In recent years, Mass Spectrometry (MS) has provided many advances in the clinical setting, from effective neonatal screening of inborn errors in metabolism to faster bacterial identification in clinical microbiology. For the latter, matrix-assisted laser desorption/ionization (MALDI) MS was developed using the conventional (solid) MALDI technique and standard time-of-flight (TOF) mass analysers. Typically, these instruments are linear axial ToF mass spectrometers using ion sources under vacuum conditions and require a vacuum-compatible MALDI sample. Current platforms work with solid (crystalline) MALDI samples, causing certain drawbacks for the analysis such as low ion signal stability. Conventional MALDI on axial linear TOF instrumentation also lacks the ability to create predominately multiply charged analyte ions for superior MS/MS analysis, which allows informative structural information to be obtained and to gain specificity in the identification of biomarkers. It also provides higher background noise, mainly from interfering ions of the MALDI matrices, thus hindering detection of a more comprehensive set of biomolecules throughout the entire measured mass spectrum.
The group of Prof Rainer Cramer at the University of Reading (Mass Spectrometry and Bioanalytical Sciences) has recently developed liquid atmospheric pressure (LAP)-MALDI, a technique requiring small droplets (<2uL) instead of crystallized spots for analysis and using atmospheric pressure conditions in the ion source, addressing all of the above shortcomings of conventional MALDI MS. The advantages of this technique for high-throughput analysis have been demonstrated in several relevant publications [Krenkel, H. et.al., Anal Chem, 2022, 94 (10). pp. 4141-4145 or C. Piras et.al., Chem Sci, 2022, 13 (6). pp. 1746-1758, doi: https://dx.doi.org/10.1039/D1SC05171G. For more: see “Our publications”].
Utilizing a modified TOF-MS instrument the group was able to apply this technology successfully in the veterinary field. In one study, analyzing small volumes of cow milk collected during routine milking, bovine mastitis was accurately detected 2 days before the detection by current methods, using a simple, fast and cost-effective sample preparation protocol [O. J. Hale et. al., ACS Omega, 2019 Jul 26;4(7):12759-12765. doi: 10.1021/acsomega.9b01476].
Within the HIP project, we will modify a state-of-the-art commercial benchtop Q-TOF mass spectrometer and implement a high-speed LAP-MALDI ion source. These activities are supported by the instrument supplier (Waters Corporation), who are one of the cooperation partners in this project. The goal is to develop an instrument capable of performing fast and accurate analyses of up to 100k (clinical) samples per day with the ability of multiplexing analysis. Our clinical partners from the Royal Berkshire Hospital (RBH) in Reading will support us in collecting biofluid samples from patients and advise on the clinical aspects of the project. Developing appropriate methods and protocols for reliable analysis will be a major task in this project, including the evaluation and selection of adequate data processing and class prediction software for multivariate statistical analysis, and thus the best microbial (disease) classification.