Scopus İndeksli Yayınlar Koleksiyonu / Scopus Indexed Publications Collection
Permanent URI for this collectionhttps://hdl.handle.net/11147/7148
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Article Developing Gold Nanoparticles Decorated With Carbon-Dots for Multiplexed Cellular Imaging(IOP Publishing Ltd, 2025) Kavuranpala, Tugce; Saydullaeva, Iroda; Ozcelik, SerdarThis study focuses on developing a novel hybrid nanomaterial composed of gold nanoparticle decorated with carbon dots, termed AuNP@C-dot, as a versatile platform for multiplexed imaging. Structural and spectral characterizations confirmed the successful conjugation of C-dots to AuNPs via covalent bonding, as evidenced by FTIR, X-ray photoelectron spectra, HRTEM analyses, and UV-Vis and fluorescence spectroscopies. The fluorescence intensities of C-dots are doubled through the conjugation to the AuNPs. The conjugation of fluorescent C-dots to plasmon-resonant AuNPs enables simultaneous multicellular imaging by taking advantage of the fluorescent signaling of C-dots and the scattering signaling of AuNPs. In vitro studies using human lung cell lines (A549 and BEAS-2B) confirmed the multiplexed imaging and revealed efficient cellular uptake and subcellular localization of AuNP@C-dots, including nuclear translocation, which is critical for radiotherapy and photodynamic therapy. Cell viability assessments utilizing a colorimetric assay for measuring cell metabolic activity and a colony formation assay demonstrated good biocompatibility of AuNP@C-dots at relevant concentrations. It can be envisioned that the AuNP@C-dot hybrid system may improve the detection and monitoring of cell health and disease due to its dual-modal imaging capability. Furthermore, they could be used for supervising controlled release of therapeutic agents, tailored for enhanced treatment efficacy. This study demonstrates the potential of C-dot-conjugated AuNPs as a multifunctional tool with inherent control mechanisms for the next-generation cellular analysis, drug administration, and diagnostic strategies.Article Host Isotope Effects on the Oxygen Local Vibrations in Cdte(IOP Publishing Ltd, 2023) Tarhan, Enver; Ramdas, Anant K.Strong absorption peak observed near 350 cm-1 in the infrared spectrum of CdTe is assigned to a localized vibrational mode of 16O impurity atoms at tellurium sites. In this work, we studied the nature of these vibrations in terms of the effect of isotopic mass variations in the nearest neighbor Cd atoms. We showed that Cd atoms with 8 stable natural isotopes of varying abundances cause the observed line shape in the observed localized vibrational absorption peak. To calculate the effect of isotopic mass variations, we used the XY4 molecular model, X being the impurity atom at a host Te atom site and Y's are various isotopes of the host Cd atoms. Corresponding frequencies of local modes were calculated for each possible combinations of neighboring Cd atoms. For an XY4 molecule with Td symmetry, only the triply degenerate Gamma 5 mode is infrared active. The energies of this mode are higher than those of the others. This mode is possible only when all neigboring Cd atoms are the same isotope. To simulate the absorption data, we used a dynamical matrix approach where a force constant is given for each of the bending and stretching potential energy terms. By diagonalization of the dynamical matrix we were able to fit the calculated spectrum to the data with a proper choice of the bending and stretching force constants. A good agreement with the experiment as well as reported force constants for other impurities in CdTe is obtained.