Research
I am currently working with Paul Atzberger. Using techniques from calculus of variations, stochastic calculus, and numerical analysis we are developing methods for the robust measurement of biopolymer stiffness from fluorescence microscopy data. Such experimental data for especially stiff biopolymers, such as microtubules, have eluded accurate measurement due to inherent limits in resolution. We have developed a suite of algorithms and benchmarking tests that show significant progress in resolving images accurately even in the presence of significant noise. See the movies on the left panel for more detail.
With better resolution we are interested in probing finer-scale phenomenon; namely, a current direction of our research is to investigate heterogeneities in stiffness along microtubules. This provides a lens into investigating whether other physical attributes, such as growth rate, binding proteins, length, fraying ends, have an effect on stiffness.
We are also currently working on combining these methods into a useable software GUI in MATLAB ®, and also a plugin for ImageJ. Please check back soon for updates.
Publications
Force Spectroscopy of Complex Biopolymers with Heterogeneous Elasticity, D. Valdman, B. Lopez, M. T. Valentine, and P.J. Atzberger, Soft Matter, The Royal Society of Chemistry, (2013). Preprint
Spectral Analysis Methods for the Robust Measurement of the Flexural Rigidity of Biopolymers D. Valdman, P.J. Atzberger, D. Yu, and M. T. Valentine, Bio. Phys. J., Vol. 102, Iss. 5 (2012) Preprint
Movies
[Click on an image to download the movie]
Fitting procedure for a numerically generated fluorescence image under various background noise and gap noise conditions
The fitting of an experimental ensemble of microtubules