Abstract:The cover picture shows a branched poly(proline) peptide whose synthesis has successfully been achieved using a combination of step-wise and convergent solid-phase peptide methodology. Aminoproline was used as a branching unit in order to maintain structural coherence with the rest of the sequence, although other trifunctional amino acids were also tested. Assembly of different units of this peptide could lead to poly(proline) dendrimers. These new biocompatible architectures may have interesting applications … Show more
“…These molecules showed in vitro capacity to cross the eukaryotic cell membrane and moderate cytotoxicity, thus opening up their use as drug delivery systems 11. However, the rigidity of the polyproline branches hampered the synthesis, mainly as a result of the highly compact core space, which was translated into low yield and purity 8a–8c…”
Highly photoluminescent carbon nanodots (CNDs) were synthesized for the first time from metal-organic framework (MOF, ZIF-8) nanoparticles. Coupled with fluorescence and non-toxic characteristics, these carbon nanodots could potentially be used in biosafe color patterning.
“…These molecules showed in vitro capacity to cross the eukaryotic cell membrane and moderate cytotoxicity, thus opening up their use as drug delivery systems 11. However, the rigidity of the polyproline branches hampered the synthesis, mainly as a result of the highly compact core space, which was translated into low yield and purity 8a–8c…”
Highly photoluminescent carbon nanodots (CNDs) were synthesized for the first time from metal-organic framework (MOF, ZIF-8) nanoparticles. Coupled with fluorescence and non-toxic characteristics, these carbon nanodots could potentially be used in biosafe color patterning.
“…20 This is due to the presence of pendant carboxylated aliphatic chain in the polymer structure, creating large polymeric cavities in the nanostructure for the effective preservation of various cargos. In addition, other amino acid-based biopolymers, such as polyglutamic acid, 21 poly(aspartic acid) 22 and polyproline dendrimers, 23 are also widely used in biomedical applications due to their enhanced solubility, biocompatibility and low profile cytotoxicity. Syntheses of such biomacromolecules involve polymerization of an appropriate cyclic monomer 22 or selective -NH 2 group protection and deprotection of the corresponding amino acid.…”
The development of functional amino acid based polymeric materials is emerging as a platform to create biodegradable and non-toxic nanomaterials for medical and biotechnology applications. In particular, facile synthetic routes for these polymers and their corresponding polymeric nanomaterials would have a positive impact in the development of novel biomaterials and nanoparticles. However, progress has been hampered by the need to use complex protection-deprotection methods and toxic phase transfer catalyst. In this study, we report a facile, single-step approach for the synthesis of an N-alkylated amino acid as an AB-type functional monomer to generate a novel pseudopolyamino acid, without using the laborious multi-step, protection-deprotection steps. This synthetic strategy is reproducible, easy to scale up and produces no toxic byproducts. In addition, the synthesized amino acid-based polymer is different from conventional linear polymers as the butyl pendants enhance its solubility in common organic solvents and facilitate the creation of hydrophobic nanocavities for the effective encapsulation of hydrophobic cargos upon nanoparticle formation. Within the nanoparticles, we have encapsulated a hydrophobic DiI dye and a therapeutic drug, Taxol. In addition, we have conjugated folic acid as a folate receptor-targeting ligand for the targeted delivery of the nanoparticles to cancer cells expressing the folate receptor. Cell cytotoxicity studies confirm the low toxicity of the polymeric nanoparticles and drug-release experiments with the Taxol-encapsulated nanoparticles only exhibit cytotoxicity upon internalization into cancer cells expressing the folate receptor. Taken together, these results suggested that our synthetic strategy can be useful for the one-step synthesis of amino acid-based small molecules, biopolymers and theranostic polymeric nanoagents for the targeted detection and treatment of cancer.
“…Synthesis of branched polyproline peptides is not at all straightforward. After a careful study of several different approaches, we have chosen the optimized synthetic route shown in Scheme . 2 Building Block Solid-Phase Synthesis…”
We present a new family of peptide dendrimers based on polyproline helices and cis-4-amino-L-proline as a branching unit. Dendrimers were synthesized by a convergent solid-phase peptide synthesis approach. The conformational transition between polyproline type I helix and polyproline type II helix was observed by circular dichroism in branched polyproline building blocks with more than 14 proline residues and in the resulting dendrimers. Both linear and dendritic polyprolines were found to be actively internalized by rat kidney cells. Preliminary results show that the antibiotic ciprofloxacin form complexes with branched polyproline chains in 99.5% propanol.
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