Scientists from KTH Royal Institute of Technology in Sweden have nanoengineered new DNA wires which have the potential to treat cancer, infections and other health problems.
A DNA nanowire is a molecular nanostructure composed of repeating DNA units which each have a diameter on the nanometre scale. They can be used as a platform for the ultrasensitive and direct electrical multiplexed detection of biological and chemical species.
Biological species, including viruses, bacteria, other naturally occurring pathogenic organisms and the toxins they produce, are considered far harder to detect and defend against than chemical species. Diagnosis and treatment can be hard to achieve without rapid detection and this is where DNA wires can play an important role.
Although DNA nanowires have been in development for a while, the KTH nanoengineers have created a new method to produce a unique 3D biosensor for better effectiveness than flat, 2D sensors.
Wouter van der Wijngaart, a KTH professor in the institute’s department of micro and nanosystems, said: “Our geometry makes it much easier to measure several biomolecules simultaneously and is also 100 times more sensitive. This is the first out of plane metallic nanowire formation based on stretching of DNA through a porous membrane.”
The nanowires are treated with gold to make them conductive and are created only in the presence of specific biomarker molecules in the patient sample. They can transmit evidence of their presence even when such molecules are low in concentration. The conductive wires short-circuit both sides of the membrane and this makes them easy to detect.
The nanoengineers made the wires by capturing molecules on the surface of a porous membrane which were designed to only bind with specific biomarker molecules in the sample. This kind of molecular binding event then triggers the formation of long DNA wires that are drawn through the pores by vacuum drying. The membrane is then treated with a solution of nanometre sized gold particles which can only bind to DNA molecules in a certain sequence.
The researchers believe that if this technology is further developed it could become a breakthrough technique because of its inherent potential for multiplexing–the act of measuring several biomarkers simultaneously.
They also believe that their technique is more advanced than previous DNA nanowires. Van der Wijngaart said: “The new results show how previous results can be improved in terms of speed, sensitivity and multiplexing. Also, the new approach is much easier to translate into an actual product.”
For the DNA wires to be widely used to treat cancer the next step is to turn the technology into a product. The researchers have high hopes for this.
Van der Wijngaart added: “If this approach were to be turned into a product, it potentially would be less costly than state-of-the-art methods, for example, PCR based technologies.”