Two-Dimensional Controlled Syntheses of Polypeptide Molecular Brushes via N-Carboxyanhydride Ring-Opening Polymerization and Ring-Opening Metathesis Polymerization

Abstract

Well-defined molecular brushes bearing polypeptides as side chains were prepared by a “grafting through” synthetic strategy with two-dimensional control over the brush molecular architectures. By integrating N-carboxyanhydride ring-opening polymerizations (NCA ROPs) and ring-opening metathesis polymerizations (ROMPs), desirable segment lengths of polypeptide side chains and polynorbornene brush backbones were independently constructed in controlled manners. The N2 flow accelerated NCA ROP was utilized to prepare polypeptide macromonomers with different lengths initiated from a norbornene-based primary amine, and those macromonomers were then polymerized via ROMP. It was found that a mixture of dichloromethane and an ionic liquid were required as the solvent system to allow for construction of molecular brush polymers having densely-grafted peptide chains emanating from a polynorbornene backbone, poly(norbornene-graft-poly(β-benzyl-l-aspartate)) (P(NB-g-PBLA)). Highly efficient postpolymerization modification was achieved by aminolysis of PBLA side chains for facile installment of functional moieties onto the molecular brushes.

Alpha-beta chimeric polypeptide molecular brushes display potent activity against superbugs-methicillin resistant Staphylococcus aureus

“…Polymer brushes have been explored not only for their interesting morphology [37][38][39][40][41][42][43][44][45][46][47][48][49], but also for their unique functions compared to linear polymers [50][51][52][53][54][55][56][57][58][59][60][61][62][63][64]. In this study, we designed alpha-beta chimeric polypeptide molecular brush (α/β CPMB) with β-polypeptide or poly-βamino acid (PβAA) as the backbone and poly-α-L-lysine (PαLL) grafting from the backbone for antimicrobial studies.…”

Accelerated Polypeptide Synthesis via N‐Carboxyanhydride Ring Opening Polymerization in Continuous Flow

“…This functional group enables post-polymerization modifications via thiol-ene and inverse electron demand Diels-Alder chemistries, [46,47] in addition to being readily polymerizable via ring opening metathesis polymerization, allowing the formation of complex structures such as brush polypeptides. [48,49] As a reference point, the batch reaction (NCA ROP of ZLL) was monitored online with in situ attenuated total reflectance Fourier transform infrared spectroscopy (ATR-FTIR) and was found to be relatively fast in the initial stages, reaching 50% monomer conversion within one hour. However, to reach full conversion, much longer reaction times are required.…”

Cationic Bottlebrush Polymers from Quaternary Ammonium Macromonomers by Grafting‐Through Ring‐Opening Metathesis Polymerization

“…ROMP also has demonstrated a wide functional group tolerance to produce well‐defined bottlebrush block copolymers with MMs carrying heteroatom functional groups through sequential ROMP 43–46. Well‐controlled MMs are needed for well‐defined bottlebrush polymers and they have been synthesized from a variety of techniques, which suppress side reactions of norbornene incorporation, such as reversible addition‐fragmentation chain transfer (RAFT) polymerization,47–49 atom transfer radical polymerization (ATRP),50–52 living anionic polymerization (LAP),53,54 ring‐opening polymerization (ROP),55 and other types of polymerizations 56,57. Thus, a wide library of potential MMs exist to create new bottlebrush block copolymers.…”