Gradient-Mixing LEGO Robots Developed by Bioengineers To Purify DNA Origami Nanostructures

A robot made of LEGO has found a helpful application in nanotechnology, particularly in purifying DNA origami.

What is DNA Origami?

DNA origami is the assembly technique of a single-stranded DNA template molecule being folded into target structures. It is a simplistic strategy of arranging complex nanostructures from scaffold strands (single-stranded DNA) and programmed staple strands (shorter oligonucleotides).

The design principle of DNA origami has proven to be an efficient approach to creating nanostructures with distinct shapes and geometry. Fabricating a nanoscale material's ideal shapes and features provides a powerful opportunity in nanotechnology. Since DNA has a concrete structure, it becomes very useful in fields such as microscopy, medicine, and electronics.

Efforts have been made trying to optimize the assembly of DNA origami. However, well-folded origami yields far less than 100%. Most of the applications of DNA origami need uncontaminated structures free of staple strands and misfolded origami. Because of this, a purification method is required to isolate well-defined structures.

ALSO READ: Study Finds That DNA Can Assemble Into Nanostructures

Utilizing LEGO Robot as Gradient Mixer

A research team of bioengineers from Arizona State University (ASU) transformed a LEGO robot into a gradient mixer to create DNA origami nanostructures. The experts started with a simple base and created a single-arm robot above it to make it possible. This arm holds and guides a platform where the tubes can be connected.

The conventional technique of purifying DNA origami nanostructure is usually done using rate-zone centrifugation. This process involves the use of a gradient mixer, a piece of machinery that is relatively expensive. The ASU research team has proven that building this kind of mixer can be made possible using off-the-shelf LEGO kits. In their innovation, the entire mixer, including the motors for placement and spinning, was made of LEGO parts except for the tube holder, which is made using a 3D printer.

To purify the DNA origami nanostructures, the gradient mixers work by spinning the materials inside cylindrical tubes, requiring a method to pour these ingredients into the tube. Because of this, the tubes must be positioned vertically. Caps are placed on top to avoid spilling materials, and then the tubes are moved horizontally before being spun. This way, the materials in the liquid are separated into a gradient.

In the commercial version, the robot arm spins the tubes to mix the contents once they are filled and capped slowly. Then the robot arm lowers the tubes in a vertical position where they will be spun rapidly.

Upon testing their device, the bioengineers found out that the LEGO robot can mix and separate the required materials as effectively as the commercial versions, although it offers the benefit of being less costly. The research team is confident that their LEGO robot cannot only be used as a gradient mixer in real life, but it also shows that it is possible to build expensive lab machines using a similar approach.