Chavez and Srinivasan Team Up to Make New Materials Using DNA

Chavez and Srinivasan Team Up to Make New Materials Using DNA

CBR member Ferman Chavez, of the Department of Chemistry, and Distinguished Professor Gopal Srinivasan, of the Department of Physics, have teamed up to use DNA to produce new materials with unique electric and magnetic properties. Their research was reported recently in the journal AIP Advances (Volume 6, Article Number 045202, 2016), published by the American Institute of Physics. The lead author on the paper, titled “Self-Assembly of Multiferroic Core-Shell Particulate Nanocomposites Through DNA-DNA Hybridization and Magnetic Field Directed Assembly of Superstructures,” is Gollapudi Sreenivasulu, a Research Associate working with Srinivasan. Other coauthors are Manashi Panda, a long-time collaborator with Chavez, and Thomas Lochbiler, a physics major who graduated in April 2015. The abstract to the paper is given below.

Multiferroic composites of ferromagnetic and ferroelectric phases are of importance for studies on mechanical strain mediated coupling between the magnetic and electric subsystems. This work is on DNA-assisted self-assembly of superstructures of such composites with nanometer periodicity. The synthesis involved oligomeric DNA-functionalized ferroelectric and ferromagnetic nanoparticles, 600 nm BaTiO3 (BTO) and 200 nm NiFe2 O4 (NFO), respectively. Mixing BTO and NFO particles, possessing complementary DNA sequences, resulted in the formation of ordered core-shell heteronanocomposites held together by DNA hybridization. The composites were imaged by scanning electron microscopy and scanning microwave microscopy. The presence of heteroassemblies along with core-shell architecture is clearly observed. The reversible nature of the DNA hybridization allows for restructuring the composites into mm-long linear chains and 2D-arrays in the presence of a static magnetic field and ring-like structures in a rotating-magnetic field. Strong magneto-electric (ME) coupling in as-assembled composites is evident from static magnetic field H induced polarization and low-frequency magnetoelectric voltage coefficient measurements. Upon annealing the nanocomposites at high temperatures, evidence for the formation of bulk composites with excellent cross-coupling between the electric and magnetic subsystems is obtained by H-induced polarization and low-frequency ME voltage coefficient. The ME coupling strength in the self-assembled composites is measured to be much stronger than in bulk composites with randomly distributed NFO and BTO prepared by direct mixing and sintering.



The interdisciplinary research was supported by grants from the Army Research Office and the National Science Foundation.