Use of Primary and Secondary Polyvinylamines for Efficient Gene Transfection

Abstract

Gene transfection with polymeric carrier remains a challenge; particularly, high transfection levels combined with low toxicity are hard to achieve. We herein revisit polyvinylamines, an old and neglected family of cationic polymers. They can be readily obtained by controlled hydrolysis of polyvinylamides prepared through (controlled) radical polymerization. A series of tailor-made and well-defined polyvinylamines bearing primary amino groups, and poly(N-methylvinylamine) bearing secondary amines, were evaluated for the transfection of cells with pDNA as a function of their molar mass, molar mass distribution, and degree of deacetylation. Unexpected high transfection levels, in combination with low cytotoxicity were recorded for both series. Surprisingly, a great impact of the molar mass was observed for the primary amine polyvinylamine series, whereas the results were mostly independent of molar mass or dispersity for the polymer bearing secondary amine. It was further established that a certain percentage of acetamide groups increased the transfection level, while maintaining low cytotoxicity. These results highlight for the first time the real potential of polyvinylamines as gene carriers, and make these polymers very attractive for further development in gene therapy.

Poly(N‐methylvinylamine)‐Based Copolymers for Improved Gene Transfection

“…In addition, it seems that copolymers of similar M n but significantly different molar mass distributions synthesized via different routes, i.e., FRP – P(M125‐N266)‐Fs – or OMRP – P(M90‐N240)‐Cs, does not have any significant influence on the transfection efficiency (Table , entries 5 and 8). This last observation is in line with our former work on PMVAm homopolymers, highlighting the poor influence of the molar mass and dispersity on the transfection efficiency in the studied range …”

“…For instance, the minimum required N/P ratios for PN255‐Cs‐plex, P(M114‐N114)‐Fh‐plex, and PM140‐Fh‐plex, exhibiting comparable degrees of acetylation, were, respectively 6, 5, and 4 (Table ). This difference can be explained by the difference of p K a , being 10.6 and 12.4 for PVAm and PMVAm, respectively . When the particle size and the zeta (ζ)‐potential of polyplexes were determined, it appeared that almost all polyplexes had a hydrodynamic diameter ranging from 100 to 300 nm, and they were positively charged with a ζ‐potential ranging from +30 to +55 mV (Table ).…”

“…We therefore evaluated also the transfection efficiency for P(MVAm‐ co ‐VAm) possessing different molar masses, i.e., DP n ranging from 120 to 550 (with a NMVA/NVA composition close to 50/50, and a comparable global degree of deacetylation close to 80%) (Figure S4, Supporting Information). As with the PMVAm homopolymers, no influence of the molar mass on the transfection efficiency (10 9 RLU mg −1 proteins is reached for all polymers) nor on the viability was observed for P(MVAm‐ co ‐VAm). Copolymers of the same chemical composition, possessing a similar degree of hydrolysis and synthesized by either FRP or OMRP can thus be considered as comparable in terms of transfection efficiency.…”

“…Good results have been obtained with polyamidoamine, poly(amino‐ester), histidinylated polylysine and peptides, chitosan, poly(2‐ N ‐dimethylaminoethyl)methacrylate, and polyethylenimine (PEI), which may exhibit a branched or linear architecture (lPEI), the latter being currently considered as the gold standard . lPEI exhibits high transfection efficiency but suffers from high cytotoxicity . Modifications of the lPEI backbone have been suggested to tackle this concern by grafting cyclodextrins, different pendant amines, alkyl chains, sugars or amino acids such as histidine .…”

“…In view of the great diversity of the polymers tested, it appeared interesting to reconsider polyvinylamines. Indeed, we reported that polymethylvinylamine (PMVAm)‐based pDNA polyplexes reached transfection efficiency in the same order as the gold standard lPEI, yet with improved cell viability (>60%) . PMVAms were readily obtained by free radical polymerization (FRP) of N ‐methylvinylacetamide (NMVA), followed by acidic hydrolysis of the amide groups .…”