A research team, led by Professor Ken Shepard from Columbia Engineering in partnership with researchers from the University of Pennsylvania, has developed a measuring technique for nanopores by devising a customized IC utilizing commercial semiconductor technology.
This is a photograph of the Columbia Engineering team's custom multichannel CMOS preamplifier chip, attached to a circuit board with thin gold wirebonds. (Credit: Columbia Engineering)
Nanopores are miniscule pores in a thin membrane that are capable of detecting single biomolecules like proteins and DNA with a minimal error when compared to the accuracy of other devices. Nanopores can perform rapid DNA sequencing at lower cost, but they emit weaker signals. Hence, it is necessary to cleanly measure them.
Jacob Rosenstein, one of the researchers, stated that the researchers obtained clean signals by placing the microscopic amplifier chip straightaway into a liquid chamber adjacent to the nanopore, allowing them to see individual molecules to traverse the nanopore within 1 ms. Earlier, researchers could only view molecules that reside in the nanopore for over 10 ms.
Shepard's team, which has been working on single-molecule measurements for years, turned towards nanopore sensors after attending a seminar delivered by Professor Marija Drndic from the University of Pennsylvania, at Columbia Engineering in 2009. Drndic’s team developed the nanopores, while Rosenstein devised the novel electronics and performed most of the laboratory work.
Drndic explained that the researchers integrated the highly sensitive solid-state nanopores with the highly sensitive electronics to develop faster electronics. Rosenstein informed that the nanopore measurement setup is easy and portable and eliminates the need for a complex microscope or other high powered tools. The nanopore technology shows promise to play a major role in DNA sequencing and other medical applications in the near future.
Shepard's group is working on upgrading these techniques. According to Shepard, it is possible to achieve a further 10X enhancement using a next-generation design, which allows the measurement of molecules that last for only 100 ns. His group is also involved in other electronic single-molecule methods built upon carbon nanotube transistors that are capable of leveraging similar electronic circuits.