The Importance of Salt-Enhanced Electrostatic Repulsion in Colloidal Crystal Engineering with DNA

Journal Article · Tue Jan 08 00:00:00 EST 2019 · ACS Central Science

DOI:https://doi.org/10.1021/acscentsci.8b00826· OSTI ID:1490106

Seo, Soyoung E. ; Girard, Martin; de la Cruz, Monica Olvera; Mirkin, Chad A.

Realizing functional colloidal single crystals requires precise control over nanoparticles in three dimensions across multiple size regimes. In this regard, colloidal crystallization with programmable atom equivalents (PAEs) composed of DNA-modified nanoparticles allows one to program in a sequence-specific manner crystal symmetry, lattice parameter, and, in certain cases, crystal habit. Here, we explore how salt and the electrostatic properties of DNA regulate the attachment kinetics between PAEs. Counterintuitively, simulations and theory show that at high salt concentrations (1 M NaCl), the energy barrier for crystal growth increases by over an order of magnitude compared to low concentration (0.3 M), resulting in a transition from interface-limited to diffusion-limited crystal growth at larger crystal sizes. Remarkably, at elevated salt concentrations, well-formed rhombic dodecahedron-shaped microcrystals up to 21 μm in size grow, whereas at low salt concentration, the crystal size typically does not exceed 2 μm. Simulations show an increased barrier to hybridization between complementary PAEs at elevated salt concentrations. Therefore, although one might intuitively conclude that higher salt concentration would lead to less electrostatic repulsion and faster PAE-to-PAE hybridization kinetics, the opposite is the case, especially at larger inter-PAE distances. These observations provide important insight into how solution ionic strength can be used to control the attachment kinetics of nanoparticles coated with charged polymeric materials in general and DNA in particular.

• Research Organization: Energy Frontier Research Centers (EFRC) (United States). Center for Bio-Inspired Energy Science (CBES); Northwestern Univ., Evanston, IL (United States)
• Sponsoring Organization: USDOE Office of Science (SC), Basic Energy Sciences (BES)
• Grant/Contract Number: AC02-06CH11357; SC0000989
• OSTI ID: 1490106
• Alternate ID(s): OSTI ID: 1494055; OSTI ID: 1508768
• Journal Information: ACS Central Science, Journal Name: ACS Central Science Vol. 5 Journal Issue: 1; ISSN 2374-7943
• Publisher: American Chemical Society
• Country of Publication: United States
• Language: English

Related Subjects

36 MATERIALS SCIENCE
37 INORGANIC, ORGANIC, PHYSICAL, AND ANALYTICAL CHEMISTRY