title: Dispersing Zwitterions into Comb Polymers for Nonviral Transfection: Experiments and Molecular Simulation.
abstract: Polymer-based gene delivery vehicles benefit from the presence of hydrophilic groups that mitigate the inherent toxicity of polycations and that provide tunable polymer-DNA binding strength and stable complexes (polyplexes). However, hydrophilic groups screen charge, and as such can reduce cell uptake and transfection efficiency. We report the effect of embedding zwitterionic sulfobetaine (SB) groups in cationic comb polymers, using a combination of experiments and molecular simulations. Ring-opening metathesis polymerization (ROMP) produced comb polymers with tetralysine (K4) and SB pendent groups. Dynamic light scattering, zeta potential measurements, and fluorescence-based experiments, together with coarse-grained molecular dynamics simulations, described the effect of SB groups on the size, shape, surface charge, composition, and DNA binding strength of polyplexes formed using these comb polymers. Experiments and simulations showed that increasing SB composition in the comb polymers decreased polymer-DNA binding strength, while simulations indicated that the SB groups distributed throughout the polyplex. This allows polyplexes to maintain a positive surface charge and provide high levels of gene expression in live cells. Notably, comb polymers with nearly 50 mol % SB form polyplexes that exhibit positive surface charge similarly as polyplexes formed from purely cationic comb polymers, indicating the ability to introduce an appreciable amount of SB functionality without screening surface charge. This integrated simulation-experimental study demonstrates the effectiveness of incorporating zwitterions in polyplexes, while guiding the design of new and effective gene delivery vectors.
authors.affiliation: Department of Chemical and Biomolecular Engineering, University of Delaware , 150 Academy Street, Newark, Delaware 19716 United States.
authors.forename: Ahmadreza F
authors.initials: AF
authors.lastname: Ghobadi
authors.affiliation: Department of Polymer Science and Engineering, University of Massachusetts , 120 Governors Drive, Amherst, Massachusetts 01003, United States.
authors.forename: Rachel
authors.initials: R
authors.lastname: Letteri
authors.affiliation: Department of Polymer Science and Engineering, University of Massachusetts , 120 Governors Drive, Amherst, Massachusetts 01003, United States.
authors.forename: Sangram S
authors.initials: SS
authors.lastname: Parelkar
authors.affiliation: Quantum Beam Science Center, Japan Atomic Energy Agency , Tokai, Ibaraki 319-1195, Japan.
authors.forename: Yue
authors.initials: Y
authors.lastname: Zhao
authors.affiliation: Institut Charles Sadron UPR22-CNRS, 23 rue du Loess, 67034 Strasbourg, France.
authors.forename: Delphine
authors.initials: D
authors.lastname: Chan-Seng
authors.affiliation: Department of Polymer Science and Engineering, University of Massachusetts , 120 Governors Drive, Amherst, Massachusetts 01003, United States.
authors.forename: Todd
authors.initials: T
authors.lastname: Emrick
authors.affiliation: Department of Chemical and Biomolecular Engineering, University of Delaware , 150 Academy Street, Newark, Delaware 19716 United States.|Department of Materials Science and Engineering, University of Delaware , 201 DuPont Hall, Newark, Delaware 19716 United States.
authors.forename: Arthi
authors.initials: A
authors.lastname: Jayaraman
mesh_terms: D045744:Cell Line, Tumor; D034242:Cyclooctanes / Q000737:chemistry*; D004247:DNA / Q000737:chemistry; D015316:Genetic Therapy; D006801:Humans; D056004:Molecular Dynamics Simulation; D011108:Polymers / Q000737:chemistry; D014162:Transfection
chemical_list: D034242:Cyclooctanes; D011108:Polymers; D004247:DNA