Peptide‐poly(ε‐caprolactone) biohybrids by grafting‐from ring‐opening polymerization: Synthesis, aggregation, and crystalline properties

Abstract

Well‐defined peptide‐poly(ε‐caprolactone) (Pep‐PCL) biohybrids were successfully synthesized by grafting‐from ring‐opening polymerization (ROP) of ε‐caprolactone (CL) using designed amine‐terminated sequence‐defined peptides as macroinitiators. MALDI‐TOF‐MS and 1H NMR analyses confirmed the successful attachment of peptide to the PCL chain. The gel permeation chromatography (GPC) measurement showed that the Pep‐PCL biohybrids with controllable molecular weights and low polydispersities (PDI <1.5) were obtained by this approach. The aggregation of Pep‐PCL hybrid molecules in THF solution resulted in the formation of micro/nanospheres as confirmed through FESEM, TEM, and DLS analyses. The circular dichroism study revealed that the secondary structure of peptide moiety was changed in the peptide‐PCL biohybrids. The crystallization and melting behavior of Pep‐PCL hybrids were somewhat changed compared with that of neat PCL of comparable molecular weight as revealed by DSC and XRD measurements. In Pep‐PCL biohybrids, extinction rings were observed in the PCL spherulites, in contrast with the normal spherulite morphology of the neat PCL. There was a substantial decrease (4–5 folds) in the spherulitic growth rate after the incorporation of peptide moiety at the end of PCL chain as measured by polarizing optical microscopy. Pseudomonas lipase catalyzed enzymatic degradation was studied for Pep‐PCL hybrids and neat PCL. © 2012 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem, 2012

Well-Defined Poly(γ-benzyl-l-glutamate)-g-Polytetrahydrofuran: Synthesis, Characterization, and Properties

“…The effect of PBLG on in crystallizaiton behavior (spherulitic geometry, size and growth rate) of PTHF segments in PBLG-g-PTHF graft copolymers are similar to the report in which PCL crystallization behavior is indeed influenced by the attachment of peptide block segments. 43 It can be inferred that spherulitic growth rate of PBLG 207 -g-PTHF 45 graft copolymer further decreased with N b,PTHF from 52 to 150 for the increases in intramolecular excluded volume interactions caused by the presence of large amount of regular side chains and the steric repulsion between densely grafted side chains. The crystallization behavior of PTHF branches could affect the morphology of the PBLG-g-PTHF graft copolymers with different N b,PTHF , as shown in Figure 10b.…”

Peptide‐poly(tert‐butyl methacrylate) conjugate into composite micelles in organic solvents versus peptide‐poly(methacrylic acid) conjugate into spherical and worm‐like micelles in water: Synthesis and self‐assembly

“…However, most of the studies mainly focused on the synthesis of peptide–polymer conjugates and their self‐assembly in organic solvents. Recently, our group has reported the synthesis of peptide–polymer conjugates by ATRP/ring‐opening polymerization using sequence defined peptide‐initiator and studied their self‐assembly into micro/nanospheres in organic solvents . But, it would be much interesting to synthesize a new type of peptide–polymer conjugate using another variety of peptide‐initiator of different sequences as well as different polymer and study their self‐assembly in different polar organic solvents and water.…”

Combined atom-transfer radical polymerization and ring-opening polymerization to design polymer-polypeptide copolymer conjugates toward self-aggregated hybrid micro/nanospheres for dye encapsulation

“…It has been reported by many groups that polymer‐ block ‐peptide/polypeptides conjugate can easily undergo self‐aggregation into micelles, vesicles, and different microstructures in both aqueous and nonaqueous medium. In this context, previously, we reported the synthesis of conjugates comprising sequence‐defined short peptide and polymer using ATRP/ROP techniques and their self‐aggregation into micro/nanospheres in different polar organic solvents . We thought that it would be interesting to synthesize polymer–polypeptide conjugates and to study their self‐aggregation behavior in different solvents.…”