Researchers at the Kavli Nanoscience Institute at the California Institute of Technology in Pasadena, California have teamed up with researchers at Commissariat à l’Energie Atomique at auxEnergies Alternatices, Laboratoire ďélectronique des technologies de l’information (CEA-LETI) in Grenoble, France to create a device that is able to measure the mass of a single molecule.
This new device, called a Nanoelectromechanical System (NEMS) Resonator, differs from current mass spectrometer technology. The device consists of a tiny, oscillating bridge-like structure which is a few millionths of a meter in size. When a particle is placed on the bridge there is a change in oscillation frequency which is proportional to the particle’s mass.
Traditional mass spectrometers are only able to calculate the mass of groups of molecules. They do this by ionizing the particles to be measured and passing them through a magnetic field. The magnetic field deflects path of the charged particles and the size of the deflection is used to calculate the particles’ mass. This technique works very well for small but not large particles. It is hard to ionize larger molecules and as a result, the charges are weak affecting the detection by the magnetic field. This makes accurately determining the mass of the molecule difficult.
In an article just published in Nature Nanotechnology, Dr. Michael Roukes and his colleagues describe using the NEMS resonator to measure an antibody (IgM) which is present in many different configurations and molecular masses within the human body. By measuring the mass of one particle at a time, scientists were able to identify and count different forms of IgM.
So what? In the future, this technology could be utilized commercially in many different areas. Environmental monitors could use it to detect nanoparticle pollution. Biologists could use this technology to study the posttranslational modification of proteins and gain a better understanding of the inner workings of cells. Doctors and other healthcare professional could detect diseases earlier. For example, a specific ratio of IgM molecules in a patient’s blood can be indicative of a type of cancer called Waldenström macroglobulinemia.
The NEMS resonator is manufactured using standard semiconductor fabrication techniques, which would make it easy to mass-produce. In addition, the researchers say that this device could be integrated with existing commercial mass spectrometers to allow for a wider mass range. The NEMS resonator is still a ways off from being commercially available and the cost is unknown. However, we do know that this is definitely a small “scale” with a big future.