TY - JOUR
T1 - Nanoenabled Direct Contact Interfacing of Syringe-Injectable Mesh Electronics
AU - Lee, Jung Min
AU - Hong, Guosong
AU - Lin, Dingchang
AU - Schuhmann, Thomas G.
AU - Sullivan, Andrew T.
AU - Viveros, Robert D.
AU - Park, Hong Gyu
AU - Lieber, Charles M.
N1 - Funding Information:
C.M.L. acknowledges the support of this work by the Air Force Office of Scientific Research (FA9550-18-1-0469) and an NIH Director’s Pioneer Award (5DP1EB025835-02). This material is based upon work supported by the National Science Foundation Graduate Research Fellowship Program under grant nos. DGE1144152 and DGE1745303 (R.D.V.). H.-G.P. acknowledges the support of this work by a National Research Foundation of Korea (NRF) grant funded by the Korean government (MSIP) (no. 2018R1A3A3000666). G.H. acknowledges the support of this work by American Heart Association Postdoctoral Fellowship 16POST27250219 and a National Institutes of Health Pathway to Independence Award (NIA 5R00AG056636-04). T.G.S.,J. acknowledges support by the Department of Defense (DoD) through the National Defense Science & Engineering Graduate Fellowship (NDSEG) program. This work was performed in part at the Harvard University Center for Nanoscale Systems (CNS), a member of the National Nanotechnology Coordinated Infrastructure Network (NNCI), which is supported by the National Science Foundation.
Publisher Copyright:
© 2019 American Chemical Society.
PY - 2019/8/14
Y1 - 2019/8/14
N2 - Polymer-based electronics with low bending stiffnesses and high flexibility, including recently reported macroporous syringe-injectable mesh electronics, have shown substantial promise for chronic studies of neural circuitry in the brains of live animals. A central challenge for exploiting these highly flexible materials for in vivo studies has centered on the development of efficient input/output (I/O) connections to an external interface with high yield, low bonding resistance, and long-term stability. Here we report a new paradigm applied to the challenging case of injectable mesh electronics that exploits the high flexibility of nanoscale thickness two-sided metal I/O pads that can deform and contact standard interface cables in high yield with long-term electrical stability. First, we describe the design and facile fabrication of two-sided metal I/O pads that allow for contact without regard to probe orientation. Second, systematic studies of the contact resistance as a function of I/O pad design and mechanical properties demonstrate the key role of the I/O pad bending stiffness in achieving low-resistance stable contacts. Additionally, computational studies provide design rules for achieving high-yield multiplexed contact interfacing in the case of angular misalignment such that adjacent channels are not shorted. Third, the in vitro measurement of 32-channel mesh electronics probes bonded to interface cables using the direct contact method shows a reproducibly high yield of electrical connectivity. Finally, in vivo experiments with 32-channel mesh electronics probes implanted in live mice demonstrate the chronic stability of the direct contact interface, enabling consistent tracking of single-unit neural activity over at least 2 months without a loss of channel recording. The direct contact interfacing methodology paves the way for scalable long-term connections of multiplexed mesh electronics neural probes for neural recording and modulation and moreover could be used to facilitate a scalable interconnection of other flexible electronics in biological studies and therapeutic applications.
AB - Polymer-based electronics with low bending stiffnesses and high flexibility, including recently reported macroporous syringe-injectable mesh electronics, have shown substantial promise for chronic studies of neural circuitry in the brains of live animals. A central challenge for exploiting these highly flexible materials for in vivo studies has centered on the development of efficient input/output (I/O) connections to an external interface with high yield, low bonding resistance, and long-term stability. Here we report a new paradigm applied to the challenging case of injectable mesh electronics that exploits the high flexibility of nanoscale thickness two-sided metal I/O pads that can deform and contact standard interface cables in high yield with long-term electrical stability. First, we describe the design and facile fabrication of two-sided metal I/O pads that allow for contact without regard to probe orientation. Second, systematic studies of the contact resistance as a function of I/O pad design and mechanical properties demonstrate the key role of the I/O pad bending stiffness in achieving low-resistance stable contacts. Additionally, computational studies provide design rules for achieving high-yield multiplexed contact interfacing in the case of angular misalignment such that adjacent channels are not shorted. Third, the in vitro measurement of 32-channel mesh electronics probes bonded to interface cables using the direct contact method shows a reproducibly high yield of electrical connectivity. Finally, in vivo experiments with 32-channel mesh electronics probes implanted in live mice demonstrate the chronic stability of the direct contact interface, enabling consistent tracking of single-unit neural activity over at least 2 months without a loss of channel recording. The direct contact interfacing methodology paves the way for scalable long-term connections of multiplexed mesh electronics neural probes for neural recording and modulation and moreover could be used to facilitate a scalable interconnection of other flexible electronics in biological studies and therapeutic applications.
KW - Double-sided metal input/output
KW - biocompatible neural probes
KW - chronic neural interface
KW - flexible electronics
KW - flexible input/output
KW - multiplexed electrophysiology
UR - http://www.scopus.com/inward/record.url?scp=85070664708&partnerID=8YFLogxK
U2 - 10.1021/acs.nanolett.9b03019
DO - 10.1021/acs.nanolett.9b03019
M3 - Article
C2 - 31361503
AN - SCOPUS:85070664708
VL - 19
SP - 5818
EP - 5826
JO - Nano Letters
JF - Nano Letters
SN - 1530-6984
IS - 8
ER -