Biotemplated semiconductor nanocrystals. The worlds of biology and semiconductor engineering have traditionally been quite distinct. The spontaneous assembly of biological materials presents a stark contrast to the rational fabrication required for high performance semiconductors. The merger of these diverse materials represents a tremendous opportunity, given that biomolecules can organize into intricate, functionally sophisticated structures – exactly the sort of precise, elegant control urgently needed to make the next generation of materials for computing, communications, energy, and the environment. Thus, we are working towards using biomolecular templates – particularly nucleic-acids based scaffolds for the synthesis of semiconductor nanocrystals. We have demonstrated that rational programming of the size and luminescence spectra of colloidal quantum dot nanocrystals is possible through the choice of nucleotide ligands responsible for nanoparticle nucleation, growth, stabilization, and passivation. Moreover, we have shown that nucleic acid conformation can be used to modulate structures of nanocrystals. Recently, we demonstrated that tRNAs can be used as a scaffold and ligand system for CdS nanocrystals. The results obtained thus far point the way to programmable synthesis of nanoparticles using precisely-controlled polynucleotide sequences.
RNA and DNA -templated quantum dots

Representative publications
“One-step Synthesis of DNA-Programmed Semiconductor Nanocrystals.” Nature Nanotechnology, 2008, in press.
"Biotemplated Nanaostructures: Directed Assembly of Electronic and Optical Materials using Nanoscale Complementarity." N. Ma, E.H. Sargent, S.O. Kelley, J. Mat. Chem., 2008, 18, 954.
"DNA-Passivated CdS Nanocrystals: Luminescence, Bioimaging, and Toxicity Profiles." N. Ma, J. Yang, K.M. Stewart, S.O. Kelley, Langmuir, 2007, 23, 12783.
"RNA-Templated Semiconductor Nanocrystals" N. Ma, C.J. Dooley, and S.O. Kelley*, J. Am. Chem. Soc., 2006, 128, 12598.
"Programming Nanoparticle Growth using Nucleic Acid Ligands" S. Hinds, B.J. Taft, L. Levina, V. Sukhovatkin, M.D. Roy, C.J. Dooley, M.D. Roy, E.H. Sargent*, S.O. Kelley*, J. Am. Chem. Soc., 2006, 128, 64.
Additional projects currently underway in the Kelley group: