Two of his recent Mint columns have been on the research by Prof. Yamuna Krishnan (NCBS) and Prof. Bikramjit Basu (IISc). Do check them out; from what Halarnkar says in the first -- "In the weeks to come, Frontier Mail will tell you what these scientists do and why it is important" -- we will get to read soon about the others as well.
Krishnan, who did her doctorate at the Indian Institute of Science (IISc) and post-doctoral work at the University of Cambridge, UK, has shown how DNA can be artificially woven into longer strands, like a weaver’s tapestry, or a child’s matchstick house. “Just in the way we make architectures on the macro scale with matchsticks and fevicol, we can do the same with DNA,” Krishnan tells me over email from Boston, where she has just given two lectures. Much like using fingers to assemble matchsticks, Krishnan uses chemicals called enzymes to manipulate strips, or sequences, of DNA to create nanoscale architecture: new structures smaller than 100 nanometres, invisible to the human eye. These DNA sequences can be copied, cut or pasted to create nanoscale machines of living matter. In contrast with non-biological options, DNA devices are biocompatible (unlikely to trigger the body’s immune system) and biodegradable (they can disintegrate harmlessly once their work).
This May, in a paper published in the journal Nature Nanotechnology, Krishnan and her team demonstrated for the first time how two nanomachines constructed from DNA could test acidity in two different places inside a living cell, an advance from running a single DNA nanomachine at a time. Abnormal cellular acidity is a marker for many diseases, and the use of DNA devices promises tools for future probes or disease therapies.
At the heart of Basu’s investigations is electricity, more precisely the mastery of extremely mild electric currents, which course through and serve as the language of living cells. The idea that electricity informs cells how to grow is not new. Living things have a constant, though very gentle, flow of electricity. Over decades, scientists have even fiddled with voltages to create frogs with eyes on their back and hearts in the wrong places.
What Basu does is apply electricity to grow bone, cardiac, nerve and even stem cells (which can grow into other types of cells) atop an artificial substrate, or surface, somewhat like butter on toast—except that this butter must spread itself on the diner’s urging.
This is not easy. The bioengineer requires a precise knowledge of when and how much electric current to apply to cells growing on foreign foundations. “Cell division should not be affected and the cells should not die,” says Basu. “When two cells talk to each other, the material has to facilitate that crosstalk.”