Protein Ions: A Breakthrough In Quantum Physics

Superconducting nanowires detect single protein ions. A groundbreaking achievement in the detection of protein ions has been accomplished by...

Superconducting nanowires detect single protein ions.

A groundbreaking achievement in the detection of protein ions has been accomplished by an international research team led by quantum physicist Markus Arndt from the University of Vienna. The team utilized superconducting nanowire detectors, which demonstrated almost 100% quantum efficiency, surpassing the detection efficiency of conventional ion detectors at low energies by up to a factor of 1,000. 

This breakthrough opens new possibilities for more sensitive protein detection and provides additional insights in mass spectrometry, a vital method in life sciences. Mass spectrometry is a common technique for detecting and analyzing macromolecules, including proteins, by separating charged particles based on their mass-to-charge ratio and measuring signal intensity. However, traditional detectors faced limitations in achieving high efficiency and spatial resolution for particles with low impact energy.

The international consortium, coordinated by the University of Vienna and including partners in Delft (Single Quantum), Lausanne (EPFL), Almere (MSVision), and Basel (University), demonstrated the effectiveness of superconducting nanowires as detectors for protein beams in quadrupole mass spectrometry. The nanowires, entering a superconducting state at very low temperatures, exhibit a unique property that allows them to lose electrical resistance, enabling lossless current flow.

The nanowire detectors leverage the quantum transition from the superconducting to the normal conducting state when excited by incoming ions. This transition, interpreted as a detection signal, enables nanowire detectors to outperform conventional ion detectors by up to three orders of magnitude at exceptionally low impact energies. The quantum yield of nanowire detectors at low-impact energies redefines the possibilities of conventional detectors.

Project leader Markus Arndt highlights that nanowire detectors not only enhance molecule detection based on mass-to-charge state but also enable classification based on kinetic energy. This advancement improves detection capabilities and offers the potential for better spatial resolution. 

The applications of nanowire detectors extend to various fields, including mass spectrometry, molecular spectroscopy, molecular deflectometry, and quantum interferometry of molecules, where high efficiency and resolution are crucial, especially at low impact energy levels. The study's results were published in the journal Science Advances.