Using DNA to Control the Mechanical Response of Nanoparticle Superlattices

Abstract

Nanoparticle superlattice assembly has been proposed as an ideal means of programming material properties as a function of hierarchical organization of different building blocks. While many investigations have focused on electromagnetic, optical, and transport behaviors, nanoscale self-assembly via supramolecular interactions is also a potentially desirable method to program material mechanical behavior, as it allows the strength and three-dimensional organization of chemical bonds to be used as handles to manipulate how a material responds to external stress. DNA-grafted nanoparticles are a particularly promising building block for such hierarchically organized materials because of DNA's tunable and nucleobase sequencespecific complementary binding. Using nanoindentation, we show here that the programmability of oligonucleotide interactions allows the modulus of DNA-grafted nanoparticle superlattices to be easily tuned overly nearly 2 orders of magnitude. Additionally, we demonstrate that alterations to the supramolecular bond strength between particles can alter how a lattice deforms under applied mechanical force. As a result, the superlattices can be programmed either to reorganize their internal structures to dissipate mechanical energy or to completely recover their initial structure upon relaxation, independently of how the particles are arranged in 3D space. These behaviors are subsequently explained as a function of the hierarchical structure of the DNA-guided assemblies by using a simple truss-structure model. Altering the supramolecular DNA connections between particles therefore provides a simple and rational means of dictating different aspects of material mechanical response to produce tailorable properties that are not typically observed in conventional bulk materials. Ultimately, these studies enable control over the deformation behavior of future DNA-assembled nanomaterials and provide evidence that supramolecular chemistry is an effective tool in controlling the mechanical properties of nanomaterials as a function of their hierarchical design.

DNA-Grafted 3D Superlattice Self-Assembly

“…Elasticity and hardness reflected the mechanical performance, which depended on the surface ligand of superlattice. Macfarlane’s group used DNA-grafted superlattice assembly to investigate the material mechanical behavior [ 82 ]. Due to the tunability of DNA via specific nuclease pairing, the modulus of superlattice could be tuned nearly two orders of magnitude.…”

“…Surface stabilizer-mediated compositionally heterogeneous nanocrystal superlattice with catalytic property have been reported [ 83 , 84 ]. For instance, binary Pt-Pd superlattice Au/Fe 3 O 4 superlattice after postprocessing could catalyze the reduction of oxygen to water [ 82 ] and oxidation of carbon monoxide [ 84 ] at a faster rate than the homogeneous nanocrystal. Though the catalysis function of DNA-grafted superlatticehas not been employed to date, the catalytic application of DNA-grated superlattice will not be far.…”

Nanoparticle Assembly as a Materials Development Tool

“…Mechanical Properties of NPSLs. Because there are multiple methods and ligand interactions that can be used to govern their assembly, different NPSLs have been found to exhibit a wide range of mechanical properties depending on their composition and processing conditions: 130 Young's moduli can range from 100 kPa for hydrated PAE lattices, 131 to 100 MPa for dried hydrogen-bonded polymer-grafted nanoparticles, 65 to 64 GPa for dried NPSLs with cross-linked molecular ligands. 132 In general, however, the mechanical properties of most NPSLs to date have been determined to be comparable to that of glassy polymers, with Young's moduli between 1−10 GPa and hardness on the order of 100 MPa.…”

Photonic band structure calculation of 3D-finite nanostructured supercrystals

“…In recent years, DNA-linked 3D superlattices composed of metallic NPs have been investigated. 33,35,37,39,[42][43][44][45] In their pioneering work, Mirkin and Schatz have shown that such 3D supercrystals exhibit strong novel optical behaviours resulting from the coexistence of plasmonic and photonic modes. 28,35,46,47 By continuously varying the NPs orientation, periodicity, spacing, size, and shape, as well as the crystal habit, an enormous set of fundamentally interesting metamaterials can be designed.…”