Incorporation of Indole Significantly Improves the Transfection Efficiency of Guanidinium‐Containing Poly(Methacrylamide)s

Abstract

A highly efficient transfection agent is reported that is based on terpolymer consisting of N‐(2‐hydroxypropyl)methacrylamide (HPMA), N‐(3‐guanidinopropyl) methacrylamide (GPMA), and N‐(2‐indolethyl)methacrylamide monomers (IEMA) by analogy to the amphipathic cell‐penetrating peptides containing tryptophan and arginine residues. The incorporation of the indole‐bearing monomer leads to successful plasmid DNA condensation even at a nitrogen‐to‐phosphate (N/P) ratio of 1. The hydrodynamic diameter of polyplexes is determined to be below 200 nm for all N/P ratios. The transfection studies demonstrate a 200‐fold increase of the transgene expression in comparison to P(HPMA‐co‐GPMA) with the same guanidinium content. This study reveals the strong potential of the indole group as a side‐chain pendant group that can increase the cellular uptake of polymers and the transfection efficiency of the respective polyplexes.

Tuning of endosomal escape and gene expression by functional groups, molecular weight and transfection medium: a structure–activity relationship study

“…47,48 Since this feature is of great importance in applications such as drug or gene delivery, the guanidinium group is frequently exploited for the development of synthetic vectors. 46,[49][50][51][52][53] Regarding examples possessing vinylic polymeric backbones, Funhoff et al reported promising transfection and uptake in COS-7 cells for poly(3-guanidinopropyl methacrylate) (PGPMA) homopolymers prepared via free radical polymerization. 38 However, well-defined homopolymers of guanidinium-functional PAms have not been systematically studied as gene delivery vectors, nor compared with other cationic moieties.…”

PEGylation of Guanidinium and Indole Bearing Poly(methacrylamide)s – Biocompatible Terpolymers for pDNA Delivery

“…[ 26 ] GPMA was utilized due to the excellent ability of the guanidinium group to interact with genetic material, while HPMA was selected as a spacer unit to ensure the colloidal stability of the polyplexes. [ 26,36–39 ] IEMA was included to allow hydrophobic interactions with pDNA and cell membranes, to improve the cellular uptake and the transfection efficiency of the polyplexes. [ 26,36 ]…”

“…[ 26,36–39 ] IEMA was included to allow hydrophobic interactions with pDNA and cell membranes, to improve the cellular uptake and the transfection efficiency of the polyplexes. [ 26,36 ]…”

“…For the synthesis of P(MEO 9 MA) macro‐RAFT agents, the same CTA (4‐Cyano‐4‐(phenylcarbonothioylthio)pentanoic acid) was used due to its proven suitability with the employed monomers. [ 40,41 ] Molecular weights from 3 to 40 kg mol –1 were targeted by changing the [M] 0 /[CTA] 0 ratios while keeping the [CTA] 0 /[INI] 0 ratio constant. The nomenclature of the P(MEO 9 MA)‐based macro‐RAFT agents was chosen according to the targeted molecular weight (Scheme S2 and Table S1, Supporting Information; Table 1).…”

Indole, Phenyl, and Phenol Groups: The Role of the Comonomer on Gene Delivery in Guanidinium Containing Methacrylamide Terpolymers

“…[17] Moreover, we revealed that the incorporation of indole comonomer mimicking the side chain of the amino acid tryptophan, leads to a 200-fold increase of the transgene expression in comparison to a copolymer with comparable guanidinium content. [18] To understand to what extent the origin of the hydrophobic residue influences the internalization, complexation of pDNA, and the ability of the polymers to act as gene carriers, we designed terpolymers that contain side chains mimicking hydrophobic residues found in the side chains of amino acids.…”