Functionalisation and immobilisation of an Au(110) surface via uracil and 2-thiouracil anchored layer

We have constructed thin films of organic–inorganic hybrid character by combining titanium tetra-isopropoxide (TTIP) and the nucleobases thymine, uracil or adenine using the molecular layer deposition (MLD) approach. Such materials have potential as bioactive coatings, and the bioactivity of these films is described in our recent work [Momtazi, L.; Dartt, D. A.; Nilsen, O.; Eidet, J. R. J. Biomed. Mater. Res., Part A 2018, 106, 3090–3098. doi:10.1002/jbm.a.36499]. The growth was followed by in situ quartz crystal microbalance (QCM) measurements and all systems exhibited atomic layer deposition (ALD) type of growth. The adenine system has an ALD temperature window between 250 and 300 °C, while an overall reduction in growth rate with increasing temperature was observed for the uracil and thymine systems. The bonding modes of the films have been further characterized by Fourier transform infrared spectroscopy, X-ray photoelectron spectroscopy and X-ray diffraction, confirming the hybrid nature of the as-deposited films with an amorphous structure where partial inclusion of the TTIP molecule occurs during growth. The films are highly hydrophilic, while the nucleobases do leach in water providing an amorphous structure mainly of TiO2 with reduced density and index of refraction.

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“…Carbon peak splitting in all three bases is similar to the previously reported XPS results on pure bases in powder form (Fig. 11) [25–26].…”

Section: Resultssupporting

confidence: 88%

Biocompatible organic–inorganic hybrid materials based on nucleobases and titanium developed by molecular layer deposition

Momtazi¹,

Sønsteby²,

Nilsen³

2019

Beilstein J. Nanotechnol.

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“…We identify the sulphur 2 p -photoelectron line (blue) at a kinetic energy of 103.5 eV in agreement with the literature 39 . The width of about 4 eV does prevent us from distinguishing the spin-orbit splitting 39 , 40 . The photoelectron line is accompanied by shake-up satellites at around 91 and 96 eV 41 .…”

Section: Resultsmentioning

confidence: 99%

Following excited-state chemical shifts in molecular ultrafast x-ray photoelectron spectroscopy

et al. 2022

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The conversion of photon energy into other energetic forms in molecules is accompanied by charge moving on ultrafast timescales. We directly observe the charge motion at a specific site in an electronically excited molecule using time-resolved x-ray photoelectron spectroscopy (TR-XPS). We extend the concept of static chemical shift from conventional XPS by the excited-state chemical shift (ESCS), which is connected to the charge in the framework of a potential model. This allows us to invert TR-XPS spectra to the dynamic charge at a specific atom. We demonstrate the power of TR-XPS by using sulphur 2p-core-electron-emission probing to study the UV-excited dynamics of 2-thiouracil. The method allows us to discover that a major part of the population relaxes to the molecular ground state within 220–250 fs. In addition, a 250-fs oscillation, visible in the kinetic energy of the TR-XPS, reveals a coherent exchange of population among electronic states.

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“…For warm Ur films, this orientation of the molecules was observed experimentally. 25 However, deposition of the molecules on a mirror at 6 K leads to an amorphous structure of the film with disordered arrangement of the molecules and disordered structure of the intermolecular hydrogen bonds. Due to the amorphous nature of the film, the absorption bands are broadened.…”

Section: Resultsmentioning

confidence: 99%

Enhancement of infrared absorption of low-temperature uracil thin films by a nanostructured silver surface

Ivanov

Stepanian

Adamowicz

et al. 2016

Low Temperature Physics

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Enhancement of infrared absorption (SEIRA) of adsorbed biological molecules by a nanostructured metal surface is one of the main routes to increasing the sensitivity of modern optical biosensors. The FTIR absorption spectra of thin films of the RNA base uracil deposited on low-temperature substrate (T ¼ 6 K) with nanoscale silver structures were investigated in the spectral range 2700-600 cm-1. It was shown that the intensity of the absorption bands corresponding to CO stretching vibrations (range 1800-1600 cm-1) of uracil (Ur) thin films increases 3-4 fold. For multilayer films, the influence of the nanostructures on the vibrational spectra weakens, and for the film layers more than 15 nm away from the surface, the enhancement is essentially absent. The energies and the vibrational spectra of the complexes of uracil monomers and dimers with 20-atom tetrahedral silver nanoclusters were calculated by the quantum-mechanical method DFT/B3LYP. The most stable complexes have the coordination bond between the top of the silver tetrahedron and the oxygen of the carbonyl group C4O. It was found that the formation of such complexes significantly (3-5 fold) enhances the intensity of the C4O stretching vibration of uracil, while the intensities of the bNH, bCH and ring bending vibrations do not increase significantly.

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Functionalisation and immobilisation of an Au(110) surface via uracil and 2-thiouracil anchored layer

Cited by 9 publications

References 52 publications

Biocompatible organic–inorganic hybrid materials based on nucleobases and titanium developed by molecular layer deposition

Biocompatible organic–inorganic hybrid materials based on nucleobases and titanium developed by molecular layer deposition

Following excited-state chemical shifts in molecular ultrafast x-ray photoelectron spectroscopy

Enhancement of infrared absorption of low-temperature uracil thin films by a nanostructured silver surface

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