The ideal material for interfacing electronics with living tissue is soft, stretchable, and just as water-loving as the tissue itself—in short, a hydrogel. Semiconductors, the key materials for bioelectronics such as pacemakers, biosensors, and drug delivery devices, on the other hand, are rigid, brittle, and water-hating, impossible to dissolve in the way hydrogels have traditionally been built.

A paper published today in Science from the UChicago Pritzker School of Molecular Engineering (PME) has solved this challenge that has long stymied researchers, reimagining the process of creating hydrogels to build a powerful semiconductor in hydrogel form. Led by Asst. Prof. Sihong Wang’s research group, the result is a bluish gel that flutters like a sea jelly in water but retains the immense semiconductive ability needed to transmit information between living tissue and machine.

The material demonstrated tissue-level moduli as soft as 81 kPa, stretchability of 150% strain, and charge-carrier mobility up to 1.4 cm² V^-1 s^-1. This means their material—both semiconductor and hydrogel at the same time—ticks all the boxes for an ideal bioelectronic interface.

Over time, scar tissue slows or stops implanted bioelectronics. But new interdisciplinary research could help pacemakers, sensors and other implantable devices keep people healthier for longer.

In a paper published in Nature Materials, a group of researchers led by University of Chicago Pritzker School of Molecular Engineering Asst. Prof. Sihong Wang has outlined a suite of design strategies for the semiconducting polymers used in implantable devices, all aimed at reducing the foreign-body response triggered by implants.

The immune system is primed to detect and respond to foreign objects. In some cases, the immune system might reject lifesaving devices such as pacemakers or drug delivery systems. But in all cases, the immune system will encase the devices in scar tissue over time, hurting the devices’ ability to help patients.