The functionality of proteins and the genetic code of DNA are stored in the sequence of building blocks in these biopolymers chains. To directly read out the sequence, a system is needed of the same dimensions as the building blocks themselves.
This is why we aim to use nano-meter sized pores in atomically thin graphene as a way to look at DNA. Under the influence of an applied electric field, the DNA strand passes through the pore and temporarily blocks it, thereby decreasing the background current of the electrolyte solution. This current blockade gives us information about the translocating DNA.
The DNA molecule passes through under a microsecond, too fast for the sequence to be resolved. In our lab, we are looking for various methods to control the DNA translocation speed through the nanopore, for example by employing chemically modified hydrogels or chemical functionalization of the membrane surface or pore edge. Moreover, we develop unconventional approaches to scale up the fabrication of DNA sequencing nanostructures in the form of nanopores, nanogaps, nanoribbons and nanochannels.
Part of this research is done in collaboration with the Department of Physics (LION). This has resulted in the fabrication of the first twisted tunnel junction across a single pair of carbon atoms lying on the edges of two graphene electrodes and of a “zero thickness” nanopore to allow, for the first time, to study dynamic tunneling in graphene.