Combinatorial synthesis of chemically diverse core-shell nanoparticles for intracellular delivery

TLDR

The ability to tune the chemical nature of the core and shell may afford utility of these materials in additional applications. We used a modular, high‑throughput assembly‑line approach, combining robotic automation to cross‑link epoxide‑functionalized block polymers with diverse amines and then measuring size, weight, RNA complexation, cellular uptake, and in‑vitro siRNA/pDNA delivery across 1,536 nanoparticles. The study revealed structure‑function relationships and design guidelines, such as a higher reactive block weight fraction, stoichiometric epoxide‑amine equivalence, thin hydrophilic shells, optimal tertiary dimethylamine or piperazine cross‑linkers, and that covalent cholesterol attachment enabled in‑vivo liver hepatocyte transfection.

Abstract

Analogous to an assembly line, we employed a modular design for the high-throughput study of 1,536 structurally distinct nanoparticles with cationic cores and variable shells. This enabled elucidation of complexation, internalization, and delivery trends that could only be learned through evaluation of a large library. Using robotic automation, epoxide-functionalized block polymers were combinatorially cross-linked with a diverse library of amines, followed by measurement of molecular weight, diameter, RNA complexation, cellular internalization, and in vitro siRNA and pDNA delivery. Analysis revealed structure-function relationships and beneficial design guidelines, including a higher reactive block weight fraction, stoichiometric equivalence between epoxides and amines, and thin hydrophilic shells. Cross-linkers optimally possessed tertiary dimethylamine or piperazine groups and potential buffering capacity. Covalent cholesterol attachment allowed for transfection in vivo to liver hepatocytes in mice. The ability to tune the chemical nature of the core and shell may afford utility of these materials in additional applications.