title: Aligned carbon nanotube-based flexible gel substrates for engineering bio-hybrid tissue actuators.
abstract: Muscle-based biohybrid actuators have generated significant interest as the future of biorobotics but so far they move without having much control over their actuation behavior. Integration of microelectrodes into the backbone of these systems may enable guidance during their motion and allow precise control over these actuators with specific activation patterns. Here, we addressed this challenge by developing aligned CNT forest microelectrode arrays and incorporated them into scaffolds for stimulating the cells. Aligned CNTs were successfully embedded into flexible and biocompatible hydrogel exhibiting excellent anisotropic electrical conductivity. Bioactuators were then engineered by culturing cardiomyocytes on the CNT microelectrode-integrated hydrogel constructs. The resulting cardiac tissue showed homogeneous cell organization with improved cell-to-cell coupling and maturation, which was directly related to the contractile force of muscle tissue. This centimeter-scale bioactuator has excellent mechanical integrity, embedded microelectrodes and is capable of spontaneous actuation behavior. Furthermore, we demonstrated that a biohybrid machine can be controlled by an external electrical field provided by the integrated CNT microelectrode arrays. In addition, due to the anisotropic electrical conductivity of the electrodes provided from aligned CNTs, significantly different excitation thresholds were observed in different configurations such as the ones in parallel vs. perpendicular direction to the CNT alignment.
authors.affiliation: Biomaterials Innovation Research Center, Department of Medicine, Brigham and Women's Hospital, Harvard Medical School, Boston, MA 02139, USA. Harvard-MIT Division of Health Sciences and Technology, Massachusetts Institute of Technology, Cambridge, MA 02139, USA. Wyss Institute for Biologically Inspired Engineering, Harvard University, Boston, MA 02115, USA.
authors.forename: Su Ryon
authors.initials: SR
authors.lastname: Shin
authors.affiliation: Biomaterials Innovation Research Center, Department of Medicine, Brigham and Women's Hospital, Harvard Medical School, Boston, MA 02139, USA. Harvard-MIT Division of Health Sciences and Technology, Massachusetts Institute of Technology, Cambridge, MA 02139, USA.
authors.forename: Courtney
authors.initials: C
authors.lastname: Shin
authors.affiliation: Center of Nanotechnology, King Abdulaziz University, Jeddah, 21589, Saudi Arabia.
authors.forename: Adnan
authors.initials: A
authors.lastname: Memic
authors.affiliation: Department of Chemistry & Waterloo Institute for Nanotechnology, University of Waterloo, 200 University Ave. West, Waterloo, Ontario, N2L 3G1, Canada.
authors.forename: Samaneh
authors.initials: S
authors.lastname: Shadmehr
authors.affiliation: Biomaterials Innovation Research Center, Department of Medicine, Brigham and Women's Hospital, Harvard Medical School, Boston, MA 02139, USA. Harvard-MIT Division of Health Sciences and Technology, Massachusetts Institute of Technology, Cambridge, MA 02139, USA.
authors.forename: Mario
authors.initials: M
authors.lastname: Miscuglio
authors.affiliation: Department of Mechanical and Industrial Engineering, Northeastern University, Boston, Massachusetts 02115, USA.
authors.forename: Hyun Young
authors.initials: HY
authors.lastname: Jung
authors.affiliation: Department of Electrical Engineering and Computer Science, Massachusetts Institute of Technology, Cambridge, Massachusetts 02139, USA.
authors.forename: Sung Mi
authors.initials: SM
authors.lastname: Jung
authors.affiliation: College of Animal Bioscience and Technology, Department of Bioindustrial Technologies, Konkuk University, Hwayang-dong, Kwangjin-gu, Seoul 143-701, Korea.
authors.forename: Hojae
authors.initials: H
authors.lastname: Bae
authors.affiliation: Biomaterials Innovation Research Center, Department of Medicine, Brigham and Women's Hospital, Harvard Medical School, Boston, MA 02139, USA. Harvard-MIT Division of Health Sciences and Technology, Massachusetts Institute of Technology, Cambridge, MA 02139, USA. Department of Physics, King Abdulaziz University, Jeddah 21569, Saudi Arabia. Wyss Institute for Biologically Inspired Engineering, Harvard University, Boston, MA 02115, USA. Department of Maxillofacial Biomedical Engineering and Institute of Oral Biology, School of Dentistry, Kyung Hee University, Seoul 130-701, Republic of Korea.
authors.forename: Ali
authors.initials: A
authors.lastname: Khademhosseini
authors.affiliation: Department of Chemistry & Waterloo Institute for Nanotechnology, University of Waterloo, 200 University Ave. West, Waterloo, Ontario, N2L 3G1, Canada.
authors.forename: Xiaowu Shirley
authors.initials: XS
authors.lastname: Tang
authors.affiliation: Biomaterials Innovation Research Center, Department of Medicine, Brigham and Women's Hospital, Harvard Medical School, Boston, MA 02139, USA. Harvard-MIT Division of Health Sciences and Technology, Massachusetts Institute of Technology, Cambridge, MA 02139, USA. Wyss Institute for Biologically Inspired Engineering, Harvard University, Boston, MA 02115, USA.
authors.forename: Mehmet R
authors.initials: MR
authors.lastname: Dokmeci
keywords: Bioactuators; Carbon Nanotubes; Cardiac tissue engineering; Hybrid hydrogels; Microelectrode arrays