5 research outputs found
Rapid Evaporative Ionization Mass Spectrometry Imaging Platform for Direct Mapping from Bulk Tissue and Bacterial Growth Media
Rapid evaporative ionization mass
spectrometry (REIMS) technology
allows real time intraoperative tissue classification and the characterization
and identification of microorganisms. In order to create spectral
libraries for training the classification models, reference data need
to be acquired in large quantities as classification accuracy generally
improves as a function of number of training samples. In this study,
we present an automated high-throughput method for collecting REIMS
data from heterogeneous organic tissue. The underlying instrumentation
consists of a 2D stage with an additional high-precision <i>z</i>-axis actuator that is equipped with an electrosurgical diathermy-based
sampling probe. The approach was validated using samples of human
liver with metastases and bacterial strains, cultured on solid medium,
belonging to the species <i>P. aeruginosa</i>, <i>B.
subtilis</i>, and <i>S. aureus</i>. For both sample
types, spatially resolved spectral information was obtained that resulted
in clearly distinguishable multivariate clustering between the healthy/cancerous
liver tissues and between the bacterial species
Investigation of the Impact of Desorption Electrospray Ionization Sprayer Geometry on Its Performance in Imaging of Biological Tissue
In
this study, the impact of sprayer design and geometry on performance
in desorption electrospray ionization mass spectrometry (DESI-MS)
is assessed, as the sprayer is thought to be a major source of variability.
Absolute intensity repeatability, spectral composition, and classification
accuracy for biological tissues are considered. Marked differences
in tissue analysis performance are seen between the commercially available
and a lab-built sprayer. These are thought to be associated with the
geometry of the solvent capillary and the resulting shape of the primary
electrospray. Experiments with a sprayer with a fixed solvent capillary
position show that capillary orientation has a crucial impact on tissue
complex lipid signal and can lead to an almost complete loss of signal.
Absolute intensity repeatability is compared for five lab-built sprayers
using pork liver sections. Repeatability ranges from 1 to 224% for
individual sprayers and peaks of different spectral abundance. Between
sprayers, repeatability is 16%, 9%, 23%, and 34% for high, medium,
low, and very low abundance peaks, respectively. To assess the impact
of sprayer variability on tissue classification using multivariate
statistical tools, nine human colorectal adenocarcinoma sections are
analyzed with three lab-built sprayers, and classification accuracy
for adenocarcinoma versus the surrounding stroma is assessed. It ranges
from 80.7 to 94.5% between the three sprayers and is 86.5% overall.
The presented results confirm that the sprayer setup needs to be closely
controlled to obtain reliable data, and a new sprayer setup with a
fixed solvent capillary geometry should be developed
Rapid Evaporative Ionization Mass Spectrometry Imaging Platform for Direct Mapping from Bulk Tissue and Bacterial Growth Media
Rapid evaporative ionization mass spectrometry (REIMS) technology allows real time intraoperative tissue classification and the characterization and identification of microorganisms. In order to create spectral libraries for training the classification models, reference data need to be acquired in large quantities as classification accuracy generally improves as a function of number of training samples. In this study, we present an automated high-throughput method for collecting REIMS data from heterogeneous organic tissue. The underlying instrumentation consists of a 2D stage with an additional high-precision z-axis actuator that is equipped with an electrosurgical diathermy-based sampling probe. The approach was validated using samples of human liver with metastases and bacterial strains, cultured on solid medium, belonging to the species P. aeruginosa, B. subtilis, and S. aureus. For both sample types, spatially resolved spectral information was obtained that resulted in clearly distinguishable multivariate clustering between the healthy/cancerous liver tissues and between the bacterial species