Creation of mini-cubes
© Johns Hopkins University
"Our group has developed a new process for fabricating three-dimensional micropatterned containers for cell encapsulation and drug delivery," said David H. Gracias, who led the lab team. "We're talking about an entirely new encapsulation and delivery device that could lead to a new generation of 'smart pills'."
To make the self-assembling containers, Gracias and his colleagues begin with some of the same techniques used to make microelectronic circuits: thin film deposition, photolithography and electrodeposition. These methods produce a flat pattern of six squares, in a shape resembling a cross. Each square, made of copper or nickel, has small openings etched into it, so that it eventually will allow medicine or therapeutic cells to pass through.
The researchers use metallic solder to form hinges along the edges between adjoining squares. When the flat shapes are heated briefly in a lab solution, the metallic hinges melt. High surface tension in the liquified solder pulls each pair of adjoining squares together like a swinging door. When the process is completed, they form a perforated cube. When the solution is cooled, the solder hardens again, and the containers remain in their box-like shape. "The self-assembly technique allows us to make a large number of these microcontainers at the same time and at a relatively low cost," Gracias said.
The tiny cubes are coated with a very thin layer of gold, so that they are unlikely to pose toxicity problems within the body. The microcontainers have not yet been implanted in humans or animals, but the researchers have conducted lab tests to demonstrate how they might work in medical applications. Because of their metallic nature, the cubic container's location in the body could easily be tracked by magnetic resonance imaging.
COMPAMED.de; Source: Johns Hopkins University