A tiny electrode fuels smart bandage technology

(Phys.org)—Band-​​aid tech­nology has made incre­mental improve­ments in the years since its com­mer­cial intro­duc­tion in the late 1960s, the most impor­tant of which has been the incor­po­ra­tion of antibi­otics into the non­ad­he­sive padding. But imagine if adhe­sive ban­dages could do more than pas­sively pre­vent the growth of bac­teria—imagine if they could mon­itor a wound and pre­dict that growth.

DiP­i­etro assis­tant pro­fessor of chem­ical engi­neering Edgar Goluch has devel­oped an elec­tro­chem­ical sensor that could some day make these so-​​called "smart ban­dages" a reality.

Bac­teria pro­duce a host of com­pounds, he said, some of which are elec­tro­chem­i­cally active. Goluch's device, which he devel­oped with the help of grad­uate stu­dent Thad­daeus Web­ster, works by detecting these charged molecules.

Sim­ilar devices have been devel­oped in the past, Goluch noted, but they were all hin­dered by a single com­po­nent that could not be minia­tur­ized to enable the smart-​​bandage idea. Elec­tro­chem­ical sen­sors need at least two things to work: a ref­er­ence and a working elec­trode. Most of the microscale devices pre­vi­ously devel­oped used macroscale ref­er­ence elec­trodes; oth­er­wise, they were unstable in com­plex chem­ical environments.

In a paper pub­lished in the journal Lab on a Chip, Goluch and Web­ster detail the inner work­ings of a stable, microscale ref­er­ence elec­trode, which they used to detect the pres­ence of a com­pound called pyocyanin that can be found only in the bac­teria Pseudomonas aerug­i­nosa.

Goluch said P. aerug­i­nosa is an old, pre­his­toric organism. As he put it, "It can sur­vive under extremely harsh conditions."

The organism is present just about every­where and nor­mally that would not be a problem because it doesn't make healthy people sick. But for patients with com­pro­mised immune sys­tems, these bac­teria are deadly.

"We want to be able to detect the bac­teria before a biofilm forms," Goluch explained, adding that his inter­dis­ci­pli­nary back­ground, which includes grad­uate degrees in mechan­ical engi­neering and bio­engi­neering, gave him the exper­tise to develop this unique sensing system. "Early detec­tion of infec­tion and con­t­a­m­i­na­tion greatly improves a patient's chances of survival."

His device can do exactly that.

The new ref­er­ence elec­trode is made of pal­la­dium, which is capable of storing more than 900 times its volume in hydrogen, making it an extremely stable ref­er­ence. The mate­rial has pre­vi­ously been used as a pH detector for its storage capabilities.

The project's key break­through lies is palladium's ease of use and ability to be shaped into minia­ture wires, making it an ideal mate­rial to incor­po­rate into microscale sensors.