Peptide‐poly(2‐(dimethylamino)ethyl methacrylate) conjugates: Synthesis and aqueous/nonaqueous self‐aggregation into nanostructures of dendritic and spherical morphologies

Abstract

Peptide-polymer conjugate consisting of a sequence-defined tripeptide and poly(2-(dimethylamino)ethyl methacrylate) (PDMAEMA) is synthesized by a simple "grafting from" atom transfer radical polymerization (ATRP) approach. The ATRP of PDMAEMA using peptide-macroinitiator and CuBr/1,1,4,7,10,10-hexamethyltriethylenetetramine system in anisole follows pseudo first order kinetics up to a conversion of about 25% within a time span of 125 min. The attachment of peptide moiety at the end of PDMAEMA chain is confirmed from MALDI-TOF-MS and circular dichroism analyses. The selfassembly of as-synthesized peptide-PDMAEMA conjugate in organic solvents leads to the formation of spherical nanoparticles as observed through FESEM. Peptide-PDMAEMA conjugate become soluble in water due to the protonation of the pendent AN(CH 3 ) 2 moiety of DMAEMA group of the conjugate. Owing to the amphiphilic nature of the protonated conjugate (peptide-PDMAEMAH), it also undergoes self-aggregation in water into nanostructures of various morphologies such as dendrite, small sphere and large sphere at pHs of 2, 8, and 10, respectively. Peptide-PDMAEMA-IBu conjugate obtained by the post-modification of AN(CH 3 ) 2 moiety of DMAEMA group of the conjugate with n-butylbromide also undergoes selfaggregation into dendritic nanostructures in water.