There are now drugs that exploit these specific mutations and fight the cancer, significantly extending patients’ life expectancy. However, they work only if the corresponding genetic mutation is actually present. Where it is not, they give rise to severe side effects without producing the desired effect. “It is therefore essential that we are able to identify the mutations reliably in tissue samples. That is the only way of ensuring that patients get the right treatment and successful outcomes,” explains the paper’s co-author, Professor Katharina Glatz of the Institute of Pathology at University Hospital Basel.

Coated microcantilevers

In a clinical pilot study, the team led by Professor Ernst Meyer and Professor Christoph Gerber at the Swiss Nanoscience Institute and the Department of Physics at Basel University used nanosensors for the first time to detect the mutations in tissue samples from patients with malignant melanoma. To do so, the researchers employed tiny cantilevers that were coated in different ways. Some of them carried a recognition sequence for the mutation the researchers were targeting.

Then genetic material (RNA) from the patients’ tissue samples was isolated and applied to the cantilevers. If the genetic change is present, the patient’s RNA binds to the recognition sequence on the cantilever. The resulting surface stress leads to bending of the cantilever, which can be measured. If the mutation is absent from the RNA sample, this bending does not occur – in other words, only a specific binding produces a signal. The advantage of using nanocantilevers is that no time-consuming procedures are needed. It takes less than a day to move from performing the biopsy to diagnosis.