Latest Instrumental Developments Research Articles

Matrix-Free High-Resolution Atmospheric-Pressure SALDI Mass Spectrometry Imaging of Biological Samples Using Nanostructured DIUTHAME Membranes.

Applications of mass spectrometry imaging (MSI), especially matrix-assisted laser desorption/ionization (MALDI) in the life sciences are becoming increasingly focused on single cell analysis. With the latest instrumental developments, pixel sizes in the micrometer range can be obtained, leading to challenges in matrix application, where imperfections or inhomogeneities in the matrix layer can lead to misinterpretation of MS images. Thereby, the application of premanufactured, homogeneous ionization-assisting devices is a promising approach. Tissue sections were investigated using a matrix-free imaging technique (Desorption Ionization Using Through-Hole Alumina Membrane, DIUTHAME) based on premanufactured nanostructured membranes to be deposited on top of a tissue section, in comparison to the spray-coating of an organic matrix in a MALDI MSI approach. Atmospheric pressure MALDI MSI ion sources were coupled to orbital trapping mass spectrometers. MS signals obtained by the different ionization techniques were annotated using accurate-mass-based database research. Compared to MALDI MSI, DIUTHAME MS images captivated with higher signal homogeneities, higher contrast and reduced background signals, while signal intensities were reduced by about one order of magnitude, independent of analyte class. DIUTHAME membranes, being applicable only on tissue sections thicker than 50 µm, were successfully used for mammal, insect and plant tissue with a high lateral resolution down to 5 µm.

Organophosphorus pesticide determination in biological specimens: bioanalytical and toxicological aspects.

Organophosphorus insecticides, such as parathion-ethyl, quinalphos, chlorpyrifos, chlorfenvinphos or diazinon, are still widely used for pest control on crops. These compounds are extremely toxic to humans, and, even though specific legislation exists that controls the use of these substances, the frequency of toxic and/or fatal events and the existing data suggest that they are still easily accessed and the knowledge associated to the risks is not well-recognized. For these reasons, the determination of the exposure to these compounds, their detection (and of their metabolites as well) in biological samples, is of great importance in clinical and forensic toxicology, and, therefore, the development of techniques for this evaluation is an important task for laboratories. Most confirmatory analyses use blood, serum, plasma and urine as biological samples and are performed by either gas chromatographic-mass spectrometric or liquid chromatographic-mass spectrometric instrumentation, which represents the gold standard in what concerns high sensitivity. This paper will not only address the physical-chemical and toxicological aspects of this class of compounds but also perform a comprehensive and critical review on the analytical methods available for their determination in biological specimens, with special focus on the latest instrumental developments and sample preparation approaches.

Conference Report: 60Th American Society For Ms Conference on Ms And Allied Topics

The 60th American Society for Mass Spectrometry (ASMS) Conference on MS and Allied Topics was held in May 2012 at Vancouver in Canada. This international congress is the largest forum exclusively dedicated to MS through its diverse aspects: fundamental, method development and applications to biomolecules. This 4-day conference is also highly appreciated for discussion with the MS manufacturers presenting their latest instrumental developments.

TU‐D‐J‐6B‐03: Physics and Applications of Preclinical Micro‐Ultrasound Imaging

Bioresearch in functional genomics is poised to make major contributions to our understanding of normal development and human disease. This promise will, in part, rely on the development of new micro‐imaging technologies to provide quantitative longitudinal assessment of morphological and functional development of normal and abnormal tissues. In addition, imaging tools will need to be further refined to enable high throughput phenotypic assessment of the rapidly escalating numbers of targeted and random mouse mutations. This presentation will focus on the development of high frequency (20 to 70 MHz) ultrasound biomicroscopy (UBM) for mouse imaging. While UBM does not provide molecular specificity, it has the advantage of low cost, rapid imaging speed, portability and high resolution (30–100 microns). The physics of high frequency ultrasound will be reviewed and the latest developments in instrumentation will be presented. Applications of 2 and 3D imaging to mouse cardiovascular assessment, cancer and ocular diseases will be described. Recent advances in 3D UBM imaging now permit the volumes of growing experimental tumors to be assessed with relative ease. Examples of tumor growth studies will be presented. In particular, a human melanoma (MeWo) and a model of retinoblastoma will be examined. Further analysis of Doppler and other flow related data offers insight to microvascular development and its alteration during treatment. This is particularly relevant to angiogenesis and antiangiogenic treatments. As an example of antiangiogenic therapy, a study of DC101 (ImClone Systems), a monoclonal anti‐VEGFR2 antibody will be presented. The authors wish to acknowledge the financial support of the Canadian Institutes for Health Research, the National Cancer Institute of Canada with funds from the Terry Fox Foundation, the Ontario Research and Development Challenge Fund, and VisualSonics Inc. FSF also discloses a financial interest in VisualSonics Inc.

Instrumental Limitations and Current Prospects for Materials Research with the Latest Generation of High-Resolution Electron Microscopes

The macroscopic properties of most materials depend directly on their microstructure and its local variability at the atomic level. Recent trends in high resolution electron microscopes (HREMs) have led to resolving powers on this scale, which in turn has made these instruments invaluable to many materials science investigations. The purposes of this short review are firstly to outline some of the fundamentals of high resolution image formation and interpretation and then to summarise some of the latest instrumental developments. Some recent applications are briefly described to provide some appreciation of the wide range of materials currently being investigated with the HREM. The impact of this work should be apparent from reference to other papers in this volume as well as several recent reviews [1–3] and special conference proceedings [4–5]. The likelihood of further developments in instrumentation and the necessity for complementary information from other techniques are also briefly considered.