Computational Reverse-Engineering Analysis for Scattering Experiments on Amphiphilic Block Polymer Solutions

Abstract

In this paper, we present a computational reverse-engineering analysis for scattering experiments (CREASE) based on genetic algorithms and molecular simulation to analyze the structure within self-assembled amphiphilic polymer solutions. For a given input comprised of scattering intensity profiles and information about the amphiphilic polymers in solution, CREASE outputs the structure of the self-assembled micelles (e.g., core and corona diameters, aggregation number) as well as the conformations of the amphiphilic polymer chains in the micelle (e.g., blocks’ radii of gyration, chain radii of gyration, monomer concentration profiles). First, we demonstrate CREASE’s ability to reverse-engineer self-assembled nanostructures for scattering profiles obtained from molecular simulations (or in silico experiments) of generic coarse-grained bead–spring polymer chains in an implicit solvent. We then present CREASE’s outputs for scattering profiles obtained from small-angle neutron scattering (SANS) experiments of poly­(d-glucose carbonate) block copolymers in solution that exhibit assembly into spherical nanoparticles. The success of this method is demonstrated by its ability to replicate, quantitatively, the results from in silico experiments and by the agreement in micelle core and corona sizes obtained from microscopy of the in vitro solutions. The primary strength of CREASE is its ability to analyze scattering profiles without an off-the-shelf scattering model and the ability to provide chain and monomer level structural information that is otherwise difficult to obtain from scattering and microscopy alone.

Computational Reverse-Engineering Analysis of Scattering Experiments (CREASE) on Amphiphilic Block Polymer Solutions: Cylindrical and Fibrillar Assembly

“…In this study, we extend our previous work where we developed and applied CREASE to spherical micelles to fibrillar and cylindrical micelles with varying cross-sectional shapes ( e.g. , rectangular and elliptical) (Figure ).…”

“…The I exp ( q ) values generated from in silico experiments mimic realistic BCP solutions, whereas the I exp ( q ) values generated from the placement of scatterers in set dimensions serve as mathematical tests for CREASE. For studies where we have used CREASE on I exp ( q ) from real scattering experiments, we direct the reader to our recent publications. , …”

“…However, with the advances in synthesis and assembly/processing techniques, there are many novel polymer chemistries and architectures exhibiting previously unseen assembled states; the existing library of analytical models does not work well for these unconventional polymer chemistries and their assembled structures. This limitation was demonstrated in our recent work where the chosen polymer backbone chemistry and architecture did not fit the conventional Pedersen spherical micelle model and presented an opportunity for the development of computational reverse-engineering analysis for scattering experiments (CREASE) that side-steps this need for an analytical model that are mostly relevant for conventional polymers or assembly shapes.…”

Highly Ordered Pt-Based Nanoparticles Directed by the Self-Assembly of Block Copolymers for the Oxygen Reduction Reaction

“…Integrating with other metals to prepare Pt–M alloys is one feasible way to address these difficulties for the Pt-based catalysts. − Core–shell structure NPs with Pt as shells attract much attention for the low Pt loading and the promotion on ORR activity. − However, most of the core–shell NPs are prepared by solution-phase synthesis requiring complicated conditions. − The template- and scaffold-assisted fabrication of NP arrays through block copolymers (BCPs) interests researchers with the large-scale morphologies in controllable distributions, shapes, and sizes. − The microphase segregation of BCP blocks can compartmentalize the NPs into the interfaces between the different polymer chains or the microdomains of the polymers. − As a result, the BCP approach is capable of fabricating highly ordered metal NP arrays fulfilling the requirements for a variety of practical applications. − …”

Dual responsive PMEEECL–PAE block copolymers: a computational self-assembly and doxorubicin uptake study

“…These computational methods have been previously used to study block copolymer self-assembly providing good agreement with experimental results. [31][32][33][34] It is best suited to study macromolecular aggregates because the coarse-graining allows describing the system with less degrees of freedom, making the simulation much faster than all-atom MD. The encapsulation of DOX within PMEEECL 20 -PAE 5 spherical micelles at different DOX concentrations has been investigated by MARTINI CG force eld simulations.…”