Issue 14, 2018

Methionine-based cationic polypeptide/polypeptide block copolymer with triple-stimuli responsiveness: DNA polyplexation and phototriggered release

Abstract

This study demonstrates the synthesis of positively charged 2-nitrobenzyl functionalized polymethionine (P[MetNB][Br]) and its block copolymer of pseudopeptidic poly(2-ethyl-2-oxazoline) (PEtOx-b-P[MetNB][Br]) by firstly employing ring-opening polymerization (ROP), followed by post-functionalization through nucleophilic substitution. The as-prepared cationic P[MetNB][Br] and PEtOx-b-P[MetNB][Br] are readily soluble in water, exhibiting responsiveness towards multiple stimuli such as ions, temperature and light. The aqueous solutions of both of the cationic polypeptides become cloudy in the presence of anions like I, ClO4 and SCN due to the formation of insoluble anionically cross-linked colloidal aggregates of cationic polypeptides. These cloudy solutions of the polypeptide and polypeptide block copolymer both show reversible upper critical solution temperature (UCST)-type phase transitions due to the dissolution of the aggregates upon heating. The parameters, polypeptide concentrations and the nature of the anion and its concentration affect the cloud points in aqueous solutions. Upon irradiation with UV light (λ = 350 nm), the pendent nitrobenzyl sulfonium moiety of both of the cationic polypeptides undergoes photocleavage to a neutral polypeptide/polypeptide block copolymer. This study further demonstrates the binding of a cationic polypeptide/polypeptide block copolymer with calf thymus DNA (ctDNA) through electrostatic complexation and its phototriggered release as monitored by fluorescence spectroscopy and gel electrophoresis.

Graphical abstract: Methionine-based cationic polypeptide/polypeptide block copolymer with triple-stimuli responsiveness: DNA polyplexation and phototriggered release

Supplementary files

Article information

Article type
Paper
Submitted
01 Feb 2018
Accepted
23 Feb 2018
First published
26 Feb 2018

Polym. Chem., 2018,9, 1869-1884

Methionine-based cationic polypeptide/polypeptide block copolymer with triple-stimuli responsiveness: DNA polyplexation and phototriggered release

S. Jana, Y. Biswas and T. K. Mandal, Polym. Chem., 2018, 9, 1869 DOI: 10.1039/C8PY00178B

To request permission to reproduce material from this article, please go to the Copyright Clearance Center request page.

If you are an author contributing to an RSC publication, you do not need to request permission provided correct acknowledgement is given.

If you are the author of this article, you do not need to request permission to reproduce figures and diagrams provided correct acknowledgement is given. If you want to reproduce the whole article in a third-party publication (excluding your thesis/dissertation for which permission is not required) please go to the Copyright Clearance Center request page.

Read more about how to correctly acknowledge RSC content.

Social activity

Spotlight

Advertisements