Richard B. Dickinson - Chemical Engineering at the University of Florida

UF Chemical Engineering > People > Faculty > Richard B. Dickinson

	Richard B. Dickinson Ph.D., 1992, University of Minnesota
	Professor and Chair
	Ph : 352-392-0898 dickinson@che.ufl.edu

	Areas
	Biomolecular Motors and Cell Motility
	Biomedical Device-Centered Infections
	Adhesion-Mediated Cell Migration

We apply engineering principles to study the behavior of living cells or other small-scale biological systems (e.g. bionanotechnological systems). That is, we use a combination of mathematical modeling, quantitative experimentation, together with the tools of biochemistry and molecular cell biology to better understand the relationship between cell function and the physical and molecular properties of cells and their surroundings. The field is often called cellular bioengineering or cellular engineering.

Biomolecular Motors and Actin-Based Cell Motility

Keywords: Biomolecular/Biomedical, Nanosciences, Soft Matter

We are studying the mechanisms of actin-based cell motility using a combination of mathematical modeling, small-scale biophysical measurements, biochemistry, and molecular biology. In collaboration with faculty in the College of Medicine, we have defined and are investigating a new class of biomolecular motors, called “ filament end-tracking motors ”, that we believe are responsible for force generation by actin polymerization, which drives cell protrusions during cell crawling, as well as the intracellular transport of vesicles and some invasive pathogenic microorganisms such as Listeria monocytogenes. This mechanism has wide-ranging relevance in cell biology and microbiology, as it has been cited by others to explain plasmid segregation in prokaryotes by polymerization of actin homologs, and to explain the force-generating properties by end-tracking proteins called formins in yeast-cell division.

In addition to fundamental studies, we are currently working to exploit filament end-tracking motors for transporting biomolecules and microorganisms in biosensing devices. We are developing nanoscale actuators and molecular shuttles consisting of surface-tethered biomotors (Figure 1) propelled by actin polymerization on patterned and microfabricated substrata. This system will serve as an alternative to microfluidics or electric fields to transport and sort these species in 220lab-on-a-chip ” applications.

Figure 1 – A. Processive elongation of single actin filament from an 50 nm bead coated with filament end-tracking proteins. B. Two-color fluorescence image and line scan indicating actin monomer insertion at the bead surface (right).

Microbial Adhesion and Device-centered Infections

Keywords: Biomolecular/Biomedical, Nanosciences, Surface Science

Another major area of focus is cell adhesion, which is relevant to applications such as the design of biomaterials for biomedical implants, cell carriers for bioreactors in the bioprocessing industry, and filters to remove microorganisms in water purification. Our goal is to develop models that can predict the probability and strength of adhesion as a function of measurable molecular and physical properties of the cell and substratum. In addition to “ macroscopic ” surface properties such as hydrophobicity and surface charge, we are interested in the role of specific interactions between cell surface molecules and the substratum. We have developed a novel force-measurement instrument involving an optical trap force-transducer and evanescent wave light scattering to probe dynamic interaction forces between a single microbe and a surface with nanometer resolution and a sensitivity of tens of femptoNewtons. Our technique was the first to measure the force-distance profile between a single bacterium and a substratum.

Recent Publications

1.	Dickinson, R.B., A Multi-Scale Mechanistic Model for Actin-Propelled Bacteria. Cellular and Molecular Bioengineering, in press (2008).
2.	Dickinson, R.B., “Models for Actin Polymerization Motors,” J. Math. Biol., 58(1-2) (2009) 81.
3	Interliggi, K.A., Zeile, W.L., Hens, S., McGuire, G.E., Purich, D.L. and Dickinson, R.B., “ Guidance of Actin Filament Elongation on Filament-Binding Tracks,” Langmuir, 23(23) (2007) 11911.
4.	Dickinson, R.B. and Purich, D.L., “ Diffusion Rate Limitations in Actin-Based Propulsion of Hard and Deformable Particles,” Biophysical Journal, 91(4) (2006) 1548.
5.	Sharp, Jeffrey M., Duran, Randolph S. and Dickinson, Richard B., “Direct Measurement of Forces between a Colloidal Particle and a Phospholipid Bilayer,” J. Colloid Interface Sci., 299(1) (2006) 182.