“Does not swell in the body”: 3D-printed hydrogel brain interface

Chinese researchers have developed a new hydrogel that does not swell in the body, potentially paving the way for the commercialization of implantable electronic devices, including long-term stable brain-computer interfaces (BCIs).

According to Chinese life sciences media outlet BioOn, a joint research team led by Professors Zhou Nanja, Tao Liang and Yao Yuan of Westlake University published a paper detailing the findings in the international journal Nature Materials on July 31 (local time).

Hydrogel-based bioelectronic materials have attracted attention because of their high water content, tissue-like flexibility and excellent biocompatibility. However, conventional hydrogels tend to swell in the body, limiting their ability to maintain structural stability and electrical performance.

The research team developed a soft, stretchable hydrogel that does not swell in the body using a “micelle self-assembly” method. Based on this material, the team created a 3D-printable biphasic conductive hydrogel ink and successfully fabricated implantable electronic devices.

The new hydrogel significantly reduced the foreign-body response compared with conventional materials and demonstrated high conductivity of up to 4000S/cm and an electrical breakdown strain of more than 1300%. Using the technology, the research team fabricated brain-computer interfaces, wireless optoelectronic devices and sciatic nerve stimulators, implanted them in rats, and confirmed stable, reliable operation for several months.

The study is expected to accelerate the development of implantable therapeutic devices designed for long-term use in various fields, including nerve regeneration, cardiovascular disease treatment and pain management.