New DNA wires are 100 times more sensitive than other biosensors

While DNA nanowires have been in development for some time, the method developed at KTH Royal Institute of Technology and Stockholm University produces a unique three-dimensional biosensor for better effectiveness than flat, two-dimensional sensors. "Our geometry makes it much easier to measure several biomolecules simultaneously, and is also 100 times more sensitive," says KTH Professor Wouter van der Wijngaart.

"This is the first out-of-plane metallic nanowire formation based on stretching of DNA through a porous membrane," van der Wijngaart says.

The DNA nanowires, treated with gold to make them conductive, are created only in the presence of specific biomarker molecules in the patient sample and transmit evidence of their presence, even when such molecules are low in concentration. The conductive wires short-circuit both sides of the membrane, which makes them easy to detect.

To make the wires, the team first captured molecules on the surface of a porous membrane, which were designed to only bind with specific biomarker molecules in the sample. Such molecular binding events then trigger the formation of long DNA wires that were drawn through the pores by vacuum drying. Then the membrane is treated with a solution of nanometer sized gold particles, which can only bind to DNA molecules in a certain sequence, van der Wijngaart says.

The researchers published their results today in Microsystems and Nanoengineering (Nature Publishing Group). In addition to van der Wijngaart and Stockholm University Professor Mats Nilsson, the authors include Maoxiang Guo (KTH) and Iván Hernández-Neuta and Narayanan Madaboosi (Stockholm University).

The research work was funded in part by the China Scholarship Council and the Swedish Research Council.