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Thiol‐ene/acrylate substrates for softening intracortical electrodes
Author(s) -
Ware Taylor,
Simon Dustin,
Liu Clive,
Musa Tabassum,
Vasudevan Srikanth,
Sloan Andrew,
Keefer Edward W.,
Rennaker Robert L.,
Voit Walter
Publication year - 2014
Publication title -
journal of biomedical materials research part b: applied biomaterials
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.665
H-Index - 108
eISSN - 1552-4981
pISSN - 1552-4973
DOI - 10.1002/jbmb.32946
Subject(s) - materials science , electrode , electroplating , acrylate , substrate (aquarium) , softening , composite material , softening point , differential scanning calorimetry , photolithography , polymer , biomedical engineering , nanotechnology , chemistry , layer (electronics) , medicine , oceanography , physics , monomer , thermodynamics , geology
Neural interfaces have traditionally been fabricated on rigid and planar substrates, including silicon and engineering thermoplastics. However, the neural tissue with which these devices interact is both 3D and highly compliant. The mechanical mismatch at the biotic–abiotic interface is expected to contribute to the tissue response that limits chronic signal recording and stimulation. In this work, novel ternary thiol‐ene/acrylate polymer networks are used to create softening substrates for neural recording electrodes. Thermomechanical properties of the substrates are studied through differential scanning calorimetry and dynamic mechanical analysis both before and after exposure physiological conditions. This substrate system softens from more than 1 GPa to 18 MPa on exposure to physiological conditions: reaching body temperature and taking up less than 3% fluid. The impedance of 177 µm 2 gold electrodes electroplated with platinum black fabricated on these substrates is measured to be 206 kΩ at 1 kHz. Specifically, intracortical electrodes are fabricated, implanted, and used to record driven neural activity. This work describes the first substrate system that can use the full capabilities of photolithography, respond to physiological conditions by softening markedly after insertion, and record driven neural activity for 4 weeks. © 2013 Wiley Periodicals, Inc. J Biomed Mater Res Part B: Appl Biomater, 102B: 1–11, 2014.