Microscale 3D Printing Inks greatly expanding kinds of things that can be printed
In spite of all the fuss and enthusiasm that 3D printing has created, its sphere of usage is still quite limited. You can use it to create complex shapes mainly of plastic. Producers that use an advanced version of the technology that can print things of metals know that they can use only a small number of various metals and metal mixtures. Suppose 3D printers could use a wider variety of materials, like semiconductors or living cells that would revolutionize goods manufacturing.
Materials scientist from the University of Harvard Jennifer Lewis is trying to work out the ways to make this true. She prints out objects of complex shapes adding various materials that are proper according to their mechanical, optical and electrical properties. She supposes that this would help to create items that respond to the environment. The combination of form and function will be the further step in 3D printing. This means 3D printing technology could make objects that sense and respond to their environment.
During one of the experiments Jennifer took four polymer “inks” of different colours, which were placed in conventional print heads. By adding inks to the process with the special software the printer produced a colourful lattice frame.
A group of scientists from Princeton University 3D printed a bionic ear from a combination of electronics and biological tissue. Their colleagues from Cambridge University printed out retinal cells for composite eye tissue. But Lewis’s lab is foregrounded because of the number of materials she uses and the type of things she can print. Last year she and her students 3D printed microscopic electrodes and other parts for small lithium-ion batteries.
Among other projects there are sensors on plastic patches for athletes to wear and measure violent impacts. Quite recently they printed a combination of biological tissue and a network of blood cells. They had to make ink from different kinds of cells that would form a matrix to support them. They aim at producing artificial organs for drug tests or even to use them for replacement.
Lewis’s creations are peculiar as each ink she uses is different. All of them can be printed at room temperature. Different inks serve to print different objects: cells, for instance, are too smooth and can be damages easily when pushed through printing nozzles. All types of ink will flow through the nozzles under pressure but they should preserve the necessary form once out, just like toothpaste.
Set of polymer inks
Before achieving the results Lewis spent years trying to work out 3D printing with ceramics, polymers and nonbiological stuff. At the very beginning of her study, when she just opened her lab Jennifer thought that working with biological tissue was almost no different from synthetic materials. Now she says how naive she was. Printing blood vessels was a huge step towards creating tissue with complex biological functions. But there is still a lot of work to do before they are able to print a proper liver or heart.