14 DAY TRIAL // A new type of semiconductor membrane actually displays better electrical performances than its biological cousins and could find its way into many electronic applications, from single-molecule detection devices to DNA sequencing.
"By creating nanopores in the membrane, we can use the membrane to separate charged species or regulate the flow of charged molecules and ions, thereby mimicking the operation of biological ion channels," said lead researcher Jean-Pierre Leburton, the Stillman Professor of Electrical and Computer Engineering at Illinois.
Together with postdoctoral research associate Maria Gracheva and graduate student Julien Vidal, he performed various simulations of the new membrane's operating characteristics, at various electrostatic potentials and found it to be more efficient than currently used biological membranes.
Made of two 12-nanometer-thick silicon layers with opposite (p- / n-) doping, the membrane is embedded with nanopores and has a positive electrostatic potential on the n-side and a negative one on the p-side. The artificial nanopores can control the ion flow with a tunability never previously achieved in biological ion channels.
This solid-state semiconductor membrane could be uses as replacement for biological ion channels and could find its way into many applications, like DNA sequencing and protein filtering. The sequence of DNA constitutes the heritable genetic information in nuclei, plasmids, mitochondria and chloroplasts that forms the basis for the developmental programs of all living organisms. Many medical sciences use this process to study fundamental biological processes and as reliable methods in diagnosis and forensic research.
"Using semiconductor technology to sequence the DNA molecule would save time and money," Leburton said. "By biasing the voltage across the membrane, we could pull DNA through the nanopore. Since each base pair carries a different electrical charge, we could use the membrane as a p-n junction to detect the changing electrical signal."