Braun Group People
Margarety Shyr
Former Graduate Student in Materials Science and Engineering
B.S. Chemical Engineering MIT 2003
Many attractive features of biological self-assembly make it both a paradigm and an implement for the bottom-up assembly of new materials. Nucleic acids, DNA in particular, are easy to synthesize and chemically robust, making them a popular tool for micro-and nano-scale materials assembly. Hybridization and melting of DNA molecules is well characterized. Assembly of DNA via Watson-Crick pairing can be tuned by varying the sequence order, strand length, pH, salt concentration, and temperature. DNA can be modified with different functional groups for attachment to various inorganic and organic building blocks, such as: metal nanoparticles and surfaces; quantum dots; glass surfaces; and polymer colloids.
Polystyrene colloidal particles modified with DNA and assembled into various structures can be investigated using techniques, which have long been invaluable for the study of biological systems: optical, fluorescence, and confocal microscopy. By incorporating a combination of molecular and microscale self-assembly techniques, as well as the unique functionality of DNA, we demonstrate a simple and robust route towards DNA-patterned glass substrates, on which large 2D colloidal arrays can be assembled via sequence-specific hybridization. Laser diffraction as well as optical and fluorescence microscopy was used to monitor the quality of the arrays. In addition, these arrays could be disassembled and reassembled via thermal cycling, i.e. melting and rehybridization of DNA. Finally we demonstrate additional functionality of DNA-directed assembly by utilizing a Pb(II) sensitive DNAzyme sequence (collaboration with Prof. Yi Lu).
We hope to incorporate DNA functionalization and sequence-specific assembly as well as other unique biochemical features of DNA into self-assembly of three-dimensional micro-and nanoscale materials.