title: Synthesis of 28-membered macrocyclic polyammonium cations functionalized gold nanoparticles and their potential for sensing nucleotides.
abstract: A new synthesis of underivatized gold nanoparticles (Au-NPs) in water stabilized by the highly water soluble 28-membered macrocyclic polyammonium chloride, [28]ane-(NH(2)(+))(6)O(2)6Cl(-) (28-MCPAC) is reported. In addition to providing stability, 28-MCPAC with its cationic form functionalizes the Au-NPs for sensing anions in water. The 28-MCPAC-Au-NPs show a surface plasmon band in the visible region (>520 nm). By tuning the 28-MCPAC:HAuCl(4) ratio, Au-NPs with different core diameters ranging from 4 nm to 6 nm, as determined by TEM analysis, can be obtained. Particles are spherical, discrete, and appeared to have narrow size distributions. Raman spectroscopy confirms that the physisorption is responsible for the interaction between Au-NP surface and 28-MCPAC. The potential of the as-synthesized particles for sensing monophosphorylated nucleosides (nucleotides): 5-adenosine monophosphate (5-AMP), 5-cytosine monophosphate (5-CMP), 5-guanine monophosphate (5-GMP), and 5-uridine monophosphate (5-UMP) is investigated spectroscopically. Nucleotides-assisted agglomerations of 28-MCPAC-Au-NPs follow the order: 5-UMP>5-GMP>5-CMP>5-AMP. An attempt is taken to prepare Au-NPs in water at pH 4.55 without an added stabilizer. Particles without an added stabilizer are short lived, and the TEM image shows that the particles aggregate following a quasi-two-dimensional self-assembly array.
authors.affiliation: Department of Chemistry, National Taiwan University, Taipei 10617, Taiwan.
authors.forename: Tarun Kumar
authors.initials: TK
authors.lastname: Misra
authors.forename: Chuen-Ying
authors.initials: CY
authors.lastname: Liu
mesh_terms: D002412:Cations / Q000737:chemistry; D006046:Gold / Q000737:chemistry*; D006863:Hydrogen-Ion Concentration; D047028:Macrocyclic Compounds / Q000737:chemistry*; D053768:Metal Nanoparticles / Q000737:chemistry*; D046529:Microscopy, Electron, Transmission; D036103:Nanotechnology / Q000379:methods*; D009711:Nucleotides / Q000032:analysis*; D000644:Quaternary Ammonium Compounds / Q000737:chemistry*; D012995:Solubility; D013059:Spectrum Analysis, Raman; D013499:Surface Properties; D014867:Water / Q000737:chemistry
chemical_list: D002412:Cations; D047028:Macrocyclic Compounds; D009711:Nucleotides; D000644:Quaternary Ammonium Compounds; D014867:Water; D006046:Gold