Method for the detection of protein ions developed
Scientists have developed a new technique that produces flash photos of protein ions.
Researchers, from the FOM institute AMOLF (Utrecht, The Netherlands), have reported the first application of a highly sensitive detector to a commercial mass spectrometer, which produces images of protein ions during deposition and ionization.
The team, led by Ron Heeren, applied the highly sensitive detector, termed Timepix active pixel detector, to a conventional MALDI-TOF-MS.
The study involved adapting the Timepix active pixel detector for protein analysis, previously this instrument had been used for high-energy physics. This was achieved by replacing a photon sensitive plate with a plate that could detect charged ions. The research reported ion acceleration voltages of up to 25 kV, which combined with the sensitive detector, allows detection of larger proteins.
As described in the research paper, previous systems used to detect proteins were limited due to the inability to detect singly charged ions with high m/z ratios. However, the detection technique developed by the team can reportedly detect ions as large as 400 kDa.
The developed technique can, therefore, be utilized for the detection of larger proteins, for example, the antibody immunoglobulin G, which the team utilized their new technique to image. Previous studies on the same antibody using a conventional mass spectrometer had comparatively low sensitivity.
Heeren described the advantage of this new detection technique, “The advantage of the Timepix detector is that besides being able to measure more than 100-times more sensitively, you can also use it to make detailed images.” Heeren went on to explain, “With the detector, molecular flash photography has now become a mature technique.”
Sources: Ellis SR, Jungmann JH, Smith DF et al. Enhanced detection of high-mass proteins by using an active pixel detector. Angewandte Chemie Int. (2013) (Epub ahead of print); New detection technique makes flash photos of proteins.
