No abstract

ABSTRACT:Four new phosphorus dendrimeric phase-transfer catalysts are prepared containing on the surface twelve (+)-cinchoninium salts, obtained by quaternisation of the quinuclidinic nitrogen. Asymmetric alkylation of a glycinate Schiff base with benzyl bromide is used as a benchmark reaction, showing that the more active dendrimeric catalyst is the one containing an allyl group on the O-9 hydroxy group of the cinchonine units. The recovery and reuse of the catalyst are possible for five consecutive runs without loss of activity and slight decrease in enantioselectivity. When other electrophiles are used, substituted benzyl bromides give better results than other activated alkyl bromides affording the corresponding (R)-amino acids derivatives. Comparison of these results with the ones previously reported for similar cinchoninium salts, shows that dendrimers could be a better support than other polymers for this type of organocatalysis.

Five peptide ligands of four different cell surface receptors (nucleolin, CXCR1, CMKLR1, and CD44v6) have been evaluated as targeting moieties for triple-negative human breast cancers. Among them, the peptide F3, derived from phage display, promotes the fast and efficient internalization of a genetically fused green fluorescent protein (GFP) inside MDA-MB-231 cancer stem cells in a specific receptor-dependent fashion. The further engineering of this protein into the modular construct F3-RK-GFP-H6 and the subsequent construct F3-RK-PE24-H6 resulted in self-assembling polypeptides that organize as discrete and regular nanoparticles. These materials, 15−20 nm in size, show enhanced nucleolin-dependent cell penetrability.We show that the F3-RK-PE24-H6, based on the Pseudomonas aeruginosa exotoxin A (PE24) as a core functional domain, is highly cytotoxic over target cells. The combination of F3, the cationic peptide (RK) n , and the toxin domain PE24 in such unusual presentation appears as a promising approach to cell-targeted drug carriers in breast cancers and addresses selective drug delivery in otherwise difficult-to-treat triple-negative breast cancers.

Lateral flow assays (LFA) are an affordable, easy-touse, qualitative rapid test for clinical diagnosis in nonlaboratory environments and low-resource facilities. The control line of these tests is very important to provide a valid result, confirming that the platform operates correctly. A clear, nondiffused line is desirable. The number of colored nanoparticles that reach the control line in a positive test can be very small, and they should all be trapped efficiently by the molecules adsorbed there. In this work, we proposed the use of robust biotinylated dendrimers of two different generations as signal amplifiers in control lines of LFA, able to react with streptavidin-modified gold nanoparticles. Besides the synthesis and characterization, the analytical performance as control lines will be studied, and their response will be compared with other commercially available biotinylated molecules. Finally, the utility of the dendrimer implemented in a NALF (Nucleic Acid Lateral Flow) strip was also demonstrated for detection of the amplicons obtained by double-tagging PCR (polymerase chain reaction) for the detection of E. coli as a model of foodborne pathogen.