I'm looking for information of the limitations/shortcomings of PDMS in MEMS
(BioMEMS) applications.  Aside from its lack of mechanical rigidity, do people
have problems with: non-specific protein absorption, arcing or shorting in
electrical fields, restrictive surface chemistry, difficulty in integrating
with electrical circuits, changes in properties over time, poor stability in
solvents or low/high pH, high background fluorescence?

What would be the characteristics of the "best polymer" for
biological/analytical microfluidic applications?