The miniaturization of electronics continues to revolutionize the medical industry with tiny, swallowable devices and minuscule, implanted sensors. Researchers at Tel Aviv University (TAU) have kept the ball rolling with the development of a new micro-printing process that allows the production of flexible and energy-efficient microelectromechanical (MEMS) devices that can be safely used in the human body.

Generally, MEMS come in two forms; sensors and actuators. The sensors convert movement or chemical signals into electrical signals, which can then be interpreted within the system, while the MEMS actuators work like any other actuator and convert a signal into mechanical movement. The membranes that are typically used to measure or produce the necessary movement are usually produced in a manufacturing process similar to that used in the semiconductor industry with silicon used as a base material for micro- and nano-sized components.

The new process developed by the TAU team replaces the silicon with a non-toxic organic polymer that results in rubbery, paper-thin membranes that are more biocompatible than silicon-based MEMS. They are also more flexible, which TAU claims could enable more sensitive MEMS sensors and more energy-efficient MEMS actuators that could be safely implanted in the human body, while also being more comfortable. The researchers say the new printing technology also provides the potential for quick, low-cost production of MEMS devices.

According to the team, the polymer base for the membranes and some funds were supplied by Arkema/Piezotech, a French chemical producer. "They just gave us the material and asked us to see what devices we could create with it," Leeya Engel, engineering doctoral candidate at TAU, said. "This field is like Legos for grownups."

At the moment, the team is only producing components with this process, but they hope to begin creating fully functioning, micro- and nano-scale sensors and actuators that could be utilized in the consumer electronics and medical industries. This includes devices for controlling bionic limbs of amputees in response to signals from their nervous system and prosthetic bladders that regulate urination for people paralyzed below the waist.

Looking further ahead, the TAU team hopes their new printing process could be used to make flexible MEMS almost entirely out of the polymer, which could be used in artificial muscles or, in the consumer space, in displays that are flexible enough to be rolled up and put in a pocket. The improved sensitivity and energy-efficiency of MEMS sensors and motors could also help extend the battery life of portable devices.

A paper detailing TAU's new printing process appears in the journal Microelectronic Engineering.