At the heart of the device are a number of 500 nm thick cantilevers, two of which have antibodies for the proteins attached to one side. When a protein molecule joins onto one of the antibodies it causes the cantilever to bend and the device tracks this motion optically. The sensor can detect the proteins independently in real time in less than 10 minutes, providing a measure of the protein's concentration.

The scientists say their work has future applications in fast bedside diagnostics, for example in intensive care units. The concentration of the biomarkers - creatin kinase and myoglobin - indicates the severity of a heart attack.

"Detailed knowledge of these protein levels would allow life-saving treatments for patients suffering from acute myocardial infarction [AMI]," the team told nanotechweb.org. "Currently the most reliable diagnosis of AMI is based on the detection of a temporary significant increase of a few protein levels in the blood."

As yet, the sensors are not sensitive enough for clinical use. But the scientists reckon that packing more antibody fragments onto the cantilever surfaces and improving the orientation of the antibodies should increase sensitivity enough to make diagnosis at the bedside a feasible proposition. They are also working to miniaturize the device and integrate microfluidic components.

The scientists reported their work in Nanotechnology.