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Article Citation - WoS: 24Citation - Scopus: 27The Pimpled Gold Nanosphere: a Superior Candidate for Plasmonic Photothermal Therapy(Dove Medical Press Ltd, 2020) Nasseri, Behzad; Turk, Mustafa; Kosemehmetoglu, Kemal; Kaya, Murat; Piskin, Erhan; Rabiee, Navid; Webster, Thomas J.Background: The development of highly efficient nanoparticles to convert light to heat for anti-cancer applications is quite a challenging field of research. Methods: In this study, we synthesized unique pimpled gold nanospheres (PGNSs) for plasmonic photothermal therapy (PPTT). The light-to-heat conversion capability of PGNSs and PPTT damage at the cellular level were investigated using a tissue phantom model. The ability of PGNSs to induce robust cellular damage was studied during cytotoxicity tests on colorectal adenocarcinoma (DLD-1) and fibroblast cell lines. Further, a numerical model of plasmonic (COMSOL Multiphysics) properties was used with the PPTT experimental assays. Results: A low cytotoxic effect of thiolated polyethylene glycol (SH-PEG400-SH-) was observed which improved the biocompatibility of PGNSs to maintain 89.4% cell viability during cytometry assays (in terms of fibroblast cells for 24 hrs at a concentration of 300 mu g/mL). The heat generated from the nanoparticle-mediated phantom models resulted in Delta T=30 degrees C, Delta T=23.1 degrees C and Delta T=21 degrees C for the PGNSs, AuNRs, and AuNPs, respectively (at a 300 mu g/mL concentration and for 325 sec). For the in vitro assays of PPTT on cancer cells, the PGNS group induced a 68.78% lethality (apoptosis) on DLD-1 cells. Fluorescence microscopy results showed the destruction of cell membranes and nuclei for the PPTT group. Experiments further revealed a penetration depth of sufficient PPTT damage in a physical tumor model after hematoxylin and eosin (H&E) staining through pathological studies (at depths of 2, 3 and 4 cm). Severe structural damages were observed in the tissue model through an 808-nm laser exposed to the PGNSs. Conclusion: Collectively, such results show much promise for the use of the present PGNSs and photothermal therapy for numerous anti-cancer applications.Research Project Yüksek Kükürt İçerikli Polimerik Malzemelerin Sentezi ve Uygulamaları(2021) Yağan, İbrahim Aziz; Kaya, Murat; Berk, Hasan; Balcı, Burcu; Cihaner, AtillaDoğal kaynaklardan ve petrol rafinerilerinden elde edilen elementel kükürt, yaygın olarak bulunan pahalı ve zehirli olmayan bir malzeme olmasına rağmen, kükürt için endüstride büyük ölçekli üretken kullanımlar bulmak önemli bir ilerleme olacaktır. Öte yandan, gelecekte bitkisel yağların yenilenebilir kaynaklardan polimer üretiminde kilit rol oynaması beklenmektedir. Bu çalışmada, ters vulkanizasyon yöntemi kullanılarak farklı yağ asitleri (oleik asit (OA), linoleik asit (LA) ve linolenik asit (LnA)) ve elementel kükürtten, yüksek kükürt içerikli yeni bir poli(kükürt-rastgele-yağ asidi) (poli(S-r-YA)) polimer serisi sentezlenmiş ve başarılı bir şekilde karakterize (NMR, Raman, FTIR, UV, GPC, SEM, DSC, TGA vb.) edilmiştir. Özellikle, çift bağların ve serbest alkil zincirlerinin polikükürt kopolimerleri üzerindeki etkisi, bir çift bağlı OA, iki çift bağlı LA ve üç çift bağlı LnA kullanılarak, sistematik olarak araştırılmıştır. İlgili kopolimerler yaygın organik çözücülerde çözünür ve işlenebilirdir. Öte yandan, polimer yapısında yağ asitlerinin bulunması nedeniyle, kopolimerler reaktif fonksiyonel birimlere (karboksilik grup-COOH) sahip olup diol ve diaminlerle kimyasal modifikasyonları sonrasında polimer zincirleri arasında veya zincir içinde sırasıyla ester ve amid bağlarının oluşumuna yol açar. Bu modifikasyon işlemi yüksek moleküler ağırlıklı yeni polimerlerin elde edilmesi ile sonuçlanmıştır. Ayrıca, kg ölçeğinde ağırlıkça %90 kükürt ve %10 OA içeren polikükürt kopolimeri sentezi başarılı bir şekilde gerçekleştirilmiştir. Son olarak, tüm kopolimerlerin fotokatalitik boya gideriminde, ağır metal iyonlarının (Pd2+ ve Hg2+) uzaklaştırılmasında ve Li-S pillerde katot malzemesi olarak kullanımı test edilmiştir. Özellikle kopolimerlerin sulu çözeltideki ağır metal iyonlarının neredeyse tamamını tuttukları/uzaklaştırdıkları gözlenmiştir. Sonuçlar, termal olarak kararlı polikükürt kopolimerlerinin özellikle boya giderimi ve ağır metal iyonu uzaklaştırılması konularında potansiyel malzemeler olabileceğini göstermiştir.Article Citation - WoS: 35Citation - Scopus: 32Preparation of Silica Coated Cobalt Ferrite Magnetic Nanoparticles for the Purification of Histidine-Tagged Proteins(Pergamon-elsevier Science Ltd, 2015) Aygar, Gulfem; Kaya, Murat; Ozkan, Necati; Kocabiyik, Semra; Volkan, MurvetSurface modified cobalt ferrite (CoFe2O4) nanoparticles containing Ni-NTA affinity group were synthesized and used for the separation of histidine tag proteins from the complex matrices through the use of imidazole side chains of histidine molecules. Firstly, CoFe2O4 nanoparticles with a narrow size distribution were prepared in an aqueous solution using the controlled co-precipitation method. In order to obtain small CoFe2O4 agglomerates, oleic acid and sodium chloride were used as dispersants. The CoFe2O4 particles were coated with silica and subsequently the surface of these silica coated particles (SiO2-CoFe2O4) was modified by amine (NH2) groups in order to add further functional groups on the silica shell. Then, carboxyl (-COOH) functional groups were added to the SiO2-CoFe2O4 magnetic nanoparticles through the NH2 groups. After that N alpha,N alpha-Bis(carboxymethyl)-L-lysine hydrate (NTA) was attached to carboxyl ends of the structure. Finally, the surface modified nanoparticles were labeled with nickel (Ni) (II) ions. Furthermore, the modified SiO2-CoFe2O4 magnetic nanoparticles were utilized as a new system that allows purification of the N-terminal His-tagged recombinant small heat shock protein, Tpv-sHSP 14.3. (C) 2015 Elsevier Ltd. All rights reserved.Article Gold-Assembled Silica-Coated Cobalt Nanoparticles as Efficient Magnetic Separation Units and Surface-Enhanced Raman Scattering Substrate Lütfiye Sezen Yildirim1,, Murat Kaya2,∗,, Mürvet Volkan(Tubitak Scientific & Technological Research Council Turkey, 2019) Yıldırım, Lütfiye Sezen; Kaya, Murat; Volkan, MürvetMagnetic and optical bifunctional nanoparticles that combine easy separation, preconcentration, and efficientSERS capabilities have been fabricated with high sensitivity and reproducibility through a low-cost method. Thesegold nanoparticles attached on magnetic silica-coated cobalt nanospheres (Co@SiO2 /AuNPs) display the advantageof strong resonance absorption due to gaps at nanoscale between neighboring metal nanoparticles bringing large fieldenhancements, known as “hot spots”. The prepared particles can be controlled by using an external magnetic field,which makes them very promising candidates in biological applications and Raman spectroscopic analysis of dissolvedorganic species. The magnetic property of the prepared particles lowers the detection limits through preconcentrationwith solid-phase extraction in SERS analysis. The performance of the prepared nanostructures was evaluated as a SERSsubstrate using brilliant cresyl blue (BCB) and rhodamine 6G (R6G) as model compounds. The solid-phase affinityextraction of 4-mercapto benzoic acid (4-MBA) using bifunctional Co@SiO2 /AuNPs nanoparticles followed by magneticseparation and the measurement of the SERS signal on the same magnetic particles without elution were investigated.Approximately 50-fold increase in SERS intensity was achieved through solid-phase extraction of 8.3 × 10 −6 M 4-MBAin 10 min.
