title: ROMP- and RAFT-Based Guanidinium-Containing Polymers as Scaffolds for Protein Mimic Synthesis.
abstract: Cell-penetrating peptides are an important class of molecules with promising applications in bioactive cargo delivery. A diverse series of guanidinium-containing polymeric cell-penetrating peptide mimics (CPPMs) with varying backbone chemistries was synthesized and assessed for delivery of both GFP and fluorescently tagged siRNA. Specifically, we examined CPPMs based on norbornene, methacrylate, and styrene backbones to determine how backbone structure impacted internalization of these two cargoes. Either charge content or degree of polymerization was held constant at 20, with diguanidinium norbornene molecules being polymerized to both 10 and 20 repeat units. Generally, homopolymer CPPMs delivered low amounts of siRNA into Jurkat T cells, with no apparent backbone dependence; however, by adding a short hydrophobic methyl methacrylate block to the guanidinium-rich methacrylate polymer, siRNA delivery to nearly the entire cell population was achieved. Protein internalization yielded similar results for most of the CPPMs, though the block polymer was unable to deliver proteins. In contrast, the styrene-based CPPM yielded the highest internalization for GFP (≈40 % of cells affected), showing that indeed backbone chemistry impacts protein delivery, specifically through the incorporation of an aromatic group. These results demonstrate that an understanding of how polymer structure affects cargo-dependent internalization is critical to designing new, more effective CPPMs.
authors.affiliation: Department of Polymer Science and Engineering, University of Massachusetts Amherst, Amherst, MA, 01003, USA.
authors.forename: Joel M
authors.initials: JM
authors.lastname: Sarapas
authors.affiliation: Department of Polymer Science and Engineering, University of Massachusetts Amherst, Amherst, MA, 01003, USA.
authors.forename: Coralie M
authors.initials: CM
authors.lastname: Backlund
authors.affiliation: Department of Polymer Science and Engineering, University of Massachusetts Amherst, Amherst, MA, 01003, USA.
authors.forename: Brittany M
authors.initials: BM
authors.lastname: deRonde
authors.affiliation: Department of Molecular and Cellular Biology, Department of Veterinary and Animal Sciences, University of Massachusetts Amherst, Amherst, MA, 01003, USA.|Department of Veterinary and Animal Sciences, Department of Molecular and Cellular Biology, University of Massachusetts Amherst, Amherst, MA, 01003, USA.
authors.forename: Lisa M
authors.initials: LM
authors.lastname: Minter
authors.affiliation: Department of Polymer Science and Engineering, University of Massachusetts Amherst, Amherst, MA, 01003, USA.|Department of Molecular and Cellular Biology, Department of Veterinary and Animal Sciences, University of Massachusetts Amherst, Amherst, MA, 01003, USA.|Department of Veterinary and Animal Sciences, Department of Molecular and Cellular Biology, University of Massachusetts Amherst, Amherst, MA, 01003, USA.
authors.forename: Gregory N
authors.identifier: http://orcid.org/0000-0003-3277-7925
authors.initials: GN
authors.lastname: Tew
mesh_terms: D001672:Biocompatible Materials / Q000138:chemical synthesis* / Q000737:chemistry; D057846:Cell-Penetrating Peptides / Q000737:chemistry; D005434:Flow Cytometry; D049452:Green Fluorescent Proteins / Q000737:chemistry / Q000378:metabolism; D019791:Guanidine / Q000737:chemistry*; D006801:Humans; D057927:Hydrophobic and Hydrophilic Interactions; D019169:Jurkat Cells; D020366:Methylmethacrylate / Q000737:chemistry; D009636:Norbornanes / Q000737:chemistry; D011108:Polymers / Q000737:chemistry*; D034741:RNA, Small Interfering / Q000737:chemistry / Q000378:metabolism; D014162:Transfection / Q000379:methods
chemical_list: D001672:Biocompatible Materials; D057846:Cell-Penetrating Peptides; D009636:Norbornanes; D011108:Polymers; D034741:RNA, Small Interfering; D049452:Green Fluorescent Proteins; D020366:Methylmethacrylate; C046060:2-norbornene; D019791:Guanidine
keywords: biomimicry; cell-penetrating peptide mimics; controlled polymerization; protein delivery; siRNA