Browsing by Subject "Adenine"

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    From aluminum foil to two-dimensional nanocrystals using ultrasonic exfoliation
    (American Chemical Society, 2021-04-15) Lu, W.; Birmingham, B.; Voronine, D. V.; Stolpman, D.; Ambardar, S.; Erdoğan, Deniz Altunöz; Özensoy, Emrah; Zhang, Z.; Solouki, T.
    Al nanostructures have unique optical properties such as widely tunable surface plasmon resonances from deep UV to NIR that can be used for label-free fluorescence enhancement and surface-enhanced Raman scattering. Various Al nanostructures have been fabricated using sophisticated “top-down” lithographic and “bottom-up” colloidal methods. Here, we developed a simple and efficient method of synthesizing two-dimensional (2D) aluminum (Al) nanocrystals from commercially available Al foil using ultrasonic exfoliation under ambient environment. 2D Al nanocrystals with sizes from a few hundred nanometers to several micrometers and thickness in the tens of nanometers were isolated through centrifugation separation. The exfoliated 2D Al nanocrystals are covered with a passivated Al2O3 nanolayer. The determined exfoliation mechanism is a combination of the preferred cleavage along the (111) surface planes and layer-by-layer Al2O3 exfoliation from the surface of the 2D Al nanocrystals. We demonstrate that the 2D Al nanocrystals can be assembled at water/air interface and transferred to different substrates to form 2D Al nanocrystal films. These 2D Al nanocrystal films exhibit surface plasmon resonance in the visible spectral range and show enhanced Raman signals of adenine using a 532 nm excitation. These 2D Al nanocrystal films could be further developed for new optical and sensing applications.
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    Synthesis of novel substituted purine derivatives and identification of the cell death mechanism
    (Elsevier Masson SAS, 2015) Demir, Z.; Guven, E.B.; Ozbey, S.; Kazak, C.; Atalay, R.C.; Tuncbilek, M.
    Novel substituted adenine and purine derivatives were designed and synthesized.Compound 36 displayed the greatest cytotoxic activity with IC50 less than 1 1/4M.36 induces senescence associated cell death, which was demonstrated with SA2-Gal assay. © 2014 Elsevier Masson SAS.
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    The mechanisms of ATP - biomacromolecule interactions
    (2023-12) Ayvaz, Cansın
    Adenosine triphosphate (ATP), one of the most important biomolecules of life, plays a vital role as the primary energy source within cells for essential biological functions. It has recently been discovered that ATP can also serve as a biological hydrotrope to destabilize protein aggregates and fibers. This thesis aims to investigate the recently discovered hydrotropic behavior of ATP and its interaction mechanisms with biomacromolecules, particularly poly(N-isopropylacrylamide) (PNIPAM), using a multi-experimental approach combined with molecular dynamics (MD) simulations. Adapting the bottom-up approach, the phase behavior of macromolecules is examined through phase transition and ATR-FTIR measurements. Additionally, site-specific interactions are identified with quantitative 1H-NMR spectroscopic studies, and the hydration shell structure and cluster morphologies of ATP molecules are explored through Multivariate Curve Resolution (MCR) Raman experiments. It is demonstrated that adenine and adenosine subgroups show negligible effect on the solubility of macromolecules, whereas ATP, AMP, and triphosphate exhibited purely salting-out behavior, and induced the aggregation of macromolecules. In stark contrast to the recently discovered hydrotropic behavior of ATP, no specific interactions between the macromolecule and ATP were observed in spectroscopic ATR-FTIR and 1H-NMR measurements, as well as MD simulations. Surprisingly, at elevated concentrations, self-association of ATP was observed leading to partial destabilization of larger PNIPAM aggregates to smaller ones. In the absence of ATP binding sites, interactions with random-coil-like structured macromolecules do not lead to effective hydrotropic action of ATP. Instead, they function more as stabilizers rather than solubilizing the macromolecules.