Chirality dependent corona phase molecular recognition of DNA-wrapped carbon nanotubes

Corona phase molecular recognition (CoPhMoRe) is a phenomenon whereby a polymer or surfactant corona phase wrapped around a nanoparticle selectively recognizes a particular molecule. The method can potentially generate non-biological, synthetic molecular recognition sites, analogous to antibodies, for a broad range of biomedical applications, including new types of sensors, laboratory and clinical assays, as well as inhibitors and targeted therapeutics. In this work, we utilize near infrared fluorescent single-walled carbon nanotubes (SWNTs) wrapped with specific single stranded DNA sequences to explore the (n,m) chirality dependence of CoPhMoRe. Specific DNA oligonucleotide sequences are known to recognize and interact uniquely with certain (n, m) SWNTs enabling their enrichment in ion exchange chromatography. We explore the CoPhMoRe effect using corona phases constructed from a library of 24 such sequences, screening against a biomolecule panel that includes common neurotransmitters, amino acids, saccharides and riboflavin. Example sequences include (ATT)(4), (TAT)(4) and (ATTT)(3) which recognize (7,5), (6,5) and (8,4) SWNTs, respectively. We find that these recognition sequences indeed form CoPhMoRe phases that are distinct among SWNT chiralities, and appear to pack more densely as to exclude analyte adsorption on the chirality they recognize. These results have encouraging implications for the controlled design of CoPhMoRe phases for biomedical applications. (C) 2015 Elsevier Ltd. All rights reserved.