Label-Free Confocal Raman Mapping of Transportan in Melanoma Cells.

Cell-penetrating peptides (CPPs) are promising vectors for the intracellular delivery of a variety of membrane-impermeable bioactive compounds. The mechanisms by which CPPs cross the cell membrane, and the effects that CPPs may have on cell function, still remain to be fully clarified. In this work, we employed confocal Raman microscopy (CRM) and atomic force microscopy (AFM) to study the infiltration and physiological effects of the amphipathic CPP transportan (Tp) on the metastatic melanoma cell line SK-Mel-2.

Ammonium catalyzed cyclitive additions: evidence for a cation-π interaction with alkynes.

The addition of carbamate nitrogen to a non-conjugated carbon-carbon triple bond is catalyzed by an ammonium salt leading to a cyclic product. Studies in homogeneous systems suggest that the ammonium agent facilitates nitrogen-carbon bond formation through a cation-π interaction with the alkyne unit that, for the first time, is directly observed by Raman spectroscopy.

Site-specific dynamics of amyloid formation and fibrillar configuration of Aβ(1-23) using an unnatural amino acid.

We identify distinct site-specific dynamics over the time course of Aβ1-23 amyloid formation by using an unnatural amino acid, p-cyanophenylalanine, as a sensitive fluorescent and Raman probe. Our results also suggest the key role of an edge-to-face aromatic interaction in the conformational conversion to form and stabilize β-sheet structure.

Solid-phase synthesis, characterization, and cellular activities of collagen-model nanodiamond-peptide conjugates.

Nanodiamonds (NDs) have received considerable attention as potential drug delivery vehicles. NDs are small (∼5 nm diameter), can be surface modified in a controllable fashion with a variety of functional groups, and have little observed toxicity in vitro and in vivo. However, most biomedical applications of NDs utilize surface adsorption of biomolecules, as opposed to covalent attachment.