A Common Practice Takes a Nano-Scale Form

DNA Origami
DNA Origami
Image from Wikimedia Commons

As soon as the word “origami” is uttered, one’s mind immediately jumps to paper cranes and various like-structures that stem from the old Japanese tradition. This art of paper folding (origami directly translates to “paper folding”) began in the 1700’s and became popular worldwide by the mid 1900’s. Though origami has evolved over the past years to encompass many different shapes, a new macro-evolved aspect of it has emerged in the recent years. It ventures to a cellular realm where our influence has been previously assumed to be close to nonexistent. This new form is called DNA origami, and as one might guess, it is a manipulation of DNA strand(s) (the exact definition is as follows: the nanoscale folding of DNA to create arbitrary two and three-dimensional shapes at the nanoscale). Though said easily, it is a tedious process that, when mastered, still requires weeks in order to obtain the desired end result.

The process of DNA origami was first put into practice all the way back in the 1980’s. Scientists were able to construct sheets, tubes, and simple mechanisms such as tweezers all made out of small fragments of DNA made up of no more than 150 nucleotide base pairs long (and as we have learned in class, these must be very short strands of DNA). DNA was chosen as the perfect polymer due to it’s tangibility in how its nucleotides can be taken apart (spliced, like we learned in class) and reconstructed. In 2006, however, a new and improved form of DNA origami emerged from a man named Paul Rothemund. Rothemund understood the widespread application of being able to bend and alter longer DNA strands to fit any desired form, thus, he began work in the most high-tech laboratory he had access to at the time, his basement.

Rothemund realized that a single stranded piece of DNA would be the most suitable to use in his experiment, thus, he order DNA from the virus known as M13 which is a bacteriophage (we have learned in class that a can have either single or double stranded DNA, or single or double stranded RNA). The problem since the 1980’s with DNA origami is that the DNA was extremely difficult to maintain since it is constantly in motion and always changing form. Rothemund’s idea, however, was to use 16 nucleotide long sequences to “staple” the DNA strand down in various places by binding to it. The M13 viral DNA strand is roughly 7,000 nucleotides long, with the entire sequence of the genome known. This allowed Rothemund to figure where exactly in the sequence his staples would be placed, and how those staples would bend the DNA strand in order to fit his desired 2D model. He started his experiment with making sure that the staples would rush to the desired spot on his DNA that he put into a buffer to stabilize, he then heated and cooled his mixture that bound the staples to his DNA. The resulting shape was his desired 2D picture, a smiley face. Rothemund’s experiment was a success!

Today, Rothemund’s hard work has transformed modern science. With scientists now being able to alter long strands of DNA, there is a plethora of shapes to create that will aid in multiple areas of study (now in 3D as seen in the attached picture, not just 2D). Applications consist of shapes that act as boxes that will be used as delivery systems. A nanoscale ruler that can measure exactly 100 nanometers, to give you an idea of just how tiny that is, A nanometer is one billionth of a meter, and a human hair is easily 100,000 nanometers in diameter. This means that it would take 1,000 of these rulers to measure the diameter of a hair! Possibly the most exciting application is a large sheet of DNA that might have the effect of a negative refractive index. This will not only allow the creation for a super-powered microscope with a DNA lens, it would also allow the creation of a cloak of invisibility. Which for the Harry Potter fans out there is a huge deal, or anyone for that matter whom “solemnly swear that they are up to no good”. The applications for this newly emerging technique are endless, and we all have Paul Rothemund to thank, him and his high tech laboratory.

About Mr. Mohn

Biology Teacher

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