Thursday, 26 May 2011

Peruvian Kidney Donors


So I talked about the use of surface tension for vaginal and seminal fluids.  I then touched upon Zombie blood without any really understanding the answer for the latter.  Lastly I found that surface tension has been used as a simple test for jaundice.  Can surface tension be used for other medical and diagnostic applications?
I recently went to a talk by Prof. Paul Janmey from the University of Pennsylvania.  His group works with the mechanical properties of the cell membrane and proteins associated with the membrane.  He explained in his talk why it was difficult to grow neurons originating from stem cells in a glass jar.  I quickly got the idea that Richard Nixon's head in a glass jar in Futurama.  The brain cells (and other organ cells like kidney cells) closer to the glass do not represent healthy brain cells but the ones surrounded by brain cells are more likely to be closer to what we have in our brain.  The glass may not be the right material in which to grow these cells for proper differentiation. 

One parameter that Janmey's group looked into was the cell mechanical stiffness. As explained in their abstract: 'The mechanical properties of cells and extracellular matrices are critical determinants of function in contexts including oncogenic transformation, neuronal synapse formation, hepatic fibrosis and stem cell differentiation.'  Janmey's group found that many tissue samples are heterogenous with a length scale existing between the micrometers to millimeters.  Current commercial instruments were only good for centimeter or nanometer (nanometer scale instruments like atomic force microscopy, optical trapping and magnetic bead microrheometry).  So what do scientists do when they cannot find a solution?  They invent one.

With the help of a Kibron tensiometer (micronewton resolution force probe) and a micromanipulator for probing soft biological samples at sub-millimeter spatial resolution.  Janmey's group described several applications one interesting one being the  quantification of the inner wall stiffness of healthy and diseased mouse aortas.  They also showed stiffness of an intact, isolated mouse glomerulus (a capillary tuft that performs the first step in filtering blood to form urine in the kidney).  This device could potentially one day grow new kidney's originating from a self donor in the presence of materials (unlike glass) that would represent actual kidney tissue that can then be transplanted.  The usefulness of this device could one day grow kidney's so Americans would not need to illegally buy them from Peruvian donors.