Copolymers of NVAm and NVP for Efficient Gene Delivery

Tom Fielitz; Christopher Raab; Vitalii Tkachenko; Kristine M Oleszkiewicz; Hendrik Fuchs; Matthias Hartlieb

doi:10.1021/acspolymersau.5c00167

Copolymers of NVAm and NVP for Efficient Gene Delivery

ACS Polym Au. 2026 Jan 16;6(1):426-436. doi: 10.1021/acspolymersau.5c00167. eCollection 2026 Feb 11.

Authors

Tom Fielitz¹, Christopher Raab^{2

3}, Vitalii Tkachenko¹, Kristine M Oleszkiewicz^{2

4}, Hendrik Fuchs², Matthias Hartlieb^{1

5}

Affiliations

¹ Institute of Chemistry, University of Potsdam, Karl-Liebknecht-Straße 24-25, Potsdam DE-14476, Germany.
² Institute of Diagnostic Laboratory Medicine, Clinical Chemistry and Pathobiochemistry, Charité - Universitätsmedizin Berlin, corporate member of Freie Universität Berlin and Humboldt-Universität zu Berlin, Augustenburger Platz 1, Berlin DE-13353, Germany.
³ Institute of Pharmacy, Freie Universität Berlin, Königin-Luise-Straße 2 and 4, Berlin DE-14195, Germany.
⁴ Institute of Chemistry and Biochemistry, Freie Universität Berlin, Arnimallee 20, Berlin DE-14195, Germany.
⁵ Fraunhofer Institute for Applied Polymer Research IAP, Geiselbergstraße 69, Potsdam 14476, Germany.

Abstract

Gene delivery lies at the heart of many approaches for treating a host of different diseases. Promising candidates for the delivery of genetic material are polycationic vectors; however, managing toxicity arising from adverse interactions with the lipid bilayer remains a challenge. In this work, photoiniferter reversible addition-fragmentation chain-transfer (PI-RAFT) polymerization was used to synthesize statistical copolymers of N-vinyl formamide (NVF) and N-vinyl pyrrolidone (NVP). Subsequent selective hydrolysis of NVF was used to introduce polyvinyl amine (PVAm) repeats. The resulting library of polymers with varying charge densities and molar masses was probed for biocompatibility with erythrocytes and MDA-MB-468 cells, revealing substantially reduced cytotoxicity compared with linear polyethylene imine (lPEI) and Lipofectamine 2000. Using an ethidium bromide (EtBr) replacement assay, PVAm copolymers were shown to replace EtBr at low N/P-ratios. The transfection conditions were optimized in terms of the N/P-ratio and polyplex concentration by a Renilla luciferase reporter assay. This revealed 30-fold less cytotoxicity, a much wider viable concentration range, and a 2-fold greater transfection efficiency for the PVAm copolymer compared to lPEI. This study provides insights into the PI-RAFT copolymerization of the less activated monomers NVF and NVP and highlights the potential of polyvinyl amine copolymers resulting from selective hydrolysis for the transfection of genetic material compared with lPEI.

Keywords: N-vinyl formamide; charge density control; gene delivery vectors; photoiniferter RAFT polymerization (PI-RAFT); polyamine; transfection optimization.