Dissipative Particle Dynamics Simulations of a Protein-Directed Self-Assembly of Nanoparticles

Abstract

Design and fabrication of multifunctional porous structures play key roles in the development of high-performance energy storage devices. Our experiments demonstrated that nanostructured porous components, such as electrodes and interlayers, generated from the protein-directed self-assembly of nanoparticles can significantly improve the battery performances. The protein-directed assembly of nanoparticles in solution is a complex process involving the complicated interactions among proteins, particles, and solvent molecules. In this paper, we investigate the effects of coating proteins and specific solvent environments on the assembled porous structures. Comprehensive dissipative particle dynamics (DPD) simulations have been implemented to explore the molecular interactions and uncover the fundamental mechanisms in a gelatin-directed self-assembly of carbon black particles under different solvent conditions. Our simulations show that compact triple-strand “rod-like” structures are formed in water while loose curved “sheet-like” structures are formed in an acetic acid/water mixture. The structural difference is mainly due to the redistribution of the charges on the gelatin side chains under specific acid-solvent conditions. The strong and flexible “sheet-like” structures lead to a homogenous porous structure with high porosity and with large functionalized surfaces. Our simulations results can reasonably explain the experimental observations; this work demonstrates the great potential of DPD as a powerful tool in guiding future experimental design and optimization.

Protein‐Engineered Functional Materials for Bioelectronics

“…The generated porous structure was an advantage for electrode applications as illustrated in Figure 4c. Besides SP, the same research group [ 49b ] reported that gelatin protein also showed the capability to drive the self‐assembly of CB particles, leading to rational porous structures. Interestingly, it was found that the solvent influenced the self‐assembly process and more optimized porous structure could be obtained in acetic acid/deionized water (AA/DI) solvent (Figure 4d,e).…”

“…On the contrary, DI treated sample presented a severe coverage of protein on the CB surface (Figure 4f). The researchers [ 49 ] systematically investigated through comprehensive dissipative particle dynamics (DPD) simulations on the self‐assembly process. The solvent environments played key roles in the assembled structure because the solvent changed the distribution of charges on the gelatin side chains.…”

“…Dissipative particle dynamics (DPD) simulations of gelatin‐directed self‐assembly (Reproduced with permission. [ 49 ] Copyright 2019, American Chemical Society): DPD simulations of the self‐assembled structure of gelatin/CB in h) DI water and i) the AA/DI mixture solvents.…”

“…To this end, gelatin protein was used to generate porous separator coating with conductive fillers to trap polysulfides by Fu and coworkers. [ 49 ] Molecular dynamic simulations were performed to study the adsorption process of polysulfides onto gelatin in Figure a. It shows that the polysulfides were mostly adsorbed onto the protein surface by the oxygen atoms in the backbone and COO − end groups in the protein chains because of strong electrostatic interactions.…”

Parametrizing hydrogen bond interactions in dissipative particle dynamics simulations: The case of water, methanol and their binary mixtures

“…The calculation of the Flory-Huggins parameters from the individual bead solubilities causes quite a versatile parameterization of the coarse-grained DPD interactions. The DPD method has found an enormous area of application in modeling and simulation of complex soft matter [15] from polymers [16,17] to proteins [18,19]. Nevertheless, the DPD method has employed certain critical assumptions limiting the applicability of the method, one of which is that beads have comparable sizes.…”