High-Yield Synthesis and Optical Properties of Carbon Nanotube Porins

Carbon nanotube porins (CNTPs) are a convenient membrane-based model system for studying nanofluidic transport that replicates a number of key structural features of biological membrane channels. We present a generalized approach for CNTP synthesis using sonochemistry-assisted segmenting of carbon nanotubes. Prolonged tip sonication in the presence of lipid molecules debundles and fragments long carbon nanotube aggregates into stable and water-soluble individual CNTPs with lengths in the range 5-20 nm. We discuss the main parameters that determine the efficiency and the yield of this process, describe the optimized conditions for high-yield CNTP synthesis, and demonstrate that this methodology can be adapted for synthesis of CNTPs of different diameters. We also present the optical properties of CNTPs and show that a combination of Raman and UV-vis-NIR spectroscopy can be used to monitor the quality of the CNTP synthesis. Overall, CNTPs represent a versatile nanopore building block for creating higher-order functional biomimetic materials.