Polymer-Enabled Carbon Nanotube Deposition for Cellular Interrogation Applications

We have utilized a block copolymeric thin film as a modality to template the deposition of single-walled carbon nanotubes towards applications in single cell interrogation. Transmembrane studies of cellular activity (e.g. neurons, cardiomyocytes, etc.) have often been limited by the invasiveness of probe-induced membrane rupture. This often precludes chronic activity analysis. We have developed a copolymer-carbon nanotube (P-CNT) hybrid material for potential applications in non-invasive cell probing with attenuated inflammation due to the biomimetic stiffness of the copolymer coupled with nanoscale dimensions of the P-CNT complex. We applied both a diblock copolymer comprised of poly(ethylene oxide-b-methyl methacrylate; PEO-PMMA) as well as an acrylate-terminated amphiphilic `ABA' triblock copolymer comprised of polymethyloxazoline-polydimethylsiloxane-polymethyloxazoline; PMOXA-PDMS-PMOXA) as the supporting matrix for carbon nanotube deposition via the Langmuir-Blodgett methodology. This enabled the suspension of the carbon nanotubes on the air-water interface for transfer to a gold substrate. Cyclic voltammetry measurements confirmed that the CNT's were interfaced directly with the gold substrates to enable electrical functionality. In addition, cellular adhesion to the polymeric substrate was demonstrated, confirming the biocompatibility of the P-CNT material. CNT-coated electrodes were also examined as biological electrodes for the monitoring of oxidation-reduction processes driven by the cytochrome c mediator, where CNT/polymer-coated surfaces were also capable of facilitating anti-protein adsorption, resulting in the observation of reversible electron transfer between the protein and electrode. This was demonstrated via acquisition of pronounced anodic and cathodic peaks with peak separations of 64mV, which confirmed a reversible transfer process.