New York: To help children born with neuromotor and cognitive developmental disabilities, Harvard University researchers have developed a soft, non-toxic wearable sensor that attaches to the hand and measures the force of a grasp and the motion of the hand and fingers. One novel element of the sensor is a non-toxic, highly conductive liquid solution.
"We have developed a new type of conductive liquid that is no more dangerous than a small drop of salt water," said Siyi Xu, a graduate student at Harvard's School of Engineering and Applied Sciences first author of the paper. "It is four times more conductive than previous biocompatible solutions, leading to cleaner, less noisy data," he added in a paper published in the journal Advanced Functional Materials.
The sensing solution is made from potassium iodide, which is a common dietary supplement, and glycerol, which is a common food additive. "Previous biocompatible soft sensors have been made using sodium chloride-glycerol solutions but these solutions have low conductivities, which makes the sensor data very noisy, and it also takes about 10 hours to prepare," said Xu. "We've shortened that down to about 20 minutes and get very clean data."
The design of the sensors also takes the need of children into account. Rather than a bulky glove, the silicon-rubber sensor sits on top of the finger and on the finger pad. "We often see that children who are born early or who have been diagnosed with early developmental disorders have highly-sensitive skin," said Eugene Goldfield from Boston Children's Hospital and Harvard Medical School.
"By sticking to the top of the finger, this device gives accurate information while getting around the sensitively of the child's hand," Goldfield added. Early diagnosis is the name of the game when it comes to treating developmental disabilities and this wearable sensor can give us a lot of advantages not currently available, the researchers noted. This paper only tested the device on adult hands. The researchers plan to scale down the device and test it on the hands of children.