Matrix-assisted laser desorption/ionization mass spectrometry (MALDI-MS) is a valuable tool for the analysis of molecules
directly from tissue. Imaging of phospholipids is gaining widespread interest, particularly as these lipids have been implicated
in a variety of pathologic processes. Formalin fixation (FF) is the standard protocol used in histology laboratories worldwide
to preserve tissue for analysis, in order to aid in the diagnosis and prognosis of diseases. This study assesses MALDI imaging
of phospholipids directly in formalin fixed tissue, with a view to future analysis of archival tissue. This investigation
proves the viability of MALDI-MSI for studying the distribution of lipids directly in formalin fixed tissue, without any pretreatment
protocols. High quality molecular images for several phosphatidylcholine (PC) and sphingomyelin (SM) species are presented.
Images correspond well with previously published data for the analysis of lipids directly from freshly prepared tissue. Different
ionization pathways are observed when analyzing fixed tissue compared with fresh, and this change was found to be associated
with formalin buffers employed in fixation protocols. The ability to analyze lipids directly from formalin fixed tissue opens
up new doors in the investigation of disease profiles. Pathologic specimens taken for histologic investigation can be analyzed
by MALDI-MS to provide greater information on the involvement of lipids in diseased tissue. 相似文献
Tissue imaging using matrix assisted laser desorption/ionization mass spectrometry (MALDI-MS) is a well-established technique that, in recent years, has seen wider adoption and novel application. Applications such imaging mass spectrometry (IMS) and biotyping are beginning to gain greater exposure and use; however, with limitations in optimization methods, producing the best result often relies on the ability to customize the physical characteristics of the instrumentation, a task that is challenging for most mass spectrometry laboratories. With this in mind, we have described the effect of making simple adjustments to the laser optics at the final collimating lens area, to adjust the laser beam size and shape in order to allow greater customization of the instrument for improving techniques such as IMS. We have therefore been able to demonstrate that improvements can be made without requiring the help of an electrical engineer or external funding in a way that only costs a small amount of time.
As a low molecular weight protein with the ability of binding metal ions and high inducibility, metallothionein (MT) is often regarded as an important biomarker for assessment of heavy metal pollution in water environment. In the light of that the traditional process of enrichment and identification is time-consuming and complicated, we prepared a core-shell nanoparticle, gold-coated iron oxide nanoparticles (Fe3O4@Au NPs) herein. It possessed the advantages of fast response to magnetic fields and optical properties attributing to Fe3O4 and Au nanoparticles, respectively. The Fe3O4@Au nanoparticles could be used to enrich MT simply through Au–S interaction, and the purified proteins were determined by matrix assisted laser desorption ionization time-of-flight mass spectrometry (MALDI-TOF/MS). The results showed that the Fe3O4@Au nanoparticles could directly enrich MT from complex solutions and the detection limit could be as low as 10 fg mL?1. 相似文献
Measurement of glycated hemoglobin is widely used for the diagnosis and monitoring of diabetes mellitus. Matrix assisted laser desorption/ionization (MALDI) time of flight (TOF) mass spectrometry (MS) analysis of patient samples is used to demonstrate a method for quantitation of total glycation on the β-subunit of hemoglobin. The approach is accurate and calibrated with commercially available reference materials. Measurements were linear (R2 > 0.99) across the clinically relevant range of 4% to 20% glycation with coefficients of variation of ≤ 2.5%. Additional and independent measurements of glycation of the α-subunit of hemoglobin are used to validate β-subunit glycation measurements and distinguish hemoglobin variants. Results obtained by MALDI-TOF MS were compared with those obtained in a clinical laboratory using validated HPLC methodology. MALDI-TOF MS sample preparation was minimal and analysis times were rapid making the method an attractive alternative to methodologies currently in practice.
