128-channel ECoG array, 9 micrometers thick, made entirely of a conductive hydrogel (CHIP) printed on parylene, at 853 channels per cm2. Xu Xiaomin's group at Tsinghua Shenzhen International Graduate School with SIAT; rabbit recordings to 550 days (PNAS 2026).
Independent, source-linked catalog sheet. Not a manufacturer-issued datasheet, regulatory decision or instructions for clinical use. Human evidence does not establish approval. Source-specific restrictions, conflicts and missing specifications are retained below.
An ECoG array whose sites, traces and pads are all a conductive hydrogel, with no metal conductors, built by Xu Xiaomin’s group at Tsinghua Shenzhen International Graduate School with the Shenzhen Institute of Advanced Technology (Li Xiaojian) and international collaborators. Details are from the open-access PNAS paper (2026, Europe PMC full text) and Tsinghua’s Chinese release.
Identity
Field
Value and source scope
Device
CHIP-based ultraflexible ECoG array; CHIP is a PEDOT:PSS-based conductive hydrogel with an interfacial percolation microstructure [1][2]
Origin
Tsinghua Shenzhen International Graduate School and SIAT; IACUC approvals at both [1]
Interface class
Cortical-surface array [1]
Species studied
New Zealand rabbits (128 channels over cingulate and parietal cortex); porcine brain tissue for adhesion tests [1]
Regulatory status
Research device; no human use reported [1]
Geometry and architecture
Field
Value and source scope
Channel count
128 [1]
Density
853 channels/cm2, more than 10 times earlier hydrogel-only arrays (about 46/cm2) [1]
Total thickness
About 9 µm [1][2]
Layers
Polyimide carrier, 1.5 µm parylene-C, 2 µm PAAm-alginate hydrogel, CHIP conductor about 4 µm in total, a second 1.5 µm parylene-C layer and a further 2 µm hydrogel interface layer [1]
Site and pitch dimensions
Materials and fabrication
Field
Value and source scope
Conductor
Entire conductive network is CHIP; in-plane conductivity 235 to 2,512 S/cm across 85.9 to 36.4% water content [1]
Patterning
Two routes: aerosol printing of the array, and blade-coated ink with a 30 nm gold sacrificial mask, AZ10XT photoresist, Ar RIE then O2 plasma etch for fine patterning; an anisotropic-swelling strategy limits in-plane swelling [1]
Hydrogel substrate
PAAm-alginate hydrogel transferred onto O2-plasma-activated parylene and heated to bond [1]
Openings
A polyimide/50 µm PDMS bilayer mask prepatterned by laser, then O2 and SF6 plasma etching [1]
Performance envelope
Field
Value and source scope
Impedance
Tissue-electrode impedance 8.9 ± 1.2 kΩ at 1 kHz [1]
Chronic recording
Longest recording 550 days in freely moving rabbits; all 128 channels acquired signal on day 1 with no electrical failures; high-gamma (60 to 120 Hz) power rose during exploration [1][2]
Accelerated aging
Swelling controlled for an equivalent of about 35 days at elevated temperature [1]
Limits
Rabbit only, one longest-run animal named in the supplementary movie; the paper and release do not report decoding or any human work.
References
Zhu R et al., An exceptionally conductive hydrogel for all-organic, ultraflexible, and chronic neural interfaces, PNAS (2026), PMC13142910, DOI 10.1073/pnas.2532840123.