Quantification of DNA/SWCNT Solvation Differences by Aqueous Two-Phase Separation

• Published in: Langmuir 2018-02, Vol.34 (5), p.1834-1843
• Main Authors: Yang, Yoona, Shankar, Akshaya, Aryaksama, Thibault, Zheng, Ming, Jagota, Anand
• Format: Article
• Language: English
• Subjects: DNA - chemistry; Nanotubes, Carbon - chemistry; Solubility; Solvents - chemistry; Thermodynamics; Water - chemistry
• ISSN: 0743-7463; 1520-5827
• DOI: 10.1021/acs.langmuir.7b03186

Single-walled carbon nanotubes (SWCNTs) coated with single-stranded DNA can be effectively separated into various chiralities using an aqueous two-phase (ATP) system. Partitioning is driven by small differences in the dissolution characteristics of the hybrid between the two phases. Thus, in addition to being a separation technique, the ATP system potentially also offers a way to quantify and rank the dissolution properties of the solute (here the DNA/SWCNT hybrids), such as the solvation free energy and solubility. In this study, we propose two different approaches to quantitatively analyze the ATP partitioning of DNA/SWCNT hybrids. First, we present a model that extracts the relative solvation free energy of various DNA/SWCNT hybrids by using an expansion relative to a standard state. Second, we extract a solubility parameter by analyzing the partitioning of hybrids in the ATP system. The two approaches are found to be consistent, providing some confidence in each as a method of quantifying differences in the solubility of various DNA/SWCNT hybrids.