Int J Med Sci 2012; 9(1):1-10. doi:10.7150/ijms.9.1 This issue

Research Paper

Improved Synthesis Strategy for Peptide Nucleic Acids (PNA) appropriate for Cell-specific Fluorescence Imaging

Rüdiger Pipkorn1✉, Manfred Wiessler2, Waldemar Waldeck3, Ute Hennrich2, Kiyoshi Nokihara4, Marcel Beining3, Klaus Braun2

1. DKFZ, Central Peptide Synthesis Unit, INF 580, D-69120 Heidelberg, Germany
2. DKFZ, Dept. of Imaging and Radiooncology, INF 280, D-69120 Heidelberg, Germany
3. DKFZ, Div. of Biophysics of Macromolecules, INF 580, D-69120 Heidelberg, Germany
4. HiPep Laboratories, Nakatsukasa-cho, 486-46, Kamigyo-ku, Kyoto 602-8158, Japan

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Pipkorn R, Wiessler M, Waldeck W, Hennrich U, Nokihara K, Beining M, Braun K. Improved Synthesis Strategy for Peptide Nucleic Acids (PNA) appropriate for Cell-specific Fluorescence Imaging. Int J Med Sci 2012; 9(1):1-10. doi:10.7150/ijms.9.1. Available from

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Progress in genomics and proteomics attended to the door for better understanding the recent rapid expanding complex research field of metabolomics. This trend in biomedical research increasingly focuses to the development of patient-specific therapeutic approaches with higher efficiency and sustainability. Simultaneously undesired adverse reactions are avoided. In parallel, the development of molecules for molecular imaging is required not only for the imaging of morphological structures but also for the imaging of metabolic processes like the aberrant expression of the cysteine protease cathepsin B (CtsB) gene and the activity of the resulting product associated with metastasis and invasiveness of malign tumors. Finally the objective is to merge imaging and therapy at the same level. The design of molecules which fulfil these responsibilities is pivotal and requires proper chemical methodologies. In this context our modified solid phase peptide chemistry using temperature shifts during synthesis is considered as an appropriate technology. We generated highly variable conjugates which consist of molecules useful as diagnostically and therapeutically active molecules. As an example the modular PNA products with the complementary sequence to the CtsB mRNA and additionally with a cathepsin B cleavage site had been prepared as functional modules for distinction of cell lines with different CtsB gene expression. After ligation to the modular peptide-based BioShuttle carrier, which was utilized to facilitate the delivery of the functional modules into the cells' cytoplasm, the modules were scrutinized.

Keywords: Click Chemistry, Diels Alder Reactioninverse (DARinv), Fluorescence Imaging, Peptide Nucleic Acid (PNA), PNA building block functionalization