Single- and multi-component chiral supraparticles as modular enantioselective catalysts

Si Li,Nicholas A Kotov,Hendrik Heinz,Juan Liu,Liguang Xu,Chuanlai Xu,Naomi S Ramesar

doi:10.1038/s41467-019-12134-4

Abstract

Nanoscale biological assemblies exemplified by exosomes, endosomes and capsids, play crucial roles in all living systems. Supraparticles (SP) from inorganic nanoparticles (NPs) replicate structural characteristics of these bioassemblies, but it is unknown whether they can mimic their biochemical functions. Here, we show that chiral ZnS NPs self-assemble into 70–100 nm SPs that display sub-nanoscale porosity associated with interstitial spaces between constituent NPs. Similarly to photosynthetic bacterial organelles, these SPs can serve as photocatalysts, enantioselectively converting L- or D-tyrosine (Tyr) into dityrosine (diTyr). Experimental data and molecular dynamic simulations indicate that the chiral bias of the photocatalytic reaction is associated with the chiral environment of interstitial spaces and preferential partitioning of enantiomers into SPs, which can be further enhanced by co-assembling ZnS with Au NPs. Besides replicating a specific function of biological nanoassemblies, these findings establish a path to enantioselective oxidative coupling of phenols for biomedical and other needs.

Highlights

Nanoscale biological assemblies exemplified by exosomes, endosomes and capsids, play crucial roles in all living systems
Since inorganic nanoparticles (NPs) have essentially the same ability to spontaneously assemble into complex superstructures[20], it is possible to recreate some of these assemblies and functions from inorganic components that are robust and inexpensive, which is explored in this study
The interstitial spaces between NPs in these nanospheroids are subnanometer in width and are comparable to the dimensions of small molecules serving as catalytic substrates

Summary

Introduction

Nanoscale biological assemblies exemplified by exosomes, endosomes and capsids, play crucial roles in all living systems. Nanoscale biological assemblies are composed of a diverse spectrum of (bio)organic components, which are common in all living systems[1,2] They have characteristic dimensions ranging from 50 to 500 nm and are exemplified by viral capsids[3], endosomes[4], exosomes, carboxysomes[5], azurophilic granules[6], light-harvesting bacterial organelles[7], cellular vesicles[8], intraluminal vesicles, stress granules[9], and a wide spectrum of intracellular membraneless compartments. Several recent studies on NPs as heterogeneous chiral catalysts have demonstrated their synthetic simplicity and catalytic activity[31,32,33,34]

Methods

Results

Conclusion