Abstract
Under an applied magnetic field, superparamagnetic Fe3O4 nanoparticles with complementary DNA strands assemble into crystalline, pseudo-1D elongated superlattice structures. The assembly process is driven through a combination of DNA hybridization and particle dipolar coupling, a property dependent on particle composition, size, and interparticle distance. The DNA controls interparticle distance and crystal symmetry, while the magnetic field leads to anisotropic crystal growth. Increasing the dipole interaction between particles by increasing particle size or external field strength leads to a preference for a particular crystal morphology (e.g., rhombic dodecahedra, stacked clusters, and smooth rods). Molecular dynamics simulations show that an understanding of both DNA hybridization energetic and magnetic interactions is required to predict the resulting crystal morphology. Taken together, the data show that applied magnetic fields with magnetic nanoparticles can be deliberately used to access nanostructures beyond what is possible with DNA hybridization alone.
| Original language | English (US) |
|---|---|
| Article number | 1906626 |
| Journal | Advanced Materials |
| Volume | 32 |
| Issue number | 4 |
| DOIs | |
| State | Published - Jan 1 2020 |
Funding
S.S.P. and Z.J.U. contributed equally to this work. This material was based upon work supported by the following awards: Air Force Office of Scientific Research award FA9550-17-1-0348 (oligonucleotide synthesis and purification and DNA-functionalization of Fe3O4 nanoparticles), and the Center for Bio-Inspired Energy Science, an Energy Frontier Research Center funded by the U.S. Department of Energy, Office of Science, Basic Energy Sciences award DE-SC0000989 (colloidal crystal assembly under magnetic field and theory and simulation). SAXS studies were performed at the DuPont-Northwestern-Dow Collaborative Access Team (DND-CAT) located at Sector 5 of the Advanced Photon Source (APS). DND-CAT is supported by Northwestern University, the Dow Chemical Company, and DuPont de Nemours, Inc. This research used resources of the APS, a U.S. Department of Energy (DOE) Office of Science User Facility operated for the DOE Office of Science by Argonne National Laboratory under Contract No. DE-AC02-06CH11357. Z.J.U. gratefully acknowledges support from the National Defense Science and Engineering Graduate Fellowship. Electron microscope imaging work was supported by the Air Force Research Laboratory grant FA8650-15-2-5518. The U.S. Government is authorized to reproduce and distribute reprints for governmental purposes notwithstanding any copyright notation thereon. The views and conclusions contained herein are those of the authors and should not be interpreted as necessarily representing the official policies or endorsements, either expressed or implied, of the Air Force Research Laboratory or the U.S. Government. K.A.P. acknowledges the National Science Foundation Graduate Research Fellowship Program. This work made use of the Materials Characterization Facility in the Materials and Manufacturing Directorate at the Air Force Research Lab, Dayton, OH, and the Electron Probe Instrumentation Center and BioCryo facilities of Northwestern University's NUANCE Center, which has received support from the Soft and Hybrid Nanotechnology Experimental (SHyNE) Resource (NSF ECCS-1542205); the Northwestern University Materials Research Science and Engineering Center (NU-MRSEC) (NSF DMR-1720139); the International Institute for Nanotechnology (IIN); the Keck Foundation; and the State of Illinois, through the IIN. The authors thank J. Bussan for magnetic stage setup, Dr. J. E. Rix and Dr. S. Weigand for in situ magnetic stage setup, and Prof. D. E. Freedman for helpful discussions.
Keywords
- colloidal crystals
- high-aspect ratio crystals
- iron oxide nanoparticles
- magnetic nanoparticles
- nanoparticle superlattices
ASJC Scopus subject areas
- Mechanics of Materials
- Mechanical Engineering
- General Materials Science