A surface-modified dendrimer set for potential application as drug delivery vehicles: synthesis, in vitro toxicity, and intracellular localization

The synthesis, cytotoxicity, and behavior in cell culture of a new set of first- (G1) and second-generation (G2) dendrimers is reported. The surface functionality of these dendrimers has been varied to see whether structure/toxicity relations can be observed. The outermost functional groups are amines that are decorated either with protons, tert-butoxycarbonyl (Boc) or benzyloxycarbonyl (Cbz) protecting groups, Boc-protected or unprotected natural amino acid residues, ethylenediamine ligands, and/or dansyl fluorescence labels. The cytotoxicity was determined in vitro in concentration-dependent assays using the human MCF-7 breast cancer cell line. Cellular uptake and intracellular distribution was monitored by confocal fluorescence microscopy after internalization of the dansyl-labeled dendrimers by HeLa cells.