Scientists at the Laboratory for Attosecond Physics (LAP) have developed a spectrometer for the analysis of the molecular composition of biological samples, capable of detecting minimal variations in the chemical makeup of organic systems.

The research team led by Ferenc Krausz of the Max Planck Institute of Quantum Optics built its device to capture spectra of infrared light, revealing the molecular signatures of precancerous and malignant cells that are often found in biological samples too small to detect.

The research builds on technologies originally developed in the LAP for the production of ultrashort laser pulses. The spectrometer, built by Ioachim Pupeza and his colleagues, is designed to emit pulses of laser light that cover a broad segment of the spectrum in the infrared wavelength. Each of these pulses lasts for a few femtoseconds, causing the bonds that link atoms together to vibrate. After the passage of the pulse, the vibrating molecules emit coherent light at highly characteristic wavelengths or oscillation frequencies, making it possible to capture the complete ensemble of wavelengths emitted.

“With this laser, we can cover a wide range of infrared wavelengths, from 6 to 12 micrometers, that stimulate vibrations in molecules,” said Marinus Huber, a co-author of the study. “Unlike mass spectroscopy, this method provides access to all the types of molecules found in biological samples.”

Each of the ultrashort laser pulses can reach up to twice the spectral brightness of conventional synchrotrons, a radiation source with a comparable approach to molecular spectroscopy, enabling the device to illuminate samples of living tissue up to 0.1 mm thick. In initial experiments, the team at the LAP has applied the technique to leaves and other living cells, as well as blood samples.

“This ability to accurately measure variations in the molecular composition of body fluids opens up new possibilities in biology and medicine,” said Mihaela Zigman, who led a team of biologists in the study. “In the future the technique could find application in the early detection of disorders.”