April 2012, Vol. 1 - BioScope Catalyst

A key feature of AFM is its ability to interact mechanically with samples. This is central to some of the most common applications within biology and biophysics, which rather than focusing on the imaging capabilities of AFM instead leverage its ability to both precisely apply and measure ultra-low forces in the pico- and nano-newton regime. AFM has therefore become a key enabling technology within the emerging field of research known as mechanobiology, which broadly considers how molecules and cells both respond to mechanical stimuli and themselves exert forces on their surroundings and how these interactions relate to normal biological function as well as various disease states.

For several years now, a particularly active area of research where AFM is being used has been cell mechanics. It is well established now that mechanical interactions play a major role in the life cycle of many cells. For instance, the mechanical properties of a substrate and mechanical stimuli transmitted through it can directly affect cell differentiation and development. Similarly, the mechanical properties of cells themselves change in response to both chemical and mechanical triggers and these changes appear to directly influence the progression of some diseases.

A common use of AFM in these investigations is to measure the mechanical properties of either the cells themselves or of the cell substrate. This can be done by measuring the force-distance interaction (i.e., force curve) between the AFM probe and the cell or substrate as the probe indents it. Using indentation models borrowed or sometimes adapted from classic contact mechanics theory, the effective elastic modulus (or colloquially, "stiffness") of the cell or substrate can be derived. The nanoscale nature of AFM makes it possible to probe many points on a single cell and even generate high-resolution maps of cell elasticity.

The BioScope Catalyst AFM has already proven itself as the ideal platform for these experiments. Its physical and functional integration with light microscopy allows researchers to quickly target individual cells and then also correlate mechanical measurements with light microscope observations. The Perfusing Stage Incubator accessory makes it possible to maintain healthy cells for experimentation for many hours by carefully controlling the local environment within ideal cell culture parameters. Its real-time force measurement capabilities can easily access forces all the way down to the piconewton scale with remarkable accuracy and stability.

Bruker is pleased to announce the introduction of several new software tools that make these types of measurements easier to perform from start to finish. New tools within our industry-leading "NanoScope Analysis" offline software now enable the researcher to quickly take these measured force curves and derive modulus values using indentation models that are widely accepted in the cell mechanics field including the Hertz sphere and Sneddon cone models. Additional features enable more advanced post-processing of force curves to adjust experimental parameters, correct baseline tilt and filter the force data. These capabilities can be applied to single force curves or batch processing can quickly analyze hundreds of curves at once. For the most advanced "cell mechanics", we are introducing a programmer's toolbox of MatLab functions that can be used to develop new customized analysis routines.

Discover more about the BioScope Catalyst and our Proprietary NanoScope Analysis Software: send questions to productinfo@Bruker-nano.com or visit our website for product literature and application notes.