is force mapping, which involves taking individual force curves at discrete sites across a region of interest. The limitations of force mapping include long testing times and low resolution. While newer AFM methodologies, like modulated scanning and torsional oscilla ...[more]

PMID: 21411911

Similar Datasets

Project description:Structural properties of articular cartilage such as proteoglycan content, collagen content and collagen alignment are known to vary over length scales as small as a few microns (Bullough and Goodfellow, 1968; Bi et al., 2006). Characterizing the resulting variation in mechanical properties is critical for understanding how the inhomogeneous architecture of this tissue gives rise to its function. Previous studies have measured the depth-dependent shear modulus of articular cartilage using methods such as particle image velocimetry (PIV) that rely on cells and cell nuclei as fiducial markers to track tissue deformation (Buckley et al., 2008; Wong et al., 2008a). However, such techniques are limited by the density of trackable markers, which may be too low to take full advantage of optical microscopy. This limitation leads to noise in the acquired data, which is often exacerbated when the data is manipulated. In this study, we report on two techniques for increasing the accuracy of tissue deformation measurements. In the first technique, deformations were tracked in a grid that was photobleached on each tissue sample (Bruehlmann et al., 2004). In the second, a numerical technique was implemented that allowed for accurate differentiation of optical displacement measurements by minimizing the propagated experimental error while ensuring that truncation error associated with local averaging of the data remained small. To test their efficacy, we employed these techniques to compare the depth-dependent shear moduli of neonatal bovine and adult human articular cartilage. Using a photobleached grid and numerical optimization to gather and analyze data led to results consistent with those reported previously (Buckley et al., 2008; Wong et al., 2008a), but with increased spatial resolution and characteristic coefficients of variation that were reduced up to a factor of 3. This increased resolution allowed us to determine that the shear modulus of neonatal bovine and adult human tissue both exhibit a global minimum at a depth z of around 100 microm and plateau at large depths. The consistency of the depth dependence of |G*|(Z) for adult human and neonatal bovine tissue suggests a functional advantage resulting from this behavior.

Dataset Information

Force scanning: a rapid, high-resolution approach for spatial mechanical property mapping.

Publications

Force scanning: a rapid, high-resolution approach for spatial mechanical property mapping.

Similar Datasets

OmicsDI is part of the ELIXIR infrastructure

Tweets