Simulation guided design of globular single-chain nanoparticles by tuning the solvent quality

Abstract

The control of primary and further structures of individual folded/collapsed synthetic polymers has received significant attention in recent years. However, the synthesis of single-chain nanoparticles (SCNPs) showing a compact, globular conformation in solution has turned out so far to be highly elusive. By means of simulations, we propose two methods for obtaining globular SCNPs in solution. The first synthesis route is performed in the bad solvent, with the precursor anchored to a surface. In the second route we use a random copolymer precursor with unreactive solvophilic and reactive solvophobic units, which form a single core-shell structure. Both protocols prevent intermolecular cross-linking. After recovering good solvent conditions, the swollen nanoparticles maintain their globular character. The proposed methods are experimentally realizable and do not require specific sequence control of the precursors. Our results pave the way for the synthesis via solvent-assisted design of a new generation of globular soft nanoparticles mimicking global conformations of native proteins in solution.

Tunable slow dynamics in a new class of soft colloids

“…It is worth noting that, even by starting from the same precursors (same molecular weight and fraction of reactive groups), the topologies of the obtained SCNPs are intrinsically polydisperse. Still, the former routes lead to much narrower distributions in size and shape than those obtained by performing the synthesis in good solvent 13 . Recently, we have introduced a new route in good solvent, where formation of long loops is promoted by using long multifunctional cross-linkers.…”

“…13 , which are designed to prevent intermolecular aggregation, i.e., cross-linking is purely intramolecular by construction. Briefly, in the synthesis of the P72-SCNPs, cross-linking is performed in bad solvent, with the precursors anchored to a surface.…”

“…We use a bead-spring model 13,17 to simulate the SCNPs. We consider two different types of SCNPs, denoted as P30 and P72.…”

“…These experimentally accessible protocols 14,15 , described in detail in Ref. 13 , prevent interparticle aggregation and do not require specific sequence control of the precursors. In all cases, after completing the cross-linking and restoring good solvent conditions, the swollen SCNPs are globular objects.…”

“…To bypass the intrinsic limitations of the synthesis in good solvent, and to obtain globular SCNPs, we have recently designed solvent-assisted syn- 13 that promote bonding over long contour distances. These experimentally accessible protocols 14,15 , described in detail in Ref.…”