A group of researchers at the Massachusetts Institute of Technology (MIT) has devised a method to shrink objects to nanoscale, smaller than what is visible under a microscope, using a laser. It can also be used to pattern the objects with a range of useful materials such as metals, DNA, and quantum dots.
MIT’s cutting-edge technology called ‘Implosion Fabrication’ could be applied to a variety of tasks from making cell phone lenses and small microscopes to developing small robots that enhance everyday life. Further, it requires materials that most engineering and biology labs already have, mainly a laser and absorbent gel (commonly found in baby diapers).
According to lead researcher and neurotechnology professor Edward Boyden, researchers around the world have been trying to invent novel equipment to create materials at nanoscale for years. There are all kinds of things one can do with the new technology, he added.
While scientists are finding ways to add tiny robotic particles to drugs for cancer that can seek out only the cancerous cells, MIT’s new technology could be used to develop even smaller ‘nanochip’ electronics.
The research team created a scaffold out of polyacrylate (absorbent gel) for their nanofabrication process. It is then soaked in a solution containing fluorescein molecules, which attach to the scaffold when activated using a laser light. The molecules of fluorescein could be attached to specific locations within the gel by using two-photon microscopy which enables accurate targeting of points deep within a structure. In addition, these molecules serve as anchors that can attach other types of molecules such as DNA, quantum dot, or gold nanoparticles.
It’s a bit like film photography, Daniel Oran said, who is study co-author and an MIT graduate student. By exposing a sensitive material in an absorbent gel to light, a latent image is formed. This latent image can then be developed into a real image by binding another material, silver afterwards, he added. In this way, the new technology can be deployed to develop all sorts of structure such as multi-material patterns, unconnected structures, and gradients. Once the desired molecules are attached to specific locations, the team shrink an entire structure by adding an acid.
The researchers discovered implosion fabrication by reversing a common technique, originally designed by Boyden to enlarge images of the brain tissue, known as ‘expansion microscopy’. The process involves injecting a material into a gel and making it larger, thereby easier to see.
Through the reversing process, the research team have been able to develop nanosized objects. Earlier, similar techniques could only create structures in 2D but not 3D. Although it was possible to make 3D nanostructures, the process was slow, restrictive and challenging.
According to the researchers, the new technology could become easily accessible in the future and be used at common places such as school and home, as all the materials are nontoxic.