Molecular Bottlebrushes for Immunostimulatory CpG ODN Delivery: Relationship among Cation Density, Complex Formation Ability, and Cytotoxicity

Abstract

Artificially designed short single-stranded DNA sequences containing unmethylated CG (CpG ODNs) are agonists for toll-like receptor 9 (TLR9); thus, they have great potential as vaccine adjuvants for cancer immunotherapy and preventing infectious diseases. To deliver effectively CpG ODNs into cells bearing TLR9, nanoparticle polyion complexes of cationic polymers that are able to ingest multiple CpG ODN molecules have been developed; however, their structures and synthesized polycations are hard to control and bioincompatible, respectively. To solve these issues, we designed cationic molecular bottlebrushes (CMBs) with branches that are made from copolymers of 2-methacryloyloxyethyl phosphorylcholine and 2-methacryloyloxyethyl trimethylammonium chloride. Several instrumental methods were carried out to determine the structure of a CMB and its complex with CpG ODNs. The complexation did not change the overall shape of the original CMB, and the bound CpG ODNs were captured by the outer layer of the CMB. The moderation of cations was important to reduce toxicity and improve secretion of inflammatory cytokines.

Nanogels designed for cell-free nucleic acid sequestration

“…Since the surface charge density, σ c , of cNGs is the key parameter for electrostatically driven binding events, 16,54 we quantified this characteristic from the dimensions and ζ-potential values of different cNGs 55 (see details in ESI †) and examined its effect on the binding constant K a of cfDNA to cNGs with varying σ c values. In the 150 mM PBS buffer, the K a value increased from 1.99 × 10 5 to 4.13 × 10 5 M −1 when σ c increased from 2.9 to 15.8 mC m −2 , respectively (Fig.…”

Erythrocyte membrane-camouflaged DNA-functionalized upconversion nanoparticles for tumor-targeted chemotherapy and immunotherapy

“…However, it has been reported that ICD cannot generate a sufficient antitumor immune response because of the ITM. 14,15 Cytosine-phosphate-guanosine oligonucleotides (CpG ODNs), 16 as toll-like receptor 9 (TLR9) agonists of DCs, can trigger strong immunostimulatory activity via MyD88-dependent NF-κB and MAPK signaling and subsequently promote the release of proinflammatory cytokines such as interleukin 6 (IL-6), IL-12, and tumor necrosis factor-α (TNF-α), ultimately inducing a Th1-like innate immune response and adaptive immunity. 17,18 The antigens generated by ICD can be efficiently delivered to APCs with the aid of the immunoadjuvant CpG.…”

Activation of Upper Critical Solution Temperature Behaviors of Zwitterionic Poly(l-methionine-g-poly(sulfobetaine methacrylate)m) with a Bottlebrush Structure

“…Spacer segments have been introduced between initiating groups to decrease the reactivity of zwitterionic monomers. , Additionally, bottlebrush zwitterionic polymers with a multiblock structure have been synthesized to explore the effect of intermolecular interactions on their formation. ,, The spatial shape of bottlebrush macromolecules in solution can be explained by Pedersen’s model . By modifying the types and proportions of the copolymerization monomers, zwitterionic bottlebrush polymers with different performances can be obtained. − ,,,− …”