I have been interested for a long time in material-level (as opposed to molecular) approaches to measuring and understanding the dynamics of living cells. If we want to get beyond the limiting ideas of the interior of cells being membrane-bound compartments of diffusing molecules we need some alternative physics of cells which is consistent with experiment. The big question is: are there some principles (or laws) that apply to the material architecture of cytoplasm of all living cells that distinguishes it from non-living matter?

If we could, somehow, look at the first proto-cells it would probably be easier to guess an answer; but, all living cells that that we can observe today have undergone considerable evolutionary fine-tuning. Their complex webs on interacting molecules have been optimized, by natural selection, for potentiating individual reproduction (that is: for biological function). Molecular diversity and refinement makes it very difficult to see the subtle commonalities in cell-scale structure.

Still, much recent research on mechanics of cells does indicate that there may be some universal physical properties of living matter: the apparent "soft-glassy" mechanics of cells.

I am interested in developing tools to look at molecular-scale mechanics within living cells. One current project is to develop a fluorescence-lifetime vs. emission wavelength (time-spectra) laser scanning microscopy system. The detector is based on a wire delay-line on a multi-anode photomultiplier. This is combined with multi-channel time correlated single photon counting electronics. Such a device determines time-resolved fluorescence Stoke's shift over a few orders in time (depending of the reporter dye used). These type of experiments fit very well with recent research in glassy materials.