Electrochemical Properties and Myocyte Interaction of Carbon Nanotube Microelectrodes

Abstract

Arrays of carbon nanotube (CNT) microelectrodes (nominal geometric surface areas 20-200 μm(2)) were fabricated by photolithography with chemical vapor deposition of randomly oriented CNTs. Raman spectroscopy showed strong peak intensities in both G and D bands (G/D = 0.86), indicative of significant disorder in the graphitic layers of the randomly oriented CNTs. The impedance spectra of gold and CNT microelectrodes were compared using equivalent circuit models. Compared to planar gold surfaces, pristine nanotubes lowered the overall electrode impedance at 1 kHz by 75%, while nanotubes treated in O(2) plasma reduced the impedance by 95%. Cyclic voltammetry in potassium ferricyanide showed potential peak separations of 133 and 198 mV for gold and carbon nanotube electrodes, respectively. The interaction of cultured cardiac myocytes with randomly oriented and vertically aligned CNTs was investigated by the sectioning of myocytes using focused-ion-beam milling. Vertically aligned nanotubes deposited by plasma-enhanced chemical vapor deposition (PECVD) were observed to penetrate the membrane of neonatal-rat ventricular myocytes, while randomly oriented CNTs remained external to the cells. These results demonstrated that CNT electrodes can be leveraged to reduce impedance and enhance biological interfaces for microelectrodes of subcellular size.

Carbon nanotube interaction with extracellular matrix proteins producing scaffolds for tissue engineering

“…In that position, they were able to penetrate the membrane of neonatal rat ventricular myocytes, while the randomly oriented ones remained external to the cells. 139 In a study using the electrospinning technique, McKeonFischer and collaborators used coaxially electrospun poly(ε-caprolactone), acid MWNT, and a hydrogel consisting of polyvinyl alcohol and polyacrylic acid (PCL-MWNT-H) to create a self-contained nanoactuating scaffold for skeletal muscle-tissue replacement. 140 This nanocomposite was biocompatible, and the acid MWNT increased its conductivity and acted as an inner electrode.…”

Low-impedance Tetrodes using Carbon Nanotube-Polypyrrole Composite Deposition

“…These surface modification techniques are primarily focused on increasing the electrochemical surface area (ESA) [7] through micro/nano-structures, using conductive polymers [8][9][10], iridium oxide films [11,12], and carbon nanotubes (CNTs) [13][14][15][16][17].…”

Upside-down Carbon nanotube (CNT) micro-electrode array (MEA)

“…Previous work [1,3] has shown how CNT coatings can drastically improve the SNR of recorded cell potential by increasing double-layer charge capacity as a consequence of their high SSA/GSA. Furthermore, CNTs provide additional advantages such as high mechanical and electrical stability, good electrical conductance [3] and good cell-electrode coupling [4].…”