Thursday, April 9, 2009

Frontiers in Biophysics

In March I had the opportunity to attend the annual Biophysical Society meeting here in Boston.  I've been meaning to write about it for a weeks now, because I did attend an interesting session at the meeting entitled 'Frontiers in Biophysics'.  Hagan Bayley from Oxford presented some unusual work using what he termed 'droplets'.  These droplets are small aqueous drops surrounded by a monolayer (or single layer) of lipid that can be held on the end of a movable pipette, or anchored to a tether of some sort.  When two of these droplets are brought into close proximity, a lipid bilayer forms at the interface between them.  The lipid bilayer is the double layer of lipid that surrounds all living cells and provides cells with features fundamental to their function and survival.  For example, a bilayer is necessary for the proper function of many of the proteins that allow the cell to communicate with its surroundings, or with other cells.  

Any purified membrane proteins present in the droplets will self-insert into the newly formed bilayer.  Ion channels and pumps, responsible for controlling the electrical properties of cells, can be inserted and their activity measured; Bayley claims this system is more stable than conventional bilayer recording techniques.  However, the interesting part comes when you start to take advantage of the scalability of the technique.

Many of these droplets can be assembled in an array with different proteins in each droplet.  Using a combination of ion channels and pumps, like the components of an electrical circuit board, actual circuits performing computations and even acting as batteries can be assembled from these droplets.  These circuits are really something of a novelty, as they would be much larger and difficult to maintain than current circuitry.  But Bayley's aim is larger than mere circuits; he is actually hoping to recreate entire cellular functions from the droplets as well, such as signal transduction, production and secretion of factors (proteins or other molecules) in a highly controlled manner.  Potential applications might be a more stable or more realistic assay system for various biological processes, testing the functions of new proteins associated with those processes, and perhaps the ability to create a responsive secretion apparatus (insulin, perhaps?) comprised entirely of biological material.

Yeah, I said it was 'Frontiers'.  I enjoy this kind of work for its own sake.