Systems based on a new type of synthetic material could in the future enable us to develop devices and even buildings that are as self-regulating as the human body.
The SMARTS system (for “Self-regulated Mechano-chemical Adaptively Reconfigurable Tunable System”) was developed by a team of engineers from Harvard University and the University of Pittsburgh. The system is based on a novel material made with a hydrogel embedded with tiny hair-like posts with catalysts that react with the fluid.
The combination of elements enabled the team to create a system that could eventually self-regulate a variety of conditions. In lab tests, the engineers chose elements that were sensitive to temperature. When the hair-like posts stood upright, they set off a reaction that generated heat. But the heat then caused the temperature-sensitive gel to shrink, bending the posts and switching off the heat-generating reaction and causing the system to cool down. That in turn, caused the gel to expand, setting the posts upright and repeating the cycle.
“The reconfiguration of the gel creates an on/off switch of sorts for the system,” said Olga Kuksenok, a research professor at the University of Pittsburgh’s Swanson School of Engineering. “The system oscillates back and forth between these two states and, in this manner, regulates the overall temperature. While none of the individual components exhibit oscillatory behavior, the combination of these elements leads to an oscillatory system, which maintains the temperature at a constant level.”
The research team believes such systems could one day be used to improve handheld medical diagnostic devices like the ones increasingly being used in developing and rural areas.
“Many biomedical analyses require specific temperatures, pH, or other conditions and are hard to do outside a lab, but if a portable device contains homeostatic materials that can autonomously regulate these conditions, it could bring many more sophisticated analyses to many more people,” said Anna Balazs, research team co-investigator and a professor of chemical and petroleum engineering at Pitt’s Swanson School.