Bioadhesive and conductive hydrogel-integrated brain-machine interfaces for conformal and immune-evasive contact with brain tissue

SUMMARY Brain-machine interfaces (BMIs) enable communication between the brain and external machines. However, mechanical and biological mismatches, as well as weak physical adhesion-induced shifts between rigid electronic devices and soft brain tissue, generally trigger a host immune response, affecting signal recording and reducing the lifespan of BMIs in clinics. Herein, we design a bioadhesive ultrasoft BMI based on integration of bioelectronics with a dopamine methacrylate-hybridized poly(3,4-ethylenedioxythiophene) nanoparticle (dPEDOT NP)-incorporated hydrogel with high conductivity. The hydrogel exhibits robust adhesiveness, enabling tight integration with metallic microcircuits and seamless adhesion to the brain tissue. Most importantly, the hydrogel exhibits a brain-level modulus that reduces its mechanical discrepancy with brain tissue. Meanwhile, the hydrogel possesses immune evasive ability, which actively prevents fibrous tissue encapsulation and neuroinflammation after implantation. Consequently, the immune-evasive, bioadhesive, ultrasoft, and conductive hydrogelintegrated BMI permits long-term and accurate electroencephalographic signal acquisition and communication with minimal foreign body reaction.

Automated summary

This study presents a bioadhesive ultrasoft brain-machine interface (BMI) by integrating bioelectronics with a dopamine methacrylate-hybridized poly(3,4-ethylenedioxythiophene) nanoparticle hydrogel. The hydrogel exhibits strong adhesiveness for tight integration with brain tissue, reduces mechanical discrepancy with the brain, and possesses immune evasive ability to prevent immune reactions and neuroinflammation. The ultrasoft BMI enables long-term and accurate signal acquisition and communication with minimal foreign body reaction.