First 3-D DNA-nanogold imaging promises more intricate delivery structures

DNA and nanogold structured into flexible strands
(Berkeley Lab)

The proteins that comprise DNA can be used to create complex structures for drug delivery and other applications because of their flexibility and ability to be shaped. And researchers at UC's Berkeley Lab have captured high-resolution 3-D images of DNA strands attached on either end to gold nanoparticles, a compound that can be used to create functional molecules with many uses.

The scientists used individual-particle electron tomography (IPET) that they developed to take two-dimensional pictures of the same objects from many different angles to compile three dimensions and examine the objects in real space. They have used it before to capture detailed images of human proteins, but this is the first time researchers have visualized an individual double-stranded DNA segment in 3-D.

They published their results in the journal Nature Communications.

The team examined frozen DNA-nanogold samples with cryo-electron microscopy and then applied the IPET to produce the images. This process preserved the shape of the DNA, which wouldn't be possible using normal X-ray visualization, according to a Berkeley report.

Down the road, this type of imaging could be used to create and test DNA-based treatments and delivery techniques. One method that has gained steam in the research sector is called DNA origami, which, as its name suggests, involves the folding of DNA strands to develop more complex structures, including delivery vehicles.

"DNA is easy to program, synthesize and replicate, so it can be used as a special material to quickly self-assemble into nanostructures and to guide the operation of molecular-scale devices," research leader Gang "Gary" Ren said in a statement. "Our current study is just a proof of concept for imaging these kinds of molecular devices' structures."

- here's the Berkeley release
- and here's the study abstract