Synthetic Polypeptides with Cationic Arginine Moieties Showing High Antimicrobial Activity in Similar Mineral Environments to Blood Plasma.

Translocation of cell-penetrating peptides is promoted by incorporated arginine or other guanidinium groups. However, relatively little research has considered the role of these functional groups on antimicrobial peptide activity. A series of cationic linear-, star- and multi-branched-poly(L-arginine-co-L-phenylalanine) have been synthesized via the ring-opening copolymerizations of corresponding N-carboxyanhydride monomers followed by further modifications using the N-heterocyclic carbene organocatalyst.

-Heterocyclic Carbene-Catalyzed Random Copolymerization of -Carboxyanhydrides of α-Amino Acids.

Synthetic polypeptides prepared from -carboxyanhydrides (NCAs) of α-amino acids are useful for elucidating the relationship between the primary structure of natural peptides and their immunogenicity. In this study, complex copolypeptide sequences were prepared using a recently developed technique; specifically, the random copolymerization of l-alanine NCA with NCAs of l-glutamic acid 5-benzylester (Bn-Glu NCA), -benzyl-cysteine (Bn-Cys NCA), -benzyl-l-serine (Bn-Ser NCA), and l-phenylalanine (Phe NCA) was performed using -heterocyclic carbene (NHC) catalysts. The NHC-initiated Ala NCA/Bn-Glu NCA and Ala NCA/Bn-Cys NCA copolymerization reactions achieved 90% conversion within 30 min.

Multistimuli-Responsive Polymeric Vesicles for Accelerated Drug Release in Chemo-photothermal Therapy.

Multistimuli-responsive nanomedicines present great potential for cancer therapy, as they can be featured as simple, selective, and smart carriers that can release their payload on-demand. In this study, we prepared a multifunctional polymeric vesicular nanocarrier (PVN) based on robust and triple stimuli-responsive micelles that could encapsulate chemotherapeutic drugs (doxorubicin (DOX)) and photothermal agents (IR780 iodide) for combined chemo-photothermal therapy. The size of the PVNs was stable and uniform (∼100 nm), and its DOX and IR780 loading were high: 26.

Multi-stimuli-responsive nanomicelles fabricated using synthetic polymer polylysine conjugates for tumor microenvironment dependent drug delivery.

A series of multi-stimuli-responsive poly(N-isopropylacrylamide)-SS-block-poly(L-lysine)-block-poly(caprolactone) (p(NIPAM)-SS-b-p(Lys)-b-p(CL)) (n = 50, 75, 100, 125) triblock copolymers have been synthesized by combining reversible addition-fragmentation chain transfer polymerization of NIPAM, organo-catalyzed ring-opening polymerization (ROP) of Z-lysine N-carboxyanhydride and metal-catalyzed ROP of CL with an azide-alkyne click reaction. The pH-responsive p(Lys) and temperature-responsive p(NIPAM) blocks are tethered by a redox-responsive disulfide linker and biodegradable p(CL) blocks with different lengths are also combined to tune the lower critical solution temperature and drug loading capacity of the resulting polymers. Highly uniform micelles with ∼200 nm size were fabricated by the self-assembly of the resultant copolymers in the presence of doxorubicin (Dox) with a high Dox encapsulation efficiency of around 50%.