DNA with Ionic, Atomic, and Clustered Silver: An XPS Study

Abstract

The rapidly developing field of bionanotechnology requires detailed knowledge of the mechanisms of interaction between inorganic matter and biomolecules. Under conditions different from those in an aqueous solution, however, the chemistry of these systems is elusive and may differ dramatically from their interactions in vitro and in vivo. Here, we report for the first time a photoemission study of a metal silver-DNA interface, formed in vacuo, in comparison with DNA-Ag and fluorescent DNA-Ag complexes formed in solution. The high-resolution photoelectron spectra reveal that in vacuo silver atoms interact mainly with oxygen atoms of the phosphodiester bond and deoxyribose in DNA, in contrast to the behavior of silver ions, which interact preferentially with the nitrogen atoms of the bases. This offers new insight into the mechanism of DNA metallization, which is of importance in creating metal-bio interfaces for nanotechnology applications.

A Simple Approach to Design Proteins for the Sustainable Synthesis of Metal Nanoclusters

“…This suggests that both Au 0 and Au I coexist in the AuNCs,as has been previously observed ( Figure 3A). [35] The Ag 3d 5/2 peak centered at 368.2 eV lies in between the value for Ag 0 (368.0 eV) [36] and that of Ag I salt (368.4 eV), [36] which suggests the presence of Ag I in AgNCs,ashas been previously observed. [35] The Ag 3d 5/2 peak centered at 368.2 eV lies in between the value for Ag 0 (368.0 eV) [36] and that of Ag I salt (368.4 eV), [36] which suggests the presence of Ag I in AgNCs,ashas been previously observed.…”

“…[34] TheX PS spectrum of AgNCs showed two binding energy values at 368.2 eV for Ag 3d 5/2 and 374.3 eV for Ag 3d 3/2 ,c onfirming the presence of elemental Ag 0 in the AgNCs,consistent with the standard spectrum for AgNCs ( Figure 3A). [35] The Ag 3d 5/2 peak centered at 368.2 eV lies in between the value for Ag 0 (368.0 eV) [36] and that of Ag I salt (368.4 eV), [36] which suggests the presence of Ag I in AgNCs,ashas been previously observed. [36,37] MALDI-TOF, LC-ESI-TOF,and ICP-MS mass spectrometry were used to determine the number of metal atoms in the Prot-NCs.T he MALDI-TOFand LC-ESI-TOF mass spectra of the Prot-NCs showed broad peaks with ac lear shift with respect to the protein, which confirmed the coordination of metals by the protein and indicated that the metal NCs present certain polydispersity in size ( Figure 3B;S upporting Information, Table S1, Figure S6).…”

“…[35] The Ag 3d 5/2 peak centered at 368.2 eV lies in between the value for Ag 0 (368.0 eV) [36] and that of Ag I salt (368.4 eV), [36] which suggests the presence of Ag I in AgNCs,ashas been previously observed. [36,37] MALDI-TOF, LC-ESI-TOF,and ICP-MS mass spectrometry were used to determine the number of metal atoms in the Prot-NCs.T he MALDI-TOFand LC-ESI-TOF mass spectra of the Prot-NCs showed broad peaks with ac lear shift with respect to the protein, which confirmed the coordination of metals by the protein and indicated that the metal NCs present certain polydispersity in size ( Figure 3B;S upporting Information, Table S1, Figure S6). An average of 14 AE 7 copper atoms,5AE 2g old atoms,a nd 9 AE 4s ilver atoms per protein were calculated for the Prot-NCs from MALDI spectra, in agreement with the size range obtained by LC-ESI-TOF (Supporting Information, Table S1).…”

“…[34] TheX PS spectrum of AgNCs showed two binding energy values at 368.2 eV for Ag 3d 5/2 and 374.3 eV for Ag 3d 3/2 ,c onfirming the presence of elemental Ag 0 in the AgNCs,consistent with the standard spectrum for AgNCs ( Figure 3A). [36,37] MALDI-TOF, LC-ESI-TOF,and ICP-MS mass spectrometry were used to determine the number of metal atoms in the Prot-NCs.T he MALDI-TOFand LC-ESI-TOF mass spectra of the Prot-NCs showed broad peaks with ac lear shift with respect to the protein, which confirmed the coordination of metals by the protein and indicated that the metal NCs present certain polydispersity in size ( Figure 3B;S upporting Information, Table S1, Figure S6). [36,37] MALDI-TOF, LC-ESI-TOF,and ICP-MS mass spectrometry were used to determine the number of metal atoms in the Prot-NCs.T he MALDI-TOFand LC-ESI-TOF mass spectra of the Prot-NCs showed broad peaks with ac lear shift with respect to the protein, which confirmed the coordination of metals by the protein and indicated that the metal NCs present certain polydispersity in size ( Figure 3B;S upporting Information, Table S1, Figure S6).…”

Crystal structure of a NIR‐Emitting DNA‐Stabilized Ag16 Nanocluster

“…DNA oligomers allow the creation of atomically monodisperse silver nanoclusters (DNA–AgNCs), usually below 30 Ag atoms that, depending on the DNA sequence, can result in bright emitters . Since their introduction in 2004, attempts have been made to characterize the exact composition and structure of these DNA–AgNCs using techniques such as mass‐spectroscopy, extended X‐ray absorption fine structure (EXAFS), X‐ray photoelectron spectroscopy (XPS), and more recently the first atomic structure information appeared using X‐ray diffraction . In the study of Huard et al., the cationic silver–DNA precursor was first crystallized and then chemically reduced.…”