(706b) Influence of Sonication Conditions and Wrapping Type on Yield and Fluorescent Quality of Noncovalently Functionalized Single-Walled Carbon Nanotubes

As nanomaterials have become more accessible and manufacturable, nanoscale biosensors have become an increasingly relevant area of research. One such nanomaterial is the suspended single-walled carbon nanotube (SWNT), which fluoresces in the near-infrared window of biological material, making it ideal for in vivo applications. SWNT may be suspended in water if wrapped with an amphiphilic polymer or surfactant; the suspended SWNT can act as a simple optical probe or as a sensor by engineering the wrapping to have selective domains that cause a change in fluorescence when bound by a target analyte. The process of suspending nanotubes is typically achieved by sonication. While much application-focused research has been performed on suspended SWNT sensors and probes, little has been done to understand factors affecting SWNT fluorescent quality after suspension. We have explored effects of sonication power and duration on an array of 9 potential wrappings including proteins, DNA, oligosaccharides, polysaccharides, synthetic polymers, and surfactant solutions. Optimal sonication conditions were found to vary on an individual wrapping basis. Trends between polymer length and fluorescence properties suggest fragmentation of the wrapping to play a role in SWNT functionalization. These trends may be used to predict optimal processing conditions to create suspended SWNT with maximal start fluorescence for various wrapping types, improving sensor dynamic range and sensitivity. These results also point to the need for control of sonication conditions in large scale synthesis to ensure tighter batch to batch reproducibility of nanotube sensors.