Scopus İndeksli Yayınlar Koleksiyonu / Scopus Indexed Publications Collection
Permanent URI for this collectionhttps://hdl.handle.net/11147/7148
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Article Citation - WoS: 2Citation - Scopus: 2Vibrational Spectroscopy Unveils Distinct Cell Cycle Features of Cancer Stem Cells in Melanoma(Nature Portfolio, 2025) Uslu, Bensu Ruya; Ozdil, Berrin; Tarhan, Enver; Ozcelik, Serdar; Aktug, Huseyin; Guler, GunnurCancer stem cells (CSCs) play a central role in melanoma growth, resistance to treatment, and relapse, however, their dynamic regulatory behavior remains poorly understood. Vibrational spectroscopy offers a unique, label-free approach to investigate cellular heterogeneity at the molecular level. Here, we explored the biochemical and regulatory dynamics of CSCs identified by using a time-course design, integrating infrared and Raman spectroscopies with cell cycle analysis and immunocytochemistry targeting the checkpoint proteins p16 and p21. CSCs, non-cancer stem cells (NCSCs), and bulk CHL-1 melanoma cells were monitored at 11, 24, 48, and 72 h. CSCs showed a steady S-phase with an early rise in p16 followed by a subsequent increase in p21 expression, indicating a dynamic state of cell cycle checkpoints. In contrast, NCSCs and CHL-1 cells showed more transient p16/p21 expression and CHL-1 exhibited a marked p16 increase at 24 h. Spectroscopic analysis revealed that CSCs exhibited distinct vibrational profiles, predominantly in the nucleic acid-, protein- and lipid-associated regions. These differences were further supported by principal component and hierarchical clustering analyses, which consistently distinguished CSCs from NCSCs. Our findings underline the potential of vibrational spectroscopy to sensitively detect CSC-specific regulatory patterns and support its use in detecting new therapeutic targets in melanoma.Article Citation - WoS: 8Citation - Scopus: 8Influence of Applied Current Density on the Nanostructural and Light Emitting Properties of N-Type Porous Silicon(World Scientific Publishing Co. Pte Ltd, 2015) Çetinel, A.; Artunç, N.; Şahin, Gündoğdu; Tarhan, EnverEffects of current density on nanostructure and light emitting properties of porous silicon (PS) samples were investigated by field emission scanning electron microscope (FE-SEM), gravimetric method, Raman and photoluminescence (PL) spectroscopy. FE-SEM images have shown that below 60 mA/cm2, macropore and mesopore arrays, exhibiting rough morphology, are formed together, whose pore diameter, pore depth and porosity are about 265-760 nm, 58-63 μ m and 44-61%, respectively. However, PS samples prepared above 60 mA/cm2 display smooth and straight macropore arrays, with pore diameter ranging from 900-1250 nm, porosity of 61-80% and pore depth between 63-69 μm. Raman analyses have shown that when the current density is increased from 10 mA/cm2 to 100 mA/cm2, Raman peaks of PS samples shift to lower wavenumbers by comparison to crystalline silicon (c-Si). The highest Raman peak shift is found to be 3.2 cm-1 for PS sample, prepared at 90 mA/cm2, which has the smallest nanocrystallite size, about 5.2 nm. This sample also shows a pronounced PL, with the highest blue shifting, of about 12 nm. Nanocrystalline silicon, with the smallest nanocrystallite size, confirmed by our Raman analyses using microcrystal model (MCM), should be responsible for both the highest Raman peak shift and PL blue shift due to quantum confinement effect (QCE).