The structure and morphology of single-component oligomeric RNA delivery vectors derived from amphiphilic Charge-Altering Releasable Transporters

Published

November 6, 2025

Author(s)

Paul Hurst, Yuan Jia, Summer Ramsay-Burrough, Rebecca McClellan, Joshua Arens, Samuel Khasnavis, Trevor del Castillo, Mahmoud AbdElwakil, Michael Lueckheide, Vivek Prabhu, Robert Waymouth

Abstract

Recent advances in nucleic acid delivery have been inspired by efforts to mimic the function of natural viruses through the development of self-assemblies capable of transporting oligonucleotides across the cell and endosomal membranes. Lipid nanoparticles have emerged as a leading RNA delivery system with demonstrated application in vaccination and immunotherapies. The development of LNPs has been accompanied by structural and morphological studies which provide insights into the physicochemical factors governing their self-assembly. These insights have established some principles for developing more effective gene-delivery agents. Conversely, the structural and morphological factors of cationic polymer-based gene delivery systems are less understood. Here, we report the structure and morphology of cationic polymer nucleic acid complexes composed of charge altering releasable transporter (CARTs) based block copolymers and mRNA or siRNA. Cryogenic electron microscopy and small-angle neutron and X-ray scattering reveal that CART/RNA complexes form nanoparticles with a disordered bicontinuous worm-like internal morphology. Variation in the chemical structure of the lipophilic and cationic blocks influences the morphology of the CART/RNA nanoparticles. Oligomeric CARTs are unable to form well-defined nanoparticles with a bicontinuous morphology in the absence of nucleic acid. Our data also suggest that this bicontinuous morphology cannot be obtained in higher molar mass CART-based complexes. This study paves the way for future studies with the goal of understanding the structure property relationships of CART/RNA nanoparticles.

Citation

ACS Nano

Volume

19

Pub Type

Journals

Download Paper

https://doi.org/10.1021/acsnano.5c07147

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Keywords

polyelectrolyte complexation, small angle neutron scattering, small angle x-ray scattering, mRNA delivery, crygenic transmission electron microscopy

Citation

Hurst, P. , Jia, Y. , Ramsay-Burrough, S. , McClellan, R. , Arens, J. , Khasnavis, S. , del Castillo, T. , AbdElwakil, M. , Lueckheide, M. , Prabhu, V. and Waymouth, R. (2025), The structure and morphology of single-component oligomeric RNA delivery vectors derived from amphiphilic Charge-Altering Releasable Transporters, ACS Nano, [online], https://doi.org/10.1021/acsnano.5c07147, https://tsapps.nist.gov/publication/get_pdf.cfm?pub_id=959876 (Accessed November 25, 2025)