Enzymatic disassembly of DNA-gold nanostructures

The process of cleavage of preassembled DNA-modified gold nanostructures using DNA-processing enzymes is described. The enzymatic reaction resulted in a redispersion of the aggregates to form a clear solution. Transmission electron microscopy (TEM) images showed that three-dimensional aggregations of particles were dispersed after reaction with EcoRI. It was found that the small two-dimensional aggregations present after the enzymatic cleavage may be due to weak association between the four-nucleotide cohesive ends generated on half of the resulting single particles. When DNA was recovered from particles after EcoRI treatment, this was replaced by a broad band of approximately 25 bp consistent with a mixture of the two cleaved DNAs. The efficiency of the process is dependent on the design of the linker system, with the more controllable assembly afforded by the three-strand linking system being much more effectively manipulated by a restriction enzyme.