Fabrication of Responsive, Softening Neural Interfaces

A novel processing method is described using photolithography to pattern thin-fi lm fl exible electronics on shape memory polymer substrates with mechanical properties tailored to improve biocompatability and enhance adhesion between the polymer substrate and metal layers. Standard semiconductor wafer processing techniques are adapted to enable robust device design onto a variety of softening substrates with tunable moduli. The resulting devices are stiff enough (shear modulus of ≈ 700 MPa) to assist with device implantation and then soften in vivo ( ≈ 300 kPa) approaching the modulus of brain tissue ( ≈ 10 kPa) within 24 h. Acute in vivo studies demonstrate that these materials are capable of recording neural activity. Softening multi-electrode arrays offer a highly customizable interface, which can be optimized to improve biocompatibility, enabling the development of robust, reliable neural electrodes for neural engineering and neuroscience.

[1]  P R Kennedy,et al.  Direct control of a computer from the human central nervous system. , 2000, IEEE transactions on rehabilitation engineering : a publication of the IEEE Engineering in Medicine and Biology Society.

[2]  Ken Gall,et al.  Toward a self-deploying shape memory polymer neuronal electrode. , 2006, Journal of neural engineering.

[3]  B. Pesaran,et al.  Cognitive neural prosthetics , 2004, Trends in Cognitive Sciences.

[4]  N. Birbaumer.  Breaking the silence: brain-computer interfaces (BCI) for communication and motor control. , 2006, Psychophysiology.

[5]  Yiping Liu,et al.  Thermomechanics of the shape memory effect in polymers for biomedical applications. , 2005, Journal of biomedical materials research. Part A.

[6]  Ken Gall,et al.  Long-term toughness of photopolymerizable (meth)acrylate networks in aqueous environments. , 2011, Acta biomaterialia.

[7]  D. Kipke,et al.  Insertion shuttle with carboxyl terminated self-assembled monolayer coatings for implanting flexible polymer neural probes in the brain , 2009, Journal of Neuroscience Methods.

[8]  Raafat R. Mansour,et al.  Fabrication and characterization of the flexible neural microprobes with improved structural design , 2011 .

[9]  T. Someya,et al.  A Rubberlike Stretchable Active Matrix Using Elastic Conductors , 2008, Science.

[10]  Qibing Pei,et al.  Highly Flexible Silver Nanowire Electrodes for Shape‐Memory Polymer Light‐Emitting Diodes , 2011, Advanced materials.

[11]  Wei Min Huang,et al.  Effects of moisture on the glass transition temperature of polyurethane shape memory polymer filled with nano-carbon powder , 2005 .

[12]  Jean-Marc Fellous,et al.  In vitro model of glial scarring around neuroelectrodes chronically implanted in the CNS. , 2006, Biomaterials.

[13]  D. A. Shirley,et al.  High-Resolution X-Ray Photoemission Spectrum of the Valence Bands of Gold , 1972 .

[14]  P. Tresco,et al.  Response of brain tissue to chronically implanted neural electrodes , 2005, Journal of Neuroscience Methods.

[15]  David F Meaney,et al.  Matrices with compliance comparable to that of brain tissue select neuronal over glial growth in mixed cortical cultures. , 2006, Biophysical journal.

[16]  Nicholas B Langhals,et al.  In vivo performance of a microelectrode neural probe with integrated drug delivery. , 2009, Neurosurgical focus.

[17]  Ken Gall,et al.  Radiation crosslinked shape-memory polymers , 2010 .

[18]  B. Luther-Davies,et al.  Significant improvement of adhesion between gold thin films and a polymer , 2004 .

[19]  M. Rafailovich,et al.  Green thin polymer film metallization using supercritical carbon dioxide , 2007 .

[20]  Stéphanie P. Lacour,et al.  Flexible and stretchable micro-electrodes for in vitro and in vivo neural interfaces , 2010, Medical & Biological Engineering & Computing.

[21]  Ken Gall,et al.  Effect of chemical structure and crosslinking density on the thermo-mechanical properties and toughness of (meth)acrylate shape-memory polymer networks , 2008 .

[22]  Vadim S. Polikov,et al.  Reactive microgliosis: extracellular micro-calpain and microglia-mediated dopaminergic neurotoxicity. , 2010, Brain : a journal of neurology.

[23]  James P. Harris,et al.  Mechanically adaptive intracortical implants improve the proximity of neuronal cell bodies , 2011, Journal of neural engineering.

[24]  James P. Harris,et al.  In vivo deployment of mechanically adaptive nanocomposites for intracortical microelectrodes , 2011, Journal of neural engineering.

[25]  R. Langer,et al.  Light-induced shape-memory polymers , 2005, Nature.

[26]  Yonggang Huang,et al.  Materials and Mechanics for Stretchable Electronics , 2010, Science.

[27]  T. Ware,et al.  High‐Strain Shape‐Memory Polymers , 2010 .

[28]  Andrew B. Schwartz,et al.  Brain-Controlled Interfaces: Movement Restoration with Neural Prosthetics , 2006, Neuron.

[29]  X Liu,et al.  Stability of the interface between neural tissue and chronically implanted intracortical microelectrodes. , 1999, IEEE transactions on rehabilitation engineering : a publication of the IEEE Engineering in Medicine and Biology Society.

[30]  R. Langer,et al.  Biodegradable, Elastic Shape-Memory Polymers for Potential Biomedical Applications , 2002, Science.

[31]  Thomas Stieglitz.  Neuro-technical interfaces to the central nervous system , 2006, Poiesis Prax..

[32]  Jit Muthuswamy,et al.  Assessment of gliosis around moveable implants in the brain , 2009, Journal of neural engineering.

[33]  P. Renaud,et al.  Demonstration of cortical recording using novel flexible polymer neural probes , 2008 .

[34]  R. L. Rennaker,et al.  A comparison of chronic multi-channel cortical implantation techniques: manual versus mechanical insertion , 2005, Journal of Neuroscience Methods.

[35]  Carl F. Lagenaur,et al.  The surface immobilization of the neural adhesion molecule L1 on neural probes and its effect on neuronal density and gliosis at the probe/tissue interface. , 2011, Biomaterials.

[36]  John P. Donoghue,et al.  Connecting cortex to machines: recent advances in brain interfaces , 2002, Nature Neuroscience.

[37]  D. Tyler,et al.  Stimuli-Responsive Polymer Nanocomposites Inspired by the Sea Cucumber Dermis , 2008, Science.

[38]  Justin C. Williams,et al.  Flexible polyimide-based intracortical electrode arrays with bioactive capability , 2001, IEEE Transactions on Biomedical Engineering.