(July 31, 2015) A
synthetic membrane that self assembles and is easily produced may lead to
better gas separation, water purification, drug delivery and DNA recognition,
according to an international team of researchers.
This biomimetic membrane is composed of lipids -- fat
molecules -- and protein-appended molecules that form water channels that
transfer water at the rate of natural membranes, and self-assembles into
2-dimensional structures with parallel channels.
"Nature does things very efficiently and transport
proteins are amazing machines present in biological membranes," said
Manish Kumar, assistant professor of chemical engineering, Penn State.
"They have functions that are hard to replicate in synthetic
systems."
The researchers developed a second-generation synthetic
water channel that improves on earlier attempts to mimic aquaporins – natural
water channel proteins -- by being more stable and easier to manufacture. The
peptide-appended pillar[5]arenes (PAP) are also more easily produced and
aligned than carbon nanotubes, another material under investigation for
membrane separation. Kumar and co-authors report their development in a recent
issue of the Proceedings of the National Academy of Science.
"We were surprised to see transport rates approaching
the 'holy grail' number of a billion water molecules per channel per
second," said Kumar. "We also found that these artificial channels
like to associate with each other in a membrane to make 2-dimentional arrays
with a very high pore density."