Molecular nano-identification

In 1994, we proposed that a metallic needle having a nano-tip at its apex be employed as a nano-light-source for microscopy attaining nanometric spatial resolution [2]. Later, we expanded the technique to Raman spectroscopy for molecular nano-identification, nano-analysis and nano-imaging. In this chapter, we give a brief introduction to local plasmons and microscopy using a metallic nano-needle to produce the local plasmons. Then, we describe the microscope that we built and... 

Hofmann, S., Gluckmaim, M., Kausche, S., Schmidt, A., Corvey, C., Lichtenfels, R., Huber, C., Albrecht, C., Karas, M., and Herr, W., Rapid and sensitive identification of major histocompatibility complex class 1-associated tumor peptides by nano-LC MALDI MS/MS, Molecular and Cellular Proteomics 4(12), 1888-1897, 2005. 

With respect to sample preparation, it is necessary to develop effective and fast procedures involving only a few steps in order to avoid contamination, reduce analysis time and to improve the quality of analytical work. Microsampling and the use of smaller sample sizes is required and also the further development of analytical techniques. In particular, there is a need for the development of online and/or hyphenated techniques in ICP-MS. Microsampling combined with the separation of small amounts of analytes will be relevant for several chromatographic techniques (such as the development of micro- and nano-HPLC). There is a demand for further development of the combination of LA-ICP-MS as an element analytical technique with a biomolecular mass spectrometric technique such as MALDI- or ESI-MS for molecular identification and quantification of protein phosphorylation as well as of metal concentrations, this also enables the study of post-translational modifications of proteins, e.g. phosphorylation. 

Fig. (1). Peptidomics strategies used to study Drosophila immunity. (A) Using antimicrobial assays (antibacterial and antifungal), the bioactive peptides were isolated from the blood of bacteria-challenged Drosophila. MS was used for molecular mass assignment, to identify post-translational modifications, and for primary structure elucidation (B) Identification of peptidic immune effectors through differential display analysis (DD) by MALDI-MS and micro/nano RP-HPLC coupled (online) or not (off-line) to ESI-MS. When the HPLC was performed off-line to the mass spectrometer, fractions were individually analyzed by MALDI-MS. The identification and the structural characterization were performed either by molecular mass assignment and/or sequencing by ESI-MS/MS.

IsHiDA, M. Yamazaki, T. Houjou, T. Imagawa, M. Harada, a. Inoue, K. Taguchi, R. High-resolution analysis by nano-electrospray ionization Fourier transform ion cyclotron resonance mass spectrometry for the identification of molecular species of phospholipids and their oxidized metabolites. Rapid Commun. Mass Spectrom. 2004,18, 2486-2494. 

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