DNA origami

As promised, today's topic will be DNA origami. Folding DNA into cool shapes.

I initially wanted to start with a very basic background information about DNA that would explain why DNA is very cool and unique, but I think for this post, I want to show the invention first.

 Figure 1. Shapes made of DNA origami. Adapted from [1]

These are tiny at around 100 nm in width. They are smaller than what your eyes can see and ethis is so small that you can't use typical light microscopes to see it. They used AFM which is an interesting device for visualizing topology (heights). Again, maybe a topic for another post.

All the folding patterns shown here are 2D but it could be expanded to make 3D shapes or containers. Even more interestingly, the box state (ex. open or closed) can be responsive to the environment. This is an amazing capability. Imagine if you can have these nanomachines in your body and it senses problems and unloads cargo (ex. medicine) in the appropriate location. You don't need to take medication when you feel sick. These can find out before you feel sick.

There has been some development focusing cancer treatment. One of the problems with cancer is that the cancer cells are a version of your own cell. Killing just cancer cells is very difficult with conventional drugs. What if these nanomachines can probe the entire body and find cancer cells and unload medicine only in that region. This idea of local drug delivery is a commonly used technique. Think about eye drops or eating Strepsils. The compounds in the eye drop mostly stay in the eye. For Strepsils, only your tongue/throat area is numb. This is due to local delivery. If the things in strepsils were applied to your arm, your arm would be numb.

These nanomachines can sense the presence of two biomarkers for cancer and unload medication in the area if both biomarkers are present. 

Figure 2. Nanorobot made of DNA. In pink are the cargo. Top left shows the geometry while closed. The blue and green boxes are highlighting the lock mechanisms.Adapted from [2].

This is conceptually very cool. Considering how there are mechanisms made of DNA that can act as logic gates, it is actually possible to make a more complex DNA based computer. At least in theory...for now. 

[1] Rothemund, P. W. K. Folding DNA to create nanoscale shapes and patterns. Nature 2006, 440, 297-302.

[2] Douglas, S. M.; Bachelet, I.; Church, G. M. A Logic-Gated Nanorobot for Targeted Transport of Molecular Payloads. Science 2012, 335, 831-834.