Spiral Countercurrent Chromatography Enrichment, Characterization, and Assays of Carbon Nanotube Chiralities for Use in Biosensors

Abstract

Single-walled carbon nanotubes (SWCNTs) are synthetic materials that hold great promise for electronics that are smaller and more versatile than the current silica-based technologies. But as-produced SWCNTs are generally a mixture of nanotubes with different structures that have vastly different properties. Separating these SWCNTs from multiwalled and metallic carbon nanotubes is vital to explore their individual properties and commercial utility ranging from optics to semiconductors. Compounding the problem of commercial investigation is that the semiconducting SWCNTs are also a mixture of different diameters and/or chiralities with different properties. Analyzing properties of enriched semiconducting SWCNT chiralities has only recently been possible through separation techniques such as aqueous two-phase solvent systems. Our study illustrates a semipreparative spiral countercurrent chromatography (CCC) separation of a commercial mixture of SWCNTs into distinct enriched fractions. A new mixer–settler spiral disk rotor was applied in this study, in which we compare the enriched SWCNTs for their effectiveness in biosensors with a high-throughput model assay, followed by antibody-mediated detection of Escherichia coli. Our results demonstrate that CCC-enriched responsive SWCNTs for biosensors can be used in our model assay, as well as for the detection of E. coli. To date, we believe that this is the first study along with Liu et al. [Chirality-controlled synthesis of single-wall carbon nanotubes using vapour-phase epitaxyNat. Commun.201231199] to demonstrate a specific utility of separated SWCNT species.

Aqueous two-polymer phase extraction of single-wall carbon nanotubes using surfactants

“…Automation of diameter-separation ATPE using a surfactant gradient such as in a counter current chromatography instrument 46,47 is one possible solution to this problem. An example of the chromatographic output for CoMoCat SWCNTs is reproduced from Zhang et al 46 in Fig.…”

Recent Advances in Applications of Sorted Single‐Walled Carbon Nanotubes

“…Excellent progress has been made in CNT‐based chemical and biological sensors, and these areas have already been the topic of several reviews . Of particular interest in this review is the application of sorted SWCNTs for a comprehensive range of sensing technologies …”